Correct Answer: D

Rationale: Charcot joint, also known as neuropathic arthropathy, is a serious complication of diabetes mellitus that affects the joints. It commonly affects the foot, especially the midfoot and hindfoot. The condition is characterized by joint deformities, fractures, and dislocations due to nerve damage and loss of sensation in the foot. The repetitive stress on the foot from walking or weight-bearing activities can lead to progressive joint destruction and deformity. It is important for individuals with diabetes to monitor their foot health closely and seek prompt medical attention if they notice any changes or deformities in their feet.

Correct Answer: C

Rationale: Tetany is a condition characterized by involuntary muscle spasms and contractions due to low levels of calcium in the blood. The signs associated with tetany include Trousseau's sign, which is the carpal spasm elicited by inflating a blood pressure cuff above systolic pressure, and Chvostek's sign, which is the facial muscle spasm elicited by tapping on the facial nerve. Peroneal sign is not specifically associated with tetany but can be seen in conditions like peroneal nerve injury. Erb's sign, on the other hand, is not a recognized sign of tetany. It is associated with Erb's palsy, a condition resulting from injury to the brachial plexus nerves, typically during childbirth. Tinel's sign, which is a tingling sensation elicited by tapping over a compressed nerve, is also not a characteristic sign of tetany.

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.

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.

Correct Answer: A

Rationale: The most common cause of Addison's disease is autoimmune adrenalitis, also known as autoimmune adrenal insufficiency. In autoimmune adrenalitis, the adrenal glands are damaged by immune system-mediated processes, leading to their dysfunction. This autoimmune destruction typically presents as bilateral adrenal cortex atrophy due to the formation of granulomas. Therefore, the commonest cause of Addison's disease is the presence of granulomas in the adrenal glands, making option A, Granuloma, the correct choice.