Nokea
Which of the following is the most common cause of hypothyroidism worldwide?
- A. Graves' disease
- B. Hashimoto's thyroiditis
- C. Iatrogenic hypothyroidism
- D. Iodine deficiency
Correct Answer: D
Rationale: Iodine deficiency is the most common cause of hypothyroidism worldwide. Iodine is an essential mineral required for the production of thyroid hormones. Without sufficient iodine, the thyroid gland is unable to produce an adequate amount of thyroid hormones, leading to hypothyroidism. Areas with low iodine levels in the soil or water are more prone to iodine deficiency, which can result in a range of thyroid disorders, including hypothyroidism. Efforts to prevent iodine deficiency include iodized salt programs and dietary interventions to ensure an adequate intake of iodine.
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Phaeochromocytoma is not associated with:
- A. Weight gain
- B. Fear of death (angor animi)
- C. Paroxysmal hypertension
- D. Constipation
Correct Answer: A
Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.
Regarding syndrome of inappropriate antidiuretic hormone (SIADH), which is true?
- A. Hyponatremia is dilutional
- B. Urine is relatively hypertonic to plasma
- C. ADH-mediated water reabsorption does not occur
- D. Renal function is jeopardized
Correct Answer: A
Rationale: In the syndrome of inappropriate antidiuretic hormone (SIADH), there is excessive secretion of antidiuretic hormone (ADH) leading to increased water reabsorption in the kidney tubules. This results in dilutional hyponatremia because the amount of water reabsorbed is greater than the electrolytes, such as sodium, leading to a relative decrease in their concentration in the blood. As a result, hyponatremia occurs in SIADH, contributing to symptoms such as nausea, confusion, and seizures due to the imbalance in electrolytes.
All of the following are potential causes of elevated LDL , except:
- A. Cirrhosis
- B. Hypothyroidism
- C. Nephrotic syndrome
- D. Thiazide diuretics
Correct Answer: A
Rationale: Cirrhosis is not a potential cause of elevated LDL cholesterol levels. The liver plays a significant role in cholesterol metabolism, and liver disease like cirrhosis can actually lead to decreased levels of LDL cholesterol. Elevated LDL cholesterol levels can be caused by conditions such as hypothyroidism, nephrotic syndrome, or the use of certain medications like thiazide diuretics.
What is Addison's disease?
- A. Addison's disease is a long-term endocrine disorder in which the adrenal glands do not produce enough steroid hormones.
- B. Addison's disease involves the overproduction of cortisol and aldosterone by the adrenal cortex.
- C. Addison's disease involves the overproduction of androgens by the adrenal medulla.
- D. Addison's disease involves the underproduction of androgens by the adrenal medulla.
Correct Answer: A
Rationale: Addison's disease, also known as primary adrenal insufficiency, is a condition where the adrenal glands do not produce enough steroid hormones, mainly cortisol and sometimes aldosterone. This deficiency in steroid hormone production is typically caused by autoimmune destruction of the adrenal cortex. Without enough cortisol and aldosterone, various symptoms may arise, such as fatigue, weight loss, low blood pressure, and skin discoloration. Therefore, option A accurately describes the nature of Addison's disease.
Growth hormone:
- A. induces gigantism in adults.
- B. is the only pituitary hormone synthesized from cholesterol.
- C. stimulates its own secretion.
- D. is released during sleep.
Correct Answer: D
Rationale: Growth hormone is primarily released during sleep, particularly during the first few hours of deep sleep. This release is pulsatile in nature, with the majority occurring at night. Growth hormone plays a critical role in growth, repair, and development of body tissues during periods of rest and sleep. Additionally, the secretion of growth hormone is also influenced by factors such as stress, exercise, and nutritional status.