Endocrinology Exam Questions and Answers

Correct Answer: D

Rationale: Persistent muscular weakness is characteristic of myxoedema, which is severe hypothyroidism. Myxoedema can lead to general weakness and fatigue, as thyroid hormones play a crucial role in controlling metabolism and energy production in the body. Other symptoms of myxoedema include cold intolerance, weight gain, dry skin, and hair loss. Conn's syndrome (hyperaldosteronism) is characterized by hypertension and low potassium levels, not persistent muscular weakness. Acromegaly is a condition resulting from excess growth hormone production, leading to enlarged body parts and metabolic changes but not specifically muscular weakness. Hyperparathyroidism is associated with high levels of parathyroid hormone, which can lead to bone weakening and calcium imbalance, but it is not typically a primary cause of muscular weakness.

Correct Answer: D

Rationale: Persistent muscular weakness is characteristic of myxoedema, which is severe hypothyroidism. Myxoedema can lead to general weakness and fatigue, as thyroid hormones play a crucial role in controlling metabolism and energy production in the body. Other symptoms of myxoedema include cold intolerance, weight gain, dry skin, and hair loss. Conn's syndrome (hyperaldosteronism) is characterized by hypertension and low potassium levels, not persistent muscular weakness. Acromegaly is a condition resulting from excess growth hormone production, leading to enlarged body parts and metabolic changes but not specifically muscular weakness. Hyperparathyroidism is associated with high levels of parathyroid hormone, which can lead to bone weakening and calcium imbalance, but it is not typically a primary cause of muscular weakness.

Correct Answer: A

Rationale: The posterior pituitary gland secretes anti-diuretic hormone (ADH) and oxytocin, which are produced in the hypothalamus and then transported and stored in the posterior pituitary before being released into the bloodstream. ADH, also known as vasopressin, helps regulate water balance in the body by controlling the reabsorption of water in the kidneys. Oxytocin, on the other hand, plays a role in various reproductive functions such as labor and lactation, as well as social bonding and behavior.

Correct Answer: A

Rationale: Hypertonicity (increased osmolarity or high concentration of solutes in the blood) is the most potent stimulus for the hypothalamic production of arginine vasopressin (also known as antidiuretic hormone or ADH). When the body senses increased plasma osmolality, the osmoreceptors in the hypothalamus stimulate the release of vasopressin from the posterior pituitary gland. Vasopressin acts on the kidneys to increase water reabsorption and decrease urine output, helping to restore normal osmolarity. This mechanism helps to conserve water and maintain body fluid balance in response to dehydration or increased solute concentration in the blood.

Correct Answer: D

Rationale: An Addisonian crisis, also known as an acute adrenal crisis, is a life-threatening medical emergency that occurs due to severe adrenal insufficiency, leading to a sudden drop in cortisol levels. Cortisol is a vital hormone produced by the adrenal glands, and its deficiency can result in serious symptoms such as hypotension, dehydration, electrolyte imbalances, and shock. If left untreated, an Addisonian crisis can be fatal. Therefore, the correct description of an Addisonian crisis is severe adrenal insufficiency resulting in dangerously low serum cortisol levels.