Correct Answer: D

Rationale: When administering an immunization, it is essential to have epinephrine available in case of an allergic reaction such as anaphylaxis. Epinephrine is the medication of choice for treating severe allergic reactions due to its ability to reverse the symptoms rapidly. Diphenhydramine and hydroxyzine are antihistamines that can help manage mild allergic reactions but are not the primary medications for severe reactions like anaphylaxis. Physostigmine is not indicated for managing allergic reactions and is used for specific conditions such as anticholinergic toxicity.

Correct Answer: B

Rationale: The primary goal of estrogen therapy in menopausal women is to prevent osteoporosis by maintaining bone density. Estrogen helps in preserving bone mass and reducing the risk of fractures. While estrogen therapy may alleviate some menopausal symptoms, such as hot flashes, its primary focus is on bone health rather than symptom management. Increasing calcium absorption and maintaining bone strength are outcomes of preventing osteoporosis rather than the primary goal of estrogen therapy.

Correct Answer: B

Rationale: The correct answer is B. Finasteride (Proscar) is used in the treatment of benign prostatic hyperplasia to improve urinary flow and decrease symptoms of urinary retention by reducing the size of the prostate gland. Choice A is incorrect because although finasteride may reduce the size of the prostate gland, the expected outcome relevant to the patient's symptoms is improved urinary flow rather than a specific change in gland size. Choice C is incorrect because finasteride actually decreases the production of prostate-specific antigen (PSA) due to its mechanism of action. Choice D is incorrect because although improved urinary flow may lead to a reduction in nocturnal awakenings, the main expected outcome of finasteride treatment is related to urinary symptoms.

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: A

Rationale: The correct answer is A: Active tuberculosis. Given the patient's history of homelessness and initiation of isoniazid (INH) treatment, the most likely diagnosis is active tuberculosis. Isoniazid is a first-line medication used in the treatment of active tuberculosis. Latent tuberculosis (choice B) would not typically necessitate treatment with isoniazid alone. Mycobacterium avium complex (choice C) is not typically treated with isoniazid alone. Human immunodeficiency virus (choice D) is a risk factor for developing tuberculosis but is not the primary diagnosis in this patient scenario.