Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Escalate
Worsening hypoxaemia, marked work of breathing, haemodynamic instability or suspected pneumothorax in possible Pneumocystis pneumonia requires immediate oxygen and critical-care assessment while diagnostic sampling and specialist antimicrobial treatment proceed in parallel.
Synopsis
Identify Pneumocystis jirovecii pneumonia in HIV and non-HIV immune suppression, grade gas-exchange impairment, secure respiratory evidence without destabilising the patient, and deliver co-trimoxazole, selected corticosteroids and prevention safely. Confirm treatment against current BHIVA, BNF, eMC and local HIV, haematology or transplant protocols.
Think of PJP with subacute dry cough, fever, exertional breathlessness, disproportionate hypoxaemia and bilateral ground-glass change in a person with impaired T-cell immunity.
Risk includes untreated or advanced HIV, prolonged corticosteroids, haematological malignancy, transplantation and selected biologic or cytotoxic therapies; a normal total white count does not reassure.
Chest radiography can be normal early. Thin-section CT usually shows diffuse or patchy bilateral ground glass but is not pathogen-specific.
Key red flags
Non-HIV fulminant presentation
A patient receiving corticosteroids, chemotherapy, transplant immunosuppression or a T-cell-active biologic develops rapidly increasing oxygen needs and bilateral ground glass over days.
Investigation priorities
01
Arterial blood gas and alveolar-arterial gradientFirst step
Grade hypoxaemia and establish whether HIV-associated disease meets the corticosteroid threshold; record FiO2 and, where safe, obtain the reference sample breathing room air.
Management branches
TreatSuspected PJP with respiratory compromise
Compatible immune risk, CT pattern and hypoxaemia, with results pending.
Stabilise using controlled oxygen to an individual target, obtain ABG and early critical-care review if oxygen needs or work of breathing rise; assess immediately for pneumothorax.
Send induced sputum or BAL only when safe and collect tests for competing infections, but start co-trimoxazole promptly when clinical probability is high.
Key medicines
Co-trimoxazoleTreatment uses 15 to 20 mg/kg/day of the trimethoprim component with 75 to 100 mg/kg/day sulfamethoxazole, divided into 3 or 4 doses intravenously or orally; adjust for renal function and follow the host-specific local duration, commonly 21 days in HIV.
Prednisolone or intravenous methylprednisoloneUse the current BHIVA or local staged regimen for moderate-to-severe HIV-associated PJP, started within 72 hours; intravenous methylprednisolone is often given at 75% of the prednisolone dose when oral therapy is unsuitable.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.