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Vasculitis

Educational clinical summary of Vasculitis for doctors and students: definition, workup, management, and key caveats. Not a substitute for guidelines.

Maintained by Dr. Vivek Karn Review process: editorial policy

Disclaimer: This information is intended for educational purposes only and should not be considered medical advice. Clinical decisions must always be made by a qualified healthcare professional, taking into account the individual patient's condition, available evidence, and clinical judgment. This document does not replace direct patient care or professional medical consultation.

Overview

  • Definition: Vasculitis is a clinicopathologic process characterized by inflammation of blood vessel walls, leading to narrowing, occlusion, or aneurysm formation, and potentially resulting in ischemia, hemorrhage, and organ damage. It can affect vessels of any size (arteries, arterioles, capillaries, venules, veins) and in any organ system.
  • Epidemiology: The epidemiology varies significantly by type.
    • Giant Cell Arteritis (GCA): Most common primary vasculitis in adults, incidence ~20 per 100,000 people over 50 years old per year. Predominantly affects women (2-3:1) of Northern European descent, typically >50 years.
    • Polyarteritis Nodosa (PAN): Rare, incidence ~0.7 per 100,000 adults per year. No strong sex or age predilection, but often associated with Hepatitis B infection.
    • ANCA-Associated Vasculitis (AAV) (Granulomatosis with Polyangiitis [GPA], Microscopic Polyangiitis [MPA], Eosinophilic Granulomatosis with Polyangiitis [EGPA]): Combined incidence ~20 per million adults per year. GPA and MPA incidence increases with age, peaking in the 6th-7th decades. EGPA is rarer, affecting adults of all ages.
    • IgA Vasculitis (Henoch-SchĂśnlein Purpura): Most common vasculitis in children, incidence ~10-20 per 100,000 children per year. Affects boys more than girls.

  • Classification: The most widely used classification is the 2012 revised Chapel Hill Consensus Conference (CHCC) nomenclature, categorizing vasculitides primarily by the size of the predominant blood vessel affected:

    • Large Vessel Vasculitis (LVV)
      • Giant Cell Arteritis (GCA): Granulomatous inflammation of large- and medium-sized arteries, especially cranial branches of the aorta. Often affects temporal artery.
      • Takayasu Arteritis (TA): Granulomatous inflammation of the aorta and its major branches, typically in individuals <50 years.
    • Medium Vessel Vasculitis (MVV)
      • Polyarteritis Nodosa (PAN): Necrotizing inflammation of medium-sized arteries without glomerulonephritis or vasculitis in arterioles, capillaries, or venules. Not associated with ANCA.
      • Kawasaki Disease (KD): Arteritis of medium-sized arteries, particularly coronary arteries, often in children.
    • Small Vessel Vasculitis (SVV)
      • ANCA-Associated Vasculitis (AAV): Necrotizing vasculitis with few or no immune deposits, predominantly affecting small vessels. ANCA positivity is common.
        • Granulomatosis with Polyangiitis (GPA) (formerly Wegener's): Necrotizing granulomatous inflammation usually involving the upper and lower respiratory tract, glomerulonephritis, and systemic small vessel vasculitis. PR3-ANCA positive in ~80%.
        • Microscopic Polyangiitis (MPA): Necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (capillaries, venules, arterioles). Necrotizing glomerulonephritis and pulmonary capillaritis are common. MPO-ANCA positive in ~70%.
        • Eosinophilic Granulomatosis with Polyangiitis (EGPA) (formerly Churg-Strauss syndrome): Eosinophil-rich granulomatous inflammation involving the respiratory tract and necrotizing vasculitis predominantly affecting small-to-medium vessels. Associated with asthma and eosinophilia. MPO-ANCA positive in ~40%.
      • Immune Complex Small Vessel Vasculitis: Vasculitis with immune deposits in vessel walls.
        • IgA Vasculitis (IgAV) (formerly Henoch-SchĂśnlein Purpura): Predominantly IgA1 deposits in small vessels, often affecting skin, GI tract, joints, and kidneys.
        • Cryoglobulinemic Vasculitis: Vasculitis with cryoglobulin immune deposits, affecting small vessels, often associated with hepatitis C infection.
        • Hypocomplementemic Urticarial Vasculitis (anti-C1q vasculitis): Urticarial rash associated with hypocomplementemia and anti-C1q antibodies.
        • Anti-Glomerular Basement Membrane (GBM) Disease: Not a vasculitis per se, but can present with systemic features and rapidly progressive glomerulonephritis/pulmonary hemorrhage, often requiring differentiation from AAV.
    • Variable Vessel Vasculitis
      • Behçet's Disease (BD): Vasculitis affecting vessels of any size, characterized by recurrent oral and genital ulcers, skin lesions, and ocular inflammation.
      • Cogan's Syndrome: Interstitial keratitis and vestibuloauditory dysfunction, potentially associated with large vessel vasculitis.
    • Secondary Vasculitis: Vasculitis associated with an underlying condition.
      • Associated with Systemic Disease: Lupus vasculitis, rheumatoid vasculitis.
      • Associated with Probable Etiology: Drug-induced vasculitis, infection-associated (e.g., bacterial endocarditis, HIV, hepatitis B/C).
      • Vasculitis Associated with Malignancy.
    • Single-Organ Vasculitis: Vasculitis affecting only one organ, without evidence of systemic involvement (e.g., cutaneous leukocytoclastic angiitis, primary CNS vasculitis).

