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.
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Effect of diabetes on foetus includes all except:
- A. Microsomia
- B. Hyperbilirubinaemia
- C. Stillbirth
- D. Open neural tube defect
Correct Answer: B
Rationale: Hyperbilirubinemia is not a common effect of diabetes on the fetus. The correct effects of diabetes on the fetus include:
Diabetes Insipidus is a deficiency of what hormone?
- A. Atrial Natriuretic Peptide
- B. Vasopressin
- C. Aldosterone
- D. Insulin
Correct Answer: B
Rationale: Diabetes Insipidus is a condition characterized by the body's inability to properly regulate water balance, leading to excessive urination and extreme thirst. This disorder is caused by a deficiency of vasopressin, also known as antidiuretic hormone (ADH). Vasopressin is a hormone produced by the hypothalamus and released by the pituitary gland to help regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. The lack of vasopressin in Diabetes Insipidus results in the kidneys producing a large volume of dilute urine, leading to dehydration and electrolyte imbalances.
Anti-diuretic hormone secretion is:
- A. increased during stress.
- B. reduced during hemorrhage.
- C. reduced by increased blood osmolality.
- D. increased by alcohol.
Correct Answer: B
Rationale: Anti-diuretic hormone (ADH), also known as vasopressin, is a hormone released by the pituitary gland in response to changes in blood osmolality, blood volume, and blood pressure. During hemorrhage (significant blood loss), the body experiences a decrease in blood volume and blood pressure. In response to this decrease in blood volume, ADH secretion is increased to help the body retain water and maintain blood pressure levels. Therefore, it is incorrect to say that ADH secretion is reduced during hemorrhage.
Increased muscle mass with slowness of activity (Hoffman syndrome) is seen in:
- A. Acromegaly
- B. Myxoedema
- C. Pseudohypoparathyroidism
- D. Myotonia dystrophica
Correct Answer: A
Rationale: Acromegaly is a disorder caused by excessive growth hormone production by the pituitary gland in adults, leading to an increase in muscle mass (hypertrophy). Hoffman syndrome, characterized by increased muscle mass with slowness of activity, is a clinical feature often seen in individuals with acromegaly. The excessive growth hormone levels in acromegaly can cause acral growth, soft tissue swelling, and muscle hypertrophy, contributing to the characteristic features of the condition, including Hoffman syndrome. Therefore, the correct answer is Acromegaly.
Myxoedema coma is characterized by:
- A. Hypertension
- B. Tachycardia
- C. Euthermia
- D. Hypoventilation
Correct Answer: B
Rationale: Myxoedema coma is a severe form of hypothyroidism that can lead to the slowing down of various body functions, including reduced heart rate (bradycardia). As the condition progresses and the body's metabolism becomes more depressed, one of the compensatory mechanisms is an increase in heart rate (tachycardia) to try to maintain adequate tissue perfusion. Therefore, tachycardia is a characteristic feature of myxoedema coma, rather than hypertension or euthermia which are not typically associated with this condition. Hypoventilation is also a common feature of myxoedema coma due to the decreased metabolic rate and respiratory drive.