Saturday, February 28, 2015

Study group discussion: Water intoxication syndrome

Water intoxication syndrome! I remember this from first year physiology!

How does water intoxication syndrome work? How much water does the person have to take?

The water that causes intoxication is mostly through intravenous fluids. I doubt a human being would have the capacity to drink enough water to cause an intoxication orally. I have heard of psychiatric disorders associated with a high water consumption though.

But if you're looking for a number - it's 16 ml/min

If you consume that much in any amount of time, you'll have exceeded intake more than the maximal urine flow.

Ummm, got it! it makes more sense than what I was thinking hahaha

Surely, drinking too much water would cause vomiting or something before the body would allow itself to become intoxicated?
Or massive impermeability of the kidney nephrons?

Does drinking too much water cause vomiting?   How permeable is the upper alimentary canal to water?  Could a large amount of water be absorbed before it reaches the stomach?

Too much water does cause vomiting! The most common symptoms suffered by this group were changes in mental status, emesis, nausea, and seizures. Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1770067/

I think there have been documented cases of people drinking enough water to die.  I imagine it's very difficult, though, and therefore rare.

Mostly psychiatric patients.

Water intoxication also occurs in SIADH and surgical trauma.

Risk factors include low body mass (infants), endurance sports, competitive drinking or latrogenic.
Treatment normally follows strict fluid restriction. In more serious cases, diuretics or vasopressin receptor antagonists are given.

Similar to SIADH treatment!

You know the artist Andy Warhol? He died of water intoxication!

Oh.

Study group discussion: Drug therapy for asthma

Which is the physiological antagonist of histamine?

Acetylcholine?

No.

It's ephedrine or adrenaline.

Which are the classes of drugs used for acute control of asthma?

B 2 agonists.

Epinephrine.

Yes, epinephrine.. But that too comes under b2 agonist.

Steroids?

No, steroids is for long term control

Two more classes of drugs!

Methylxanthine? Theophylline!
Montelukast?
Ipratropium!

Yup. Second class is theophylline or aminophyline. The third class is anti-cholinergics.

But not montelukast..That's also for chronic use.

What is the function of montelukast?

Leukotriene receptor antagonist!

Leukotrienes when binding to their receptors it cause bronchoconstriction. Monteluekast used in maintenance therapy of asthma. But not useful in acute exacerbation.

Mast cell stabilizers, that is, ketotifen and sodium chromoglycate?

Mast cell stabilizers are also chronic for use.

And IgE antibody? Omalizumab?

That too for chronic use.

Even MgSO4 is used in acute management of asthma.

Yup.

Next one.

Why does use of aspirin cause asthma?

Arachidonic acid forms two type of substances via the cyclo-oxygenase and lipo-oxygenase pathways. Aspirin inhibits the cyclooxygenase pathway.
Hence, all of the arachidonic acid gets diverted to lipo-oxygenases.
And if you remember L4, B4 are the major mediators of acute attack of asthma.

Oh yeah.. That's why leukotriene antagonists are used, they inhibit LT C4 , D4

Exactly.

There are the major cause of bronchoconstriction!

As cyclo cycle is inhibited..arachidonic acid is used more in lipo cycle!

LT antagonists act on cysLT1!

Study group discussion: Low molecular weight heparin vs unfractionated heparin

Something regarding heparins! So which one is better to use? LMWH or UFH? Why?

LMWH (Low molecular weight heparin)

Why?

Less incidence of thrombocytopenia with LMWH!
Better bioavailability, t1/2 , APTT not affected.

Right. Why APTT not affected?

Because LMWH has more predictable pharmacokinetics and anticoagulant effect, LMWH is recommended over unfractionated heparin for patients with massive pulmonary embolism.

Because LMWH acts only on AT3... Does not have the scaffolding effect of UFH.

On which part it doesn't act?
LMWH doesn't affect on thrombin..

Yes! That's the answer!

LMWH acts on AT3 only and doesn't affect thrombin.

UFH acts by 2 mechanisms
1. On AT3
2. By providing a scaffolding on which AT3 can interact with Thrombin

In LMWH, the second effect is absent, hence less interference...

Yes!! Correct!!

Which situation you would prefer UFH?

For cardiac surgeries, UFH is preferred as it can be titrated dose - by - dose with protamine sulphate.

Cardiopulmonary bypass.

Why?

Cardiopulmonary bypass....Because it's effects can easily be reversed fully by protamine. And its more effective.

Exactly! Any conditions with high risk of bleeding we prefer UFH.

Yep. Cause we will be able to reverse if we give more heparin by giving protamine sulphahte same is not possible with LMWHs.

Why?

Because action of LMWH cannot be reversed completely..

Yes, correct. It's because of the molecular weight.

So which test would you like to do before deciding whether to give UFH or LMWHs?

Any other conditions?

Ok so in cases of advanced renal failure UFH are preferred over LMWHs

Now tell me why?

No idea.. Please explain!

So we would check creatinine before starting heparin

This was the test I was taking about! LMWHs are excreted renally.

Right...UFH is metabolised by liver

On the other hand UFHs are cleared by reticuloendothelial system.

Good work guys! Hope it helped!

Yes, thanks a lot!

What about pregnancy?

Are UFH still preferred or do you give LMWH?

The major limiting factor is the cost or HIT. Heparin is still ruling the world and saving millions of lives.

Also i heard..senior doctors still prefer UFH, inspite of LMW

Ummm!! I would say LMWHs are much better!! Many trials have proved that! It's only in certain scenarios that UFHs are preffered. Nobody wants to keep monitoring APTT so just making the life easy LMWHs are good!!

Yeah. But they are more experienced in using UFH.
This was told by our residents. If a senior external asks you whether UFH or LMWH is better.. Be diplomatic in your answer.

Ohh! Yeah that can be the thing!

Updated later:
And also an addition to a previous discussion on oral anti-coagulants. Why heparin is given for the initial 5 to 7 days, when warfarin has already been started?
One reason is the preformed coagulant factors need to get depleted before warfarin starts taking effect. The other reason is that in the initial days warfarin acts as a prothombotic. Cause it depletes protein c and protein s!

Study group discussion: Fixed specific gravity

What is fixed specific gravity? Like what is the cause?

Because of renal failure, the remaining functional nephrons undergo compensatory structural and hypertrophic changes,these compensatory changes result in urine that is almost isotonic with plasma.  Therefore, a patient experiencing renal failure will present with specimens measuring the same, or fixed, specific gravity regardless of water intake

Thanks! Is there any value associated with it? Numerals?

Low specific gravity in renal failure, which results in a fixed specific gravity is between 1.007 and 1.010.

Study group discussion: Fluoroquinolones

Fluoroquinolones with
maximum phototoxicity -  sparfloxacin
100% bioavailibity - pefloxacin
Highest efficacy against tuberculosis - moxifloxacin

I don't know what is the meaning of 100 % bioavailability.

100% bioavailability means no first pass metabolism. Usually achieved on IV administering.

Study group discussion: Beta blockers

Give me two reasons why..you don't give beta blockers to diabetics.

They mask the hypoglycemic symptoms

First reason correct.

Hint - It is something to do with the liver and beta 2 receptors.

Glycogenolysis decrease.

Yup..The beta 2 receptors stimulate the glycogen breakdown and glycogenolysis.

So if you give a nonselective beta blocker.. Not only will the patient not feel the coming signs of hypoglycemia but also the liver will fail to release glucose in the blood.

Side effects of beta blockers?

Bradycardia
Breathlessness is due to bronchoconstriction
Rise in lipid level

Why won't you prescribe a beta blocker to a young man?

Sexual distress? Not sure!

Sexual dysfunction..Correct!

Vivid dreams and insomnia, and sexual dysfunction is due to beta blockers central action on the brain. They cross the blood brain barrier.

In which type of arrhythmias are beta blockers especially indicated?
The ones atrial in origin.

In which type of arrhythmia beta blockers are contraindicated?

Heart blocks.

Why so?

Cause they reduce the heart rate further.. A side effect of beta blockers is to decrease AV nodal conduction and precipitate asystole. In other words, they increase the refractory period of AV nodal cells.

Study group discussion: Locked in syndrome and total locked in syndrome

What's locked in syndrome and total locked in syndrome?

The patient is conscious, well oriented to time, place and person but is unable to carry out any voluntary movement along with loss of reflexes. Everyone else thinks the patient to be in a comatose / coma state.

Some retained cranial nerve reflexes with eye movements to communicate with no limb movement.

Yes! But in total locked in syndrome, there's no eye movement.

In locked in syndrome, I think patient communicates through blinking of eyes.

Yes. But in total locked in syndrome, they cannot.

Study group discussion: Cool fact about GLP 1 agonists

Antidiabetic derived from lizard?

It's exenatide! GLP-1 agonist.

From the gila monster, is it?

Exactly!

Is it not given orally?

I hope not

No.. Parenteral.. Subcutaneous!

Also there are extended release of exenatide available. Taken as weekly injections.

Bydureon! Weird but true! Thank you!

Study group discussion: Side effects of thiazides

What are the side effects of thiazide diuretics?

Study group discussion: Drug causing hypertrophic pyloric stenosis

Exposure to which drug leads to infantile hypertrophic pyloric stenosis?
Hint: One of the macrolides.

Erythromycin?

