Makindo Medical Notes

Related Subjects: Asthma |Acute Severe Asthma |Exacerbation of COPD |Pulmonary Embolism |Cardiogenic Pulmonary Oedema |Pneumothorax

⚠️ HIV patients are at ↑ risk of bacterial infections (e.g., Strep. pneumoniae, H. influenzae, Moraxella catarrhalis) and opportunistic infections like PCP.

📖 About

• 🦠 Formerly called Pneumocystis carinii, renamed P. jirovecii. The acronym PCP (Pneumocystis pneumonia) remains in use.
• 🍄 It is a fungus but lacks ergosterol → resistant to conventional antifungals.

🧪 Aetiology

• Occurs when immunocompromised → especially in HIV/AIDS with CD4 < 200 cells/mm³.
• Seen at HIV diagnosis or when ART is interrupted.
• Also in patients on long-term steroids, transplants, chemotherapy, or autoimmune therapy.

🩺 Clinical

• Gradual onset: breathlessness, fever 🌡️, dry cough, malaise.
• Non-HIV patients may deteriorate more acutely.
• Findings: tachypnoea, hypoxia, fine crackles.
• ⬇️ O₂ sats on exertion = classic clue.
• ⚡ Pneumothorax is a severe complication.

🔍 Investigations

• Sputum induction + IF staining (or PCR) → may detect organism.
• BAL via bronchoscopy = gold standard if sputum negative.
• CXR/CT: diffuse bilateral ground-glass opacities 🌫️, sometimes pneumatocele/cystic changes.
• LDH ↑ (>500 U/L, nonspecific marker).
• ABG: PaO₂ ≤ 9.3 kPa → severe disease.
• Beta-D-glucan ↑ (fungal marker, nonspecific).
• Always do HIV test + CD4 count + viral load.

🧾 Differentials

• Bacterial/viral pneumonia (incl. COVID-19, influenza).
• Pulmonary embolism 🫀 (if hypoxia unexplained).
• Asthma (though minimal wheeze here).
• Pulmonary oedema 💧 (radiology overlap).
• HIV-related TB or atypical mycobacteria.

💊 Management

• Stabilise with O₂, monitor, urgent HIV referral.
• Prophylaxis: Co-trimoxazole 960 mg OD (or 3x weekly) if CD4 < 200 or previous PCP.
• Treatment – Mild/Moderate:
  • Co-trimoxazole PO 1920 mg TDS x 21d.
  • Atovaquone 750 mg BD with fatty meal 🍳 if intolerant.
  • Dapsone 100 mg OD + Trimethoprim (20 mg/kg/day).
• Treatment – Severe:
  • IV Co-trimoxazole 120 mg/kg/day (→ 90 mg/kg after 3 days).
  • Clindamycin IV + Primaquine PO.
  • Pentamidine IV (third-line).
• 💊 Steroids: If PaO₂ ≤ 9.3 kPa or sats < 92%. Prednisolone 40 mg BD → taper over 21 days. IV methylprednisolone if unable to take PO.
• 🚨 Monitor for complications esp. pneumothorax.
• Ventilatory support if progressive RF (but risk of barotrauma).
• Start/optimise HAART to restore CD4 >200 and prevent relapse.

📉 Prognosis & Complications

• Untreated → very high mortality. Early Rx improves survival.
• Relapse risk if ART adherence poor.
• Pneumothorax in 5–10% → poor prognosis.
• Secondary bacterial/mycobacterial infections common.

🛡️ Prevention & Long-Term

• Continue Co-trimoxazole prophylaxis until CD4 >200 for 3–6 months on ART.
• Education on ART adherence + follow-up.
• Monitor lung function + imaging if residual damage.

📚 References

• BNF – PCP
• NHS Tayside PCP Guidelines
• NIH HIV Info – PCP