In an HIV‑positive adult with a CD4 count of 35 cells/µL and a concurrent Trichomonas vaginalis infection, what lifelong prophylaxis for opportunistic infections and what treatment regimen for trichomoniasis (including alternatives for sulfa allergy) are recommended?

Management of HIV with CD4 Count 35 cells/µL and Concurrent Trichomoniasis

For an HIV-positive patient with a CD4 count of 35 cells/µL, initiate lifelong trimethoprim-sulfamethoxazole (TMP-SMZ) one double-strength tablet daily for opportunistic infection prophylaxis, and treat trichomoniasis with metronidazole 2g as a single oral dose under directly observed therapy. 1

Opportunistic Infection Prophylaxis

Primary Prophylaxis Initiation

At a CD4 count of 35 cells/µL, this patient requires immediate prophylaxis against multiple life-threatening opportunistic infections:

• TMP-SMZ one double-strength tablet (160mg TMP/800mg SMX) daily is the preferred regimen for PCP prophylaxis in patients with CD4 counts <200 cells/µL 1
• This daily dosing provides critical cross-protection against toxoplasmosis and common respiratory bacterial infections, which is particularly important at this severely immunocompromised level 1
• Alternative acceptable regimens include one single-strength tablet daily (better tolerated) or one double-strength tablet three times weekly, though daily dosing is preferred at this CD4 level 1, 2

Alternatives for Sulfa Allergy

If the patient has a documented sulfa allergy or cannot tolerate TMP-SMZ:

• Dapsone 100mg daily is the first alternative 1
• Dapsone 50mg daily plus pyrimethamine 50mg weekly plus leucovorin 25mg weekly provides dual protection against PCP and toxoplasmosis 1
• Aerosolized pentamidine 300mg monthly via Respirgard II nebulizer is another option, though it does not provide toxoplasmosis protection 1
• Atovaquone 1500mg daily is effective but substantially more expensive 1

Managing TMP-SMZ Adverse Reactions

A critical pitfall is prematurely discontinuing TMP-SMZ for non-life-threatening reactions:

• For mild rash, fever, or mild cytopenias, continue TMP-SMZ if clinically feasible rather than switching to less effective alternatives 1, 3
• Up to 70% of patients can tolerate TMP-SMZ rechallenge using gradual dose escalation (desensitization) protocols 1, 3
• After resolution of the adverse event, strongly consider reintroducing TMP-SMZ at reduced dose or frequency before abandoning it entirely 1

Lifelong Duration

This prophylaxis must continue for life unless immune reconstitution occurs:

• Prophylaxis can only be discontinued if CD4 count rises above 200 cells/µL and remains there for at least 3 consecutive months on effective HAART 1
• Prophylaxis must be restarted immediately if CD4 count subsequently falls below 200 cells/µL 1

Trichomoniasis Treatment

Standard Treatment Regimen

Metronidazole 2g as a single oral dose under directly observed therapy is the standard treatment 4, 5

Critical Considerations in HIV-Positive Patients

HIV-positive women with trichomoniasis face unique challenges:

• Treatment failure rates are substantial (55% in one study) even with standard 2g single-dose therapy 4
• HIV-positive women have an 18.3% recurrence rate at 1 month post-treatment compared to 8.0% in HIV-negative women 4
• The majority of recurrences (87.5%) occur despite reported medication adherence and no sexual re-exposure, suggesting treatment failure rather than reinfection 5

Alternative Regimens and Escalation

For treatment failures or suspected resistance:

• Metronidazole 500mg orally twice daily for 7 days is the next step for treatment failure 4
• For persistent infection after 7-day therapy, consider higher doses or longer duration with infectious disease consultation 4
• In vitro susceptibility testing should be pursued for isolates from patients with clinical resistance 4

Partner Treatment Strategy

Patient-delivered partner treatment (PDPT) is essential but has limitations:

• Provide metronidazole treatment for all reported sex partners to deliver directly 5
• Among HIV-infected women, 75.4% successfully provided PDPT to all partners, but only 61.7% were certain partners actually took the medication 5
• Factors associated with failure to deliver partner treatment include multiple sex partners, being single, and having partners unaware of the woman's HIV status 5

Test-of-Cure Requirement

Schedule a test-of-cure visit 6-12 days after treatment completion:

• This is particularly important in HIV-positive patients given the high treatment failure rate 5
• Rescreening should be strongly considered given that standard 2g dosing may be inadequate for some HIV-positive women 4

Monitoring Requirements

Regular monitoring is essential for patients on chronic TMP-SMZ prophylaxis:

• Monitor complete blood count monthly, as hematologic toxicity increases with duration of therapy 2
• Monitor renal function and electrolytes regularly 3
• Monitor liver enzymes periodically 3
• Note that trimethoprim blocks tubular secretion of creatinine, causing serum creatinine elevation without actual GFR decline 2

Key Clinical Pitfalls to Avoid

• Do not delay initiating PCP prophylaxis at CD4 count 35 cells/µL—this patient is at extremely high risk for life-threatening opportunistic infections 1
• Do not assume trichomoniasis treatment was successful without test-of-cure in HIV-positive patients 4, 5
• Do not abandon TMP-SMZ for minor adverse reactions without attempting desensitization or dose modification 1, 3
• Do not use inadequate partner treatment strategies—directly observed therapy and partner treatment are both critical 4, 5