A patient presents with a sudden onset of severe chest pain radiating to his back. His blood pressure is significantly higher in the right arm than in the left arm. Which of the following conditions is most likely?

Correct Answer: C

Rationale: The correct answer is C, aortic dissection. Aortic dissection is characterized by sudden, severe chest pain that can radiate to the back. The discrepancy in blood pressure between the arms (higher in the right arm) is known as a 'pulse deficit' and is a classic finding in aortic dissection. This condition involves a tear in the inner layer of the aorta, leading to the abnormal flow of blood within the aortic wall. Acute myocardial infarction (choice A) presents with chest pain but typically does not cause discrepancies in blood pressure between arms. Pulmonary embolism (choice B) usually presents with chest pain and difficulty breathing but does not cause unequal blood pressures in the arms. Pericarditis (choice D) can cause chest pain exacerbated by breathing or lying down, but it does not typically lead to differences in blood pressure between arms.

Correct Answer: B

Rationale: The correct answer is B: Lifestyle modification and metformin. When managing type 2 diabetes mellitus, initial treatment often involves lifestyle changes such as adopting a healthy diet and increasing physical activity, along with the oral medication metformin. Insulin therapy (choice A) is usually reserved for cases where lifestyle changes and oral medications are not sufficient to control blood sugar levels. Sulfonylureas (choice C) and thiazolidinediones (choice D) are also oral medications used in diabetes management, but they are not typically recommended as first-line treatments due to various side effects and considerations in type 2 diabetes management.

Correct Answer: A

Rationale: A positive Homan's sign is indicative of deep vein thrombosis. This sign is elicited by dorsiflexing the foot of a patient with the knee slightly flexed, resulting in calf pain. Peripheral artery disease (choice B) is associated with decreased blood flow to the extremities, but it does not produce a positive Homan's sign. Varicose veins (choice C) are enlarged, twisted veins that are typically not related to Homan's sign. Lymphedema (choice D) is swelling caused by a lymphatic system blockage or dysfunction and is not linked to Homan's sign.

Correct Answer: B

Rationale: The scenario describes a 45-year-old woman with fatigue, weight gain, cold intolerance, low T3 and T4 levels, and elevated TSH levels, which are indicative of hypothyroidism. In hypothyroidism, there is decreased production of thyroid hormones (T3 and T4) leading to elevated TSH levels as the pituitary gland tries to stimulate the thyroid gland to produce more hormones. Therefore, the correct answer is hypothyroidism (Choice B). Choice A, Hyperthyroidism, is incorrect as the patient's symptoms and thyroid function tests point towards decreased thyroid hormone levels, which is characteristic of hypothyroidism, not hyperthyroidism. Choice C, Euthyroid sick syndrome, is incorrect because this condition typically presents with normal to low T3 and T4 levels in the setting of non-thyroid illness, unlike the elevated TSH levels observed in this case. Choice D, Subclinical hyperthyroidism, is also incorrect as the patient has low T3 and T4 levels, which is not consistent with hyperthyroidism, whether clinical or subclinical.

Correct Answer: A

Rationale: Primary aldosteronism is a common cause of secondary hypertension. In primary aldosteronism, there is an overproduction of aldosterone from the adrenal glands, leading to increased sodium retention and potassium excretion, ultimately resulting in high blood pressure. Essential hypertension (Choice B) is the most common type of hypertension, but it is considered primary hypertension, not secondary. White coat hypertension (Choice C) refers to elevated blood pressure readings in a clinical setting due to anxiety but not in daily life. Prehypertension (Choice D) is a condition where blood pressure levels are elevated but not high enough to be classified as hypertension.