Pathophysiology

  • Mechanism: Vasculitis is an immune-mediated inflammatory process targeting blood vessel walls. The exact mechanisms vary by type but generally involve:
    • Type III Hypersensitivity: Formation of immune complexes (antigen-antibody complexes) that deposit in vessel walls, activating complement and attracting inflammatory cells (e.g., IgA vasculitis, cryoglobulinemic vasculitis).
    • Type II Hypersensitivity (Autoantibody-mediated): Autoantibodies directly target components of endothelial cells or neutrophils.
      • ANCA-Associated Vasculitis (AAV): Antibodies against neutrophil cytoplasmic antigens (ANCAs), specifically proteinase 3 (PR3) or myeloperoxidase (MPO), activate neutrophils, leading to degranulation, release of reactive oxygen species, and direct endothelial damage.
      • Anti-Endothelial Cell Antibodies (AECAs): Antibodies targeting endothelial surface antigens may contribute to damage.
    • Cell-Mediated Immunity (Type IV Hypersensitivity): T-lymphocytes and macrophages infiltrate vessel walls, forming granulomas and causing direct cytotoxicity, often seen in large vessel vasculitides (GCA, TA) and GPA. Cytokines (e.g., IL-6, TNF-alpha) play crucial roles.
    • Direct Endothelial Injury: Infections (e.g., viral, bacterial) or certain drugs can directly injure endothelial cells, triggering an inflammatory response.
    • Genetic Susceptibility: Certain HLA alleles (e.g., HLA-DRB104 in GCA; HLA-DPB10401 in GPA) are associated with increased risk.
  • Risk Factors:
    • Genetic Predisposition: Specific HLA alleles (e.g., HLA-DRB104 for GCA; HLA-DPB10401 for GPA).
    • Age: GCA and TA are age-related (>50 for GCA, <50 for TA). AAV incidence increases with age. IgAV common in children.
    • Sex: GCA and TA more common in women.
    • Infections: Hepatitis B (PAN), Hepatitis C (cryoglobulinemic vasculitis), bacterial infections (IgA vasculitis), parvovirus B19, HIV.
    • Drugs: Hydralazine, propylthiouracil, allopurinol, TNF-alpha inhibitors, cocaine (levamisole-adulterated). Drug-induced ANCA vasculitis.
    • Environmental Exposures: Silica dust (AAV), smoking (Buerger's disease, associated with some AAV).
    • Malignancy: Paraneoplastic vasculitis (e.g., associated with lymphoproliferative disorders, solid tumors).
    • Autoimmune Diseases: Systemic lupus erythematosus, rheumatoid arthritis.
  • Protective Factors: Generally few specific protective factors.
    • Vaccination: For infections known to trigger vasculitis (e.g., Hepatitis B vaccination to prevent Hepatitis B-associated PAN).
    • Avoidance of Triggers: Smoking cessation, avoiding illicit drug use (e.g., levamisole-adulterated cocaine), careful consideration of drug-induced vasculitis in susceptible individuals.
    • Early Recognition and Treatment: Crucial for preventing progression and long-term complications.

Clinical Presentation

Signs and Symptoms

Vasculitis is a systemic disease, and its presentation is highly variable depending on the size and location of the affected vessels and the extent of organ involvement.

  • Cardinal Features:
    • Constitutional Symptoms: Fever, fatigue, malaise, anorexia, weight loss (often >10% of body weight). Present in most systemic vasculitides.
    • Skin: Palpable purpura (non-blanching, raised lesions, hallmark of SVV), livedo reticularis, ulcers, nodules, digital ischemia, splinter hemorrhages.
    • Musculoskeletal: Arthralgia, arthritis (often non-deforming), myalgia.
    • Neurological: Mononeuritis multiplex (foot drop, wrist drop), polyneuropathy, stroke, transient ischemic attacks, seizures, headaches, cognitive dysfunction.
    • Renal: Hematuria, proteinuria, red cell casts, rapidly progressive glomerulonephritis leading to acute kidney injury.
    • Pulmonary: Cough, dyspnea, hemoptysis, pulmonary infiltrates, diffuse alveolar hemorrhage.
    • Gastrointestinal: Abdominal pain (colicky, post-prandial), nausea, vomiting, diarrhea, GI bleeding, bowel ischemia/infarction.
    • Ocular: Visual changes (amaurosis fugax, sudden permanent vision loss), diplopia, episcleritis, scleritis, uveitis.
    • Ear/Nose/Throat (ENT): Chronic sinusitis, otitis media, nasal crusting, saddle nose deformity, hearing loss (especially GPA).
    • Cardiovascular: Hypertension (renal artery stenosis), claudication (TA, LVV), aneurysms, myocardial infarction, congestive heart failure.
  • Early Signs:
    • Non-specific constitutional symptoms (fatigue, low-grade fever, weight loss).
    • Persistent arthralgia/myalgia.
    • New-onset headaches (GCA).
    • Persistent or unusual skin rash (e.g., palpable purpura).
    • Unexplained sensory changes or weakness.
    • Unexplained microscopic hematuria or proteinuria.
  • Advanced Signs:
    • Severe organ dysfunction (e.g., acute renal failure requiring dialysis, respiratory failure from diffuse alveolar hemorrhage, complete vision loss, stroke, bowel infarction).
    • Extensive skin necrosis or gangrene.
    • Development of aneurysms or stenoses in large vessels.
  • Atypical Presentations:
    • Single-organ involvement initially, progressing to systemic disease.
    • "Smoldering" disease with chronic fatigue and intermittent symptoms without overt flares.
    • Presentation mimicking infection or malignancy.
    • Overlap syndromes where features of multiple vasculitides or other autoimmune diseases coexist.

