Vasculitis

Inflammation of blood vessel walls leading to vessel wall damage, thickening, narrowing/occlusion, and reduced blood flow (ischemia).

• Can cause severe organ damage (renal failure, blindness, stroke) or death if untreated. Early recognition and immunosuppressive therapy can prevent irreversible complications (e.g., blindness in giant cell arteritis). Vasculitides also appear on exams as classic multisystem cases requiring integration of systemic symptoms, lab clues (like ANCA), and organ involvement.

• Often presents with constitutional symptoms (fever, fatigue, weight loss) plus signs of multisystem involvement. Clues like palpable purpura, unexplained ischemic events (digital gangrene), or pulmonary-renal syndrome should raise suspicion for vasculitis.
• Large-vessel vasculitis: e.g., Giant cell (temporal) arteritis in adults >50 with new headaches, scalp tenderness, jaw claudication, vision changes; very high ESR. Takayasu arteritis in young (<40) women causing arm claudication, absent pulses, and BP differences between arms.
• Medium-vessel vasculitis: e.g., Polyarteritis nodosa (PAN) – systemic necrotizing vasculitis (often hepatitis B–associated) causing varied findings: skin nodules, livedo reticularis, hypertension (renal artery), abdominal pain (mesenteric ischemia), neuropathy; classically spares the lungs. Kawasaki disease – pediatric vasculitis with ≥5 days fever, conjunctivitis, mucous membrane inflammation ("strawberry tongue"), rash, hand-foot edema/desquamation, lymphadenopathy; risk of coronary aneurysms. Buerger disease (thromboangiitis obliterans) – smokers with medium/small artery thrombosis causing limb ischemia (digital ulcers, gangrene).
• Small-vessel vasculitis: often causes palpable purpura, glomerulonephritis (hematuria), and/or alveolar hemorrhage (hemoptysis). ANCA-associated examples: Granulomatosis with polyangiitis (GPA, Wegener) – upper airway (chronic sinusitis, otitis, nasal ulcer), lungs (nodules → hemoptysis), kidneys (RPGN); usually c-ANCA (PR3) positive. Microscopic polyangiitis (MPA) – similar lung & kidney involvement but no granulomas or nasopharyngeal disease; typically p-ANCA (MPO) positive. Eosinophilic GPA (Churg–Strauss) – adult-onset asthma, allergic rhinitis, eosinophilia, pulmonary infiltrates; ~40% p-ANCA positive.
• Immune-complex small-vessel vasculitis: IgA vasculitis (Henoch–Schönlein purpura) – usually children post-URI with palpable purpuric rash on buttocks/legs, arthritis, crampy abdominal pain (possible intussusception), and IgA nephropathy (hematuria). Cryoglobulinemic vasculitis – often in hepatitis C; causes purpura, arthralgias, peripheral neuropathy, and MPGN (immune complexes with low complement levels).

1. Always rule out other causes first: e.g., infection (endocarditis, sepsis) or malignancy can mimic vasculitis. Also evaluate for secondary vasculitis (autoimmune disease, drugs).
2. Check inflammatory markers – most systemic vasculitides have markedly ↑ESR and ↑CRP. Obtain relevant serologies: ANCA panel for small-vessel (c-ANCA vs p-ANCA); test for HBV (PAN) and HCV (cryoglobulinemic vasculitis).
3. Biopsy affected tissue whenever possible for definitive diagnosis (e.g., temporal artery biopsy in GCA, kidney/lung biopsy in ANCA vasculitis, skin biopsy in leukocytoclastic vasculitis).
4. Use imaging for large/medium-vessel disease: e.g., angiography (CTA/MRA) can show multiple small aneurysms in mesenteric arteries (PAN) or arterial stenoses/occlusions in Takayasu. Temporal artery ultrasound ("halo" sign) can aid GCA diagnosis.
5. If giant cell arteritis is suspected, start high-dose corticosteroids immediately (do not wait for biopsy) to prevent vision loss.

1. Corticosteroids are the cornerstone for most vasculitides – high-dose prednisone (or IV methylprednisolone) to rapidly reduce inflammation. Start immediately if critical organ involvement (e.g., vision symptoms in GCA).
2. For severe cases, add immunosuppressants: e.g., cyclophosphamide or rituximab for ANCA-associated vasculitis induction (with transition to azathioprine or methotrexate for maintenance); IVIG (plus high-dose aspirin) for Kawasaki disease. Address any underlying trigger (treat HBV/HCV, malignancy, discontinue causative drug).
3. Newer therapies & adjuncts: Tocilizumab (IL-6 inhibitor) for refractory GCA; plasmapheresis in life-threatening cases (e.g., diffuse alveolar hemorrhage or concurrent anti-GBM disease); Avacopan (C5a receptor inhibitor) can be used in ANCA vasculitis to reduce steroid requirement.

• Mnemonic: Wegener = WeCener – Granulomatosis with Polyangiitis (Wegener) is c-ANCA (think of adding a "C").
• P-ANCA is associated with Polyangiitis (microscopic) and pulmonary problems in EGPA (Churg–Strauss) – both typically anti-MPO.
• PAN spares Pulmonary: Polyarteritis nodosa usually involves multiple organs but spares the lungs (no pulmonary vasculitis).
• Age matters: Giant cell arteritis patients are typically >50, whereas Takayasu arteritis patients are <40.

• Vision changes (amaurosis fugax, blurred vision) in suspected temporal arteritis – emergency: start high-dose steroids immediately to prevent permanent blindness.
• Hemoptysis + rapidly progressive GN (pulm-renal syndrome) – suggests life-threatening capillaritis (e.g., GPA or Goodpasture); requires aggressive therapy (immunosuppression ± plasmapheresis).
• Acute mesenteric ischemia (severe abdominal pain, GI bleeding) in vasculitis (e.g., PAN) – indicates intestinal infarction risk (surgical emergency).

1. Unexplained systemic inflammation (fever, weight loss, high ESR) + multi-organ findings (renal, skin, neuro, etc) → suspect vasculitis.
2. Initial evaluation: labs (CBC, metabolic panel), ESR/CRP, and exclude mimics (blood cultures for infection, ANA for lupus, etc). If small-vessel signs, check ANCA; consider HBV/HCV testing.
3. Biopsy an affected organ for confirmation when possible (temporal artery, kidney, skin, etc). Use angiography or appropriate imaging for large or medium vessel involvement.
4. If vasculitis is likely, begin high-dose steroids promptly (don't delay in GCA) then tailor therapy per type (e.g., cyclophosphamide/rituximab for ANCA vasculitis; IVIG for Kawasaki).
5. Consult rheumatology and relevant specialists (nephrology, pulmonology, dermatology) early for multidisciplinary management and monitoring.

• Older woman with new unilateral headache, jaw claudication, high ESR, and transient vision loss → Giant cell (temporal) arteritis.
• Middle-aged man with chronic sinusitis/otitis, perforated nasal septum, hemoptysis, hematuria (RPGN), and c-ANCA positivity → Granulomatosis with polyangiitis (Wegener).
• Child post-URI with palpable purpura on buttocks, abdominal pain, arthralgia, and hematuria → IgA vasculitis (Henoch–Schönlein purpura).