Nokea
Which of the following does the adrenal cortex produce?
- A. Adrenaline
- B. Aldosterone
- C. Cortisol
- D. Noradrenaline
Correct Answer: B
Rationale: The adrenal cortex is the outer region of the adrenal glands and is responsible for producing several hormones, including aldosterone. Aldosterone is a mineralocorticoid hormone that plays a crucial role in regulating electrolyte balance, particularly sodium and potassium, in the body. It helps maintain blood pressure and fluid balance by acting on the kidneys to reabsorb sodium and water while excreting potassium in the urine. Adrenaline and noradrenaline (also known as epinephrine and norepinephrine) are produced by the adrenal medulla, which is the inner region of the adrenal glands. Cortisol is another hormone produced by the adrenal cortex, but aldosterone specifically regulates electrolyte balance.
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Which of the following is the underlying problem in neurogenic diabetes insipidus?
- A. Overproduction of vasopressin (antidiuretic hormone)
- B. Lack of oxytocin
- C. Overproduction of oxytocin
- D. Overproduction of prolactin
Correct Answer: E
Rationale: Neurogenic diabetes insipidus is a condition characterized by a deficiency of vasopressin (antidiuretic hormone). Vasopressin is responsible for regulating the body's water balance by controlling the reabsorption of water in the kidneys. In neurogenic diabetes insipidus, there is a problem with either the production, release, or action of vasopressin, leading to excessive urination and thirst. This condition can be caused by damage to the hypothalamus or pituitary gland, which are involved in producing and releasing vasopressin. Symptoms of neurogenic diabetes insipidus include frequent urination, excessive thirst, and dehydration.
Which of the following tests should be used to make the diagnosis of Cushing's syndrome?
- A. 24-hour urine free cortisol
- B. Corticotropin-releasing hormone (CRH) level at 8 a.m.
- C. Inferior petrosal venous sampling
- D. Overnight 1-mg dexamethasone suppression test
Correct Answer: D
Rationale: The overnight 1-mg dexamethasone suppression test is commonly used as an initial screening test for Cushing's syndrome. In this test, a patient takes 1 mg of dexamethasone orally at 11 p.m., and their serum cortisol level is measured the next morning. In patients with Cushing's syndrome, the cortisol levels will not be suppressed by the dexamethasone due to the presence of excessive cortisol production.
All of the following are featured by dermal hyperpigmentation except:
- A. Conn's syndrome
- B. Bronchogenic carcinoma
- C. Addison's disease
- D. Haemochromatosis
Correct Answer: A
Rationale: Dermal hyperpigmentation, also known as hyperpigmentation of the skin, is commonly associated with conditions such as Addison's disease, hemochromatosis, and bronchogenic carcinoma. In Addison's disease, there is increased production of melanin due to elevated levels of adrenocorticotropic hormone (ACTH) which stimulates melanocytes. Hemochromatosis can cause hyperpigmentation due to excess iron deposits in the skin. Bronchogenic carcinoma can lead to a condition known as acanthosis nigricans, characterized by dark, velvety discoloration of the skin primarily around the neck and armpits. However, Conn's syndrome, which is a primary aldosteronism resulting from an adrenal adenoma or hyperplasia, is not typically associated with dermal hyperpigmentation.
Cushing's syndrome does not give rise to:
- A. Hirsutism
- B. Peripheral neuropathy
- C. Purple striae
- D. Acne
Correct Answer: B
Rationale: Cushing's syndrome is a disorder caused by prolonged exposure to high levels of cortisol hormone. While Cushing's syndrome can manifest with a variety of symptoms, peripheral neuropathy is not a typical feature of this condition. Cushing's syndrome is commonly associated with symptoms such as hirsutism (excessive hair growth), purple striae (skin stretch marks that are purple in color), and acne due to the hormonal imbalances it creates. Peripheral neuropathy, which involves damage to the peripheral nerves leading to symptoms like numbness, tingling, and weakness in the extremities, is not a characteristic symptom of Cushing's syndrome.
The triad of hyponatraemia, haemodilution and urine hypertonic to plasma suggest diagnosis of:
- A. Nephrotic syndrome
- B. SIADH
- C. Nephrogenic diabetes insipidus
- D. Addison's disease
Correct Answer: B
Rationale: The triad of hyponatremia (low sodium levels in the blood), haemodilution (increased plasma volume), and urine hypertonic to plasma (high urine osmolality compared to blood osmolality) is characteristic of Syndrome of Inappropriate Antidiuretic Hormone (SIADH). In SIADH, there is excessive release of antidiuretic hormone (ADH), also known as vasopressin, leading to water retention by the kidneys and dilutional hyponatremia. This condition results in the body holding onto water, causing hyponatremia and dilution of the blood. The urine being hypertonic compared to plasma indicates that the kidneys are reabsorbing water effectively and concentrating the urine.