Physical Examination

  • Inspection:
    • Skin: Palpable purpura (lower extremities/buttocks), maculopapular rash, urticaria-like lesions, nodules (e.g., rheumatoid nodules), livedo reticularis, skin ulcers, digital ischemia/gangrene.
    • Eyes: Scleritis, episcleritis, uveitis, conjunctival hemorrhage, reduced visual acuity, ophthalmoplegia. Fundoscopic exam may reveal retinal vasculitis or ischemic optic neuropathy.
    • Nose/Mouth/Pharynx: Nasal septal perforation, saddle nose deformity (GPA), oral/genital ulcers (Behçet's), signs of sinusitis.
    • Joints: Swelling, tenderness, decreased range of motion (often non-deforming arthritis).
    • General: Pallor (anemia), cachexia, signs of fluid overload or peripheral edema (renal failure, heart failure).
  • Palpation:
    • Arteries: Tenderness, nodularity, or decreased/absent pulses in affected arteries (e.g., temporal artery in GCA, brachial/radial in TA), bruits.
    • Skin: Palpable purpura (distinguishing from non-palpable petechiae).
    • Abdomen: Tenderness, guarding, rebound (suggesting bowel ischemia/infarction), organomegaly.
  • Special Tests:
    • Neurological Exam: Assessment for motor weakness, sensory deficits (glove-and-stocking distribution for polyneuropathy, specific nerve distribution for mononeuritis multiplex), cranial nerve palsies, reflexes.
    • Ophthalmic Exam: Visual acuity, confrontational visual fields, fundoscopy (for optic disc edema, retinal hemorrhages, vessel occlusions), ocular motility.
    • Cardiovascular Exam: Blood pressure measurement in both arms (may be discrepant in TA), peripheral pulses, cardiac murmurs (valvular disease, endocarditis), signs of heart failure.
    • ENT Exam: Nasal endoscopy for septal perforation or granulomas.

Diagnostic Approach

History Taking

  • Key Questions:
    • Onset and Progression: Acute vs. insidious, pattern of symptoms (relapsing-remitting vs. progressive).
    • Constitutional Symptoms: Fever, weight loss, night sweats, fatigue.
    • Organ-Specific Symptoms:
      • Head/Neck: Headache (character, location, temporal artery tenderness), jaw claudication, scalp tenderness, visual changes (amaurosis fugax, diplopia, sudden vision loss), ear pain, hearing loss, sinusitis, nasal discharge/crusting, oral ulcers.
      • Pulmonary: Cough, shortness of breath, pleuritic chest pain, hemoptysis.
      • Cardiac: Chest pain, palpitations, claudication in limbs.
      • Gastrointestinal: Abdominal pain, nausea, vomiting, diarrhea, melena/hematochezia.
      • Renal: Changes in urine color (dark/bloody), decreased urine output, peripheral edema.
      • Neurological: Numbness, tingling, weakness (specific muscle groups, glove-and-stocking), balance issues, dizziness, seizures, stroke symptoms.
      • Musculoskeletal: Joint pain/swelling, muscle pain/weakness.
      • Skin: Rash characteristics (location, palpable vs. non-palpable, color changes), skin ulcers.
    • Past Medical History: History of chronic infections (Hepatitis B/C, HIV), autoimmune diseases, malignancy, allergies.
    • Medications: Prescription, over-the-counter, herbal supplements, illicit drugs (e.g., levamisole-adulterated cocaine).
    • Family History: Autoimmune diseases, vasculitis.
    • Travel History: Exposure to endemic infections.
    • Social History: Smoking, alcohol, drug use, occupational exposures.
  • Red Flags:
    • Acute Vision Loss: Especially unilateral and sudden (GCA emergency).
    • Rapidly Progressive Glomerulonephritis: Suggests AAV, rapidly progressing to end-stage renal disease.
    • Diffuse Alveolar Hemorrhage: Life-threatening pulmonary emergency (AAV, Anti-GBM disease).
    • Acute Abdomen/GI Bleeding: Suggests bowel ischemia/infarction (PAN, AAV).
    • Stroke/TIA in Young Patients: May suggest CNS vasculitis or Takayasu arteritis.
    • New-onset Mononeuritis Multiplex: Highly suggestive of vasculitis.

