tag:blogger.com,1999:blog-40539923294045470522024-02-20T07:07:34.361+06:00Medicine MCQMedicine MCQs of MRCP part 1, MRCS, MRCPCH, MRCOG, Plab, USMLE, AMC, FCPS, MD, MS for higher medical studyUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comBlogger41125tag:blogger.com,1999:blog-4053992329404547052.post-26734373609028263932013-01-20T02:11:00.000+06:002013-01-20T02:11:06.714+06:00MRCP and FCPS Part 1 MCQ 47A 15-year-old young boy with short stature, bony aches and pains, and learning difficulties comes to the clinic for review.<br />
<br />
The most marked abnormality on examination is a short fifth digit on each hand.<br />
Investigations reveal a calcium of 2.05 mmol/l (2.20-2.61), and a phosphate of 1.8 mmol/l (0.8-1.5).<br />
<br />
Which of the following abnormalities is most likely to be present?<br />
<br />
a) Alpha subunit G protein mutation<br />
b) Beta subunit G protein mutation<br />
c) Gamma subunit G protein mutation<br />
d) Renal tubular disorder<br />
e) Vitamin D receptor mutation<br />
<br />
<a name='more'></a>Answer<br />
a) Alpha subunit G protein mutationUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-10371116875859448182013-01-20T01:53:00.000+06:002013-01-20T01:53:53.955+06:00MRCP and FCPS Part 1 SBA Question 46In the treatment of Migraine somatriptin is an example of <br />
<br />
a) Betablocker<br />
b) Alphablocker and a partial 5-HT2 agonist<br />
c) Specific 5-HT1 agonist<br />
d) 5-HT2 antagonist<br />
e) TCA<br />
<br />
<a name='more'></a>Answer<br />
c) Specific 5-HT1 agonistUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-8175489394954531732011-07-11T01:36:00.000+06:002011-07-11T01:36:00.185+06:00FCPS & MRCP Part-1 MTF Questions | Myocardial blood flow #1Myocardial blood flow to the left ventricle increases during:<br />
<br />
(a) Early Systole<br />
(b) Myocardial hypoxia<br />
(c) Adenosine infusions<br />
(d) Stimulation of sympathetic nerves to the heart<br />
(e) Arterial hypertention<br />
<br />
<a name='more'></a>Answer:<br />
(a) F<br />
(b) T<br />
(c) T<br />
(d) T<br />
(e) TUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-16121760696451724562011-07-09T22:55:00.000+06:002011-07-09T22:51:26.181+06:00FCPS & MRCP Part-1 MTF Questions | Body fluid #1<b>Extracellular fluid</b> differs from <b>intracellular fluid</b> in that is:<br />
<br />
(a) Volume is greater<br />
(b) Tonicity is lower<br />
(c) Aninos are mainly inorganic<br />
(d) Sodium:Potassium molar ratio is higher<br />
(e) <b>pH</b> is lower<br />
<br />
<a name='more'></a>Answer:<br />
(a) F<br />
<div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">
(b) F</div>
<div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">
(c) T</div>
<div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">
(d) T</div>
<div style="margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px;">
(e) <b>F</b></div>
<br />
<br />
<br />University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-15866363276009514102011-07-08T13:11:00.000+06:002011-07-08T13:11:00.411+06:00FCPS & MRCP Part-1 MTF Question | Bronchial asthma<b>Bronchial asthma</b> is likely to be relieved by:<br />
<br />
(a) Stimulation of cholinergic receptors<br />
(b) Stimulation of beta adrenoceptors<br />
(c) Histamin aerosols<br />
(d) Drugs which stabilize mast cell membranes<br />
(e) Glucocorticoids<br />
<br />
<a name='more'></a>Answer:<br />
(a) F<br />
(b) T<br />
(c) F<br />
(d) T<br />
(e) TUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-62599783078387241952010-11-14T12:57:00.000+06:002010-11-14T12:57:11.749+06:00FCPS & MRCP Part-1 MTF Question #27<b>Congenital Heart diseases</b> with right to left shunt:<br />
<br />
a) VSD<br />
b) TOF<br />
c) Tricuspid atresia<br />
d) Hypoplasia of left ventricle<br />
e) Ebstein's disease<br />
<a name='more'></a><br />
<br />
<b>Answer:</b><br />
a) F<br />
b) F<br />
c) T<br />
d) F<br />
e) TUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-41700008054129778762010-11-13T20:18:00.000+06:002010-11-13T20:18:51.312+06:00FCPS & MRCP Part-1 MTF Question #26<b>Cardiac</b> <b>myocyte</b>:<br />
