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.
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All of the following are associated with hyperuricemia except:
- A. Cardiovascular disease
- B. Gouty arthritis
- C. Nephrolithiasis
- D. Peripheral neuropathy
Correct Answer: D
Rationale: Hyperuricemia is a medical condition characterized by elevated levels of uric acid in the blood. This can lead to the formation of urate crystals, which are responsible for various health problems. The three main conditions associated with hyperuricemia are cardiovascular disease (A), gouty arthritis (B), and nephrolithiasis (C).
All of the following are potential signs or symptoms of growth hormone deficiency except:
- A. Abnormal lipid profile
- B. Atherosclerosis
- C. Increased bone mineral density
- D. Left ventricular dysfunction
Correct Answer: C
Rationale: Growth hormone deficiency (GHD) is commonly associated with decreased bone mineral density, leading to an increased risk of fractures and osteoporosis. Therefore, increased bone mineral density would not typically be a sign or symptom of GHD. On the other hand, abnormal lipid profile, atherosclerosis, and left ventricular dysfunction are all potential signs or symptoms of GHD. Abnormal lipid profile can manifest as increased levels of LDL cholesterol and decreased levels of HDL cholesterol. Atherosclerosis, the buildup of plaque in the arteries, can occur in individuals with GHD due to the impact on lipid metabolism. Left ventricular dysfunction may also be seen in individuals with GHD due to the role of growth hormone in cardiac function and structure.
All of the following represent examples of hypothalamic-pituitary negative feedback except:
- A. Cortisol on the CRH-ACTH axis
- B. Gonadal steroids on the GnRH-LH/FSH axis
- C. IGF-1 on the growth hormone-releasing hormone (GHRH)-GH axis
- D. Renin-angiotensin-aldosterone axis
Correct Answer: D
Rationale: The renin-angiotensin-aldosterone axis does not involve the hypothalamus or pituitary gland; instead, it primarily involves the kidneys and the renin-secreting cells. In this axis, renin is released in response to low blood pressure, leading to the formation of angiotensin II and the subsequent release of aldosterone from the adrenal glands. Feedback mechanisms for this axis primarily involve the regulation of renin release based on blood pressure rather than involving direct negative feedback from downstream hormones on the hypothalamus or pituitary gland. On the other hand, choices A, B, and C all involve classic examples of hypothalamic-pituitary negative feedback loops where the end hormone suppresses the release of the stimulating hormones at the hypothalamic and pituitary levels.
Which of the following is the most common cause of Cushing's disease?
- A. ACTH-producing pituitary adenoma
- B. Adrenocortical adenoma
- C. Ectopic ACTH secretion
- D. McCune-Albright syndrome
Correct Answer: A
Rationale: The most common cause of Cushing's disease is an ACTH-producing pituitary adenoma. In this condition, the pituitary gland produces excessive amounts of adrenocorticotropic hormone (ACTH), which stimulates the adrenal glands to produce high levels of cortisol. This leads to the signs and symptoms of Cushing's disease, such as weight gain, high blood pressure, and muscle weakness. Adrenocortical adenoma refers to a benign tumor of the adrenal cortex that can also cause Cushing's syndrome, but it is not as common as an ACTH-producing pituitary adenoma. Ectopic ACTH secretion occurs when a non-pituitary tumor produces ACTH, leading to Cushing's syndrome. McCune-Albright syndrome is a rare genetic disorder that can cause various endocrine abnormalities, but it is not a common cause of Cushing's disease.
Earliest changes observed by ophthalmoscope in background retinopathy of diabetes is:
- A. Venous dilatation
- B. Microaneurysms
- C. Increased capillary permeability
- D. Arteriovenous shunts
Correct Answer: B
Rationale: The earliest changes observed by ophthalmoscope in background retinopathy of diabetes is typically the presence of microaneurysms. These are small dilations of retinal capillaries due to weakening of the vessel walls caused by diabetes-induced damage. Microaneurysms are a hallmark sign of diabetic retinopathy and are often the first visible sign on retinal examination. Other changes in diabetic retinopathy, such as venous dilatation, increased capillary permeability, and arteriovenous shunts, may develop later in the disease process as it progresses.