Endocrinology Exam Questions

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: A

Rationale: Pseudo-Cushing's syndrome is a condition that mimics the symptoms of Cushing's syndrome but is not actually caused by excess cortisol production by the adrenal glands. It can be caused by various conditions such as chronic alcoholism, obesity, depression, and certain medications. However, myxoedema (also known as severe hypothyroidism) is not typically associated with pseudo-Cushing's syndrome. Myxoedema is characterized by low thyroid hormone levels, which would not lead to the symptoms of pseudo-Cushing's syndrome.

Correct Answer: D

Rationale: Increased serum aldosterone level is typically associated with conditions such as Conn's syndrome or primary hyperaldosteronism. These conditions lead to an excess of aldosterone, which results in increased sodium resorption and potassium excretion by the kidneys. This imbalance can lead to hypertension (Choice A), hypernatraernia (elevated sodium level) (Choice B), and hypokalaemia (low potassium level) (Choice C). However, metabolic acidosis (Choice D) is not directly associated with increased aldosterone levels. Instead, metabolic acidosis may be seen in conditions like renal tubular acidosis or diabetic ketoacidosis.

Correct Answer: A

Rationale: In the syndrome of inappropriate antidiuretic hormone (SIADH), there is excessive secretion of antidiuretic hormone (ADH) leading to increased water reabsorption in the kidney tubules. This results in dilutional hyponatremia because the amount of water reabsorbed is greater than the electrolytes, such as sodium, leading to a relative decrease in their concentration in the blood. As a result, hyponatremia occurs in SIADH, contributing to symptoms such as nausea, confusion, and seizures due to the imbalance in electrolytes.

Correct Answer: A

Rationale: C-21 hydroxylase deficiency is the most common enzymatic defect leading to the development of congenital adrenal hyperplasia (CAH). This enzyme is necessary for the synthesis of cortisol and aldosterone in the adrenal glands. When there is a deficiency in C-21 hydroxylase, the pathway is shifted towards the production of androgens instead of cortisol and aldosterone, leading to excess androgen production. This results in the characteristic features of CAH, such as ambiguous genitalia in females and virilization in both males and females. Other enzyme deficiencies listed in the choices can also lead to different types of CAH but are less common compared to C-21 hydroxylase deficiency.