<br />
a) Structural syncytium<br />
b) Rich in capillary than skeletal muscle<br />
c) A-J junction<br />
d) 80% mitochondria<br />
e) Oxidative phosphorylation in source of energy<br />
<a name='more'></a><br />
<br />
<b>Answer</b>:<br />
a) F<br />
b) T<br />
c) T<br />
d) F<br />
e) TUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-65364448172640583592010-11-13T20:01:00.000+06:002010-11-13T20:01:28.511+06:00FCPS Part-1 MTF Question #25In Case of haemodynamic effects of respiration:<br />
<br />
a) JVP falls in inspiration<br />
b) BP falls in expiration<br />
c) HR accelerate during expiration<br />
d) 2nd heart sound fuse with inspiration<br />
e) Inspiration prolongs RV injection<br />
<a name='more'></a><br />
<b>Answer:</b><br />
a) T<br />
b) T<br />
c) F<br />
d) F<br />
e) TUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-40777080003487573872010-10-29T22:05:00.001+06:002010-10-29T22:07:48.441+06:00MRCP Part 1 MCQ question #24A young girl returns from a trip to India with a protracted history of watery diarrhoea.<br />
Giardiasis is suspected but three stool samples are negative.<br />
What is the best investigation to confirm Giardia as a diagnosis?<br />
<br />
a) CT abdomen<br />
b) Rectal biopsy<br />
c) Serum IgM Giardia antibodies<br />
d) Small intestine biopsy<br />
e) Stool microscopy <br />
<br />
Answer<br />
<a name='more'></a>d) Small intestine biopsy<br />
<br />
<b>Explanation:</b><br />
Giardia may be difficult to diagnose from stool samples alone. Concentration techniques and optimising sample preparation may improve stool sample yield.<br />
<br />
However, parasitic antigen detection in stool is at least as sensitive and specific as good microscopic examination of stool, and maybe easier to perform.<br />
<br />
In this case detection of Giardia may be achieved by sampling of duodenal fluid, or small bowel biopsy.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-31570866339468223412009-10-15T04:06:00.003+07:002010-04-24T04:43:27.373+06:00MRCP Part 1 MCQ question #23<script type="text/javascript">
window.google_analytics_uacct = "UA-9092071-3";
</script><br />
A 24 year old in-patient has chronic diarrhea as well as a large draining fistula. She complains of nausea and anorexia and of marked weakness. On physical examination her blood pressures is 120/80 mmHg. When she stands up, she feels very dizzy and her blood pressure is 110/70. Her heart rate is 100. She weighs 50 kg. When the intern pinches her forehead skin, it stands up like a tent. Her eyes are sunken. Her laboratory tests are pending. The intern suspects that she has extracellular fluid volume depletion. What volume of water would be expected in the extracellular compartment of a healthy 50 kg female?<br />
<br />
a) 30 liters <br />
b) 2.5 liters <br />
c) 10 liters <br />
d) 20 liters <br />
e) 7.5 liters<br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> c) 10 liters <br />
<br />
Explanation<br />
Body water distribution can be calculated using the rule of thirds. 60% of an average persons weight is water. Of this, 2/3 is intracellular and 1/3 is extracellular. Of the extracellular water, 2/3 is interstitial and 1/3 is plasma. In a 50 kg person, there will be 30 kg of water (60%). This will be approximately 30 liters. Of this 1/3 is extracellular or 10 liters.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-11549214120579773652009-10-15T04:02:00.000+07:002009-10-15T04:06:41.930+07:00MRCP Part 1 MCQ question #22what is the main mode of action of beta-blockers in controlling hypertension ?<br />
<br />
a) decrease cardiac input<br />
b) slow the heart rate <br />
c) increase the cardiac force of contraction<br />
d) increase cardiac output <br />
e) decrease plasma volume<br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b> <br />
<a name='more'></a> b) slow the heart rate<br />
<br />
Explanation<br />