Yeah, they have found the  association in the research that was conducted!

http://www.ncbi.nlm.nih.gov/m/pubmed/12090829/

If administered in the infant, can cause hypertrophic pyloric stenosis. Within 15 days of life, that is.

Interesting.

Study group discussion: Non contraceptive uses of condom

Non contraceptive uses of condom? I was asked this question in today's viva!

To prevent STIs. Reduces incidence of HPV infection. Reduces chances of cervical cancer.

Condom pack to stop bleeding. Condom to stop PPH.

Condoms can also be used as gloves for per vaginal examination where there is unavailability of gloves mostly in rural
areas. Strange but interesting fact!

Condoms are also used to cover the USG probe in transvaginal scan.

And there exists a thing called condom catheter.. Used for weaning people off from a regular foleys! Due to prolong use of foleys patient loses urge to micturate. Sometimes.. So we use condom catheter. Which is basically a condom plus a urinary catheter attatched to it.

For vaginoplasty used to make moulds.

In treatment of infertility, used for 2-3 months.

Intra arterial administration.

Wow so many uses of condom!

Study group discussion: Hyperuricemia

Why does pyrazinamide cause hyperuricemia?

I guess it competes with uric acid for excretion because it is a weak acid.

Ohh.. Didn't know this.

There's an interesting concept I heard learnt while studying the uric acid thingy - Why does alcohol ingestion have attacks of gout? Anyone wants to guess?

Consumption of alcohol produces gout because when alcohol is coverted to acetaldehyde, NAD is converted to NADH. More NADH causes conversion of pyruvic acid to lactic acid. Lactate is not metabolised and excreted to kidney... Increased lactic acid excreation causes decreased uric acid excretion and hence gout occurs.

Alcohol produces lactic acid which competes with uric acid.
Loop and thiazide diuretics also cause hyperuricemia through this mechanism.

Correct! We have a brilliant mind in the group! B)

A random review question from top of my head since its the topic of uric acid: Which ARB drug is a uricosuric?

Angiotensin receptor blocker, right?

Losartan.

Yup.

Low dose aspirin also competes with uric acid. High dose aspirin uricosuric by inhibiting absorption.

Wow..nice info!

Any condition causing inorganic phosphate depletion also causes hyperuricemia.

Why does phosphate depletion cause hyperuricemia though?

Hypophosphatemia leads to accumulation of AMP which is then converted into uric acid. Galactosemia fructose intolerance cause hyperurecemia through this mechanism.

Amazing concept!

I feel so jealous if you.. Biochemistry is like my biggest threat!

Updated later:
Recently, we had a discussion on hyperuricemia caused by diuretics. It was mentioned it is due to the resultant acidosis that causes hyperuricemia. I read something on those lines. Diuretics do cause acidosis cause of slight CA ase inhibitory action on the PT. Thus acidosis even caused is not very marked. They cause hyperuricemia primarily by competiting with uric acid to get secreted via the organic anion transporter in the PT. Plus as the E.C.F volume is depleted due to diuretics, there is also increased absorption of the secreted uric acid. That's what I read.

Study group discussion: 45 centimetres in length and tubes

What are structures in our body about 45 cms in length?

That's an odd question. As in why do we need to know / significance?

Just to remember! Examiner here asked us in viva.

The spinal cord, Umbilical cord, Femur, Thoracic duct.

I know the esophagus is 25 cm in length. And the length from the incisor is longer. Were you given a nasogastric tube in your viva?

No.

Nasogastric tube 104 cm I guess..?

Varies 105 cms or 75 cms Ryle's.

This is gonna sound really basic but umm.. Can anyone explain the difference between an infant feeding tube, nasogastric tube and a Ryles tube?

Ryles tube is nothing but nasogastric tube.. Used for both diagnostic and therapeutic purposes.

Ohh.. I thought nasogastric and Ryle's are different.

In infant feeding tube there are no lead shots like in Ryle's tube.. And it's 52 cm in length.

Infant tube is narrow.

Infant feeding tube is used in: Tracheoesophageal fistula
Choanal atresia
Imperforate anus
Poisoning
Upper GI bleed

Thanks!

Study group discussion: Cool fact about optic nerve

I just came to know that the optic nerve is not a true nerve! It's just the extension of diencephalon..

That's the reason, in devic's disease (neuromyelitis optica) the optic nerves are involved since they are a part of central nervous system!

Wow o.O

That's why, Optic nerve is involved in multiple sclerosis too! It's the only myelinated nerve, part of the cns!

Yup. Also since it contains the same cover of meninges.. In cases of raised ICT, you see papilloedema.

Study group discussion: Leriche syndrome

What is Leriche syndrome?

Claudication. Thrombosis of iliac veins in males, especially, in heavy smokers.

It's an Aortoiliac occlusive disease, a form of peripheral artery disease involving bifurcation of  abdominal aorta.

Triad seen in males as impotence, claudication, decreased or absent femoral pulse!

It's due to Atherosclerosis. Obesity, diabetes, smoking, age are risk factors.

Patients getting treated should be checked for CNS, CVS, 1st for any thrombosis and then go for the treatment of leg.

Doppler and USG is used to diagnose it.

Yup. Also Angiography, CT or MRI.

Study group discussion: What does emulsification mean in fat digestion

What does term emulsify mean in fat digestion?

Breakage of large fat globules into small ones by bile is called emulsification of fat.

Making the fat to be smaller particles, helps it mix in with the water. Eg. Milk is an emulsion of fat and water.

Yes.. just to make it easier to be digested and absorbed.

Like fat broken down into glycerol and fatty acid? Am I right?

Not really fat into glycerol and fatty acid. More to fat droplets mixing with bile. It increases the surface area to volume ratio.

More surface area : more sites for lipase to bind and digest

Thank you, guys!

Study group discussion: Neurological emergencies and isoniazid overdose

Tell me some neurological emergencies!

Status Epilepticus, Stroke, Guillain Barre syndrome syndrome, Myasthenia gravis, Neuroleptic malignant syndrome, spinal cord compression, subarachnoid hemorrhage!

Okay!

But why Guillain-Barré syndrome?

Respiratory paralysis. That's the reason they die, I guess.

Yep. Respiratory paralysis is the cause of death.

The same reason, respiratory paralysis, for myasthenia too?

Yep.

I read about one more - Overdose of isoniazid. That can be fatal too.

Isoniazid overdose depletes vitamin B6 in the brain. And B6 is a cofactor for the enzyme that convertes glutamate to GABA.
That causes decrease in the inhibitory neurotransmitter, GABA. That's why, the acute manifestation is seizures.

Commonly seen in rural areas because patients with TB neglect doses and consume all of them together.

Didn't know about this. We'll educate our patients better in the future! Thanks!

Study group discussion: Lemierre's syndrome

What can you folks tell me about lemierre's syndrome?

Caused by fusobacterium necrophilus.. Initial presentation is like Streptococcus pharyngitis but ASLO negative.

And rapidly transforms into complication - Intravascular clots, etc.
Metronidazole and high dose penicillin used for treatment. Not very common, I think.

Interesting.

Clots in the internal jugular vein.. is fibrynolitic therapy indicated?

Dunno.

It seems that the clot dissolves itself when the infection heals, so only antibiotic therapy is indicated.

Okay!

Study group discussion: Heyde's syndrome

66 year old male, painless bright red blood per rectum started this morning. Has pansystolic murmur in right 2nd intercostal space. What is the cause of bleeding?

Right side 2nd ICS, so it's aortic stenosis. Now the patient has bleeding. How do we put together AS with bleeding?

*after putting all sorts of differentials for bleeding per rectum, we finally gave up and asked for hints!*

Okie, hint.  It's a vascular malformation.

Angiodysplasia! What's the association but?

Heyde's syndrome - Aortic valve stenosis with GI bleeding.

Elderly people have AD due to age and strain but bleeding from it associated with AS is Hyde's syndrome!

Meaning normal people have less chances compared to the ones with aortic stenosis?
That explains it.

Wow! Didn't know this. Nice, thanks people!

Study group discussion: Fontanelles and thyroid hormone

Guys, remember we were talking about craniosynotosis? I think it was Pfeiffer syndrome we were talking about. So I found out about another condition that causes craniosynotosis in the new born which is acquired and can be prevented. Anyone wants to guess?

Is it due to some drug?

No. It's a hormonal imbalance!

Due to thyroid hormone?

Hyperthyroidism!

Correct!

Yaaay.

Hyperthyroidism in pregnancy can cause craniosynotosis in the neonate!

Oh oh.. Vice versa, what happens in hypothyroidism?

Macrocephaly? Mental retardation?

Umm yes. But delayed closure of fontanelles is what I was looking for!

Oh right.

Speaking of fontanelles.. Which condition causing bulging fontanelles and which conditions cause depression of fontanelles?

Hydrocephlus - Bulging.

Bulging Fontanelles in increased intracranial tension. Depressed in dehydration.

Correct!

When does the posterior fontanelle close?

At birth. Or right before birth or right after!

When does the anterior fontanelle close?

Anterior fontanelle 15-18 months.

Correcto!

It's fun when you know the answers :D

Haha true that!

Study group discussion: Varicocele

Some questions regarding varicocele. So what is varicocele?

The increase of the testicular venous pampiniform plexus. Gives the characteristic bag of worms appearance.

