Known vasculitis, now breathless with haemoptysis, creatinine risen from 90 to 320 µmol/L, urine dipstick blood +++ and protein ++
ABCDE
Support the airway and circulation, then decide the one question that matters: is this the disease flaring, or the immunosuppression letting an infection in? Treat both until you know.
Pulmonary–renal syndrome → urgent ANCA, anti-GBM, ANA, dsDNA, complement, urine microscopy for red-cell casts, chest imaging and a renal biopsy; start pulsed methylprednisolone and discuss plasma exchange for anti-GBM disease or severe alveolar haemorrhage
Giant cell arteritis with visual loss → IV methylprednisolone 500–1000 mg daily for 3 days without waiting for the biopsy; temporal artery ultrasound or biopsy within a week, and start tocilizumab as a steroid-sparing agent
Catastrophic antiphospholipid syndrome → anticoagulate with heparin, give corticosteroids, and add plasma exchange or IVIG; look for the trigger, which is usually infection, surgery or anticoagulant withdrawal
Macrophage activation / haemophagocytic syndrome → suspect with fever, cytopenias, ferritin in the thousands, high triglycerides and low fibrinogen; treat with steroids ± anakinra or etoposide, and look for the driving infection or malignancy
Always in parallel → culture everything, cover for infection, check for Pneumocystis and tuberculosis before escalating immunosuppression, and start prophylaxis alongside high-dose steroids
Order set
- ANCA, anti-GBM, ANA, dsDNA, C3/C4, ferritin, triglycerides
- Urine microscopy for casts; protein:creatinine ratio
- Blood and sputum cultures; β-D-glucan; TB testing
- CT chest; echocardiogram if cardiac features
- Pulsed methylprednisolone once infection is covered
- Renal or tissue biopsy
- PJP and gastric prophylaxis, bone protection
Criteria
AdmitAny suspected flare with organ involvement
ICUAlveolar haemorrhage, rapidly progressive glomerulonephritis, CAPS, MAS/HLH, or airway involvement
DischargeOrgan function stable on a defined immunosuppression plan with monitoring arranged
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Haemoptysis with a falling haemoglobin
- Sudden visual loss or jaw claudication
- Creatinine doubling within days
- Ferritin above 10 000 µg/L
- New multi-territory thrombosis
Differentials
- Infection on immunosuppression
- Sepsis with acute kidney injury
- Thrombotic microangiopathy
- Drug-induced vasculitis
- Malignancy
- Cardiac failure with pulmonary oedema
Common mistakes
- Waiting for serology before treating visual loss in giant cell arteritis
- Escalating immunosuppression into an untreated infection
- Missing PJP prophylaxis with high-dose steroid
- Attributing a rising creatinine to the drug and missing the glomerulonephritis
Disposition & follow-up
Joint rheumatology, nephrology and critical care decision; the immunosuppression plan, the prophylaxis and the monitoring are all written down before the patient leaves ICU.
Discharge package
MedicationsSteroid taper with a written card; prophylaxis; bone and gastric protection
Follow-upRheumatology within 1–2 weeks with bloods before the clinic
LifestyleVaccination review, infection awareness, sun and bone protection
Warning symptomsFever, breathlessness, haemoptysis, visual change, new rash, reduced urine output
💊 Treatment detail — doses & preparation
Methylprednisolonecorticosteroid
Dose500–1000 mg IV daily × 3 days, then oral prednisolone 1 mg/kg
PreparationIn 100 mL saline over 30–60 min
MonitorGlucose, BP, mood, infection
Cyclophosphamidealkylating agent
DosePulsed IV by protocol, reduced for age and renal function
PreparationWith mesna and hydration
MonitorFBC nadir, haemorrhagic cystitis, fertility counselling
Rituximabanti-CD20 antibody
Dose375 mg/m² weekly × 4, or 1 g × 2 doses two weeks apart
PreparationSlow infusion with premedication
MonitorHepatitis B reactivation, hypogammaglobulinaemia, infusion reaction
📖 EULAR/ACR vasculitis guidance · BSR giant cell arteritis · ICU chapter 48 · Rheumatologic CrisesReviewed September 2026