Beta-blockers act by blocking the action of noradrenaline at b adrenoceptors throughout the circulatory system and elsewhere. Their major effect is to slow the heart rate and reduce its force of contraction. beta-blockers also cause some reduction in renin release and central sympathetic tone.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-56423905418657081042009-10-15T03:59:00.000+07:002009-10-15T04:03:10.969+07:00MRCP Part 1 MCQ question #21Elderly woman develops sudden onset of a right sided partial ptosis and a divergent squint , there is no pupil asymmetry. When asked to raise both arms and she has weakness of the left arm in comparison with the right arm. The likely cause is : <br />
<br />
a) pontine lesion<br />
b) lesion at cerebellpontine angle<br />
c) Weber's syndrome <br />
d) mid-brain vascular lesion<br />
e) diabetic third nerve palsy<br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> d) mid-brain vascular lesion<br />
<br />
Explanation<br />
This patient has a right sided partial ptosis and a divergent squint due to pupil sparing third nerve (oculomotor) palsy�that is, there is no pupil asymmetry. The patient also has left hemiparesis . <br />
The likely cause is a crossed hemiplegia due to a vascular lesion affecting the right mid-brain involving the right third nerve and the corticospinal tract at the level of the cerebral peduncles. <br />
The third nerve nucleus has two components in the mid-brain: the Edinger-Westphal nucleus and the motor oculomotor nucleus. <br />
The Edinger-Westphal nucleus is situated in the upper mid-brain and gives rise to the preganglionic parasympathetic neurones responsible for the pupilloconstrictor fibres. <br />
The motor third nucleus is situated in the lower mid-brain and gives rise to the motor fibres supplying the extraocular muscles. <br />
The pupilloconstrictor fibres and those innervating the levator palpebrae superioris lie superficially in the trunk of the nerve. <br />
The sudden occurrence of the pupil sparing third nerve palsy on the right side and hemiplegia on the left side indicate a mid-brain vascular lesion for the clinical manifestations of the patient. Pupil sparing third nerve palsy could occur both intra-axially (within the mid-brain) or extra-axially, that is, in the nerve trunk. Pupil sparing third palsy is a recognised complication in some patients with diabetes mellitus, and in ischaemic damage of the nerve <br />
The classical description of the Weber's syndrome includes ipsilateral third nerve palsy with mydriasis and crossed hemiplegia. However, the patient described here is similar to classical Weber's syndrome but the pupils were spared.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-17540702200736192572009-10-15T03:57:00.000+07:002009-10-15T04:07:30.788+07:00MRCP Part 1 MCQ question #24A selective, reversible alpha-1 blocker which may be used in the pre-operative preparation of patients with phaeochromocytoma<br />
<br />
a) phenylephrine <br />
b) prazosin <br />
c) clonidine <br />
d) yohimbine<br />
e) idazoxan<br />
<br />
<b><span style="color: #0b5394;">Answer:</span> </b><br />
<a name='more'></a>b) prazosin<br />
<br />
Explanation<br />
Prazosin is a selective, reversible alpha-1 blocker, and has been used to manage hypertension, and even in pre-operative preparation of patients with phaeochromocytoma. It should not be used in heart failure. Other similar agents include doxazosin, terazosin. <br />
Agents such as yohimbine and idazoxan are Alpha-2 blockers and are mainly experimental curiosities used to analyse alpha receptor subtypes.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-78907865349598279742009-10-15T03:55:00.000+07:002009-10-15T03:55:16.234+07:00MRCP Part 1 MCQ question #20A 28 patient with a 10 year history of bronchial asthma presents with footdrop, he is noted to have purpura and painful skin nodules, the chest radiograph shows several peripheral nodules, these features are characteristic of: <br />
<br />
a) Leoffler's syndrome<br />
b) Idiopathic Hypereosinophilic Syndrome<br />
