Correct Answer: D

Rationale: Step 1: Toxic thyroid adenoma is characterized by a benign tumor in the thyroid gland. Step 2: This tumor produces excessive amounts of thyroid hormones, particularly T3 and T4. Step 3: The tumor arises from the follicular cells of the thyroid gland. Step 4: Choice D accurately describes a toxic thyroid adenoma as a benign tumor producing excessive thyroid hormones from follicular cells. Summary: Choice A is incorrect because it describes autoimmune thyroid disease, not a toxic adenoma. Choice B is incorrect as it describes a malignant tumor, not a benign one. Choice C is incorrect as it describes thyroiditis, not a toxic adenoma.

Correct Answer: C

Rationale: Elevated glucose levels in obese individuals are often due to insulin resistance. Insulin resistance occurs when the body's cells do not respond effectively to insulin, leading to decreased glucose uptake. This results in elevated blood glucose levels. Diabetic acidosis (choice A) is a complication of uncontrolled diabetes characterized by high blood ketone levels, not directly related to obesity. Glucose intolerance (choice B) refers to the body's inability to regulate blood glucose levels efficiently but is not specific to obesity. Insulin deficiency (choice D) is characteristic of type 1 diabetes, where the body does not produce enough insulin, which is distinct from insulin resistance seen in obesity.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Gynaecomastia is a known side effect of spironolactone, digitalis, and cimetidine. 2. Rifampicin is not associated with gynaecomastia. 3. Rifampicin is an antibiotic used to treat tuberculosis and other infections. 4. The mechanism of action of rifampicin does not involve hormonal changes that could lead to gynaecomastia. Summary of incorrect choices: - A: Spironolactone is a potassium-sparing diuretic that can cause gynaecomastia. - B: Digitalis (digoxin) can lead to gynaecomastia as a side effect. - C: Cimetidine, an H2 receptor antagonist, is also known to cause gynaecomastia.

Correct Answer: A

Rationale: The correct answer is A: Cirrhosis. In cirrhosis, there is a decrease in the binding proteins for T4, leading to decreased total T4 levels in the plasma. Pregnancy, euthyroid sick syndrome, and familial excess thyroid binding globulin are all conditions associated with increased total T4 levels due to various physiological changes. In pregnancy, there is an increase in thyroid hormone production to support fetal development. Euthyroid sick syndrome is a condition where there is a decrease in binding proteins, leading to an increase in free T4 levels but normal total T4 levels. Familial excess thyroid binding globulin causes an increase in total T4 levels due to excessive binding proteins.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C is correct: 1. Growth hormone stimulates increased production of insulin-like growth factor 1 (IGF-1). 2. In acromegaly, there is excessive production of growth hormone. 3. Excess growth hormone leads to elevated levels of IGF-1. 4. IGF-1 is primarily produced in the liver in response to growth hormone stimulation. 5. Therefore, increased levels of growth hormone in acromegaly stimulate increased production of IGF-1 from the liver. Summary: - Choice A is incorrect because vasopressin is not produced from the adrenal glands in response to growth hormone. - Choice B is incorrect because vasopressin is not produced from the liver in response to growth hormone. - Choice D is incorrect because IGF-1 is mainly produced in the liver, not from the adrenal glands, in response to growth hormone.