Yes! So there is dilatation of this pampiniform plexus!

If it occurs suddenly on the right side. It as an indicative sign of right renal cancer.

Why is left sided varicocele  more common than right?

Left side enters at right angle!

And I am confused.. Which testicular vein drains where?

Right goes in IVC, left in renal. So that's why left is more common
Mnemonic! http://medicowesome.blogspot.ae/2014/03/left-testicular-vein-drains-into.html

What to suspect when you see right sided varicocele which are not common though?

Obstruction of IVC

Brilliant!!!

The right spermatic vein drains at more obtuse angle to IVC. So more likely some obstruction in IVC.

*a debate went on whether varicocele cause sexual dysfunction, sterility, infertility or not. The one who posts the link to the research paper, typically wins*

*Key questions raised* What is the function of this plexus? What would happens if patient is not treated? The pampiniform plexus forms a counter current system with testicular arteries. Hence. Maintaining a low temperature. They take away the heat from the arteries. So azoospermia? The sperms won't survive in the increased temperature? Does the erectile dysfunction occurs in varicocele?

*Conclusion* Varicocele (grade 3) is associated with significant reduction in testicular function with significant increase in serum levels of FSH and LH, which may cause erectile dysfunction and male infertility.
Source: http://www.ncbi.nlm.nih.gov/pubmed/11111867

Study group discussion: Ligamentum venosum and ligamentum arteriosum

Can someone explain the formation of ligamentum venosum to me? I read up on it and re-listened to the lecture but I feel like I'm confusing myself :(

The formation or why it's there?

The origin.. As in what it is a remnant of and how?

It's the remnant of the ductus venosum which shunts blood away from the developing liver to go directly into the inferior vena cava. Since the developing liver doesn't need a huge amount of blood supply.

Oh...That makes sense.

Yup. So the umbilical veins brings nutrients and oxygen from the placenta, so we need to bypass the liver via the ductus venosus. Then when we are back in the Right ventricle, we don't need much blood into the lungs so we shunt it into the main circulation via ductus arteriosus.

Which later turns into ligamentum arteriosum! :D
Now everything is in place! Thank you so much!

No problem :)

Study group discussion: Parasites that cause carcinoma of the gall bladder

Which parasites are associated with gall bladder cancer?

Chronic schistosoma is associated with bladder cancer.

Flukes!

Fasciola!

Clonorchis sinensis.
Fasciola hepatica too.

Roundworms block the the CBD.

CBD?

Common bile duct.

But that'll be associated with jaundice. Not carcinoma!

Study group discussion: Hernia

What is Richter's, Littres, pantaloon hernia?

Ritchers is the one when part of circumference of intestine is involved, right?

Yup.

How do you remember this? Any mnemonic?

You can remember richters hernia as it has C-part of Circumference of bowel.

Pantaloon is when there is indirect plus direct hernia so two sacs are there.

In Littres, I think the meckels diverticulum is a part of the sac.

Which is the commonest type of hernia in females?

Inscional hernia is commonest in females.

Aren't femoral common in females?

The most common in females in indirect inguinal. But I guess you want to ask about femoral. Femoral hernia are overall commonest in females. But they are not the most common type in females.

Because of wider pelvis.

Thanks! Got it.

Some days back I had asked about the name of hernia that includes appendix.
Finally, got its name :D
It's amyand hernia,

Study group discussion: Pfeiffer disease and Pfeiffer syndrome

What's Pfeiffer disease and Pfeiffer syndrome?

Pfeiffer disease - Glandular fever -Infectious mononucleosis - Kissing disease.

Pfeiffer syndrome is craniosynostosis with hearing loss, a genetic disorder.

Craniosynotosis?
Early fusion of premature bones.

What type of craniosynotosis? There are several types!

Sutures fused and no place for growth of brain. Accordingly you get different shapes of skull - Coronal, cloverleaf shape or a boat shaped skull.

Type 1 is classic, with no neurological impairment.
Type 2 is clover leaf shaped head and retardation of growth with neurological impairment.
There's type 3 too.

Why do you have such an extensive knowledge on this rare syndrome?

Actually, there was an infant girl with craniosynostosis.
Her mother complained that she used to regurgitate the milk after each feed. (This was probably because of the raised ICT.)
The doctor's had to operate - Break the fused bones to provide space for the brain to grow.

Breaking up bones for the brain to grow, now that's something awesome!

Wow.

She's safe now (:

Study group discussiont: Acute lymphangitis

This patient presented with rapidly progressive left arm pain and erythema. Physical examination revealed a small blister on his left third finger, which had been injured during a lacrosse game, with surrounding warmth, tenderness, erythema, and linear streaking to the elbow. diagnosis?

*a picture of acute lymphangitis was posted in the group, I can not upload it here because of copyright purposes*

Is it a lymphangitis?

Yes! acute lymphangitis!

Nice! Any further details regarding lymphangitis?

About lymphangitis.. It's inflammation of the lymphatics.

The most common cause of lymphangitis is streptococcal infection. The shape of the lesion is very caracteristic since it follows the lymphatic vessel path.

Thanks for the further information!

Or a sporothrix infection. Though the history doesn't suggest anything like it.

What history should the guy have to suggest a sporothrix infection?

The fungus can enter the skin through small cuts or punctures from thorns, barbs, pine needles, or wires. In rare cases, inhalation of the fungus can cause pulmonary infection.

Correct! Rose gardeners especially.

Thank you, IkaN, you are the best!

Haha. It's okay.

Study group discussion: Uncouplers of oxidative phosphorylation

In electron transport chain, cyanide inhibits the last step.

Even dicoumarol is an uncoupler.

There was another drug used for weight loss that's an uncoupler.. Which one was that?

Dinitrophenol?

Yes!

Review question: What do new borns have that is an uncoupler? Why is it important?

UCP 1

Brown fat

I had to Google UCP 1. The answer I was expecting was simple brown fat :P
For those who don't know, UCP 1 or thermogenin is uncoupling protein 1 present in brown fat.

UCP-1 (Thermogenin) - Non shivering thermogenesis in brown fat in

I think, these UCP play great role when polar bear comes out from hibernation and also in human infant.

Yes, the polar bear!

Speaking of bears - What will happen to you if you eat a polar bear's liver?

Vitamin A toxicity?

Yes! Vitamin A toxicity! Mostly, increased intracranial pressure.

Why given term thermogenin?

Generate heat. Uncouplers dont generate ATP.

Ya, ATP formation replace by heat releasing process.

Aspirin high dose also acts as an uncoupler. Hence, we get hyperthermia in it.

This is interesting because aspirin is used as an antipyretic and it's overdose, paradoxically, causes fever.

Yup.

What is an uncoupler?

Uncoupling protein also called ucp, cause leakage of proton from mitochondrial membrane.
This allows the proton to reenter the mitochondrial matrix without capturing ATP.
Uncoupler = Uncouples oxidation (ETC) from phosphorylation ie oxidation without phosphorylation.
So energy indtead of being trapped in ATP is displaced as HEAT (NON SHIVERING THERMOGENESIS)

Physiological uncouplers:
# UCP 1 thermogenin
# excess thyroxine
# unconjugated hyperbilirubinemia

Synthetic uncouplers:
# dicumorol (vit K analogues)
# asprin
# calcium
# valinomycin

Thanks!

Awesome!

A nice summary!

Study group discussion: To vaccinate or not to vaccinate

Something about influenza vaccine!
So 6yrs old child comes for influenza vaccine! Allergic to egg! Develops rash with the eggs! Will you give him the vaccine or not?

Why yes or why no?

Yes. Because the new ones are not produced in eggs, right?
They're subunit/recombinant/ts vaccines.

If it's an egg based vaccine, you can give a test dose and check keeping adrenaline ready.

My friend had allergy to egg. Last year when we went to take influenza vaccine, she wasn't given it.

Because it's not an important vaccine / you can do without it?

She has stomach pain on eating eggs..No rash or anything.

Yes, it's a controversial issue! Though earlier their used to be strict contraindication to egg allergy. But with the egg allergy with rash, they say it's ok to administer with an observation period of 30 minutes after the vaccine is given.
On the other hand if patient had anaphylaxis reaction then the vaccine can still be administed but under the consultation of the specialist in the allergies.
There is difference in the usage of live vs inactivated vaccine!
Egg allergic are given the inactivated one!
I found two papers let me send the links here
http://www.ncbi.nlm.nih.gov/m/pubmed/23805959/
http://www.ncbi.nlm.nih.gov/m/pubmed/23176882/

So you can give it (:

How about MMR vaccine should that be given in Egg allergy?

If you can flu, you can obviously give MMR. Plus, measles is a severe disease so I think yes.

Yes, it is not a contraindication. Very low risk for anaphylaxis as these contain only small amount of egg cross reacting proteins!! These two are the ones commonly tested.

The quantity of egg protein in a dose of MMR vaccine is approximately 40 picograms (much lower than in influenza vaccine, which contains approximately 0.02-1.0 micrograms), and this is believed to be associated with a much lower risk.
Source: Wiki

What vaccine can have an inconsolable screaming reaction to it? (>3hours)

DPT ... Due to the pertussis component.

Aha. Okay.

I have another vaccine related review question!
If a child develops convulsions after receiving his DPT shot, what will you do? Will you give him the next shot?