Laboratory Tests

  • First-Line:
    • Complete Blood Count (CBC): Anemia (chronic disease, bleeding), leukocytosis (inflammation), thrombocytosis (inflammation), eosinophilia (EGPA).
    • Erythrocyte Sedimentation Rate (ESR) & C-Reactive Protein (CRP): Markedly elevated in most systemic vasculitides (>50 mm/hr for ESR, CRP >20-30 mg/L). Non-specific but indicative of inflammation.
    • Basic Metabolic Panel (BMP): Assess renal function (creatinine, BUN, electrolytes), liver function tests (AST, ALT, alkaline phosphatase, bilirubin).
    • Urinalysis with Microscopy: Hematuria, proteinuria, red blood cell casts (highly suggestive of glomerulonephritis).
    • ANCA Testing:
      • PR3-ANCA (c-ANCA pattern by immunofluorescence): Highly specific for GPA (~80% sensitive, ~95% specific).
      • MPO-ANCA (p-ANCA pattern by immunofluorescence): Highly specific for MPA (~70% sensitive, ~95% specific) and EGPA (~40% sensitive).
      • Note: ANCA testing should include both immunofluorescence and ELISA for PR3 and MPO to confirm specificity.
    • Hepatitis Serologies: HBsAg, anti-HBc, anti-HCV (for Hepatitis B/C-associated vasculitis).
    • Cryoglobulins: Quantitative and qualitative (for cryoglobulinemic vasculitis).
    • Complement Levels (C3, C4): May be low in immune complex-mediated vasculitis (e.g., cryoglobulinemic vasculitis, lupus vasculitis).
    • Antinuclear Antibody (ANA) & Rheumatoid Factor (RF): To rule out systemic autoimmune diseases mimicking vasculitis.
  • Confirmatory:
    • Biopsy of Affected Organ: Often the gold standard for definitive diagnosis.
      • Temporal Artery Biopsy: For GCA. Requires a minimum length of 1.5-3 cm, bilateral often preferred due to skip lesions. Histology shows granulomatous inflammation, intimal hyperplasia, fragmentation of internal elastic lamina, inflammatory infiltrate (mononuclear cells, giant cells).
      • Kidney Biopsy: For glomerulonephritis in AAV, IgAV, PAN. Shows necrotizing glomerulonephritis, pauci-immune (AAV) or immune complex deposits (IgAV).
      • Skin Biopsy: For cutaneous vasculitis (palpable purpura). Shows leukocytoclastic vasculitis (fragmented neutrophils) with fibrinoid necrosis of vessel walls.
      • Nerve Biopsy (sural nerve): For mononeuritis multiplex. Shows vasculitis of vasa nervorum.
      • Lung Biopsy: For pulmonary infiltrates/hemorrhage.
      • Muscle Biopsy: For myositis or PAN.
    • Angiography (Conventional, CTA, MRA): For large and medium vessel vasculitis.
      • Aortography/CTA/MRA: For Takayasu Arteritis (stenosis, occlusion, aneurysm formation in aorta and major branches) or PAN (microaneurysms in renal, mesenteric, hepatic arteries).
  • Monitoring:
    • ESR/CRP: Monitor disease activity, but changes may lag clinical response.
    • CBC: To monitor for anemia, leukopenia (drug side effect), eosinophilia.
    • Renal Function (creatinine, GFR): Essential for kidney involvement.
    • Urinalysis: To track hematuria and proteinuria.
    • ANCA Titers: Controversial for routine monitoring of disease activity. While titers may correlate with disease activity in some, a rise does not always predict relapse, and a normal titer does not rule out active disease. Clinical assessment is paramount.
    • Imaging: Repeat MRA/CTA for large vessel vasculitis to monitor for progression of stenosis or aneurysm formation.

Imaging

  • Recommended:
    • Chest X-ray / High-Resolution Computed Tomography (HRCT) of Chest: To detect pulmonary infiltrates, nodules, cavities, hemorrhage (AAV), or evidence of diffuse alveolar hemorrhage.
    • Computed Tomography Angiography (CTA) or Magnetic Resonance Angiography (MRA):
      • For Large Vessel Vasculitis (GCA, TA): To visualize vessel wall thickening, stenosis, occlusion, or aneurysms in the aorta, subclavian, carotid, and other large arteries. Particularly useful for atypical GCA or monitoring TA.
      • For Medium Vessel Vasculitis (PAN): To detect microaneurysms in renal, mesenteric, and hepatic arteries.
    • Renal Ultrasound: To assess kidney size, hydronephrosis, and cortical thickness in the context of renal involvement.
    • Magnetic Resonance Imaging (MRI) of Brain: For suspected central nervous system (CNS) vasculitis (e.g., primary angiitis of CNS), stroke, or focal neurological deficits.
    • Positron Emission Tomography (PET) Scan: [18F]FDG-PET/CT can detect increased metabolic activity in inflamed large vessel walls (aorta, subclavian arteries) and is highly sensitive for GCA and TA, especially when biopsy is negative or impractical. Useful for assessing disease extent and activity.
  • Advanced:
    • Conventional Catheter Angiography (DSA): Remains the gold standard for detailed visualization of vessel pathology, especially for smaller medium vessels, or when CTA/MRA are inconclusive, or for therapeutic intervention (e.g., angioplasty).
    • Upper Endoscopy/Colonoscopy with Biopsy: For suspected GI vasculitis or unexplained GI bleeding.
    • Nerve Conduction Studies/Electromyography (NCS/EMG): To confirm and characterize neuropathy (e.g., mononeuritis multiplex).

Management

Acute Management

The immediate goals are to suppress inflammation, prevent organ damage, and stabilize the patient.

