Friday, February 27, 2015

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.

Thursday, February 26, 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.


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!

Sunday, February 22, 2015

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.