I would say no! Anaphylaxis as well as encephalopathy are contraindications to the next shot?

This is a trick question - The convulsions occur due to the pertussis component of the vaccine.
So you will give the vaccine, but you'll give acellular pertussis instead or just give DT in the next dose.
They are life threatening diseases and it's important that the kids get vaccinated.

Ohhh!!!!

Was my viva question! (Also one of the rare instances when I knew the answer :P )

Study group discussion: Chagas disease

What comes to your mind when you hear of left ventricular apical aneurysm?

Two apical impulse.

Hint: Protozoa.

Chagas disease.

Brilliant!

Chagas disease causes destruction of the neural crest cells, right?
I know it causes Hirschprung disease. But how come apical aneurysm?

I think some parts of the heart are also formed from the neural crest cells.

The aorticopulmonary septum!

Chagas disease is associated with dilated cardiomyopathy.

I've heard of that.

Related fact: Chagas also causes achalasia.

Friday, February 27, 2015

Study group discussion: How and when do children understand the concept of death

A six year old boy with neuroblastoma has a recurrence of the tumor despite aggressive treatment. The doctor discusses the patient prognosis with his parents and recommends palliative care. Parents ask how they should tell son the prognosis and possible death. Doctor advises parents to be honest and follow patients lead. Patient most likely has which understanding of death?

1- Being asleep
2- Being final
3- Being in a long journey
4- Being temporarily separated from parents
5- No understanding of death.

3 year olds think it's temporary separation. They keep asking whether their pets will come back.

At 6 years of age the child begins to understand that death is final and fears that his or her parents will die and leave.

It is not until about age 9, however, that the child understands that he or she also can die.

Since the child was diagnosed with neuroblastoma, he will be able to understand that death is final, but will be unable to understand his possibility of death.

The answer is 2. Death is final.

Additional info about normal child development discussed by an awesomite mother:

My 6 year old doesn't understand death much. 8 year old gets it.

6 year old knows, in the abstract, what death is, because we've had a dog die. But he never showed true grief in the understanding of it, asked where you go when one does, etc.

My daughter is 8.5 and is now questioning the afterlife. She's asking questions regarding what happens, really wanting to know, etc.

Hope that helps! 

Study group discussion: Alcohol and sex

This my viva question.. The boldest I have come across. The external asked me how does alcohol affect one's sexual performance. I went through 50 shades of red within a minute!

Haha. I think it decreases sexual performance.. As in erection. I'm not sure though. Heard it somewhere.

I said, it increases the desire but decreases the performance.
He quoted a line by Shakespeare then!

Alcohol causes loss of libido.

Sexual dysfunction in the alcoholic may be due to the depressant effect of alcohol itself, alcohol-related disease or due to a multitude of psychological forces related to the alcohol use. The spectrum of sexual dysfunction encompasses:
Decreased sexual desire—persistent or recurrent deficiency or absence of desire for sexual activity giving rise to marked distress and interpersonal difficulty;
Sexual aversion disorder—persistent or recurrent aversion and avoidance of all genital sexual contact leading to marked distress and interpersonal difficulty;
Difficulty in erection—recurrent or persistent, partial or complete failure to attain or maintain an erection until the completion of the sex act;
Difficulty in achieving orgasm—persistent or recurrent delay in or absence of orgasm, following a normal sexual excitement phase;
Premature ejaculation—persistent or recurrent ejaculation with minimal sexual stimulation, before, on or shortly after penetration and before the person wishes it, which causes marked distress.

Alcohol abuse is the leading cause of impotence and other disturbances in sexual dysfunction.

Thanks!

Study group discussion: Chain messages

There was a chain message being circulated on Whatsapp which started our discussion. The discussion gave me a new perspective on things.

I never read chain messages because I find them stupid. But one awesomite pointed out on how we must be aware of chain messages, since as a doctor, we'd undoubtedly run into patients who've read things like that and we should be able to talk to them about those things.

Also, tell us about stuff you've read on the internet that had no proved scientific basis, incidents of people who have believed such messages and outcomes associated with them. I'm interested and open to these things now as I feel there is value in knowing them.

I'm posting the discussion we had here for ya'll to read -

This was the "Prevent Swine Flu" message forwarded on our study group:
1. Frequent hand-washing (well highlighted in all official communications).
2. "Hands-off-the-face" approach. Resist all temptations to touch any part of face (unless you want to eat, bathe or slap).
3. * Gargle twice a day with warm salt water (use Listerine if you don't trust salt).
* H1N1 takes 2-3 days after initial infection in the throat/ nasal cavity to proliferate and show characteristic symptoms. Simple gargling prevents proliferation. In a way, gargling with salt water has the same effect on a healthy individual that Tamiflu has on an infected one. Don't underestimate this simple, inexpensive and powerful preventative method.
4. Similar to 3 above, * clean your nostrils at least once every day with warm salt water.
* Not everybody may be good at Jala Neti or Sutra Neti (very good Yoga asanas to clean nasal cavities), but * blowing the nose hard once a day and swabbing both nostrils with cotton buds dipped in warm salt water is very effective in bringing down viral population.
5. * Boost your natural immunity with foods that are rich in Vitamin C (Amla and other citrus fruits).
* If you have to supplement with Vitamin C tablets, make sure that it also has Zinc to boost absorption.
6. * Drink as much of warm liquids (tea, coffee, etc) as you can.
* Drinking warm liquids has the same effect as gargling, but in the reverse direction. They wash off proliferating viruses from the throat into the stomach where they cannot survive, proliferate or do any harm.

Is this actually good medical advice (Except for the sensationalist language...)?
1 and 2 definitely sound like good advice, but 6 sounds a little bit questionable to me.

Forwards always sound questionable to me! I've never heard about "Drinking warm liquids to prevent viral proliferation" though.. I'll look it up!

I tried Googling all sorts of stuff for the warm tea bit and found nothing on the 6th point.
Then finally, I Googled, "Reverse Gargling" and the forward created by the same guy comes up! There is no such thing!

It seems like a publicity move by the doctor who wrote it. (Why would any one list the names of hospitals they visit in an educational advice?!)

I'm interested in understanding the yoga for nasal cleansing!?

You can Google for videos. And do not try unless you are confident enough that you can do it. Sometimes the water goes in the wrong pipe!

I didn't mean interested as in wanting to try it :P
I'm from Britain so these sort of techniques are rare to say the least.

Yoga for nasal cleaning is simply putting water in one nostril and getting it out through other nostril. Simply irrigation and drainage.

Nasal yoga reminds me of Neti pots. Anyone wants to weigh the scientific evidence of that?

I wouldn't really trust this advice. I speak this from personal experience. Some guy who used to believe in these things told my grandpa to do some of these practices. He told my granddad to basically eat upwards of 6 lemons a day and also convinced him that the lemons would reverse effects of hypertension and diabetes. It didn't work, my grandpa passed away. I know this isn't relevant to the group, but I'm always wary of advice such as this.

That sounds so much like bad advice...  Everything in moderation. Six lemons a day is not moderation. Also, lemons have so much sugar in them, wouldn't that exacerbate the diabetes?

It's so sad that people believe such things and over do it causing more harm than good.

I didn't read after I looked at the last line - "Forward this to everyone and 20 might live cause of this." :/
It's when you guys got it to my attention that I actually read the whole thing!

I'm pretty wary of any kind of chain email advice. I think there's value in discussing them and critically analyzing them from a more scientific point of view, though. Especially since as a doctor you'd undoubtedly run into patients who've read things like that, and you'd need to be able to talk to them about those things.

I agree with that!

I once read of a case where a young girl was told to rub almonds on her face to clear acne, but her "acne" just kept getting worse. Turned out she was allergic to almonds.

Our residents had a discussion on how each and every relative was asking about Ebola because of the forwards they were receiving!

My aunt is very into chain emails.   I usually try to find time to point out all the scientific inaccuracies in them.

I don't trust anything.. Except soup for cold and honey for soothing the throat!

Soup works wonders!

See some things do no harm, like old wives tales of rubbing a potato on warts then burying the potato... But others are strange and potentially harmful.

There is some good science in some of these chain emails. But there is so much bad science.
Like the one that recommended aspirin to prevent heart attacks.   I mean, yes, it can certainly help, but it can also kill you if you have certain health conditions or if you try to overdo it.   Eating as much aspirin as you possibly can is also very much a bad idea.

The one I enjoyed most was the one that said cancer cells can't grow in alkaline environments so people should eat alkaline foods! I worked in a cancer research lab.  We grew cancer cells in alkaline medium!

Hahaha! This one is hilarious.

I was about to ask for hilarious incidents and here we have one!

Hahahaha my mum believed the alkaline treatment for cancer and my expression was basically: T_T
But there seems to be substantial information on alkaline treatments for cancer. Apparently, it's all over Google.

My aunt and mother believed it too.   But then I told them about the fact that we cultured cancer in alkaline medium with great success and they decided to believe me instead.

So umm what's alkaline food anyway?

Fruits are the main source of alkali in our diet. - Ganong

I tried looking up alkaline foods...  Orange was listed as one of them...

All I can think of is.. Food that alkalinizes urine. Cause citrus fruits do that!

Ah, that makes sense!

