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Musculoskeletal

Vasculitis

Vasculitis is a group of disorders in which vessel-wall inflammation causes ischaemia, aneurysm or haemorrhage; vessel size and the organ pattern guide diagnosis, urgency and treatment.

In a nutshell

Vasculitis is vessel-wall inflammation causing ischaemia, aneurysm or haemorrhage. Classify by vessel size and organ pattern, but confirm the syndrome with clinical assessment, urine, serology, imaging and biopsy where feasible. The highest-yield emergencies are GCA with visual symptoms and the pulmonary-renal syndrome. Active AAV needs specialist induction and maintenance; severe GPA or MPA may be treated with rituximab or cyclophosphamide plus glucocorticoids, with avacopan an additional NICE option in eligible adults.

Classic presentation

A patient with constitutional symptoms, palpable purpura, haematuria and proteinuria, haemoptysis or pulmonary infiltrates, and possibly sinus or nerve disease: think small-vessel vasculitis and assess urgently for AAV, anti-GBM disease and infection.

Key points

  • AAV can be ANCA-negative; PR3 or MPO supports a phenotype but does not diagnose disease or relapse on its own.
  • Active AAV is potentially organ- or life-threatening until assessed; a pulmonary-renal syndrome is an emergency.
  • GPA often combines ENT, lung and kidney disease; EGPA combines asthma, eosinophilia and systemic organ involvement.
  • NICE TA825 recommends avacopan with cyclophosphamide or rituximab for severe active adult GPA or MPA within its marketing authorisation.
  • After GPA or MPA induction, BSR prefers rituximab maintenance; azathioprine or methotrexate are alternatives and maintenance is usually 24–48 months.
  • Suspected GCA requires immediate glucocorticoids and an urgent local diagnostic pathway; do not wait for a normal ESR or biopsy.
  • Do not treat a positive ANCA result in isolation: exclude infection, malignancy, drug-related disease and anti-GBM disease.

First-line investigation

FBC, ESR/CRP, renal function, urinalysis with protein quantification, PR3/MPO-ANCA and syndrome-directed imaging or biopsy.

Management

Recognise organ emergencies

  • Escalate visual symptoms or suspected GCA, pulmonary-renal syndrome, hypoxia, haemoptysis, rapidly worsening kidney function, severe ischaemia, neurological deficit or stridor urgently.4,5,2

Define the syndrome and exclude mimics

  • Map the organs involved, request urine and kidney assessment, PR3/MPO-ANCA and relevant immune-complex tests, and use biopsy or imaging when it will change management.2,3

Induce remission according to subtype and organ threat

  • Severe GPA or MPA needs specialist induction with rituximab or cyclophosphamide plus glucocorticoid-based therapy; eligible adults may receive avacopan with one of these regimens. Severe EGPA follows a different pathway.2,7,6

Prevent infection, toxicity and avoidable damage

  • Use current BNF and local protocols for vaccination, infection prevention, bone and cardiovascular protection, reproductive counselling, monitoring and patient-held safety-netting.2,6

Maintain remission and manage special pathways

  • Prefer rituximab maintenance after GPA or MPA induction, consider alternatives when appropriate, and manage GCA, EGPA, airway stenosis, severe renal disease and relapse through the relevant specialist service.2,3,8

Monitor relapse and long-term organ damage

  • Review symptoms, examination, urine, renal function, inflammatory markers and treatment toxicity; use ANCA trends as context rather than a stand-alone trigger for treatment.2,3

Exam traps

  • A positive ANCA is supportive, not diagnostic; a negative ANCA does not exclude AAV.
  • Normal ESR does not exclude GCA, and treatment must not wait when visual risk is present.
  • Plasma exchange is selective in severe renal GPA or MPA and is not routine for pulmonary haemorrhage without severe kidney involvement.
  • EGPA treatment is not interchangeable with GPA or MPA: eosinophilic and asthma disease may need anti-IL-5 or IL-5-receptor therapy.
  • AAV maintenance is a separate phase from induction; relapse, infection and treatment toxicity all need active monitoring.
  • Stridor or exertional dyspnoea in GPA can indicate subglottic stenosis and needs urgent specialist airway assessment.

Illustrations

Palpable purpura of small-vessel vasculitisA clinical photograph of palpable purpura on the lower legs, with accessible colour and skin-tone context. Do not imply that all vasculitis is cutaneous.James Heilman, MD, Wikimedia Commons · CC-BY-SA-3.0

Key sources

  1. NHS, Vasculitis (NHS condition information covering representative small-, medium- and large-vessel syndromes, symptoms and broad treatment pathways; page last reviewed 17 February 2023)
  2. British Society for Rheumatology 2025 management recommendations for ANCA-associated vasculitis (Rheumatology 2025;64:4470-4494; UK recommendations covering GPA, MPA, EGPA, induction, maintenance, plasma exchange, airway and sinonasal disease)Published 12 Jun 2025
  3. Executive summary: the 2025 BSR management recommendations for ANCA-associated vasculitis (Rheumatology 2025;64:4463-4469; executive summary of the current UK AAV recommendations)Published 12 Jun 2025
  4. NICE NG127, Suspected neurological conditions: recognition and referral (Updated 2 October 2023; includes the recommendation that scalp tenderness or jaw claudication suggestive of temporal arteritis needs blood tests and a local suspected-GCA pathway, and that normal ESR does not exclude GCA)Updated 2 Oct 2023
  5. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis (UK specialist guideline covering urgent assessment, glucocorticoids, diagnostic testing, large-vessel disease and follow-up)
  6. BNF, current prescribing information for vasculitis treatment (Current UK prescribing source for glucocorticoids, rituximab, cyclophosphamide, avacopan, tocilizumab, anti-IL-5 therapy, prophylaxis and monitoring; direct access was restricted and the browser session was unavailable, so unsupported doses were omitted)
  7. NICE TA825, Avacopan for severe active GPA or MPA (NICE recommendation for avacopan with cyclophosphamide or rituximab within its marketing authorisation for severe active adult GPA or MPA)Published 21 Sept 2022
  8. NICE TA518, Tocilizumab for treating giant cell arteritis (NICE recommendation for relapsing or refractory adult GCA, subject to eligibility and a maximum of one year uninterrupted treatment)Published 18 Apr 2018 | Updated 1 Jun 2024

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.