Correct Answer: B

Rationale: The correct answer is B: Metronidazole (Flagyl). When treating extraintestinal amebiasis, chloroquine is often used in combination with metronidazole to ensure the eradication of the parasite. Metronidazole helps to target the infection more effectively. Choices A, C, and D are incorrect. Iodoquinol (Yodoxin) is another antiprotozoal agent but is not typically used in combination with chloroquine for amebiasis. Metyrosine (Demser) is used in the management of pheochromocytoma, and carbamazepine (Tegretol) is an anticonvulsant and mood-stabilizing drug, neither of which are indicated for extraintestinal amebiasis.

Correct Answer: B

Rationale: The correct answer is B: Chronic obstructive pulmonary disease (COPD). COPD is often associated with a chronic cough and shortness of breath, especially in individuals with a history of smoking. Pulmonary fibrosis (choice A) typically presents with progressive dyspnea and dry cough. Lung cancer (choice C) may present with a chronic cough, shortness of breath, and other symptoms like weight loss and hemoptysis. Pulmonary edema (choice D) presents with symptoms such as acute shortness of breath, orthopnea, and pink, frothy sputum.

Correct Answer: C

Rationale: The correct answer is C: Serum sickness. Serum sickness is characterized by the formation of immune complexes in response to certain medications or proteins. These immune complexes can deposit in tissues, leading to inflammation and tissue damage. Bronchial asthma (Choice A) is a chronic inflammatory condition of the airways not primarily mediated by immune complexes. Contact dermatitis (Choice B) is a type IV hypersensitivity reaction mediated by T cells, not immune complexes. Rheumatoid arthritis (Choice D) is an autoimmune disease where antibodies target self-antigens, but it is not primarily mediated by immune complexes.

Correct Answer: C

Rationale: The correct answer is C. In assessing a child for migraines, asking about food allergies is least likely to yield data that will confirm or rule out migraines as the cause of his headaches. Food allergies are unrelated to the typical symptoms and triggers of migraines, such as family history, associated symptoms like nausea and vomiting, and pain-free intervals between headaches. Therefore, in this scenario, focusing on food allergies is less relevant for identifying migraines as the cause of the boy's headaches.

Correct Answer: A

Rationale: The Golgi tendon reflex is the correct answer. This reflex protects the muscle and tendons from excessive force by causing the muscle to relax. In this scenario, the downward pressure applied just above the elbow joint triggers the Golgi tendon reflex, resulting in the attacker's collapse. The other options are incorrect: - The myotatic reflex (also known as the stretch reflex) is responsible for contracting a muscle in response to its stretch, not relaxing it. - The withdrawal reflex is a spinal reflex that moves a body part away from a painful stimulus, not directly related to the scenario described. - The crossed-extensor reflex is a reflex that occurs on the opposite side of the body in response to a withdrawal reflex, which is not the case in this situation.