Hmm. I wonder if perhaps the foods that alkalinize urine can prevent cancer.  I doubt that causing the body to be more alkaline (Can that even be done?) would help with cancer, but perhaps the thing that makes foods alkalinize urine, or something else those foods have in common, also helps with cancer.

The only benefit alkalinizing foods can offer is prevention of kidney stones and maybe overdose of a few drugs, scientifically.

But then surely we would circulate "Food that contains this compound..." Rather than food that alkalised. If there was a common anticancer property that wasn't anything to do with alkaline food.

Hmm...  I'm disinclined to believe that The importance of knowing chain messages in modern Medicine it has any genuine anticancer properties, but I'm equally disinclined to reject the possibility.  I would like to see scientific evidence before forming an opinion either way. Medical research is constantly happening.  Just because we haven't discovered something doesn't mean it doesn't have merit.

I think the creator of the chain message (Considering he considered anything!) wanted to highlight that we should consume fruits to prevent colon cancer - so they used words like alkaline and stuff to make it all science-y and legit to the lay man?

That makes some sense, although I don't know why on earth they couldn't just use legitimate science.   It's possible to use fancy science words to make even basic science seem legitimate to people.   Especially with medicine where all the parts of the body can be expressed in fancy Latin.

But it spooks the lay-man into overdoing it. It's potentially harmful.

I agree so much. That's a very genuine concern. Even too much water can kill you, and I think that's a thing people fail to appreciate.

Yes, but in a perfectly healthy individual - Fruits would do no harm.

I must say, it's those who are affected by chronic diseases are more inclined to believe "Anything that could be of potential help" to them in curing their sickness.

*We discussed water intoxication syndrome. Since it's irrelevant to this post, I wrote a separate blog post on it here --> *

Woah. There are always some messages circulating on whatsapp regarding some wonder drug with a 100% guarantee.

My father gets influenced too. Due to some video.. I spent 15 mins explaining that white bread is bad for health and brown bread is good.

But but...Aren't the benefits of fiber well known?

White bread is simple nonsense.. It's bad for your intestines.. Plus no real nutrient benefit. It is refined wheat.. So there is hardly and fibre property to it.

How is it bad for the intestines?

I had come across a patient who had an intestinal onstruction. She was denied eating white bread. It reduces bowel movements.

“The Whiter The Bread, The Sooner
You’re Dead.” I've heard the phrase somewhere!

Exactly.

Wow. Seriously.

Whole wheat is all good. Except in patients suffering from celiac disease..I haven't come across any other condition where they shouldn't be eaten.

Gluten freeee.

Yup.

My mother was convinced that she should go on a gluten free, casein free diet even though she isn't diagnosed with celiac disease or anything like that. Someone told her that going GF, CF was good for everyone regardless of medical history.

It's not a bad idea per se, but I reckon patients who are not trained or well informed about nutritional science are at higher risks of deficiencies especially if they restrict their food choices. I think as physicians we should inform them of the possible risks and still provide them the autonomy and explain how to alter their diet to prevent deficiencies. Like vegetarians basically.

I guess I minded more that she wanted me to go on a GF CF diet and I enjoy too many gluten and casein containing foods for that to make sense for me.

Lol. Well I feel the same way. But we shud be realistic about the risks and not overexaggerate the dangers of gluten free diet because then the Coeliac's society might be affected as well.

But vaccines on the other hand, I'm sorry but we need to jab everyone possible because it's a public health issue.

Yes. Vaccines causing autism is utter bull. People are forgetting how bad the vaccine preventable diseases are (Since they don't see them anymore, thanks to the vaccines) and are being ignorant!

Study group discussion: CHARGE syndrome and related case

A newborn turns cyanotic upon breast feeding and crying turns him pink again? What's happening here? Also the mechanism?

Tracheo esophageal fistula?
That explains the cyanosis part only but in that crying won't turn him pink again.

Laryngomalacia?
In laryngomalacia, the cartilage collapses inward upon inhalation.
But that's not the answer.

Nasal polyps?
It is unlikely to have been formed in a new born infant.

Nasal or Choanal atresia.
He is breathing through mouth. Breast feeding obstructs his only breathing route. So he turns cyanotic. Crying allows him to turn breathe through the mouth, turning him pink again.

Correct! Full marks!

Thank you :P

What's CHARGE syndrome?

C coloboma
H heart defects
A atresia choanal
R retardation (mental and growth) G genital defect
E ear defect

Excellent!

Study group discussion: Mechanism of tet spells

Can anyone explain why crying causes cyanosis in Tetralogy of Fallot? I don't get the concept crystal clear.

In TOF, patient has the suck rest suck cycle. Starts sweating and cyanotic in breast feeding because he can't do the work of suckling. I think it's grade 2 dyspnea according to NYHA.

But how cyanosis and crying are related?

Increased catecholamines during crying causes increased right to left shunt.

Crying causes decrease in the pulmonary blood flow, increased right to left shunt and systemic desaturation that lead to cyanosis.

It also leads to peripheral vasodilation and further increase in R-L shunt when crying. There is release of catecholamines too which contributes as well.

But shouldn't catecholamines cause vasoconstriction?

Same doubt!

Yup, catecholamines causes vasoconstriction. Increased catecholamines causes decreased pulmonary blood flow and increased right to left shunt. That leads to activation of mechanoreceptors in right ventricle that inturn leads to peripheral vasodilation. Sorry if I'm confusing you all!

Ohh.. I get it. Basically, the pulmonary resistance increases.. Which causes shunting of blood, right? And the mechanism for vasodilation is different?

Yes. The mechanism is different.

They're called tet spells, right?

Yes, known as tet spells.

So it all begins with the catecholamines? Are they the main player here?

Yup it all begins with catecholamines.

So this phenomenon happens in a normal child too and it is aggravated in TOF due to pulmonary stenosis?

Obviously, due to pulmonary stenosis and ventricular septal defect.

Here's a link on tet spells! http://kidshearticu.com/cyanoticspells.asp

Of Iron, bacteria, hemochromatosis and plague

Iron is one unsung hero in our body. Apart from oxygen transport, it plays a vital role in constituting important enzymes as well as some detoxification reactions and also in converting sugars into energy.

But, during infections,the same iron stored in our body can prove lethal. It has been studied that bacteria use our very own iron stores to launch a full scale attack. That is why, intracellular bacteria like Mycobacteriae which use iron repositories in macrophages can cause so much damage.
It has been observed that a certain Somalian population, despite being anaemic was resistant to diseases like malaria, tuberculosis and so on. When doctors prescribed iron supplements, infections gained an upper hand. Actually, the population wasn't facing the infection despite the anaemia, but because of it!

Going by this, wouldn't patients with hemochromatosis be a playground for bacteria?

No!

Let me explain. Patients of hemochromatosis also have an another mutation, C282Y on HFE gene. This results into decreased levels of the C282Y protein, resulting into increased sensitivity of the WBCs to the chelator, transferrin resulting further into bacteria being unable to use iron as it remains 'locked' away at sites rather inaccessible to them.

Where does plague come into this?
It is being thought that when plague was rampaging through Europe, population with hemochromatosis was rather resistant and hence the gene for the disease was selected. This is why people of northern and western European descent have a higher prevalence of hemochromatosis.


Thursday, February 26, 2015

Study group discussion: Shift to left

Would someone tell me what exactly is 'shift to left' in WBCs?

The production of immature cells... And release of them in circulation.

If you draw the stages of white blood cells from left to right, becoming more mature.. Shift to left would mean immature WBC's have been released into circulation.

Woah. Didn't know it.

Oh, thanks! Had this query since second year! :D

In which conditions do we get a left shift?

Infection, inflammation, leukemia.

Which leukemia? Acute or chronic? Myeloid or lymphoid?

I think it's fair to say it occurs in all leukemias.. I couldn't find a reliable resource online on the same.

Study group experience #12

So someone came up with this great idea about having study days. For example - Tuberculosis day, ECG day, anatomy day, etc.
The idea is - we could all study a particular topic and then discuss the same topic through out the day - as and when we come online, considering time zone differences.
It's all experiment-y, let's see how it goes though. Really excited!

Monday, February 23, 2015

Abnormal breath sounds: Crackles, Wheeze, Rhonchi and Stridor

Crackles (Also Known as Rales)
What do crackles sound like?
Roll your hair between your fingers next to your ear.. That's what fine crackles sound like! (Or the sound of salt heated on a frying pan, if you've ever tried cooking :P)
Coarse crackles sound like ripping open Velcro.

When are crackles heard?
Crackles are much more common during the inspiratory than the expiratory phase of breathing, but they may be heard during the expiratory phase.

Mechanism of crackles:
Crackles are the sounds you will hear in a lung field that has fluid in the small airways or if atelectasis is present.

Causes of crackles:
Crackles is often a sign of adult respiratory distress syndrome, early congestive heart failure, asthma, and pulmonary edema.

Rhonchi
What do Rhonchi sound like?
Try making a snoring sound or try to make a sound as if you're gargling your mouth. That's what Rhonchi sounds like!

When are Rhonchi heard?
Rhonchi are more prominent on exhalation.

Mechanism of Rhonchi:
Secretions in large airways, as occurs with bronchitis, may produce these sounds; they may clear somewhat with coughing.

Causes of Rhonchi:
Pneumonia, chronic bronchitis, and cystic fibrosis are patient populations that commonly present with rhonchi.