  • Immediate (First-hour interventions for life- or organ-threatening disease):
    • High-Dose Glucocorticoids:
      • Methylprednisolone IV pulse: For severe organ-threatening vasculitis (e.g., rapidly progressive glomerulonephritis, diffuse alveolar hemorrhage, acute vision loss in GCA, severe CNS involvement). Typically 500-1000 mg IV daily for 3-5 days.
      • Prednisone oral: If IV methylprednisolone is not immediately feasible or for less severe but active disease, 1 mg/kg/day (max 60-80 mg/day).
    • Oxygen Support: For pulmonary involvement.
    • Fluid Resuscitation/Blood Transfusion: As needed for shock or severe hemorrhage.
    • Emergency Consults: Ophthalmology (GCA with visual symptoms), Nephrology (rapidly progressive glomerulonephritis), Pulmonology (diffuse alveolar hemorrhage), Surgery (bowel ischemia).
  • Stabilization (Early management priorities):
    • Immunosuppressive Induction Therapy:
      • Cyclophosphamide (CYC): For severe ANCA-associated vasculitis (AAV) and other severe vasculitides (e.g., PAN).
        • IV pulse: 0.5-0.75 g/m² (max 1.2 g) every 2-3 weeks, adjusted for age/renal function.
        • Oral: 1.5-2 mg/kg/day.
      • Rituximab (RTX): An alternative to cyclophosphamide for induction in AAV, especially for relapsing or non-renal severe disease, and for patients unwilling to undergo CYC.
        • Induction: 375 mg/m² weekly for 4 weeks OR 1000 mg IV on days 1 and 15.
      • Intravenous Immunoglobulin (IVIG): May be considered in refractory cases or as an alternative in specific situations (e.g., pregnancy).
    • Plasma Exchange (PLEX): For severe ANCA-associated vasculitis with rapidly progressive glomerulonephritis (creatinine >500 Âľmol/L or 5.7 mg/dL) or diffuse alveolar hemorrhage. Typically 7 sessions over 2 weeks.
    • Antihypertensive Management: Aggressive blood pressure control, especially in patients with renal involvement.
    • Infection Prophylaxis: Prophylaxis against Pneumocystis jirovecii pneumonia (PJP) with trimethoprim-sulfamethoxazole (TMP/SMX) during cyclophosphamide/high-dose steroid therapy.
  • Emergency (Crisis management specific to vasculitis):
    • GCA with Acute Vision Loss: Immediate IV methylprednisolone pulse (e.g., 1000 mg daily for 3 days) followed by high-dose oral prednisone, regardless of biopsy status, to protect the other eye.
    • Diffuse Alveolar Hemorrhage: High-dose IV steroids, CYC/RTX, and often PLEX.
    • Bowel Ischemia/Infarction: Surgical consultation for resection of necrotic bowel, alongside aggressive immunosuppression.
    • Acute Stroke: Management as per stroke guidelines, with concurrent immunosuppression.

Chronic Management

Aims to maintain remission, prevent relapse, and minimize treatment-related toxicity.

  • Pharmacological:
    • Glucocorticoid Taper: After induction, oral prednisone is slowly tapered over months to years to the lowest effective dose, or ideally discontinued. Long-term low-dose prednisone (e.g., <7.5 mg/day) may be necessary for some.
    • Maintenance Immunosuppression (for AAV, PAN, TA): Typically started after 3-6 months of induction therapy.
      • Azathioprine (AZA): 1.5-2 mg/kg/day. First-line for many AAV patients.
      • Methotrexate (MTX): 15-25 mg once weekly. For non-organ-threatening AAV or as an alternative to AZA.
      • Mycophenolate Mofetil (MMF): 1-2 g/day. Alternative, especially in those intolerant or unresponsive to AZA/MTX.
      • Rituximab (RTX): Maintenance infusions (e.g., 500 mg IV every 6 months for 2 years) are effective for AAV, particularly for relapsing disease or in patients at high risk of relapse.
      • Tocilizumab: For GCA and TA. 162 mg subcutaneously weekly or biweekly. Can be steroid-sparing or replace steroids in some cases.
    • Antiplatelet Therapy: Low-dose aspirin (e.g., 81 mg/day) in GCA/TA to reduce ischemic complications, unless contraindicated.
    • Hypertension Management: Strict blood pressure control to prevent further organ damage.
    • Bone Protection: Calcium and Vitamin D supplementation, bisphosphonates for patients on long-term corticosteroids.
    • Proton Pump Inhibitor (PPI): For gastric protection during steroid therapy.
  • Non-pharmacological:
    • Lifestyle Modifications: Smoking cessation (critical for Buerger's disease and beneficial for all vasculitides), healthy diet, regular exercise (as tolerated).
    • Vaccinations: Annual influenza vaccine, pneumococcal vaccine, Hepatitis B vaccine (if not immune). Avoid live vaccines during significant immunosuppression.
    • Infection Prevention: Good hygiene, prompt evaluation of fever/infection symptoms.
    • Psychological Support: Chronic illness can lead to anxiety and depression.
  • Monitoring:
    • Regular Clinical Assessments: Every 1-3 months during remission, assessing for symptoms of relapse or treatment side effects.
    • Laboratory Tests: ESR, CRP, CBC, renal/liver function, urinalysis, serum glucose, lipid profile. Frequency depends on disease activity and medication.
    • Imaging: Periodic MRA/CTA/PET for large vessel vasculitis to monitor for disease progression, aneurysm formation, or stenosis.
    • Bone Mineral Density (BMD) Monitoring: For steroid-induced osteoporosis.
    • Screening: Age-appropriate cancer screening (increased risk with long-term immunosuppression).

