MSRA Core Knowledge and Fundamentals 3

Question 1

Which of the following best describes the mechanism of action of low molecular weight heparin (LMWH)?

Accepted Answer

Primarily inhibits factor Xa via antithrombin

Answer

LMWH preferentially enhances antithrombin's inhibition of factor Xa compared to unfractionated heparin, which inhibits both Xa and IIa.

Question 2

A 45-year-old woman presents with weight gain, cold intolerance, dry skin, and bradycardia. TSH is 12 mU/L and free T4 is low. What is the diagnosis?

Accepted Answer

Primary hypothyroidism

Answer

Elevated TSH with low free T4 combined with classic symptoms confirms primary hypothyroidism.

Question 3

A 28-year-old man presents with painless lymphadenopathy, night sweats, and a 10% weight loss over 3 months. Biopsy shows Reed-Sternberg cells. What is the diagnosis?

Accepted Answer

Hodgkin lymphoma

Answer

Reed-Sternberg cells (binucleate giant cells) are pathognomonic for Hodgkin lymphoma.

Question 4

Which renal tubular segment is primarily responsible for concentrating urine?

Accepted Answer

Collecting duct (under ADH influence)

Answer

ADH acts on the collecting duct to insert aquaporin-2 channels, allowing water reabsorption and urine concentration.

Question 5

A patient with known epilepsy is started on a new medication that reduces the efficacy of their oral contraceptive pill. Which anti-epileptic drug is most likely responsible?

Accepted Answer

Carbamazepine

Answer

Carbamazepine is a potent inducer of cytochrome P450 enzymes, significantly reducing plasma levels of oestrogen and progestin.

(MSRA) Multi-Specialty Recruitment Assessment Practice Test

(MSRA) Multi-Specialty Recruitment Assessment Practice Test

MSRA Core Knowledge and Fundamentals 3