Which one of the following statements is true regarding the prevalence of acromegaly?
- A. Acromegaly affects a similar number of men and women
- B. Acromegaly affects twice as many women than men
- C. Acromegaly affects twice as many men than it does women
Correct Answer: C
Rationale: Acromegaly is a rare hormonal disorder where excess growth hormone is produced, leading to the enlargement of bones and tissues. The prevalence of acromegaly is higher in men compared to women, with a ratio of about two men affected for every woman. This gender difference is believed to be due to the impact of sex hormones on the development and progression of the condition. While acromegaly can affect both men and women, men are more commonly diagnosed with the disorder.
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Which of the following is not a recognized feature of myxoedema?
- A. Ascites
- B. Cerebellar ataxia
- C. Increased incidence of pernicious anaemia
- D. Thyroid acropachy
Correct Answer: D
Rationale: Myxoedema is a severe form of hypothyroidism characterized by a range of symptoms and signs. Ascites, cerebellar ataxia, and increased incidence of pernicious anaemia are recognized features of myxoedema. However, thyroid acropachy is not a recognized feature of myxoedema. Thyroid acropachy is a condition characterized by clubbing of the fingers and toes, swelling of the hands and feet, and periosteal new bone formation, typically seen in patients with Graves' disease, which is a form of hyperthyroidism.
All of the following are associated with hyperuricemia except:
- A. Cardiovascular disease
- B. Gouty arthritis
- C. Nephrolithiasis
- D. Peripheral neuropathy
Correct Answer: D
Rationale: Hyperuricemia is a medical condition characterized by elevated levels of uric acid in the blood. This can lead to the formation of urate crystals, which are responsible for various health problems. The three main conditions associated with hyperuricemia are cardiovascular disease (A), gouty arthritis (B), and nephrolithiasis (C).
Persistent muscular weakness is characteristic of:
- A. Conn's syndrome
- B. Acromegaly
- C. Hyperparathyroidism
- D. Myxoedema
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.
Which one of the following statements describes the underlying pathology of Grave's disease?
- A. An autoimmune disease directed against thyroid stimulating hormone (TSH) receptors. The autoantibodies stimulate the TSH receptors causing increased T3 and T4 production.
- B. Inflammation of the thyroid gland due to lymphocytic infiltration causes the stored thyroid hormones to be released into the circulation leading to hyperthyroidism.
- C. Consumption of ground beef which has been contaminated with thyroid tissue. The thyroid tissue contains metabolically active thyroid hormones which causes hyperthyroidism.
- D. A benign tumour of the thyroid gland which produces excessive amounts of thyroid hormones.
Correct Answer: A
Rationale: Graves' disease is an autoimmune disorder where autoantibodies, known as thyroid-stimulating immunoglobulins (TSIs) or thyroid-stimulating antibodies (TSAs), bind to and stimulate the thyroid-stimulating hormone (TSH) receptors on thyroid follicular cells. This leads to increased production and secretion of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine), causing hyperthyroidism. The autoantibodies essentially mimic the action of TSH, resulting in excess thyroid hormone release and manifestation of hyperthyroid symptoms. This underlying pathology of Graves' disease is distinct from other causes of hyperthyroidism, making choice A the correct statement.
Which of the following is the most potent stimulus for hypothalamic production of arginine vasopressin?
- A. Hypertonicity
- B. Hyperkalemia
- C. Hypokalemia
- D. Hypotonicity
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.