Endocrinology Practice Questions

Correct Answer: B

Rationale: The correct answer is B: Weight loss. Hypothyroidism is characterized by an underactive thyroid gland, leading to a decreased metabolic rate. This typically results in weight gain, not weight loss. Choices A, C, and D are all associated with hypothyroidism. Loss of libido can occur due to hormonal imbalances, cardiac failure can result from the decreased metabolic rate affecting the heart, and organic psychosis can be a symptom of severe untreated hypothyroidism.

Correct Answer: B

Rationale: The correct answer is B: Intranasal vasopressin may be helpful. In diabetes insipidus, there is a deficiency of vasopressin leading to excessive urination and thirst. Administering vasopressin intranasally can help replace the deficient hormone, reducing urine output and thirst. Hypernatremia (choice A) can occur due to excessive water loss, but it is not always present. There is no osmolar gap (choice C) in diabetes insipidus. Urine specific gravity (choice D) is typically low in diabetes insipidus due to the dilute urine produced.

Correct Answer: A

Rationale: The correct answer is A because ADH secretion is increased during stress to retain water in the body. This response helps maintain blood pressure and prevent dehydration under stressful conditions. Choice B is incorrect because ADH secretion is actually increased during hemorrhage to conserve water. Choice C is incorrect because increased blood osmolality triggers ADH secretion to retain water. Choice D is incorrect because alcohol inhibits ADH secretion, leading to increased urine production.

Correct Answer: C

Rationale: The correct answer is C: Purple skin striae. This is the most common sign of Cushing's syndrome due to the excessive production of cortisol leading to thinning of the skin and formation of purple stretch marks. Hirsutism (A) is excessive hair growth, not specific to Cushing's. Obesity (B) can be a symptom, but it is not the most common. Skin hyperpigmentation (D) is seen in Addison's disease, not Cushing's.

Correct Answer: C

Rationale: Increased parathyroid hormone (PTH) concentration is associated with tetany because PTH helps regulate calcium levels in the blood. When calcium levels are low, PTH is released to stimulate the release of calcium from bones and increase calcium absorption from the intestines. Tetany is characterized by muscle cramps and spasms due to low calcium levels, which can occur when PTH levels are elevated. A: Vitamin D toxicity is associated with high levels of calcium in the blood, not low calcium levels as seen in tetany. B: Rickets is a condition caused by vitamin D deficiency, leading to impaired bone growth and development, not directly related to elevated PTH levels. D: Reduced excretion of phosphate is not directly linked to elevated PTH levels, as PTH primarily regulates calcium levels.