MFDS Human Disease 2

Question 1

Which cardiac condition most significantly increases the risk of prolonged QT syndrome with erythromycin?

Accepted Answer

Pre-existing QT prolongation or concurrent QT-prolonging drugs

Answer

Erythromycin prolongs the cardiac QT interval by blocking hERG potassium channels; this risk is greatly amplified in patients with a pre-existing long QT interval or on other QT-prolonging drugs.

Question 2

Behçet's disease is characterised by the triad of:

Accepted Answer

Oral ulcers, genital ulcers and uveitis

Answer

Behçet's disease is a systemic vasculitis characterised by the classic triad of recurrent oral ulcers, genital ulcers and uveitis (International Study Group criteria).

Question 3

Which liver disease most significantly impairs drug metabolism in dental practice?

Accepted Answer

Severe cirrhosis

Answer

Severe cirrhosis markedly reduces hepatic drug-metabolising capacity (cytochrome P450 activity) and can impair clotting factor synthesis, both clinically relevant in dental prescribing.

Question 4

A patient with chronic renal failure presents for extraction. The main concern regarding drug prescribing is:

Accepted Answer

Accumulation of renally excreted drugs and metabolites

Answer

In chronic renal failure, renally excreted drugs (e.g. some penicillins, NSAIDs) accumulate to toxic levels, requiring dose reduction or alternative agents.

Question 5

Which immune deficiency syndrome most significantly predisposes to invasive oral candidiasis?

Accepted Answer

HIV/AIDS (CD4 <200)

Answer

Severe CD4 lymphocytopenia in HIV/AIDS (particularly CD4 <200 cells/μL) profoundly impairs cell-mediated immunity, predisposing to invasive and oropharyngeal candidiasis.

MFDS Part 1 Practice Test

MFDS Part 1 Practice Test

MFDS Human Disease 2