Which of the following causes of Cushing's syndrome does the phrase "Cushing's disease" specifically refer to?
- A. Iatrogenic
- B. Ectopic ACTH production
- C. Pituitary adenoma
- D. Adrenal adenoma
Correct Answer: C
Rationale: The phrase "Cushing's disease" specifically refers to the cause of Cushing's syndrome that is due to an ACTH-secreting pituitary adenoma. In this specific case, the excess production of ACTH leads to bilateral adrenal hyperplasia and oversecretion of cortisol. It is important to differentiate between Cushing's syndrome caused by a pituitary adenoma (Cushing's disease) and other causes such as adrenal adenomas, ectopic ACTH production, or iatrogenic sources.
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Which of the following are common symptoms of hyperthyroidism?
- A. Tremor
- B. Weight gain
- C. Heat intolerance
- D. Diarrhoea
Correct Answer: A
Rationale: Tremor (A): Tremors or shaky hands are common symptoms of hyperthyroidism. This is due to the increased metabolic rate caused by excess thyroid hormone in the body.
Tall stature is not characteristic of:
- A. Klinefelter's syndrome
- B. Homocystinuria
- C. Marfan's syndrome
- D. Turner's syndrome
Correct Answer: D
Rationale: Turner's syndrome is a genetic condition that affects females and is characterized by short stature and other physical abnormalities due to the absence of part or all of one of the X chromosomes. Therefore, tall stature is not characteristic of Turner's syndrome.
Which of the following are causes of nephrogenic diabetes insipidus?
- A. Sheehan's syndrome
- B. Lithium
- C. Mutations in the vasopressin (ADH) receptor gene
- D. Mutations in vasopressin gene
Correct Answer: B
Rationale: Nephrogenic diabetes insipidus (NDI) is a condition where the kidneys are unable to respond to antidiuretic hormone (ADH) as they should, leading to excessive urination and extreme thirst. One of the main causes of nephrogenic diabetes insipidus is the use of certain medications, with lithium being the most common culprit. Lithium can interfere with the kidney's response to ADH, resulting in decreased water reabsorption and the characteristic symptoms of diabetes insipidus. Other causes of NDI can include genetic mutations affecting the vasopressin receptor gene or other underlying conditions such as hypercalcemia, hypokalemia, or obstructive uropathy.
Parathyroid hormone:
- A. increases deposition of calcium in bones.
- B. causes development of goitre.
- C. is the molecule formed when T4 and T3 are degraded.
- D. is secreted in increased amounts when blood calcium level is below normal.
Correct Answer: D
Rationale: Parathyroid hormone (PTH) is a hormone produced by the parathyroid glands in response to low blood calcium levels. Its main function is to raise calcium levels in the blood by acting on the bones, kidneys, and intestines. PTH stimulates the release of calcium from the bones, enhances the absorption of calcium by the intestines, and promotes the reabsorption of calcium by the kidneys. Therefore, it is secreted in increased amounts when blood calcium levels are below normal in order to maintain overall calcium balance in the body.
Upper segment > lower segment of body is found in all (in dwarfism) except:
- A. Pituitary dwarf
- B. Cretinism
- C. Achondroplasia
- D. Juvenile myxedema
Correct Answer: D
Rationale: In dwarfism conditions, the upper body segment being greater than the lower body segment is a characteristic feature seen in Achondroplasia. This condition results in a disproportionately short stature with short limbs but a trunk of normal length.
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