c) chronic eosinophilic pneumonia<br />
d) Churg-Strauss syndrome<br />
e) Allergic bronchopulmonary aspergillosis <br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a>d) Churg-Strauss syndrome<br />
<br />
Explanation<br />
These features are suggestive of Churg-Strauss syndrome, also known as allergic granulomatosis. Almost all patients with allergic granulomatosis and angiitis have a strong history of atopic allergy with preexisting bronchial asthma for an average of 5 to 10 years before diagnosis of the vasculitis. Patients present with fever, shortness of breath, and a variety of complaints related to skin and nerve involvement (e.g., purpura, painful skin nodules, skin infarction, footdrop, wristdrop, or painful neuropathy). Myocardial involvement occurs in a minority of patients but on occasion can dominate the clinical presentation. Wheezing is common. Clinically significant renal involvement is uncommon. In 25% of cases, the chest radiograph shows peripheral infiltrates or nodules that seldom cavitate. Pleural effusion, pericardial effusion, or both may occur with or without infiltrates. Churg-Strauss syndrome, though rare, most often occurs in patients with bronchial asthma. There is an association between Churg-Stauss syndrome and treatment of asthma with leukotriene inhibitorsUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-64043625145239578072009-10-15T03:52:00.000+07:002009-10-15T03:52:57.748+07:00MRCP Part 1 MCQ question #19Muscarinic Acetylcholine receptors are selectively blocked by : <br />
<br />
a) atropine<br />
b) C5<br />
c) muscarine<br />
d) curare and C6<br />
e) nicotine<br />
<br />
<b>Answer:</b><br />
<a name='more'></a> a) atropine<br />
<br />
Explanation<br />
Acetylcholine (ACh) is the chemical neurotransmitter for both peripheral and central cholinergic receptors. These cholinoceptive sites are further divided into nicotinic and muscarinic ACh receptors because of its relative specificity of action toward cholinomimetic [L(+) muscarine, S(-) nicotine] and cholinergic blocking agents (d-tubocurarine, atropine). Nicotinic ACh receptors are selectively stimulated by nicotine and blocked by curare, C6 and C10. Muscarinic ACh receptors are activated by L (+) muscarine and blocked by atropine. It should be noted that nicotine acts at nicotinic sites to produce stimulation in low doses blockade in high doses.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-88345563168430719472009-10-15T03:51:00.000+07:002009-10-15T03:51:17.679+07:00MRCP Part 1 MCQ question #18An infarct involving the middle cerebellar peduncle is likely to be secondary to occlusion in the territory of the : <br />
<br />
a) the Posterior Cerebral Artery <br />
b) the Basilar Artery<br />
c) The superior cerebellar artery<br />
d) The anterior inferior cerebellar artery<br />
e) The posterior inferior cerebellar artery<br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> d) The anterior inferior cerebellar artery<br />
<br />
Explanation<br />
The AICA territory includes the middle cerebellar peduncle, fifth nerve sensory nucleus and tract, seventh nerve and nucleus, eighth nerve, vestibular nuclei and the descending sympathetic tracts. AICA-related lateral Pontine infarction produces a syndrome similar to Wallenberg's; but instead of hoarseness, palatal weakness and loss of taste, there is ipsilateral facial paralysis and deafness.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-5827191191306533762009-10-15T03:47:00.000+07:002009-10-15T03:47:49.319+07:00MRCP Part 1 MCQ question #17Aspirin inhibits platelet function by acetylating : <br />
<br />
a) prostaglandin reductase <br />
b) thromboxane synthetase<br />
c) cyclooxygenase <br />
d) succinic dehydrogenase <br />
e) NADH-cytochrome-c-reductase <br />
<br />
<b>Answer:</b><br />
<a name='more'></a> c) cyclooxygenase<br />
<br />
Explanation<br />
Aspirin inhibits platelet function by permanently acetylating the cyclooxygenase that forms prostaglandins<br />
<br />
