Algorithm - Approach to Fever in an HIV Patient (by CD4 Count) 🧪🌡️
Step 1 - Stabilise & Assess 🛡️ ABCDE assessment (Airway, Breathing, Circulation, Disability, Exposure) Vitals + O₂ saturation monitoring Immediate malaria screen if recent travel 🌍 Bloods: FBC, U&E, LFTs, CRP, cultures ×2, CD4 count & HIV viral load Chest X-ray ± urine/stool cultures Step 2 - Stratify by CD4 Count 📊 >500: Common infections predominate: influenza, pneumonia, UTI; HIV-related OIs rare <200: Suspect Pneumocystis jirovecii pneumonia (PCP) if cough + hypoxia + bilateral infiltrates; also oesophageal candidiasis, chronic cryptosporidiosis <100: Add Toxoplasma gondii encephalitis (focal neuro signs, MRI ring lesions), Cryptococcal meningitis (headache, raised ICP), disseminated candida, histoplasmosis (travel endemic) <50: CMV retinitis/colitis (visual changes, bloody diarrhoea), Mycobacterium avium complex (fever, night sweats, hepatosplenomegaly, raised ALP), PML (progressive neurological decline, JC virus) Step 3 - Immediate Management 🚑 Admit if unwell or CD4 <200 and start Empiric antibiotics if sepsis suspected Low threshold to start PCP therapy (high-dose co-trimoxazole ± steroids if hypoxic) LP if meningitis suspected (cryptococcus, TB) Ophthalmology review if visual symptoms (CMV retinitis) Step 4 - Long-Term Management 🏥 Ensure on ART (start or optimise) Opportunistic infection prophylaxis based on CD4 thresholds Vaccinations: influenza, pneumococcal, hepatitis Regular monitoring of CD4, viral load, and opportunistic infection screening

Algorithm - Approach to Fever in an HIV Patient (by CD4 Count) 🧪🌡️

Step 1 - Stabilise & Assess 🛡️
- ABCDE assessment (Airway, Breathing, Circulation, Disability, Exposure)
- Vitals + O₂ saturation monitoring
- Immediate malaria screen if recent travel 🌍
- Bloods: FBC, U&E, LFTs, CRP, cultures ×2, CD4 count & HIV viral load
- Chest X-ray ± urine/stool cultures
Step 2 - Stratify by CD4 Count 📊
- >500: Common infections predominate: influenza, pneumonia, UTI; HIV-related OIs rare
- <200: Suspect Pneumocystis jirovecii pneumonia (PCP) if cough + hypoxia + bilateral infiltrates; also oesophageal candidiasis, chronic cryptosporidiosis
- <100: Add Toxoplasma gondii encephalitis (focal neuro signs, MRI ring lesions), Cryptococcal meningitis (headache, raised ICP), disseminated candida, histoplasmosis (travel endemic)
- <50: CMV retinitis/colitis (visual changes, bloody diarrhoea), Mycobacterium avium complex (fever, night sweats, hepatosplenomegaly, raised ALP), PML (progressive neurological decline, JC virus)
Step 3 - Immediate Management 🚑
- Admit if unwell or CD4 <200 and start Empiric antibiotics if sepsis suspected
- Low threshold to start PCP therapy (high-dose co-trimoxazole ± steroids if hypoxic)
- LP if meningitis suspected (cryptococcus, TB)
- Ophthalmology review if visual symptoms (CMV retinitis)
Step 4 - Long-Term Management 🏥
- Ensure on ART (start or optimise)
- Opportunistic infection prophylaxis based on CD4 thresholds
- Vaccinations: influenza, pneumococcal, hepatitis
- Regular monitoring of CD4, viral load, and opportunistic infection screening

Teaching Commentary 📘

Anchor your thinking in the CD4 count: - <200 → PCP, candidiasis - <100 → toxoplasmosis, cryptococcus - <50 → CMV, MAC. Remember “common things are common” — bacterial pneumonia, sepsis still predominate in the UK. Early ART reduces severe OIs, but knowledge of CD4 thresholds is essential for exams. 🌡️ Many patients with HIV may be asymptomatic. Always consider risk factors, recent exposures, and perform early testing.