Wheezes
What do wheezes sound like?
Try whistling slowly while exhaling.. That's what wheezes sounds like! Wheezes are continuous musical tones. 

When do wheezes occur?
Wheezes are most commonly heard at end inspiration or early expiration.

Mechanism of wheeze:
As the airway lumen becomes smaller, the air flow velocity increases resulting in harmonic vibration of the airway wall and thus the musical tonal quality. They result as a collapsed airway lumen gradually opens during inspiration or gradually closes during expiration. 

Causes of wheezes:
Heard when listening to an asthmatic patient. Sibilant wheezes are caused by asthma, congestive heart failure, chronic bronchitis, and COPD too.

PS: Wheeze is also known as sibilant rhonchi.
Rhonchi is also known as sonorous wheeze.

Stridor
What does stridor sound like?
Stridor are intense, high-pitched, continuous monophonic wheezes (musical sound) heard loudest over extrathoracic airways.  Similar to a creaking or a grating sound.

When is stridor heard?
They tend to be accentuated during inspiration when extrathoracic airways collapse due to lower internal lumen pressure.

Mechanism of stridor:
It usually caused by a foreign body obstruction of the larger airways, such as the trachea or a main bronchus.

Causes of stridor:
It is also the most common type of breath sound heard in children with croup (Laryngotracheobronchitis caused by parainfluenza) and a foreign body airway obstruction.
Also heard in Bacterial tracheitis, Diphtheria, Epiglottitis (H. Influenza) and Broncholitis (RSV).

Stertor
What is Stertor?
It is like stridor but it's more harsh, less musical and low pitched.

Mechanism of stertor: Respiratory sound that originates from pharynx, basically, anywhere  above larynx.

Causes of stertor: Seen in partial obstruction  of airway above larynx characterised by heavy snoring and gasping like in obstructive sleep apnea.

Thanks Nab, for explaining stertor to me!

Study group discussion: Radiological findings in meningioma

A 36-years-old female has been complaining of recurrent headaches since four months. On examination, she has papilledema. MRI of brain showed an extra-axial, dural based and enhancing lesion in frontoparietal region with positive ‘dural tail’ sign. Diagnosis?

The dural tail sign occurs as a result of thickening of the dura. It's meningioma..

Other sign associated with meningioma is the mother in law sign..

The mother in law sign is perhaps uncharitably (depends on the mother in law I suppose) used to describe lesions that enhance early during the arterial phase and remain opacified well after the venous phase. The joke is that a mother in law comes early and stays late.

It is most frequently equated with the angiographic appearance of a meningioma.

Study group discussion: To anticoagulate or to not anticoagulate

One quick review question:
So patient has new onset atrial fibrillation. Would you start the anticoagulation right away?

Its only after 48 hrs of onset, that too you have to rule out intra-atrial thrombus by trans esophageal endoscopy. If the thrombus is present, you give heparin.

Yeah when there is thrombus that's a must! But let's say no thrombus now what? 35 yrs old male.  Can we start  anticoagulants?

There is specific criteria. For assessment of thromboembolic risk. It's called CHADS2.

Oh yes, if the score is >=1 then you start it. One point each for CHF, HTN, age >75, diabetes and 2 points for prior stroke or TIA.

If patients have not been adequately anticoagulated and the AF is more than 24–48 h in duration, a transesophageal echocardiogram (TEE) can be performed to exclude the presence of a left atrial thrombus that might dislodge with the attempted restoration of sinus rhythm with either nonpharmacologic or pharmacologic therapy.

It can be a different scenario!
* In the case I was discussing above the AF resolved soon after metoprolol.

And in that case anticoagulation are started as prophylaxis. So would be oral warfarin or the LMWHs.

Study group discussion: Charcot's in Medicine

I read about charcot and who knows the conditions, name of diseases starting with charcot?

Charcot Leyden crystals - Eosinophils in sputum of patients with allergic diseases.

Then charcot joint too.. In diabetes, syphilis. Neuropathic joints, basically.

Charcot triad is of which condition?

One is of infection of gallbladder - Jaundice, fever, right hypochondriac region pain.

Charcot's triad in multiple sclerosis is sin - Speech disturbance, intention tremors, nystagmus!

I thought intention tremors were characteristic of cerebellar disease.
Exactly but seen in MS though not pathognomonic.

More charcots?

Charcots disease is ALS.. Amyotrophic lateral sclerosis !

The ice bucket challenge one. It's other name is based on some famous baseball player, right? Lou Gehrigs disease!

Charcot's artery?
Lenticulostriate artery!

The ones responsible for lenticular infarcts? There are five types, right?

Pure motor, pure sensory, clumsy hand, ataxia and sensorimotor!

Charcot bouchard aneurysms!

Charcot marie tooth disease !

Charcot wilbrand syndrome- visual agnosia!

Nice one! Keep learning and sharing :D

Study group discussion: Pathogenesis of symptoms in glucagonoma

Why does glucagonoma cause dermatitis and DVT?

The exact cause isnt known, but one of the reasons may be, because the excess glucagon produced reduces the amount of albumin (which carries Zinc) hence producing a relative deficiency of Zinc. The similar type of which is also found in Zn deficiency. And hence, the dermal manifestation!

The dermal manifestation is called NME - Necrolytic Migratory Erythema

That was one of my MCQ! Also glucagonoma is the commonest type pancreatic tumours to occur in MEN 1 syndrome.

And deep vein thrombosis?

The mechanism for the coagulopathy is poorly understood and seems to be related to an increased factor X production by the pancreatic alpha-cells.

Anyone would like to name the 4 D's of glucagonoma?

Diabetes
Dermatitis (rash),
Deep vein thrombosis (e.g., blood clot in the legs)
Depression

Study group discussion: Can a child less than 6 months be given anything other than breast milk?

Hello. I had this little doubt, I'm in the second year and haven't been exposed to paeds yet. So...
Do you give a child below six months anything other than breast milk? If no, then what do you do if a mother isn't producing enough milk and the baby is still hungry?

What I learned in peds (only did one of three semesters so far) it's that there's very very rare for the mother to not produce enough milk. most of the times is a matter of wrong breast feeding technique.
But formulas can be used, if in the right proportion of formula to water.  Or even cow milk, but it also has a specific recipe to dilute it.

I'm not sure. It's probably not recommended as the milk will be different from the mother's.

You can use fórmulas, you can't give them cow Milk until they are one year old.

I learned that if the family can't afford formulas is ok to give cow milk since the birth. It has to be diluted with water and added some sugar and a drop of soy oil to make it more similar to breast milk.

It is possible that sometimes a woman other than the mother can breastfeed too.

In my peads wards, I have seen mothers giving top feeds with the not enough milk production excuse.

If the child doesn't have a mother, I think they're provided with diluted cows milk or infant formulas.
The only reason it isn't recommended in infants who have mothers who can feed their child is because they have nipple confusion / detachment and they won't consume the mothers milk anymore (Which is super important for the baby, since they have antibodies!)

Study group discussion: Krukenberg in Medicine

What is..
Krukenberg tumor? 
Krukenberg procedure?
Krukenberg spindle?

Study group discussion: Mifepristone

Major use of mifepristone in obstetrics gynaecology is?
A) ectopic pregnancy
B) molar pregnancy
C) fibroid uterus
D) threatened abortion

A??

Yes, it's A. Please explain.

Mifepristone is abortifacient. It causes abortion by blocking progesterone.

But what if the ectopic site is not in connection with the uterine lumen. How will it be aborted?

I guess progesterone level in required to maintain the implantation.. A decrease in progesterone will cause it ectopic pregnancy to abort from that place.

That's right.

Mifepristone is also sometimes used to end pregnancies when more than 49 days have passed since the woman's last menstrual period; as an emergency contraceptive after unprotected sexual intercourse ('morning-after pill'); to treat tumors of the brain, endometriosis (growth of uterus tissue outside the uterus), or fibroids (noncancerous tumors in the uterus); or to induce labor (to help start the birth process in a pregnant woman).

Sunday, February 22, 2015

Rh incompatibility USMLE Step 2 CK doubt

If the patient is sensitized and is making Rh antibody, there is no point giving, Rhogam right?

Nope. It is only for prevention to Rh sensitisation. It's not the treatment.

I see!

So once she is sensitized, nothing can be done?

Nope.

So, say there is a mother who had a kid with hemolytic disease last pregnancy. Will I be giving her Rhogam next pregnancy?

No.

You monitor the Rh antibody levels (by titres using indirect antiglobulin test).

If >1:4 woman is considered sensitized.

If >1:16 do the spectrometric test by using fetal cells taken by amniocentesis (To monitor bilirubin levels!)

Bilirubin low: Repeat amniocentesis in 2-3 weeks.

Bilirubin high: Measure hematocrit of baby using percutaneous umbilical blood sampling.

If the baby is affected (Fetal hematocrit low), only treatment is to give blood transfusion to the baby in utero (Intrauterine transfusion) And delivery at 37 weeks. Or even earlier.

Ooh. I get it all now <3

Study group discussion: Drugs and conditions that enhance Digoxin toxicity and the mechanism behind it

I read some cool things today on the group!

Why is there an increased risk of toxicity with digoxin in hypokalemia, hypercalcemia and hypomagnesemia?

