Which of the following statements best describes Hashimoto's thyroiditis?
- A. Inflammation of the thyroid gland as the result of a virus. The disease is often preceded by an upper respiratory tract infection.
- B. A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin.
- C. Iodine deficiency
- D. thyroid gland
Correct Answer: B
Rationale: Hashimoto's thyroiditis is an autoimmune disease where the immune system mistakenly attacks the thyroid gland. The antibodies produced by the immune system target the thyroglobulin in the thyroid gland, leading to its destruction over time. This results in decreased thyroid hormone production, leading to hypothyroidism. Therefore, choice B, "A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin," best describes Hashimoto's thyroiditis.
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Pseudohypoparathyroidism is not associated with:
- A. Cataract
- B. Raised level of plasma PIH
- C. Mental retardation
- D. Reduced level of plasma phosphate
Correct Answer: B
Rationale: Pseudohypoparathyroidism is a rare genetic disorder that mimics the symptoms of hypoparathyroidism, despite normal or elevated levels of parathyroid hormone (PTH). The condition is characterized by hypocalcemia, hyperphosphatemia, and normal or elevated PTH levels. However, it is not associated with a raised level of plasma PIH (Parathyroid Inhibiting Hormone). In pseudohypoparathyroidism, the body's tissues are resistant to the action of PTH, leading to impaired calcium regulation. Other common features of pseudohypoparathyroidism may include cataract formation, mental retardation, and reduced levels of plasma phosphate.
Which of the following is not a feature of autonomic neuropathy in diabetes?
- A. Retrograde ejaculation
- B. Gustatory sweating
- C. Mononeuritis multiplex
- D. Hypoglycemic unresponsiveness
Correct Answer: C
Rationale: Autonomic neuropathy in diabetes can manifest with various symptoms, such as retrograde ejaculation (A), gustatory sweating (B), and hypoglycemic unresponsiveness (D). Mononeuritis multiplex (C) is not typically associated with autonomic neuropathy in diabetes. Mononeuritis multiplex is a condition characterized by damage to at least two separate nerve areas resulting in weakness, pain, and sensory loss. Autonomic neuropathy in diabetes tends to affect the autonomic nerves that control involuntary bodily functions, leading to symptoms such as gastrointestinal issues, cardiovascular abnormalities, and sexual dysfunction, but mononeuritis multiplex is not a common feature of this condition.
Prolonged ingestion of iodine can produce goiter, and is known as:
- A. Jod-Basedow effect
- B. Sick euthyroid syndrome
- C. Wolf-Chaikoff effect
- D. Thyrotoxicosis factitia
Correct Answer: C
Rationale: The prolonged ingestion of iodine causing goiter is known as the Wolf-Chaikoff effect. This phenomenon occurs when high levels of iodine cause a temporary inhibition of thyroid hormone synthesis, resulting in a decrease in thyroid hormone production. In some individuals, this can lead to the development of a goiter due to the lack of thyroid hormone feedback regulation. It is important to note that the Wolf-Chaikoff effect typically resolves on its own as the thyroid gland adapts to the increased iodine levels over time.
Commonest cause of Addison's disease is:
- A. Granuloma
- B. Idiopathic atrophy
- C. Inflammatory necrosis
- D. Malignancy
Correct Answer: A
Rationale: The most common cause of Addison's disease is autoimmune adrenalitis, also known as autoimmune adrenal insufficiency. In autoimmune adrenalitis, the adrenal glands are damaged by immune system-mediated processes, leading to their dysfunction. This autoimmune destruction typically presents as bilateral adrenal cortex atrophy due to the formation of granulomas. Therefore, the commonest cause of Addison's disease is the presence of granulomas in the adrenal glands, making option A, Granuloma, the correct choice.
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.