Endocrinology Exam Questions and Answers

Correct Answer: D

Rationale: Osteomalacia is a condition in which there is a softening of the bones due to a deficiency in vitamin D or calcium. It is not a cause of hypocalcemia, as it is a result of low levels of calcium in the bloodstream. The other options listed are potential causes of hypocalcemia:

Correct Answer: D

Rationale: Grave's disease is the most common cause of hyperthyroidism. It is an autoimmune disorder where the body's immune system mistakenly attacks the thyroid gland, leading to overproduction of thyroid hormones. This results in symptoms such as weight loss, rapid heartbeat, heat intolerance, and tremors. While toxic thyroid adenoma, toxic multinodular goitre, and thyroiditis are also potential causes of hyperthyroidism, Grave's disease is the most prevalent among them.

Correct Answer: D

Rationale: Acromegaly is typically caused by the overproduction of growth hormone (GH) by the pituitary gland. In around 95% of cases, this overproduction is due to the presence of a non-cancerous tumor called a pituitary adenoma. These adenomas are benign, slow-growing tumors that cause the pituitary gland to produce excessive amounts of growth hormone, leading to the characteristic symptoms of acromegaly such as enlargement of the bones and soft tissues.

Correct Answer: D

Rationale: The renin-angiotensin-aldosterone axis does not involve the hypothalamus or pituitary gland; instead, it primarily involves the kidneys and the renin-secreting cells. In this axis, renin is released in response to low blood pressure, leading to the formation of angiotensin II and the subsequent release of aldosterone from the adrenal glands. Feedback mechanisms for this axis primarily involve the regulation of renin release based on blood pressure rather than involving direct negative feedback from downstream hormones on the hypothalamus or pituitary gland. On the other hand, choices A, B, and C all involve classic examples of hypothalamic-pituitary negative feedback loops where the end hormone suppresses the release of the stimulating hormones at the hypothalamic and pituitary levels.

Correct Answer: B

Rationale: Sheehan's syndrome, also known as postpartum hypopituitarism, is a condition characterized by pituitary gland dysfunction due to severe blood loss during childbirth, resulting in ischemic necrosis of the pituitary gland. As a consequence of pituitary hormone deficiency, one of the hallmark manifestations of Sheehan's syndrome is persistent lactation despite stopping breastfeeding. This occurs due to inadequate prolactin inhibition, leading to continuous milk production. Other common symptoms of Sheehan's syndrome include fatigue, weight loss, menstrual irregularities, hypothyroidism, adrenal insufficiency, and other pituitary hormone deficiencies. Cardiac failure, fever, and striking cachexia are not typical presentations associated with Sheehan's syndrome.