Okay, let's tackle this question about hypothyroidism. The user wants a detailed explanation for an MCQ where the correct answer is an exception among the options. First, I need to recall the key features of hypothyroidism.

Hypothyroidism is characterized by low thyroid hormone levels, leading to a slowed metabolism. Common symptoms include weight gain, cold intolerance, constipation, dry skin, fatigue, and maybe myxedema. The TSH is usually elevated because the pituitary tries to stimulate the thyroid. Now, the question is asking which statement is not true, so I need to think about what might be incorrect.

The correct answer would be the one that contradicts typical findings. For example, if one of the options mentions low TSH, that's a sign of secondary hypothyroidism, but primary hypothyroidism (like Hashimoto's) has high TSH. Wait, but if the question is about the exception, maybe the incorrect statement is something like "weight loss is common" which is actually a symptom of hyperthyroidism. Or maybe a statement that T3 and T4 are elevated, which would be wrong.

Looking at the options provided, since they're labeled A to D but not given specific text, I need to infer possible common incorrect options. Let's say one of the options is "Elevated TSH is always present," which is true for primary hypothyroidism but not in central hypothyroidism where TSH is low. So if an option states that TSH is elevated in all cases, that's incorrect. Another possible incorrect option could be "Increased heart rate" since hypothyroidism causes bradycardia, not tachycardia.

Wait, the question is about which is not true. So the correct answer is the one that's the exception. Let's structure the explanation. Core concept: Hypothyroidism leads to low T3/T4 and elevated TSH in primary cases. Why the correct answer is right: For example, if the correct answer is an option stating low TSH, that's incorrect because primary hypothyroidism has high TSH. The other options would be common features. The clinical pearl might be to remember that TSH is the best initial test for thyroid function.

Now, ensuring each section is covered. The core concept should mention the primary vs secondary hypothyroidism distinction. The correct answer's reasoning would explain why the exception is wrong. Each wrong option's flaw should be addressed. The clinical pearl would emphasize TSH as the key test and the difference between primary and secondary.

**Core Concept**
Hypothyroidism is characterized by decreased thyroid hormone (T3/T4) production, leading to elevated thyroid-stimulating hormone (TSH) in primary cases (e.g., Hashimoto’s thyroiditis). Secondary hypothyroidism (pituitary/hypothalamic dysfunction) presents with low TSH and low T3/T4. Key clinical features include weight gain, cold intolerance, dry skin, bradycardia, and myxedema.

**Why the Correct Answer is Right**
If the correct answer states "Elevated TSH is always present in hypothyroidism," this is incorrect because **secondary hypothyroidism** results from pituitary or hypothalamic failure, where TSH is **low** due to absence of

✓ Correct Answer: D. Sho fontanelle