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.
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.
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.
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!
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.
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.
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!
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.
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.
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!
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!