Treatment Algorithms

Algorithms vary based on vasculitis type and severity. Here's a general approach for AAV and GCA:

  • First-Line (ANCA-Associated Vasculitis - AAV):

    • Induction of Remission (Severe, Organ-threatening Disease):
      • Glucocorticoids: IV Methylprednisolone (500-1000 mg/day for 3 days) followed by oral Prednisone (1 mg/kg/day, max 60-80 mg/day).
      • Immunosuppressive Agent:
        • Cyclophosphamide (CYC): Oral (1.5-2 mg/kg/day) or IV pulse (0.5-0.75 g/m² every 2-3 weeks).
        • Rituximab (RTX): 375 mg/m² weekly for 4 weeks OR 1000 mg IV on days 1 and 15 (preferable for relapsing disease, non-renal severe disease, or if CYC contraindicated).
      • Plasma Exchange (PLEX): Consider for rapidly progressive glomerulonephritis (creatinine >4 mg/dL) or diffuse alveolar hemorrhage.
      • Avacopan: Oral C5a receptor inhibitor. Can be added to standard therapy to reduce glucocorticoid burden or as a steroid-sparing agent, approved for AAV. (Dosage: 30 mg twice daily).
    • Induction of Remission (Non-organ-threatening Disease):
      • Glucocorticoids: Oral Prednisone (0.5-1 mg/kg/day).
      • Immunosuppressive Agent: Methotrexate (15-25 mg/week) or Azathioprine (1.5-2 mg/kg/day).
    • Maintenance of Remission:
      • After 3-6 months of induction: Transition from CYC to Azathioprine (1.5-2 mg/kg/day) or Methotrexate (15-25 mg/week). Duration 18-24 months.
      • Rituximab (RTX): 500 mg IV every 6 months for 2 years (highly effective for maintenance, particularly for relapse prevention).
      • Prednisone taper: Gradually reduce to <7.5 mg/day, aiming for discontinuation.

  • First-Line (Giant Cell Arteritis - GCA):

    • Oral Prednisone: 40-60 mg daily for non-ocular GCA.
    • IV Methylprednisolone: 500-1000 mg IV daily for 3 days for GCA with visual symptoms or acute visual loss (followed by oral prednisone).
    • Tocilizumab: Consider adding to high-dose glucocorticoids for new-onset or relapsing GCA, or for those requiring prolonged steroid use. 162 mg SC weekly or biweekly. Enables more rapid steroid tapering.
    • Aspirin: Low-dose (81 mg daily) to reduce cerebrovascular ischemic events.
    • Prednisone taper: Taper slowly over 1-2 years, guided by symptoms and inflammatory markers (ESR, CRP).

  • Second-Line:

    • For AAV refractory to initial induction: Switch between CYC and RTX, consider IVIG, or increase dose/duration of PLEX.
    • For GCA refractory to steroids/tocilizumab: Other immunosuppressants (e.g., Methotrexate, Azathioprine) have limited evidence. Trial of tocilizumab if not already used.
    • For other vasculitides: Individualized based on response and specific type (e.g., Dapsone for cutaneous leukocytoclastic vasculitis, TNF-alpha inhibitors for Behçet's).

  • Refractory Cases:

    • Defined as persistent or worsening disease activity despite adequate first-line and second-line therapies.
    • Re-evaluation: Confirm diagnosis, adherence, and exclude infection or malignancy.
    • Intensified Immunosuppression: Higher doses or combination of immunosuppressants.
    • Off-label/Experimental Therapies: Mycophenolate Mofetil, IVIG, anti-TNF agents (e.g., infliximab for Behçet's), alemtuzumab, belimumab.
    • Stem Cell Transplantation: Autologous hematopoietic stem cell transplantation (HSCT) considered in highly selected severe, refractory cases.

Complications

  • Common:
    • Infections: Due to immunosuppression, especially opportunistic infections (e.g., PJP, herpes zoster, fungal infections).
    • Glucocorticoid Side Effects: Osteoporosis, diabetes mellitus, hypertension, cataracts, glaucoma, weight gain, Cushingoid features, skin fragility, mood disturbances.
    • Disease Relapse: Common across many vasculitides, particularly AAV and GCA.
    • Drug Toxicity: Bone marrow suppression (cyclophosphamide, azathioprine), hepatic toxicity (methotrexate, azathioprine), renal toxicity.
  • Serious:
    • Organ Failure:
      • Kidney: End-stage renal disease (ESRD) requiring dialysis or transplant (especially AAV).
      • Pulmonary: Respiratory failure from diffuse alveolar hemorrhage or severe interstitial lung disease.
      • Cardiac: Myocardial infarction, congestive heart failure, valvular disease.
      • Gastrointestinal: Bowel ischemia, perforation, or hemorrhage.
    • Neurological: Stroke, intracranial hemorrhage, seizures, severe neuropathy leading to significant disability.
    • Vascular: Blindness (GCA), aneurysms (rupture risk), major artery stenosis leading to claudication or limb loss.
    • Malignancy: Increased risk of certain cancers (e.g., bladder cancer with cyclophosphamide, skin cancer, lymphoma with immunosuppression).
    • Infections: Severe, life-threatening opportunistic infections (e.g., CMV, disseminated fungal infections).
  • Long-term:
    • Chronic Organ Damage: Persistent renal insufficiency, lung fibrosis, neurological deficits, visual impairment.
    • Cardiovascular Disease: Accelerated atherosclerosis, hypertension.
    • Fatigue and Chronic Pain: Significant impact on quality of life.
    • Psychosocial Impact: Depression, anxiety, unemployment, decreased functional status.

