NurseSavvy™
Log inSign Up

Hematology, Oncology & Immunology · Topic 25 of 26

HIV in Acute Care

Infectious disease · HIV

HIV in Acute Care

The CD4 count predicts the opportunist; ART starts early except in cryptococcal or TB meningitis; post-exposure prophylaxis starts within 72 hours.

Key numbers
CD4 under 200: Pneumocystis riskCD4 < 200 cells/µL
PJP: TMP-SMX + prednisone if PaO₂ < 70PaO₂ < 70 mmHg
PEP within 72 hours≤ 72 h
01 · The ruleCD4 under 200: Pneumocystis risk

Opportunistic infection risk tracks the CD4 count: below 200 cells/µL — Pneumocystis pneumonia, toxoplasmic encephalitis and cryptococcal meningitis; below 50 — CMV and disseminated Mycobacterium avium complex.

02 · DoPJP prophylaxis: TMP-SMX by CD4 count

Give TMP-SMX Pneumocystis prophylaxis for prior PJP or a CD4 count below 200 cells/µL in a patient not on or just starting ART; stop once ART keeps CD4 at 200 or more for 3 months.

03 · DoPEP within 72 hours

Start HIV post-exposure prophylaxis as soon as possible — ideally within 24 hours, never later than 72 hours — for 28 days; preferred: bictegravir/emtricitabine/tenofovir alafenamide or dolutegravir plus tenofovir plus emtricitabine or lamivudine.

01

Causes & risk factors

Why it happens
Stopping tenofovir can flare hepatitis BTest for hepatitis B before ART: in HIV–HBV coinfection, stopping emtricitabine or tenofovir can cause a severe hepatitis B flare, so do not interrupt these drugs during admission.
02

Presentation

What you'll see
Toxoplasmosis: multiple ring-enhancing lesions, basal gangliaToxoplasma encephalitis shows multiple ring-enhancing lesions, often in the basal ganglia, with anti-Toxoplasma IgG and a low CD4 count; treat with pyrimethamine, sulfadiazine and leucovorin, or TMP-SMX, for at least 6 weeks.
03

Diagnosis & monitoring

Work-up
Test with 4th-generation Ag/Ab; RNA if acuteScreen with a fourth-generation HIV-1/2 antigen/antibody immunoassay; when acute HIV is suspected (serology can still be negative), send HIV RNA, the most sensitive test early in infection.
04

Do right now

In this order
First moves
1
Test with 4th-generation Ag/Ab; RNA if acute
→
2
PJP: TMP-SMX + prednisone if PaO₂ < 70PaO₂ < 70 mmHg
→
3
Delay ART 4–6 weeks in cryptococcal meningitis
Why each step
Test with 4th-generation Ag/Ab; RNA if acuteScreen with a fourth-generation HIV-1/2 antigen/antibody immunoassay; when acute HIV is suspected (serology can still be negative), send HIV RNA, the most sensitive test early in infection.
PJP: TMP-SMX + prednisone if PaO₂ < 70Treat PJP with TMP-SMX for 21 days; add prednisone 40 mg twice daily (21-day taper) within 72 hours when PaO₂ < 70 mmHg or A–a gradient ≥ 35 mmHg. Start ART within 2 weeks.
Delay ART 4–6 weeks in cryptococcal meningitisStart ART within 2 weeks with most opportunistic infections, but delay it 4–6 weeks after starting cryptococcal meningitis treatment, and also defer it in tuberculous meningitis: early ART there raises adverse events and death.
05

Management

Orders
Cryptococcal meningitis: amphotericin + flucytosine, relieve pressureTreat cryptococcal meningitis with induction liposomal amphotericin B plus flucytosine; measure opening pressure at every lumbar puncture and relieve raised pressure (> 20 cm H₂O) with therapeutic lumbar punctures, which improve survival.
Serum cryptococcal antigen screening at low CD4Check serum cryptococcal antigen in patients with CD4 ≤ 200 cells/µL (especially ≤ 50); most positive patients need brain imaging and lumbar puncture to exclude meningitis before preemptive fluconazole.
Toxoplasma prophylaxis: IgG-positive with CD4 < 100Toxoplasma-seropositive patients with CD4 below 100 cells/µL need prophylaxis — daily double-strength TMP-SMX covers both Toxoplasma and Pneumocystis; dapsone alone does not protect against Toxoplasma.
06

Red flags & don'ts

Avoid harm
IRIS: worsening as immunity recovers on ART complicationImmune reconstitution inflammatory syndrome — paradoxical worsening of a treated infection or unmasking of a hidden one — appears in the first months of ART; usually self-limited, it responds to brief glucocorticoids.
Ritonavir and cobicistat: strong CYP3A4 inhibitors interactionBoosters (ritonavir, cobicistat) strongly inhibit CYP3A4: they are contraindicated with amiodarone, simvastatin, lovastatin and other CYP3A-dependent drugs, and with fluticasone or budesonide they cause Cushing syndrome and adrenal suppression.
Integrase inhibitors: separate from antacids, avoid rifampin interactionPolyvalent cations (Al/Mg antacids, calcium, iron) lower bictegravir levels — give it 2 hours before or 6 hours after antacids; bictegravir/emtricitabine/tenofovir alafenamide is contraindicated with rifampin and dofetilide.
Check G6PD before dapsone avoidIf TMP-SMX is not tolerated, dapsone is the next prophylaxis option — screen for G6PD deficiency first because of severe hemolysis; aerosolized pentamidine or atovaquone are alternatives.
07

The rules

Know these
No MAC prophylaxis if ART starts nowPrimary MAC prophylaxis is not recommended when ART is started immediately, whatever the CD4 count; it is reserved for patients with CD4 < 50 who are not on, or not suppressed by, ART.
08

More detail

Reference
Show 6 reference facts
PJP adjunctive prednisone: 40 mg twice daily on days 1–5, 40 mg daily on days 6–10, then 20 mg daily on days 11–21; IV methylprednisolone is dosed at 80% of the prednisone dose.
Before nPEP, do a rapid or laboratory antigen/antibody HIV test plus creatinine, liver enzymes, hepatitis B serology and pregnancy test, without delaying the first dose; offer a transition to PrEP for ongoing risk.
The 2025 CDC nPEP guideline covers sexual, injection and other nonoccupational exposures; occupational PEP follows separate CDC guidance.
HIV transmission risk after a needlestick with infected blood is roughly 1 in 400 without prophylaxis, higher with deep injury or a hollow-bore needle.
HLA-B*5701 testing is required before abacavir, and baseline genotypic resistance testing guides the ART regimen.
More than half of patients with cryptococcal meningitis have fewer than 20 white cells/µL in the CSF, so a bland CSF does not exclude it — send cryptococcal antigen and culture.
Pearl

Under 200, think Pneumocystis; under 50, think CMV and MAC.

Sources · Merck Manual Professional — Human Immunodeficiency Virus (HIV) Infection · National HIV Curriculum (Univ. of Washington) — Opportunistic Infections: Prevention (summarizes NIH/HIVMA/IDSA OI guidelines; updated Aug 2026) · National HIV Curriculum (Univ. of Washington) — Opportunistic Infections: Treatment (updated Aug 2026) · Tanner MR et al. Antiretroviral Postexposure Prophylaxis After Sexual, Injection Drug Use, or Other Nonoccupational Exposure to HIV — CDC Recommendations, United States, 2025. MMWR Recomm Rep 2025;74(1) · Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide) prescribing information — DailyMed · Norvir (ritonavir) prescribing information — DailyMed · Merck Manual Professional — Pneumocystis jirovecii Pneumonia · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).