Answers:
Potassium and digoxin compete for the binding site so if there will be less of potassium more of digoxin gets the chance to bind leading to toxicity. The NaKATPase is the binding site.

Digoxin toxicity is aggravated by increased calcium cause more calcium accumulates intracellulary. This leads to increased contraction.
Calcium intracellularly also increases the generation of ectopic foci within contractile cells.

Magnesium is used as treatment in the treatment of toxicity.
Magnesium is the cofactor for the Na-k pump. Less magnesium..less functioning of the pump. Hence aggaravated toxicity!

Here's an additional fun concept:
Drug of choice for supraventricular tachycardia?

Answer: Verapamil.

So if you have SVT in digoxin toxicity.. Would you give verapamil?

Answer: No.

Why not?

Don't know? Let me approach the explanation in a way which helps you think better - What is the mechanism of excretion for digoxin?

Answer: Renal excretion.
Digitoxin is via hepatic.
Here's a mnemonic on renal / liver excretion of Digoxin / Digitoxin: http://medicowesome.blogspot.ae/2014/03/how-to-remember-digoxin-is-renally.html

So when digoxin enters the tubular cell, it is excreted into the lumen via p-gp receptors. Those are the same receptors responsible for multidrug resistant. In cases of anti-cancer agents and anti-malarials. You see, verapamil is one of the rare drugs that block p-gp. Hence, decreasing digoxin excretion, thus, precipitating it's toxicity.
*pgp refers to P Glycoprotein receptors

Verapamil for the same reason is used to reverse resistance to anticancer and anti-malarials. Pretty cool info, ain't it?

I just fell in love with the whole drama digoxin plays in your body :D
So what drug is used in SVT induced by digoxin then?

Answer: Beta blocker.

That's all for today!

I'm trying to edit the stugy group discussions in a more reader friendly format. Hope you like them!

-IkaN

Study group discussion: Food analogies in Medicine

Who likes oreo cookies? I came to know about the Oreo Cookie sign today!
It's seen on a chest x ray (lateral view) when there is a pericardial effusion!
The anterior most layer (the chocolate part!) is the epicardial fat.
The mid layer (the cream part...yumm!) Is the fluid.
And the posterior layer (again, the  chocolate part) is the pericardial fat!

Coffee bean sign seen in?
Sigmoid volvulus! Also called omega sign!

Name some terms that starts with strawberry referring some conditions in our body:
Strawberry cervix - Trichomonas vaginalis infection
Strawberry tongue - Kawasaki disease, scarlet fever.
Strawberry scrotum - multiple sebaceous cysts (They're actually calcified epidermal cysts aka calcinosis cutis)
Strawberry haemangioma!

Speaking of food analogies.. Let's catch em all!

Oat cell carcinoma - Small cell carcinoma of the lung.

Cafe au lait spots - Neurofibromatosis.

We had a chart in pathology department - 'Pathology restaurant'

Apple birefringence - Amyloidosis!

Apple peel sign - Intestinal atresia.

Bread and butter appearance -  Fibrinous pericarditis.

Bread crumbs appearance in complicated cataract!

Honeycomb appearance of lungs.
Interstitial fibrosis.
Also pneumocystis, not sure.

Honey comb appearance of liver too.
Which condition is honey comb liver seen?
Seen in actinomycosis infection of liver. Burkholderia is a gram - bacteria. The honeycomb liver is seen in burkholderia infection....Which causes abcess...It's a radiologic sign!
Woah.

There's nutmeg liver - right heart failure!

Onion skin appearance - Ewings sarcoma!

Another Onion skin appearence seen in?
It's seen in Hyperplastic arteriolosclerosis!

Swiss cheese appearance - Metropathica hemorrhagica.

Also swiss cheese pattern in multiple serpingenous ventricular septal defects in VSD.

What appareance is in caseous necrosis, tuberculosis granuloma?

Cheese like?

Yeah. Here in spain is called: Queso fresco!

Cheesy necrosis in tuberculosis!

Dry cheese appearance in candida growth.

Cottage cheese appearance is found in which pathology?
Histological finding of caseous necrosis e.g in tuberculosis.

Anchovy sauce - Amoebic liver abscess!

Salt pepper appearance in?
EBV.

Salt and pepper skull - Hyperparathyroidism.

Rice water stools - cholera!! :)

Currant jelly sputum in?
Klebsiella pneumonia

Currant jelly stools in?
Intussuception!

So this is obvious - Maple syrup urine in?
Maple syrup urine disease!

Blue berry muffin rash - Congenital rubella.

Mulberry molars - Late congenital syphilis.

Olive shaped mass - Hypertrophic pyloric stenosis.

I know about Peau de orange!
Breast carcinoma.
And why is that?
Blockage of cutaneous lymphatics due to infiltration.
Blockage of lymphatic causes accumulation in the third space so it swells and the point where ligament is attached to the skin becomes pitted. Just like the skin of orange which has many small pits.

What about orange eyes?
Orange eyes are seen in Leptospirosis.

Apple core sign is found in which disease?
Colon cancer
Oesophageal carcinoma
Also a sign of IBD, I think.

What disease have Chicken drumsticks like fingers?
Psoriatic arthritis.

Napkin ring appearance also in colon cancer.

Which disease had grapefruit appearance?
Hyadatidiform mole.

There's chocolate cyst of ovary - endometriosis.

And chocolate agar!

Updated on 28th February, 2015:
A sandwich sign (sometimes known as a hamburger sign) refers to a mesenteric +/- para-aortic nodal mass giving an appearance of a hamburger. Confluent lymphadenopathy on both sides of the mesenteric vessels gives rise to an appearance described as the sandwich sign. The sign is specific for mesenteric lymphoma (typically non-Hodgkin’s)

Sandwich vertebra - Osteoporosis!

Updated on 1st March, 2015:
IkaN, did you get salt and pepper retinopathy on your foodie blog?

Yes, EBV!

Okay, I read that as a part of rubella. Could you explain what exactly happens tho?

Salt-and-pepper fundus with diffuse pigmentary lesions can be the signature of a previous systemic infection that had ocular involvement. Examples include inactive chorioretinal scars secondary to Lyme disease, tuberculosis, syphilis, congenital rubella, toxoplasmosis and bartonellosis.

There's a salt and pepper appearance in skin too! Systemic sclerosis and scleroderma have salt and pepper skin.

I found another salt and pepper term! In osteitis fibrosa cystica, punched out lesions produce a salt and pepper appearance on radiography. Multiple myeloma as well!

Updated on 3rd March, 2015:
Potato tumor: Carotid body tumor
Coconut appearance: Hyatid cyst

Saturday, February 21, 2015

Study group discussion: Fatal familial insomnia, harmful effects of working at night and sleeping during the day

By the way, I saw a video on a very bad disease the other day - Fatal familial insomnia. Caused by prions just like Creutzfeldt Jacob disease.

I know about the disease.. I can't imagine not being able to sleep!

Has a late onset and the patient or rather I say victim does within a few weeks.
It's genetic.. Thalamus, sleep centre is damaged!
Therefore no sleep!
It's progressive, one falls into coma and finally death!
They basically sleep to die!

You can live without sleep for 5 days to a week, I suppose.

I had heard in physiology too.. That mice die if they are awakened before REM sleep chronically.

Even humans have reduced life span if they sleep for less than 4 hrs chronically.

Yes, I had heard someone who survived 2 weeks. He slept for only 4 hours per day

Why would anyone do that to themselves?

Workaholics.
Medical students!
Perfectionists.
Preparing for exams xD
We awesomites!

I sleep more than I should #vacations :P

That is also harmful.

How? =(
I get rebound insomnia though.

Read it in some article.

Ah.

6 to 7 hrs optimum.

Work hard. Sleep tighter.

Btw are there any harmful effects of working at night and sleeping during the day chronically?
I don't know and someone wanted to know!

Something related to messing up the circadian cycle? Because we have a diurnal surge of hormones?

Since all hormones are secreted at night and not sleeping at night disturbs the proper hormonal process... That's the reason people who don't sleep at night are also fat...

So they'd grow fat, that's it?

Anti aging 2, remember?
Serotonin mostly secreted from 11 p.m to 2 a.m and sleep during these is essential!

I found what I was looking for: Symptoms much like jet lag are common in people who work nights or who perform shift work. Because these people's work schedules are at odds with powerful sleep-regulating cues like sunlight, they often become uncontrollably drowsy during work, and they may suffer insomnia or other problems when they try to sleep. Shift workers have an increased risk of heart problems, digestive disturbances, and emotional and mental problems, all of which may be related to their sleeping problems. The number and severity of workplace accidents also tend to increase during the night shift. Major industrial accidents attributed partly to errors made by fatigued night-shift workers include the Exxon Valdez oil spill and the Three Mile Island and Chernobyl nuclear power plant accidents. One study also found that medical interns working on the night shift are twice as likely as others to misinterpret hospital test records, which could endanger their patients. It may be possible to reduce shift-related fatigue by using bright lights in the workplace, minimizing shift changes, and taking scheduled naps.

IkaN, goodjob!

Makes sense.

Is there any treatment for insomnia, if it's familial?

I don't think there is a treatment.. Since your thalamus is damaged, no pharmacotherapy can help you.
It's like in the thalamic pain syndrome, no amount of pain killers can help you!

