Nokea
Which of the following are causes of Addison's disease?
- A. Adrenoleukodystrophy
- B. Pyelonephritis
- C. Tuberculosis
- D. Autoimmune destruction of the adrenal cortex
Correct Answer: D
Rationale: Addison's disease, also known as primary adrenal insufficiency, is mainly caused by the autoimmune destruction of the adrenal cortex. This results in the inadequate production of hormones such as cortisol and aldosterone by the adrenal glands. While other conditions such as Adrenoleukodystrophy, Pyelonephritis, and Tuberculosis can also affect the adrenal glands, they are not known to be direct causes of Addison's disease.
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All the following drugs are associated with an increased risk of osteoporosis in adults except:
- A. Cyclosporine
- B. Heparin
- C. Prednisone
- D. Ranitidine
Correct Answer: D
Rationale: Ranitidine is not associated with an increased risk of osteoporosis in adults. It is a histamine-2 blocker commonly used to reduce stomach acid production and treat conditions such as ulcers and gastroesophageal reflux disease. On the other hand, the other options listed are known to increase the risk of osteoporosis:
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.
Hormones are:
- A. biologically inert by themselves.
- B. used as an energy source
- C. incorporated as a structural moiety into another molecule
- D. always stored in secretory granules
Correct Answer: C
Rationale: Hormones are chemical messengers that are produced by various glands in the body and released into the bloodstream to signal and regulate the activity of specific target cells. Unlike energy sources that can be metabolized for energy production (like carbohydrates and fats), hormones are not typically used as an energy source themselves (Choice B). Hormones are typically not biologically inert by themselves (Choice A), as they have specific functions in regulating various physiological processes in the body. While some hormones may be stored in secretory granules before release, not all hormones are stored in this manner (Choice D). Additionally, hormones are not always released by exocytosis (Choice E), as some hormones can also be released through other mechanisms such as diffusion. The correct choice, therefore, is C: hormones are incorporated as a structural moiety into another molecule, as they bind to specific receptors on target cells to elicit a cellular response and regulate physiological functions.
In a patient with centripetal obesity, acne and hirsutism. The most likely diagnosis is:
- A. Cushing's syndrome
- B. Diabetes mellitus
- C. Hypogonadism
- D. Hypothyroidism
Correct Answer: A
Rationale: Centripetal obesity, acne, and hirsutism are classic features of Cushing's syndrome. Cushing's syndrome results from prolonged exposure to high levels of cortisol, which can be due to various causes such as adrenal tumors, pituitary adenomas, or exogenous glucocorticoid use. Centripetal obesity refers to the characteristic fat distribution pattern seen in Cushing's syndrome, where fat accumulates mainly in the face, neck, and trunk while sparing the limbs. Acne and hirsutism are also commonly seen in Cushing's syndrome due to the hormonal imbalances caused by excess cortisol. Testing for serum cortisol levels, dexamethasone suppression tests, and imaging studies can help confirm the diagnosis of Cushing's syndrome in a patient presenting with these symptoms.
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.