A 15-year-old boy is seen in the clinic for complaints of “dull pain and pulling” in the scrotal area. On examination, the nurse palpates a soft, irregular mass posterior to and above the testis on the left. This mass collapses when the patient is supine and refills when he is upright. This description is consistent with:

Correct Answer: D

Rationale: The correct answer is D: Varicocele. Varicocele is a dilatation of the pampiniform plexus of veins within the scrotum. In this case, the soft, irregular mass that collapses when the patient is supine and refills when he is upright is characteristic of a varicocele due to the pooling of blood causing the mass to vary in size with position changes. A: Epididymitis typically presents with redness, warmth, and tenderness in the epididymis, not a soft, irregular mass. B: Spermatocele is a cystic mass that is typically painless and does not change in size with position changes. C: Testicular torsion presents with severe, sudden onset of testicular pain, swelling, and discoloration, not a soft, irregular mass that changes with position. In summary, the description of a soft, irregular mass that changes with position is consistent with a varicocele,

Correct Answer: C

Rationale: The correct answer is C, Minocycline. Minocycline has a higher potential for vestibular toxicity compared to other tetracyclines due to its greater lipid solubility, leading to increased penetration of the blood-brain barrier and inner ear. This can result in dizziness, vertigo, and imbalance. Choice A, Doxycycline, is less likely to cause vestibular toxicity since it has lower lipid solubility and reduced penetration into the inner ear. Choice B, Oxytetracycline, and Choice D, Demeclocycline, also have lower potential for vestibular toxicity compared to Minocycline due to similar reasons. Overall, Minocycline stands out as the correct answer due to its unique pharmacokinetic properties that predispose it to vestibular toxicity.

Correct Answer: D

Rationale: The correct answer is D: Cefepime. Cefepime is a fourth-generation cephalosporin that has broad-spectrum activity, including against anaerobic gram-negative bacteria like Bacteroides fragilis. Its extended spectrum of activity is due to its increased stability against beta-lactamases produced by many bacteria. Choices A, B, and C (Cefdinir, Cefuroxime, Cefazolin) are not typically effective against anaerobic gram-negative bacteria. Cefdinir is primarily active against respiratory pathogens, Cefuroxime has limited anaerobic coverage, and Cefazolin is more effective against gram-positive bacteria.

Correct Answer: A

Rationale: Step-by-step rationale for choice A (Ganciclovir) being the correct answer: 1. Ganciclovir is a nucleoside analog that inhibits CMV DNA synthesis. 2. It is specifically approved for the treatment of CMV retinitis in immunocompromised patients. 3. Ganciclovir has a high specificity for CMV, making it an effective antiviral agent against CMV. Summary of why the other choices are incorrect: - Choice B (Foscarnet) is also active against CMV but is not as commonly used as Ganciclovir. - Choice C (Acyclovir) is not effective against CMV as it primarily targets herpes simplex virus and varicella-zoster virus. - Choice D ( ) is an incomplete choice and does not correspond to any known antiviral agent.

Correct Answer: B

Rationale: The correct answer is B: Lamivudine and zidovudine. Combivir is a combination therapy that consists of these two drugs. Lamivudine and zidovudine work together to inhibit the replication of the HIV virus. Lamivudine is a nucleoside reverse transcriptase inhibitor, while zidovudine is a nucleoside analog reverse transcriptase inhibitor. Both drugs target different stages of the HIV life cycle, making them effective when used in combination. Choice A (Lamivudine and stavudine) is incorrect because stavudine is not part of the Combivir combination therapy. Choice C (Abacavir and zidovudine) is incorrect because abacavir is not included in Combivir. Choice D (Abacavir and stavudine) is incorrect because stavudine is not part of the Combivir combination therapy.