Endocrinology Practice Questions

Correct Answer: B

Rationale: The correct answer is B: Inhibition of the function of thyroid peroxidase. Propylthiouracil inhibits thyroid peroxidase, an enzyme essential for thyroid hormone synthesis. By blocking this enzyme, propylthiouracil reduces the production of thyroid hormones, helping to manage hyperthyroidism in Graves' disease. Explanation: 1. Propylthiouracil directly inhibits thyroid peroxidase, unlike other antithyroid medications that target different mechanisms. 2. Inhibition of thyroid peroxidase leads to decreased synthesis of thyroid hormones, effectively controlling hyperthyroidism. 3. Other choices are incorrect because propylthiouracil does not primarily affect the production of thyroid-stimulating immunoglobulins (choice A), peripheral conversion of T4 to T3 (choice C), or iodine organification (choice D) in the treatment of Graves' disease. In summary, the inhibition of thyroid peroxidase by

Correct Answer: C

Rationale: The correct answer is C: Neovascularization. Non-proliferative diabetic retinopathy is characterized by early changes such as retinal vascular microaneurysms, blot hemorrhages, and cotton-wool spots. Neovascularization is a feature of proliferative diabetic retinopathy, not non-proliferative. Neovascularization refers to the growth of abnormal new blood vessels in the retina, which can lead to severe vision loss if not treated promptly. In summary, neovascularization is not consistent with non-proliferative diabetic retinopathy, as it is a hallmark of the proliferative stage.

Correct Answer: D

Rationale: The correct answer is D: Fine hairs. In secondary hypothyroidism, the pituitary gland fails to produce enough thyroid-stimulating hormone (TSH), resulting in low thyroid hormone levels. Fine hairs (or hair thinning) is a symptom of hyperthyroidism, not hypothyroidism. Normal cholesterol levels (Choice A) are seen in secondary hypothyroidism due to decreased metabolic rate. Menorrhagia (Choice B) can occur due to hormonal imbalances caused by untreated hypothyroidism. Low TSH levels (Choice C) are a characteristic feature of secondary hypothyroidism as the pituitary gland is not producing enough TSH to stimulate the thyroid gland.

Correct Answer: A

Rationale: The correct answer is A. Visual changes such as double vision, reduced vision, tunnel vision are common symptoms of acromegaly due to the enlargement of tissues in the eye sockets affecting the optic nerve. Paresthesia and weakness in the hands (B) are not typical symptoms of acromegaly but may be seen in conditions affecting the peripheral nerves. Diarrhoea (C) and abdominal distention (D) are not associated with acromegaly but may be seen in gastrointestinal disorders.

Correct Answer: B

Rationale: The correct answer is B: Dry skin. In hypothyroidism, the thyroid gland does not produce enough thyroid hormone, leading to decreased metabolism. This can result in several symptoms, including dry skin due to reduced sweat gland activity. Hyporeflexia (A) is not a common symptom of hypothyroidism. Oily skin (C) is more commonly associated with hyperthyroidism, where thyroid hormone levels are elevated. Excessive hair growth (D) is not typically seen in hypothyroidism; instead, hair loss is a common symptom.