So true! :(

Somogyi effect and dawn phenomenon in diabetes

So I read a lot of interesting things today and I'm formulating questions based on it.

A person took too much insulin at night and went to sleep. He checks his morning blood sugar levels and it's elevated. Why?

It's because stress hormones were released while he was asleep which caused the hyperglycemia. (This is called Somogyi effect!)

Now, a person took his appropriate dose of insulin at night and went to sleep. He checks his morning blood sugar levels and it's elevated. What happened this time?

There is a normal hormone surge at 7 am (Growth hormone, cortisol, glucagon and epinephrine) which caused the hyperglycaemia. This is called dawn phenomenon.

How will you differentiate Somogyi effect from dawn phenomenon? Why is this clinically relevant?

I guess the person with Somogyi effect will have certain signs and symptoms related to hypoglycemia. For instance, night terrors. Right?

People with hypoglycemia don't wake up but have nightmares.

The 3 am glucose levels to be precise. It is low in Somogyi effect and maybe normal or high in dawn phenomenon. You'll decrease NPH insulin at night in the former and increase the NPH insulin dose in the latter. 

NPH is an intermediate acting insulin. NPH insulin is usually taken at night. Duration of action 7- 14 hours!

In Somogyi, the excess insulin caused hyperglycemia. So you'll decrease the dose.
And similarly, in dawn phenomenon, the inadequate dosing caused the hyperglycaemia, so you'll increase NPH insulin.

If you're under the impression that is inadequate insulin and if you increase the dose of insulin, you can put the patient into a hypoglycemic coma! This is why, recognising Somogyi effect is very important.

I didn't get the management.. How is the adequacy of insulin assessed? If a patient comes with morning hyperglycemia, will you order 3 am glucose levels?

Nope. That would be hectic too. You wanna decrease the dose and see if the patient improves. If the patient doesn't, it means it wasn't the dreaded Somogyi effect and it was just the regular dawn phenomenon, so you can go ahead and increase the dose.

You keep tailoring the dose to suit the patient. 

Study group discussion: Some virology review questions

Hey everyone! I have a major virology exam coming up, would you like to go over some review questions with me? :)

Yes!!!

Great! I'll start:

Yaay!

Heterophile antibodies are positive in which viral infection?

These are multiple choice questions, shall I write the choices?

No, write them only when we can't guess it.

Ok :)

EBV?

Yes!

Which test is positive and is used to diagnose when there is an EBV infection?

Infectious mononucleosis.. Presence of human anti sheep antibodies, I think.

Yes! The test has a specific name though, anyone know it?

Umm.. Monospot test?

Coombs test ??

Neither of those

Would you like the choices?

Okay

Paul-Bunnel Test
Coombs Test
Indirect IFA
Western Blot
ELISA

Paul Bunnell! I forgot that.. Thanks!
Ok, ready for a new question?

Yes!

Which test is used to determine the specific genotype of HPV?
Another question would be, what is the first test you used to check for the existence of an HPV infection?

First test is Pap smear. Correct!

We'll need choices for the genotype - I'm guessing PCR though.

Ok here are the choices:
Consensus PCR
Line Probe Assay
Western Blot
Pap Smear
Latex aglutination

Consensus PCR?

No, I initially thought that too.

I'd say the line probe.

It is LiPA!

Why is that?

It uses the reverse hybridization to id specific  hpv genotypes by detection of specific sequences in the l1 region of the HPV genome.

It is more specific than the PCR

I see.

While we're on the topic of HPV, what are the high risk genotypes? And the most common low risk genotypes?

High risk: 16, 18
Low risk: 4, 6, 11

16 and 18 is usually used in the vaccine as well!

This changes a lot from place to place though, my medical faculty is working on developing a vaccine specially for this area/country

Oh that's great.. I didn't know that thanks.

:) no problem!

You guys want some more questions?

Yes

What is the main cause of non-bacterial gastroenteritis epidemics?

Rotavirus

That is one the choices here, but it's actually not that

Ooh. It's the main cause in India!

Choices?

Rotavirus
Norovirus
Adenovirus
Enterovirus
Astrovirus

Rotavirus usually infects infants and younger children, if I'm not mistaken.

Yup. So it's something else in adults?

Adults aren't really effected, the one we're looking for can infect people from different ages.

It's actually Norovirus!

It is the leading cause of viral gastroenteritis in the world!

Never heard of it :O
Is it the same as Norwalk virus?

Yes! Norwalk virus is a species of this genus. It's responsible for almost 90% of viral gastroenteritis epidemics globally!

Woah. That's a lot.

Norovirus happens in outbreaks, and stays infectious for a long time on surfaces yes?

Yes, exactly.

It's a calcivirus! http://medicowesome.blogspot.in/2014/04/how-i-remember-that-norwalk-virus-is.html

Family : Calcivirus, Genus: Norovirus :)

I'm going to have to leave soon, would you like 1 or 2 more questions?

Yes!

Which one of the viruses listed below, has a non-segmented genome?

Orthomyxovirus
Reovirus
Coronavirus
Arenavirus
Bunyavirus

Coronavirus?

Correct!

Review question: Does anyone know the clinical significance of the segmented genome?

A segmented genome has evolutionary advantages! Like, reassortment!

Allows reassortment and thus new viral strains in mixing vessels. Eg avian influenza.

What is the cause of Roseola?

Human herpes virus 6 or 7

Correct!

Brilliante!

One last question before I leave for now? :)

Yep yep yep

What is the most common cause of bronchiolitis in newborns?

Oh oh I know this.

RSV

Respiratory synctitial virus.

Correct :)

That was good, thanks!

I love random review question sessions!

Do it more often!

I have to go now, my friends are coming over to study! This was great, talk to you soon!

I have hundreds of review questions for my exam! Great! Looking forward to it.

This review question session was held by Fidan :) Thanks!

Friday, February 20, 2015

Study tips: Anxiety for test day

This is my first time talking to anyone I follow on anywhere... Be it twitter or tumblr. I am not very involved in social media, but I guess I am a bystander.

I am messaging you because I am in a bit of a dilemma. I am writing my USMLE step 1 exam in 5 days. I have been studying for it, believe it or not, for 2 years.

In this time, I have been home, my parents looking after me after I had gone to a med school on the island. I suffer from text anxiety... So like in the middle of the exam my brain just gives up, I feel at loss of hope. I just get this overwhelming feeling of failure.

I have bought the exam twice now and my date is scheduled for the last day possible. My parents are just fed up and they want me to get moving with my life. I have inconveninced them.

I have written all the NBMEs and I have never got a score above 300. I study so hard, but I hate to memorize if that makes sense. I have watched all the Kaplan videos, all the DIT videos and I have completed both Q banks. I know everything, but when it comes to route memorization... I can't do it for some reason, because I have this fear of it even is going to stick. I don't know what to do and I hoped some wise words from you might help me. You have some awesome things to say and they helped me lurch back up on a low day. I am literally trying to fly the coop right now.

Hope I am not intruding with my story.

- Email from an awesomite

Hey!

I'm glad you chose to speak to me.

The USMLE step 1 exam is scary. And it gets scarier as it gets closer. I had scheduled it on the last day too! My mum needed to go abroad and I had inconvenienced her. I never scored above 300 either in my NBME. But I got a good score on my step.

I'm telling you this to assure you that this is normal. That many have gone through the feelings you're going through and have made it before you. That you're not alone. That there is always hope.

You made it through various exams as you got here. Let's do this and get done with it. You have studied and you can trust yourself in midst of self doubt. You can do this.

You shouldn't be afraid of consequences. You've given your best shot. You have worked hard. Be confident that it'll work out for you in the best possible way.

Now this is a personal belief - I believe that not all five fingers are the same. Everyone is unique. That you have your own limitations and strengths. So some will score better than you, some won't. Accept it.

Once you have done your preparations well and that there is not one more thing you could've done, you must not worry about the results. Everything happens for the best. There's a good reason behind why things don't work out the way we want to - we don't see it right now but it doesn't mean it's not there. So I'm content with the results even before they come out.

I also believe that scores don't matter. That you can do wonderful things with your life without the scores. Yes, a good score will help you feel good about yourself and open doors - but a fear of a bad score shouldn't fill you with despair. The little anxiety you get should help you work hard, not come in your way.

I understand your memorization dilemma. Remembering things comes to us with repetition whether we like it or not.

There's not much you can do 5 days before the exam. But if there are certain high yield facts that you know you have not memorized - You can store facts in your short term memory and then forget them forever. We are capable of it. So you can't memorize everything, but please do what you can!

On the exam day: Focus on the question. Don't let your mind wander - go into past disappointments or future failures. Stay there. Read the question. What's the best answer to this question? Hmm.. This is an interesting one. What could the answer to this be? What are they trying to tell me in this question? Oh I don't know about this - will read about it later. The hints they're giving me are awesome. Ooh. This is a tricky one! I likey! I love medicine and it's enough. I'm living my passion. I'm lucky to be here. And that positivity, I tell you, will pull you through and give you hope.

I'm glad the things I said helped you. I hope this does too.

You're not intruding, be free to message me whenever you like (:

I understand that you might not get the time to reply after reading this - so I'll hear from you after the step. All the very best to you. I'll pray that you do well.

Love,
IkaN
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