Endocrinology Exam Questions

Correct Answer: B

Rationale: Excess prolactin typically causes gynecomastia in men. Prolactin is a hormone primarily responsible for milk production in women. However, in men, elevated levels of prolactin can lead to various symptoms, with gynecomastia being one of the most common. Gynecomastia is the development of breast tissue in males, which can result in swelling and tenderness of the breasts. It is important to investigate the underlying cause of elevated prolactin levels as it could be due to various conditions such as pituitary tumors, certain medications, or thyroid disorders.

Correct Answer:

Rationale: Oxytocin and Vasopressin, also known as antidiuretic hormone (ADH), are the hormones stored in the posterior pituitary gland. These hormones are produced by the hypothalamus and then transported and stored in the posterior pituitary gland until they are released into the bloodstream when needed. Oxytocin plays a role in uterine contractions during childbirth and milk ejection during lactation, while Vasopressin regulates water balance in the body by acting on the kidneys to reduce urine production and conserve water. The other hormones listed, such as Prolactin, TSH, GH, ACTH, FSH, and LH, are produced by the anterior pituitary gland.

Correct Answer: B

Rationale: Myxoedema coma is a severe form of hypothyroidism that can lead to the slowing down of various body functions, including reduced heart rate (bradycardia). As the condition progresses and the body's metabolism becomes more depressed, one of the compensatory mechanisms is an increase in heart rate (tachycardia) to try to maintain adequate tissue perfusion. Therefore, tachycardia is a characteristic feature of myxoedema coma, rather than hypertension or euthermia which are not typically associated with this condition. Hypoventilation is also a common feature of myxoedema coma due to the decreased metabolic rate and respiratory drive.

Correct Answer: D

Rationale: The most common cause of Cushing's syndrome is a pituitary adenoma, specifically a corticotroph adenoma. This adenoma leads to excessive secretion of adrenocorticotropic hormone (ACTH) by the pituitary gland, which in turn stimulates the adrenal glands to produce high levels of cortisol. This results in the symptoms and signs characteristic of Cushing's syndrome. Pituitary adenomas are responsible for around 70-80% of cases of Cushing's syndrome, making it the most common cause.

Correct Answer: C

Rationale: Hypercalcemia refers to elevated levels of calcium in the blood. The effects of hypercalcemia include increased urinary frequency (polyuria), gastrointestinal symptoms such as constipation rather than diarrhea, kidney stones (nephrolithiasis), and various cardiac abnormalities. One key cardiac abnormality associated with hypercalcemia is a prolonged QT interval rather than a shortened QT interval. Prolongation of the QT interval can predispose individuals to arrhythmias, particularly Torsades de pointes. Therefore, the correct answer is C, as a shortened QT interval is not a typical effect of hypercalcemia.