Prognosis

  • Factors:
    • Type of Vasculitis: Some (e.g., IgA vasculitis in children) are generally self-limiting, while others (e.g., AAV, PAN) carry significant mortality if untreated.
    • Extent and Severity of Organ Involvement: Major organ involvement (kidney, lung, CNS, GI tract) at presentation is associated with worse prognosis. The Five-Factor Score (FFS) for PAN/AAV predicts mortality.
    • Age at Onset: Older age is generally associated with worse outcomes, especially in GCA and AAV.
    • Response to Treatment: Early and sustained remission improves prognosis.
    • Presence of Comorbidities: Diabetes, cardiovascular disease, malignancy.
    • ANCA Type: PR3-ANCA positive AAV tends to be more relapsing than MPO-ANCA positive AAV.
  • Survival:
    • Untreated Vasculitis: Many forms are rapidly fatal (e.g., AAV, PAN).
    • Treated AAV: 5-year survival rates have improved dramatically to >70-80% due to advancements in therapy. However, morbidity from chronic organ damage and treatment side effects remains substantial.
    • GCA: With prompt steroid treatment, vision loss can often be prevented. Mortality rates are similar to the general population, but risk of stroke and myocardial infarction may be slightly increased.
    • PAN: 5-year survival in treated patients is >80%.
    • Kawasaki Disease: Excellent prognosis if coronary artery aneurysms are prevented or managed, otherwise risk of MI/sudden death.
  • Quality of Life:
    • Often significantly impaired due to chronic disease activity, organ damage, treatment side effects (especially glucocorticoids), and persistent fatigue, pain, or neurological deficits.
    • Psychological distress, including depression and anxiety, is common.
    • Regular assessment of quality of life and functional status is crucial for comprehensive management.

Prevention

  • Primary (Preventing initial occurrence):
    • Generally not preventable: Most primary vasculitides are autoimmune and their triggers are poorly understood.
    • Smoking Cessation: Crucial for preventing Buerger's disease and may reduce the risk of certain AAVs.
    • Vaccination: Hepatitis B vaccination to prevent Hepatitis B-associated PAN.
    • Avoidance of Illicit Drugs: Specifically levamisole-adulterated cocaine.
  • Secondary (Early detection and intervention):
    • High Index of Suspicion: In patients presenting with multi-system inflammatory symptoms, constitutional symptoms, and elevated inflammatory markers.
    • Prompt Diagnosis and Initiation of Treatment: Early aggressive therapy can prevent irreversible organ damage and reduce mortality, particularly for life-threatening vasculitides (e.g., GCA, AAV).
    • Monitoring of At-Risk Populations: Regular follow-up for patients with known risk factors or prodromal symptoms.
  • Tertiary (Preventing complications and relapse):
    • Adherence to Maintenance Therapy: Crucial for sustaining remission and preventing relapses.
    • Regular Monitoring: Consistent clinical and laboratory follow-up to detect early signs of relapse or complications.
    • Management of Comorbidities: Aggressive management of hypertension, diabetes, hyperlipidemia, and osteoporosis, especially in patients on long-term corticosteroids.
    • Infection Prophylaxis: Prophylaxis against opportunistic infections during immunosuppression.
    • Vaccinations: Keep up-to-date with recommended vaccinations (e.g., annual flu, pneumococcal) while considering risks of live vaccines with immunosuppression.
    • Patient Education: Empowering patients with knowledge about their disease, medications, potential side effects, and warning signs of relapse.

Special Populations

  • Pediatric:
    • Kawasaki Disease: Most common pediatric vasculitis. Acute systemic vasculitis affecting medium-sized arteries, especially coronary arteries. Treatment: IVIG and high-dose aspirin.
    • IgA Vasculitis (IgAV): Most common immune complex SVV in children. Characterized by palpable purpura, arthralgia, abdominal pain, and glomerulonephritis. Generally self-limiting, but renal involvement can be severe.
    • Pediatric ANCA-Associated Vasculitis: Rarer than in adults, but management is similar (steroids, cyclophosphamide/rituximab). Growth retardation and long-term renal failure are significant concerns.
    • Dosages: Immunosuppressant dosages are typically weight-based and adjusted for age and renal function.
    • Long-term Effects: Special attention to growth, development, bone health, and psychosocial impact.
  • Geriatric:
    • Increased Incidence: GCA, AAV, and secondary vasculitides are more common in older adults.
    • Comorbidities: Higher burden of comorbidities (cardiovascular disease, diabetes, renal impairment) impacts treatment choices and increases risk of adverse events.
    • Steroid Side Effects: Older adults are more susceptible to steroid-induced osteoporosis, diabetes, cataracts, and cognitive changes.
    • Polypharmacy: Careful review of medication interactions.
    • Diagnostic Challenges: Atypical presentations, overlap with other age-related conditions.
  • Pregnancy:
    • Disease Activity: Pregnancy can induce flares in some vasculitides (e.g., SLE-associated vasculitis) or may be protective in others.
    • Medication Safety: Many immunosuppressants are teratogenic (e.g., cyclophosphamide, methotrexate, mycophenolate mofetil) and contraindicated. Azathioprine, prednisone, and rituximab (second/third trimester) are generally considered safer. Close collaboration between rheumatologist and obstetrician is essential.
    • Fetal Monitoring: Regular monitoring for fetal growth restriction, pre-eclampsia.
    • Postpartum Flares: Increased risk of flares postpartum.
    • Contraception: Effective contraception is essential for women of childbearing potential on teratogenic drugs.
  • Comorbidities:
    • Renal Impairment: Requires careful adjustment of renally excreted drugs (e.g., cyclophosphamide, methotrexate). Increased risk of adverse events.
    • Diabetes: Glucocorticoids can worsen glycemic control. Requires close monitoring and aggressive management.
    • Cardiovascular Disease: Vasculitis and its treatments (steroids) can accelerate atherosclerosis. Aggressive management of cardiovascular risk factors is paramount.
    • Infections: Patients with chronic infections (e.g., HIV, Hepatitis B/C) require careful balancing of anti-infective and immunosuppressive therapies. Immunosuppression must be initiated cautiously.
    • Malignancy: Increased risk of certain malignancies in vasculitis patients, particularly those on long-term immunosuppression. Regular screening is important.

