Long-term Crohn’s disease management centers on reducing the immune-driven inflammation with immunomodulators or biologic therapies to maintain remission. 5-fluorouracil is a chemotherapy agent used to treat cancer by targeting rapidly dividing cells; it does not reliably alter the inflammatory pathways in Crohn’s and has significant mucosal toxicity, making it unsuitable for chronic Crohn’s therapy. Azathioprine, in contrast, suppresses the immune system to prevent relapses, and is a standard maintenance option for Crohn’s disease. Omeprazole, a proton-pump inhibitor, lowers stomach acid and can help with unrelated GI symptoms or ulcers but doesn’t address Crohn’s inflammation itself. Allopurinol treats hyperuricemia/gout and isn’t a Crohn’s therapy; though it has notable drug interaction considerations with immunosuppressants like azathioprine, it still isn’t used to manage Crohn’s disease. So, the medication not typically used for long-term Crohn’s disease therapy is 5-fluorouracil.

When subarachnoid hemorrhage is suspected but the initial head CT is negative, you need a test that directly shows blood or its breakdown products in the cerebrospinal fluid. A lumbar puncture provides that answer. CT scans are most sensitive for SAH in the first hours after onset, but their sensitivity wanes with time. If suspicion remains after a negative CT, examining CSF can confirm bleeding. The key findings from a lumbar puncture are red blood cells in the CSF or xanthochromia, which is a yellowish discoloration from bilirubin as blood products break down in the CSF. Xanthochromia usually appears several hours after the hemorrhage, helping to confirm SAH even if the initial bleed wasn’t seen on CT. Interpreting the sample also involves distinguishing a true SAH from a traumatic tap: persistent red blood cells across multiple collected CSF tubes or visible xanthochromia supports SAH, whereas a decreasing number of RBCs in successive tubes with no xanthochromia suggests the blood came from the tap rather than the subarachnoid space. Other options like complete blood count, lipid profile, or electrocardiogram don’t diagnose SAH; they’re not direct tests for bleeding in the subarachnoid space.

Candida vulvovaginitis mainly presents with intense itching and vulvar irritation, often with redness and swelling of the vulvar area. The itching is usually the most prominent symptom, sometimes accompanied by burning or discomfort during urination or intercourse. Discharge, when present, tends to be thick, white, and cottage-cheese–like rather than purulent. Tender lymphadenopathy isn’t typical, and a firm, painless ulcer is not characteristic of candidal infection. So, extreme vulvar irritation from itching best fits the presentation of candidal vulvovaginitis.

This presentation points to bacterial vaginosis, an overgrowth of anaerobic bacteria such as Gardnerella vaginalis. The clue cells on microscopy and the fishy odor with gray-white discharge are characteristic. The treatment of choice is metronidazole because it is highly effective against anaerobes that drive BV. A common regimen is oral metronidazole 500 mg twice daily for 7 days (alternatively, metronidazole vaginal gel 0.75% applied intravaginally for several days). It’s important to avoid alcohol during treatment and for 24 hours after the last dose to prevent a disulfiram-like reaction. The other medications listed target different infections (yeast, gonorrhea, or chlamydia) and are not appropriate for BV.