DHA Medical Knowledge 3

Question 1

A 58-year-old patient on warfarin is prescribed ciprofloxacin for a urinary tract infection. What is the most important monitoring consideration?

Accepted Answer

INR levels, as ciprofloxacin potentiates warfarin's anticoagulant effect

Answer

Ciprofloxacin inhibits the metabolism of warfarin by suppressing gut flora that produce vitamin K and by inhibiting CYP1A2, leading to elevated INR and increased bleeding risk. Close INR monitoring and possible warfarin dose reduction are required.

Question 2

Which of the following is the MOST common opportunistic infection seen in HIV-positive patients with a CD4 count below 200 cells/μL?

Accepted Answer

Pneumocystis jirovecii pneumonia (PCP)

Answer

Pneumocystis jirovecii pneumonia (PCP) is the most common AIDS-defining opportunistic infection when the CD4 count drops below 200 cells/μL. Prophylaxis with trimethoprim-sulfamethoxazole is recommended at this threshold. The other infections typically occur at lower CD4 counts.

Question 3

A 45-year-old woman presents with fatigue, weight gain, cold intolerance, and constipation. Her TSH is 12 mIU/L and free T4 is low. What is the first-line treatment?

Accepted Answer

Levothyroxine (T4) replacement therapy

Answer

The clinical picture and lab findings are consistent with primary hypothyroidism. Levothyroxine (synthetic T4) is the standard first-line treatment. It is converted peripherally to the active T3 form. PTU and radioactive iodine are used for hyperthyroidism, not hypothyroidism.

Question 4

A patient develops sudden-onset severe headache described as 'the worst headache of my life,' with neck stiffness and photophobia. CT head is negative. What is the NEXT most critical diagnostic step?

Accepted Answer

Lumbar puncture to examine cerebrospinal fluid

Answer

A 'thunderclap' headache with meningismus and a negative CT scan requires lumbar puncture to rule out subarachnoid hemorrhage (SAH). Up to 5% of SAH cases have a normal CT, and CSF analysis for xanthochromia or red blood cells is the definitive next step. Delaying this test is dangerous.

Question 5

In managing Type 2 Diabetes Mellitus, which medication class has demonstrated the GREATEST cardiovascular mortality benefit in patients with established atherosclerotic cardiovascular disease?

Accepted Answer

SGLT-2 inhibitors (e.g., empagliflozin)

Answer

SGLT-2 inhibitors, particularly empagliflozin (EMPA-REG OUTCOME trial) and canagliflozin (CANVAS trial), have demonstrated significant reductions in cardiovascular death, heart failure hospitalization, and kidney disease progression in T2DM patients with established cardiovascular disease, making them a preferred add-on to metformin in this population.

DHA - Dubai Health Authority Practice Test

DHA - Dubai Health Authority Practice Test

DHA Medical Knowledge 3