Hypocalcemic tetany:

Correct Answer: C

Rationale: Step-by-step rationale: 1. Hypocalcemic tetany is associated with low levels of calcium in the blood. 2. Parathyroid hormone (PTH) plays a crucial role in calcium regulation. 3. A deficiency of PTH can lead to decreased calcium levels, causing tetany. 4. Therefore, choice C is correct as hypocalcemic tetany may be caused by a deficiency of PTH. Summary: A: Incorrect. Hypocalcemic tetany leads to muscle spasms, not flaccid paralysis. B: Incorrect. Curare blockade affects neuromuscular transmission, not calcium levels. D: Incorrect. Insulin deficiency is associated with hyperglycemia, not hypocalcemia leading to tetany.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Hypocalcemic tetany results from low blood calcium levels. 2. Parathyroid hormone (PTH) regulates calcium levels by increasing calcium release from bones and reabsorption in the kidneys. 3. A deficiency in parathyroid activity leads to decreased calcium levels, causing tetany. 4. Choice D is correct as it directly links hypocalcemic tetany to parathyroid dysfunction. Summary: A: Incorrect, calcitonin lowers blood calcium levels. B: Incorrect, TSH regulates thyroid function, not calcium levels. C: Incorrect, osteoclasts break down bone tissue but are not directly related to hypocalcemic tetany.

Correct Answer: A

Rationale: The correct answer is A: Adrenal medulla. The adrenal medulla secretes adrenaline and noradrenaline, which are hormones that enhance the sympathetic response of the body. This response includes increased heart rate, dilation of airways, and increased blood flow to muscles. The other choices, B: Pancreas, C: Adrenal cortex, and D: Parathyroid, do not directly enhance sympathetic responses. The pancreas regulates blood sugar levels, the adrenal cortex produces cortisol and aldosterone, and the parathyroid regulates calcium levels. Therefore, only the adrenal medulla directly contributes to the sympathetic response, making it the correct choice.

Correct Answer: C

Rationale: The correct answer is C: Replacement dose of thyroid hormones. In newly diagnosed cretinism, there is a deficiency of thyroid hormones, leading to developmental delays and other health issues. Administering replacement thyroid hormones is crucial to normalize hormone levels and support proper growth and development. Thyroidectomy (choice A) is not necessary in this case as the goal is to supplement the missing hormones. Option B, the administration of radioactive iodine cocktail, is used to treat hyperthyroidism, not hypothyroidism. Choice D, replacement dose of calcitonin, is not relevant as calcitonin is involved in calcium regulation, not thyroid hormone production. Thus, the most critical need for the child with newly diagnosed cretinism is the replacement dose of thyroid hormones to address the underlying hormonal deficiency.

Correct Answer: A

Rationale: The correct answer is A: diabetes mellitus. This term describes the breakdown of body tissues for energy due to lack of insulin, leading to the production of ketones in the urine. In diabetes mellitus, the body cannot use glucose properly, causing the breakdown of fats and proteins. Addison's disease (B) involves adrenal insufficiency, not tissue breakdown. Diabetes insipidus (C) is a disorder of water balance, not tissue breakdown. Cushing syndrome (D) is characterized by excess cortisol production, not tissue breakdown into urine.