August 03, 2010

MRCP 2 Question 20

Mike comes into the office complaining of pain in his chest that comes and goes when he is emotionally distressed. Mike is 55 years old with an intracranial tumor.

Further review of the ECG reveals a 2nd degree heart block.

What is the best treatment for this patient:

a) Nitroglycerin
b) Propranolol
c) Nifedipine
d) Verapamil
e) None of the above







ANSWER
The correct answer is C

Explanation

Mike has a list of problems. First he has an intracranial tumor. Second, he is complaining of chest pains that occurs when emotionally disturbed. This is a typical sign of variant angina, also known as prizemetal angina. He also has a 2nd degree heart block.

Therefore, the list of the problems that Mike has are is as follows: 1. Variant angina; 2. Intracranial tumor; 3. 2nd degree heart block.

When dealing with angina we have to understand the cause of the underlying problem. Basically, angina is pain in the chest which is referred pain from the heart. It is a result of decrease in oxygen supply to the heart.

In exertional angina, the heart is putting in a lot of work and it requires more oxygen than what it's supplied with. When looking at the coronary arteries, one will find atherosclerotic plaques covering the intima of these vessels.

In variant angina, the coronary vessels are spastic. The spasticity is triggered by an emotional stress.
Atherosclerosis is not directly related to variant angina.

To treat each of these two problems we have two different approaches.

To treat variant angina we have to relax the coronary vessels. We can use nitroglycerin, but it would be of no good to Mike. Mike has an intracranial tumor. Nitroglycerin increases intracranial pressure, thus making Mike's life more miserable.

We can also use Beta blockers or verapamil, a calcium channel blocker. This is not true in Mike's situation because he has a 2nd degree heart block. Both will agrevate it.

We can use nifedipine. This is because it has an action on calcium channels of arteries more than on the heart. It has negligible effect on the heart. So it vasodilates Mike's coronary vessels without aggravating any of his existing problems.

Therefore, the correct is answer is choise C.

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