Showing posts with label MBBS. Show all posts
Showing posts with label MBBS. Show all posts

Friday, August 4, 2023

Threshold for surgical repair of thoracic aortic aneurysm in patients with Marfan syndrome mnemonic

What is the threshold for surgical repair of thoracic aortic aneurysm in patients with Marfan syndrome? 

5 cm

Marfan, MarFIVE

The threshold for surgical repair in patients with Marfan syndrome is an external diameter of 5 cm. Factors that will prompt repair at a diameter <5 cm include rapid growth of >0.5 cm in 1 year, family history of aortic dissection at a diameter <5 cm, or the presence of significant aortic regurgitation.

Sunday, December 25, 2022

Transposition of the Great Arteries: D-TGA & L-TGA (congenitally corrected TGA) mnemonic

Here's a mnemonic I made:

D the arteries. 

And L flipped 45 degrees counter clock wise looks like a V for ventricles so ventricles are transpositioned. Ventricles also have C that reminds me it's congenitally corrected. 

That's all! 

-IkaN (Nakeya Dewaswala) 

Thursday, July 7, 2022

Low voltage criteria on ECG mnemonic

Entire amplitude of the QRS (R + S wave) must be < 5mm in all limb leads or < 10mm in all precordial leads. How do I remember this? Mnemonic!​

- IkaN (Nakeya Dewaswala)

Monday, May 30, 2022

Sunday, January 2, 2022

MCQ: Carbamazepine

Q1) Which of the following statements is true about carbamazepine:-
A) It is indicated in complex partial seizures.
B) It is an enzyme inhibitors
C) It can cause megaloblastic anaemia
D) It is the drug of choice for status epilepticus.


So, the answer to the above question is an option 
A) It is indicated in complex partial seizures.

Let's get started with Carbamazepine:-
It is an antiepileptic drug that acts by lengthening the inactivated state of the Na+ channel. 
1) DOC for Partial seizure/trigeminal neuralgia.
2) Bipolar disorder.
3) Acute mania
4) GTCS.

Let's rule out other options:-
Option B) It's an enzyme inducer. It is a substrate as well as inducer for CYP3A4 and CYP2C9. Oxcarbazepine is a less powerful CYP enzyme inducer.

Option C) Carbamazepine causes agranulocytosis or aplastic anaemia and not megaloblastic anaemia.

Other side effects include:
1) Hyponatremia: Delayed and more common in the elderly. Risk is higher in Oxcarbazepine.
2) Hypersensitivity
4) Hepatoxicity 
3) Steven Johnson syndrome (Associated with HLA-B 1502 gene)
4) Ataxia 
4) Blurred vision/ Diplopia 
For the last two side effects, we need TDM for adjusting the dose. Remember, Ataxia and Blurred vision is not a Idiosyncratic reactions.

Let's do questions related to Carbamazepine!

Q1) What adverse effect is risked to ongoing valproate therapy?


Q2) A cancer patient is on anticancer drugs (vincristine etc) and develops multiple episodes of seizures, refractory to diazepam and lidocaine. Blood tests show elevated ADH and euvolemic hyponatremia. Which drug can be used to treat this patient?

- You can't use Carbamazepine because it causes increase sensitivity of renal tubules to ADH levels. 
In this case, we use Phenytoin which causes a decrease in ADH secretion and corrects hyponatremia.