Synopsis
Recognise diffuse alveolar haemorrhage with or without glomerulonephritis, secure respiratory and renal support, and obtain urgent multidisciplinary diagnosis before irreversible lung or kidney injury.
- Diffuse alveolar haemorrhage is bleeding into the alveolar space from pulmonary microvasculature; haemoptysis may be absent, especially in intubated or severely ill patients.
- The core pattern is acute breathlessness or hypoxaemia, new bilateral ground-glass or air-space opacity, falling haemoglobin and bloodier sequential lavage aliquots when bronchoscopy is safe.
- Pulmonary–renal syndrome combines alveolar haemorrhage with glomerulonephritis, classically from ANCA-associated vasculitis, anti-GBM disease or systemic lupus erythematosus.
Key red flags
Acute hypoxaemia, diffuse or patchy bilateral ground-glass opacity and a falling haemoglobin suggest DAH; haemoptysis strengthens but is not required for the diagnosis.
Investigation priorities
Detect blood loss, thrombocytopenia and a reversible haemostatic contributor.
Management branches
Hypoxaemia with bilateral opacities, haemoptysis or unexplained haemoglobin fall.
- Use ABCDE care, controlled oxygen and early critical-care support; crossmatch blood and assess the need for invasive ventilation.
- Stop or reverse anticoagulation and correct severe haemostatic defects when clinically justified, balancing thrombosis risk.
Key medicines
Systemic glucocorticoid inductionUse a specialist acute regimen followed by a protocolised reduction, selected for disease severity, age, infection risk and the current BSR recommendation.
RituximabGive only through the vasculitis service using a licensed or commissioned induction schedule, with pre-infusion screening and current product information.