Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which substance is used as a vitamin D supplement in end-stage renal disease?

1. Calcitriol

2. Ergocalciferol

3. Cholecalciferol

4. Erythema ab igne

The correct answer is: Calcitriol

Calcitriol is the active form of vitamin D and is used as a supplement in patients with end-stage renal disease. The kidneys are responsible for converting vitamin D into its active form, and in cases of renal failure, this conversion is impaired. Therefore, supplementation with calcitriol directly addresses vitamin D deficiency and helps maintain calcium and phosphate balance in the body, which is critical for bone health and also for the prevention of secondary hyperparathyroidism often seen in renal disease. Other forms of vitamin D, such as ergocalciferol and cholecalciferol, require conversion to the active form (calcitriol) by the liver and kidneys. In patients with end-stage renal disease, this conversion process is compromised, making these alternatives less effective as supplements. Erythema ab igne, a skin condition caused by prolonged exposure to heat, is not related to vitamin D supplementation at all and does not have any therapeutic role in end-stage renal disease. By using calcitriol, healthcare providers can effectively manage the vitamin D levels in these patients and alleviate associated complications, making it the appropriate choice for supplementation in this context.