Aspirin suppresses the production of both prostaglandins and thromboxanes. This happens because cyclooxygenase, an enzyme that participates in the production of prostaglandins and thromboxanes, is irreversibly inhibited when aspirin acetylates it. This makes aspirin different from other NSAIDS (such as diclofenac and ibuprofen), which are reversible inhibitors. <br />
More recent work has shown that there are at least two different types of cyclooxygenase: COX-1 and COX-2. Aspirin inhibits both of them. Newer NSAID drugs called COX-2 selective inhibitors have been developed that inhibit only COX-2, with the hope for reduction of gastrointestinal side-effects.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-33620649586618573032009-10-15T03:40:00.000+07:002009-10-15T03:40:06.513+07:00MRCP Part 1 MCQ question #16A carcinogen known to cause hepatocellular carcinoma <br />
<br />
a) aniline dyes<br />
b) Aflatoxins<br />
c) Tamoxifen <br />
d) Hydroquinone <br />
e) asbestos<br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> b) Aflatoxins<br />
<br />
Explanation<br />
When certain types of fungus grow on food, they produce minute amounts of toxins called mycotoxins. Most fungi-produced mycotoxins are harmless, and even helpful. For example, the antibiotic penicillin came from a fungus, and it is a mycotoxin. Some of these fungi (primarily Aspergillus flavus) produce the very lethal mycotoxins called aflatoxins. Aflatoxins are remarkably potent, often causing disease even when ingested in minute amounts. Aflatoxins can cause disease throughout the body, but are most commonly known for causing acute or chronic liver disease and liver cancer.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-19654740266995024432009-10-15T03:36:00.000+07:002009-10-15T03:40:41.216+07:00MRCP Part 1 MCQ question #15A sexually active patient presents with a pharyngitis , diarrhea and lymphadenopathy three weeks following exposure to an individual infected with HIV. <br />
What is the test of choice for HIV in acutely infected individuals during the short period between infection and seroconversion? <br />
<br />
a) viral lysate EIA<br />
b) Fluoxetine<br />
c) p24 antigen <br />
d) Radioimmunoprecipitation assay<br />
e) Polymerase chain reaction <br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b> <br />
<a name='more'></a> c) p24 antigen<br />
<br />
Explanation<br />
HIV infection should always be kept in mind when faced with a sexually active patient with lymphadenopathy, in particular the acute seroconverting illness as previously mentioned. This syndrome occurs on average 6 weeks after exposure in about half of all individuals infected with HIV. Symptoms often consist of pharyngitis, fever, diarrhea, maculopapular, truncal rash, and mucocutaneous ulcers in addition to lymphadenopathy. Of critical importance, these individuals will typically test negative for HIV at the time of illness, and so it is essential to send a p24 antigen if possible, and to retest for HIV 44 weeks later.<br />
An alternative approach to diagnosing HIV-1 infection is to detect the presence of viral antigens in the blood. The best antigen for this purpose is the capsid antigen, p24, a viral structural protein that makes up most of the virus core particle. Because high titers of p24 antigen are present in the serum of acutely infected individuals during the short period between infection and seroconversion, p24 antigen assays are useful in the diagnosis of primary HIV-1 infection.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-33758631826430220132009-10-15T03:32:00.000+07:002009-10-15T03:32:37.729+07:00MRCP Part 1 MCQ question #14A fifty-five year old with chronic cardiac failure is on treatment with digoxin and the a loop diuretic.<br />
This combination is likely to cause digoxin toxicity by the following reason:<br />
<br />
a) this combination increases the half-life of digoxin <br />
b) diuretics decrease potassium levels <br />
c) frusemide and digoxin interact to form a poisonous compound<br />
