Nokea
Phaeochromocytoma is not associated with:
- A. Weight gain
- B. Fear of death (angor animi)
- C. Paroxysmal hypertension
- D. Constipation
Correct Answer: A
Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.
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Increased serum aldosterone level is not associated with:
- A. Hypertension
- B. Hypernatraernia
- C. Hypokalaemia
- D. Metabolic acidosis
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.
Which of the following investigations is the gold standard for diagnosing acromegaly?
- A. Serum IGF1 measurement
- B. Growth hormone releasing hormone measurement
- C. Oral glucose tolerance test + Growth hormone measurement
- D. Growth hormone measurement
Correct Answer: C
Rationale: The gold standard for diagnosing acromegaly is the oral glucose tolerance test (OGTT) along with growth hormone (GH) measurement. During this test, the patient is given a glucose solution to drink, and then blood samples are taken to measure GH levels at specific time intervals. In a person without acromegaly, glucose ingestion would typically suppress GH levels. However, in individuals with acromegaly, GH levels remain elevated even after glucose administration due to the inability of glucose to inhibit GH release from the tumor.
What is Addison's disease?
- A. Addison's disease is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones.
- B. Addison's disease involves the overproduction of cortisol and aldosterone by the adrenal cortex.
- C. Addison's disease involves the overproduction of androgens by the adrenal medulla.
- D. Addison's disease involves the underproduction of androgens by the adrenal medulla.
Correct Answer: A
Rationale: Addison's disease, also known as primary adrenal insufficiency, is a condition where the adrenal glands do not produce enough steroid hormones, mainly cortisol and sometimes aldosterone. This deficiency in steroid hormone production is typically caused by autoimmune destruction of the adrenal cortex. Without enough cortisol and aldosterone, various symptoms may arise, such as fatigue, weight loss, low blood pressure, and skin discoloration. Therefore, option A accurately describes the nature of Addison's disease.
What is the most common cause of Cushing's syndrome?
- A. Ectopic ACTH production
- B. Adrenal adenoma
- C. Glucocorticoid treatment (iatrogenic)
- D. Pituitary adenoma
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.
Thyroid hormones (T3 and T4):
- A. increase metabolic rate.
- B. are hydrophilic as they are made from amino acids.
- C. contain iron atoms in ferrous form.
- D. stimulate the secretion of thyroid-stimulating hormone (TSH; thyrotropin).
Correct Answer: A
Rationale: Thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), play a crucial role in regulating metabolism in the body. They are responsible for increasing the metabolic rate of cells by influencing the production of proteins and controlling how the body uses energy. This increase in metabolic rate results in processes such as increased heart rate, enhanced nutrient breakdown, and higher body temperature. Thus, option A, "increase metabolic rate," is the correct statement regarding thyroid hormones (T3 and T4).