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.
Vasculitic neuropathy and pulmonary-renal syndrome
Essential points for quick revision.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Pulmonary-renal disease is a resuscitation diagnosis
Diffuse alveolar haemorrhage can cause severe hypoxaemia without haemoptysis, while crescentic glomerulonephritis can destroy filtration over days; new motor neuropathy also represents continuing nerve infarction.
Action: Admit immediately, involve critical care, respiratory, nephrology and rheumatology, support oxygenation and renal complications, send ANCA and anti-GBM assays and infection samples urgently, obtain kidney tissue within 24 hours when feasible, and start syndrome-appropriate treatment when delay threatens organs.
Synopsis
Recognise two sentinel patterns of systemic vessel injury, localise painful axonal neuropathy, stabilise alveolar haemorrhage and rapidly progressive glomerulonephritis, and secure tissue-directed treatment before permanent organ loss.
Vasculitic neuropathy classically begins as acute or subacute painful, asymmetric sensory or sensorimotor loss affecting separate named nerves; mononeuritis multiplex can later look confluent and symmetrical.
Map individual movements, reflexes and sensory territories, then use nerve-conduction studies and EMG to demonstrate a multifocal axonal process and select a still-active nerve for biopsy.
Pathologically definite vasculitic neuropathy requires vessel-wall inflammation with vascular damage; a combined targeted nerve and muscle biopsy increases information but a negative sample cannot exclude patchy disease.
Key red flags
Hypoxaemia, increasing work of breathing, falling haemoglobin or diffuse new ground-glass or air-space opacity suggests alveolar haemorrhage even when haemoptysis is absent.
Diffuse alveolar haemorrhage
New bilateral opacity, hypoxaemia and falling haemoglobin with or without haemoptysis requires urgent capillaritis and bleeding assessment.
Investigation priorities
01
Immediate oxygenation, haemoglobin and urine assessmentFirst step
Grade respiratory and renal threat before aetiological results return.
Management branches
Immediate stabilisationProtect lungs and kidneys
Hypoxaemia, alveolar opacity and active glomerular urine occur together.
Admit to a monitored setting, support oxygenation and circulation and treat hyperkalaemia, acidosis, overload and infection or major bleeding immediately.
Draw antibody, complement, viral and culture samples before exchange or immunosuppression when this does not delay organ rescue.
ANCA first-line inductionStop pauci-immune capillaritis
Biopsy and phenotype support organ-threatening GPA or MPA.
Key medicines
Rituximab for GPA or MPA inductionGive 375 mg/m2 intravenously once weekly for 4 weeks with glucocorticoid under the licensed adult GPA and MPA induction regimen; use infusion premedication and specialist administration.
AvacopanTake 30 mg orally twice daily with food alongside a rituximab- or cyclophosphamide-based regimen for severe active GPA or MPA; specialist treatment is generally evaluated within the licensed 52-week evidence period. Reduce to 30 mg once daily with a strong CYP3A4 inhibitor.
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.