d) digoxin is a competitive inhibitor of frusemide<br />
e) the above statement is wrong, loop diuretics are not a recognised cause of increased digoxin toxicity <br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> b) diuretics decrease potassium levels<br />
<br />
Explanation<br />
Loop and thiazide diuretics decrease potassium and magnesium levels, predisposing patients taking both a diuretic and digoxin to an increased risk of digoxin toxicity. Also, amphotericin B (Fungizone), an antifungal, has an additive potassium-lowering effect when given with a thiazide or loop diuretic. Thiazides may increase the blood levels of lithium. Bile acid sequestrants cholestyramine (Questran) and colestipol (Colestid) decrease the absorption of thiazide diuretics when given concomitantly, while nonsteroidal anti-inflammatory drugs such as indomethacin (Indocin) may decrease the therapeutic effects of both the loop and thiazide diureticsUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-69051258732611460722009-10-15T03:29:00.000+07:002009-10-15T03:29:55.770+07:00MRCP Part 1 MCQ question #13Marfan syndrome is associated with defective encoding of <br />
<br />
a) collagen<br />
b) elastin<br />
c) fibrillin<br />
d) elastin <br />
e) laminin<br />
<br />
<b><span style="color: #3d85c6;">Answer:</span></b><br />
<a name='more'></a> c) fibrillin<br />
<br />
Explanation<br />
Marfan syndrome is an autosomal dominant disorder that has been linked to the FBN1 gene on chromosome 15. FBN1 encodes a protein called fibrillin, which is essential for the formation of elastic fibres found in connective tissue.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-73610183032808208622009-10-15T03:27:00.000+07:002009-10-15T03:27:45.676+07:00MRCP Part 1 MCQ question #12A 40 yrs old man was diagnosed to have a pheochromocytoma tumor. Staging investigations showed the tumour to be operable. What definite therapy will the patient most likely be started on a few weeks before the surgery: <br />
<br />
a) verapamil <br />
b) sodium nitroprusside <br />
c) phenoxybenzamine <br />
d) nitroglycerine <br />
e) none of the above<br />
<br />
<b><span style="color: #3d85c6;">Answer:</span></b><br />
<a name='more'></a> c) phenoxybenzamine <br />
<br />
Explanation<br />
Pheochromocytoma is a tumor of the adrenal medulla.The adrenal medulla is responsible for the secretion of catecholamines(epinephrine & norepinephrine) in the body. due to the tumor, excess levels of catecholamines(CAs) are seen in the body. The main effect of the high levels of circulating catecholamines is episodes of hypertension due to peripheral vasoconstriction. The patient can have sudden episodes of very high blood pressure which can result in stroke, myocardial infarction, left ventricular failure etc.The treatment of choice for the tumor is surgical removal of the tumor. Phenoxybenzamine is the drug commonly used to prepare the patient for a pheochromocytoma surgery (startde 6wks in advance). Phenoxybenzamine belong to the class of beta-haloalkylamines and is a non selective alpha adrenoreceptor blocker. It cyclizes spontaneously in the body giving rise to a highly reactive ethylenminium intermediate which binds with alpha adrenoreceptors for a period of 3-4 days.Phenoxybenzamine is used to prepare a phechromocytoma patient for surgery because i) due to excess to excess circulating CAs there is peripheral vasoconstriction which causes the high BP. treatment with an alpha blocker produces peripheral vasodilatation and pooling of blood resulting in a decrease in BP. ii) handling of tumor during surgery causes marked outpouring of of CAs in blood causing sudden intra-operative rise in BP. this can be prevented if phenoxybenzamine has been given earlier. Verapamil though a commonly used anti hypertensive drug is not used as it is a calcium channel blocker and would not decrease the BP due to catecholamine excess. Sodium nitroprusside is a drug used in hypertensive emergency and is not useful to control the BP for a prolonged period before the surgery. It is also not very useful intraoperatively. Nitroglycerine is an anti-angina drug and not useful in controlling hypertension.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-3655124514524560332009-10-15T03:24:00.000+07:002009-10-15T03:24:36.021+07:00MRCP Part 1 MCQ question #11An 18-year-old girl has dull retrosternal pain and shortness of breath. On examination she has a heaving apical pulse, an apical systolic thrill and a short mid-diastolic rumbling murmur. The most likely diagnosis is <br />