📌 Introduction 🧬

HIV prognosis has dramatically improved with HAART.
Late diagnosis (low CD4) worsens outcomes.
Current common causes of death: CAD, liver failure (HBV/HCV), lymphoma.
HIV is now a chronic manageable disease with near-normal life expectancy if treated early.

🦠 Virus Overview

HIV-1: Globally predominant, more virulent.
HIV-2: Less virulent, mainly West Africa, resistant to NNRTIs.

🔬 Structure & Viral Cycle

Single-stranded RNA retrovirus (lentivirus)
gp120: binds CD4 + CCR5/CXCR4 → entry
gp41: fusion protein
p24 capsid antigen: diagnostic marker
Reverse transcriptase, integrase, protease: essential enzymes

🌀 Viral Life Cycle

gp120 binds CD4 → chemokine receptor (CCR5/CXCR4)
Fusion via gp41 and entry into cell
Reverse transcription: RNA → DNA
Integration into host genome via integrase
Viral proteins synthesized by host machinery
Virion assembly and release

🧬 Genes & Tropism

gag = structural proteins; pol = enzymes; env = envelope (gp120, gp41)
tat, rev = regulatory proteins; vif, vpr, vpu = accessory proteins
Targets: CD4+ T cells, macrophages, dendritic cells → gradual CD4 depletion → immunodeficiency

📡 Transmission & Epidemiology

Sexual contact (↑ risk with STIs) 💏
Blood: needles, transfusions 💉
Vertical: pregnancy, delivery, breastfeeding 🤱
Worldwide burden highest in Sub-Saharan Africa 🌍
Window period: 2–6 weeks → antibody-negative but highly infectious ⚠️

🔎 Clinical Clues to Test HIV

Herpes zoster, recurrent infections
Unexplained lymphadenopathy, fever
Recurrent pneumonia, TB, lymphoma

⚠️ AIDS-Defining Conditions

Infections: PCP, cryptococcosis, CMV, TB, MAC
Cancers: Kaposi’s sarcoma, invasive cervical cancer, NHL
Other: HIV encephalopathy, wasting syndrome

💊 ART & Prophylaxis

Start ART for all patients, irrespective of CD4
Suppress viral load, restore CD4, prevent transmission
Prophylaxis:
- CD4 <200 → co-trimoxazole for PCP
- CD4 <100 → fluconazole for cryptococcus (high-risk)
- CD4 <50 → azithromycin/clarithromycin for MAC, regular fundoscopy for CMV
Monitor: viral load, CD4, renal, liver, metabolic profile
Vaccinations: inactivated vaccines; live vaccines avoided if CD4 <200

CD4 Count Thresholds & Opportunistic Infections 📊

CD4 Count	Common Opportunistic Infections 🦠	Prophylaxis / Notes 💊
<500	Oral candidiasis, shingles, Kaposi’s sarcoma	No routine prophylaxis; start ART
<200	PCP, oesophageal candidiasis, cryptosporidium	Co-trimoxazole daily (stop once CD4 >200 on ART)
<100	Toxoplasmosis, cryptococcal meningitis, disseminated Candida	Co-trimoxazole for toxoplasmosis; consider fluconazole prophylaxis
<50	CMV retinitis/colitis, MAC, PML	Azithromycin weekly for MAC; regular fundoscopy for CMV monitoring

📚 References

NICE Guideline NG60: HIV testing and management
BHIVA Guidelines
Gazzard BG, HIV Medicine, 2018
Panel on Opportunistic Infections in HIV-Infected Adults and Adolescents, CDC

The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms.

AIDS HIV Infection and a Fever ✅