a) mitral insufficiency <br />
b) aortic stenosis <br />
c) pericarditis <br />
d) tricuspid incompetence <br />
e) costochondritic pain<br />
<br />
<b>Answer:</b><br />
<a name='more'></a> a) mitral insufficiency<br />
<br />
Explanation<br />
In severe mitral insufficiency , signs of chronic heart failure are noted. The heart is enlarged, with a heaving apical left ventricular impulse and often an apical systolic thrill. The 2nd heart sound may be accentuated if pulmonary hypertension is present. A 3rd heart sound is usually prominent. A pansystolic murmur is heard at the apex radiating to the axilla. A short mid-diastolic rumbling murmur is caused by increased blood flow across the mitral valve as a result of the insufficiencyUniversity Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-200830118880698022009-10-15T03:18:00.000+07:002009-10-15T03:18:42.952+07:00FCPS and MRCP Part 1 MCQ question #10A patient with symptomatic WPW syndrome undergoes an intracardiac electrophysiological Study and is found to have a reciprocating tachycardia using the accessory pathway for the anterograde conduction and the normal AV conduction system for retrograde conduction. This is best described as : <br />
<br />
a) Orthodromic tachycardia<br />
b) atrial fibrillation<br />
c) supraventricular tachycardia<br />
d) atrial flutter <br />
e) Ventricular tachyarrhythmias <br />
<br />
<b><span style="color: #0b5394;">Answer:</span></b><br />
<a name='more'></a> e) Ventricular tachyarrhythmiasExplanation<br />
The exact nature of the prexcitation syndrome is assessed. Most of the WPW syndrome are related to a atrioventricular accessory connection or Kent bundle : the degree of prexcitation increases during premature atrial stimulation until the refractory period of accessory pathway is reached, because the conduction time does not change in accessory pathway with the shortening of atrial cycle length while it increases in the AV node. <br />
Rarely the WPW syndrome is related to a nodoventricular accessory pathway or Mahaim bundle and the degree of preexcitation remains unchanged during premature atrial stimulation. <br />
- The accessory pathway refractory period depends on the driven cycle length. Refractory period of the accessory pathway decreases as the driven cycle length shortens.. <br />
- Beta adrenergic stimulation results in shortening of the anterograde refractory period of the accessory pathway and an increase in ventricular rates during atrial pacing and atrial fibrillation. <br />
Isoproterenol test was also previously used to verify the efficacy of antiarrhythmic drug before the era of catheter ablation of accessory pathway. The loss of efficacy of some antiarrhythmic drugs was demonstrated after isoproterenol administration. <br />
- Atrial fibrillation is easily induced during intracardiac studies by salvos of rapid atrial stimulation and is not specific. The induction of an atrial fibrillation by intracardiac programmed stimulation is obtainedin 45% in asymptomatic patients and in 75 % of patients with only documented reentrant tachycardia, atrial fibrillation is induced in 95 % of those with documented atrial fibrillation. The important variations of the incidence of induced atrial fibrillation depends on the technique of programmed stimulation, on the interpretation of the duration of induced arrhythmia and on the use of isoproterenol infusion or other means to reproduce the effects of adrenergic stimulation. <br />
The induction of an atrial fibrillation during transesophageal pacing has a best clinical significance :<br />
The incidence of induction of atrial fibrillation also depends on the presence of an associated heart disease and the age of the patient : the induction of atrial fibrillation is rarely noted in children younger than 10 years, is induced in 20 % of teenagers and adults without heart disease and becomes relatively frequent in elderly <br />
- Ventricular tachyarrhythmias also are easily induced in asymptomatic or symptomatic patients by programmed ventricular stimulation and are not specific in patients with WPW syndrome : the induction of a ventricular fibrillation is noted in 4 % of WPW syndrome and the induction of nonsustained multiform ventricular tachycardia in 37 % of them. <br />
- Antidromic tachycardia which is a reciprocating tachycardia using the accessory pathway for the anterograde conduction and the normal AV conduction system for retrograde conduction, is a rare finding (5%), more frequently noted in young patients with a good retrograde normal VA conduction or in patients with several accessory pathways and seems more frequent in patients at risk of rapid arrhythmias. <br />
- Orthodromic tachycardia which is a reciprocating tachycardia using the normal AV conduction system for the anterograde conduction and the accessory pathway for the retrograde conduction, is rarely induced in asymptomatic patients (< 10%) , but represents the most frequent tachycardia of symptomatic patients complaining tachycardia and palpitations (90 %).University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.comtag:blogger.com,1999:blog-4053992329404547052.post-70737200389603815752009-10-15T03:14:00.000+07:002009-10-15T03:14:28.219+07:00FCPS and MRCP Part 1 MCQ question #9A patient suffering from hemochromatosis classically presents with the following triad:<br />
<br />
a) micro-nodular liver cirrhosis, iron deficiency anemia & diabetes mellitus <br />
b) micro-nodular liver cirrhosis, diabetes mellitus & bronze pigmentation of skin <br />
c) diabetes mellitus, sickle cell anemia, bronze pigmentation of skin <br />
d) micro-nodular liver cirrhosis, diabetes mellitus & sickle cell anemia <br />
e) micro-nodular liver cirrhosis, Kayser-Fleischer rings & diabetes mellitus<br />
<br />
<b>Answer:</b><br />
<a name='more'></a> b) micro-nodular liver cirrhosis, diabetes mellitus & bronze pigmentation of skin <br />
<br />
Explanation<br />
Hemochromatosis is a condition caused by excessive iron accumulation in the body most of which is deposited in the parenchymal cells of various organs particularly liver and pancreas. The excess iron deposition in the parenchymal cells of various organs leads to dysfunction and ultimate failure of these organs. The organs most commonly affected are the liver and the pancreas. Liver undergoes micro-nodular cirrhosis due deposition of iron in the periportal hepatocytes and in pericanalicular lysosomes. Bile duct epithelium and kupffer cell pigmentation is less marked. Pancreas becomes intensely pigmented, has interstitial fibrosis and parenchymal atrophy. Iron deposits are found in both acinar and islet cells. This responsible for pancreatic failure and development of diabetes mellitus. The intensity of iron staining in the pancreatic islets correlates with occurrence and severity of diabetes. Bronze pigmentation of skin is due to the deposition of iron in the dermal macrophages and fibroblasts.So as per the above explanation a person suffering from hemochromatosis will present with a triad of micro-nodular liver cirrhosis, diabetes mellitus and bronze pigmentation of the skin. therefore the correct answer is B A,C,& D are not the correct answers because anemia-- sickle cell or iron deficiency is not a manifestation of hemochromatosis E is also incorrect because Kayser-Fleischer ring is seen in Wilson's disease and not in hemochromatosis.University Bloghttp://www.blogger.com/profile/04852320254860836264noreply@blogger.com