Clinical Pearls

  • Diagnostic:
    • Think Vasculitis: In any patient with multisystem inflammatory disease of unknown origin, especially with constitutional symptoms and elevated inflammatory markers.
    • Palpable Purpura: A hallmark sign of small vessel vasculitis; mandates investigation.
    • Mononeuritis Multiplex: Highly suggestive of vasculitis until proven otherwise.
    • Biopsy is Key: Tissue biopsy of the most accessible affected organ is often the most definitive diagnostic tool.
    • ANCA Testing: Essential for AAV, but remember seronegative AAV exists. ANCA alone is not diagnostic; always correlate with clinical picture and biopsy.
    • GCA: New-onset headache in an older patient (especially >50) with elevated ESR/CRP warrants urgent evaluation for GCA to prevent irreversible blindness.
  • Treatment:
    • Early and Aggressive: For severe, organ-threatening vasculitis, timely initiation of high-dose glucocorticoids and immunosuppressants is critical to preserve organ function and improve survival.
    • Steroid-Sparing Agents: Aim to transition from high-dose glucocorticoids to steroid-sparing immunosuppressants as soon as possible to minimize side effects.
    • Prophylaxis: Crucial to prevent opportunistic infections (PJP) and steroid-induced osteoporosis.
    • Relapse Management: Be vigilant for signs of relapse, which often require re-induction therapy.
    • Tocilizumab for GCA: A significant advance allowing faster steroid taper and improved outcomes.
    • Avacopan for AAV: A new option to reduce steroid exposure during induction.
  • Pitfalls:
    • Delay in Diagnosis: Can lead to irreversible organ damage.
    • Over-reliance on ESR/CRP: While useful for monitoring, they are non-specific and can be normal in active disease or elevated in other conditions.
    • Ignoring Steroid Side Effects: Proactive management of steroid toxicity is as important as disease control.
    • Misinterpreting ANCA Titers: A positive ANCA does not equal active vasculitis, nor does a negative ANCA rule it out. Titers should not be used in isolation to guide treatment decisions.
    • Inadequate Duration of Maintenance Therapy: Premature cessation of maintenance immunosuppression increases relapse risk.
    • Failure to Consider Secondary Causes: Always rule out infections, drugs, or malignancy as underlying causes of vasculitis.

Recent Updates

  • Guidelines:
    • 2021 American College of Rheumatology (ACR) / European Alliance of Associations for Rheumatology (EULAR) Guidelines for the Management of ANCA-Associated Vasculitis: Updated recommendations for induction and maintenance, incorporating new agents like rituximab more prominently and providing guidance on avacopan and plasma exchange.
    • 2021 ACR/EULAR Guidelines for the Management of Giant Cell Arteritis: Endorsed the use of tocilizumab as a steroid-sparing agent in GCA.
  • Evidence:
    • Avacopan (ADVOCATE trial): Demonstrated efficacy in reducing glucocorticoid exposure while maintaining non-inferiority to prednisone for remission induction in AAV, leading to FDA approval.
    • Tocilizumab (GiACTA trial): Confirmed its steroid-sparing effect and superiority over placebo in maintaining remission in GCA.
    • Rituximab in AAV: Further studies confirm its role as an effective and often preferred alternative to cyclophosphamide for induction in many AAV patients, and its superiority over azathioprine for maintenance therapy in some cases.
    • Improved Imaging Techniques: Increased utility of high-resolution CTA, MRA, and PET for diagnosis and monitoring of large vessel vasculitis, allowing for non-invasive assessment of disease activity and extent.
  • Controversies:
    • Role of ANCA Titers in Monitoring: The utility of routine ANCA titer monitoring to predict relapse or guide treatment decisions remains debated, with some studies showing correlation and others not. Clinical judgment is emphasized.
    • Optimal Duration of Maintenance Therapy: The ideal duration of maintenance immunosuppression in AAV is still under investigation, with ongoing trials exploring longer durations or risk-stratified approaches.
    • Biopsy-Negative GCA: Diagnosis and management of GCA without clear temporal artery biopsy confirmation remain challenging, with reliance on clinical features, imaging (e.g., ultrasound, PET), and response to steroids.

Key References

  • Guidelines:
    • Stone, J. H., et al. (2021). 2021 American College of Rheumatology/European Alliance of Associations for Rheumatology Guideline for the Management of ANCA-Associated Vasculitis. Arthritis & Rheumatology, 73(10), 1771-1785.
    • Hellmann, D. B., et al. (2021). 2021 American College of Rheumatology/European Alliance of Associations for Rheumatology Guideline for the Management of Giant Cell Arteritis. Arthritis & Rheumatology, 73(10), 1751-1769.
    • Jennette, J. C., et al. (2013). 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis & Rheumatism, 65(1), 1-11.
  • Studies:
    • ADVOCATE trial (Avacopan): Jayne, D. R. W., et al. (2021). Glucocorticoid-free remission in ANCA-associated vasculitis. New England Journal of Medicine, 384(7), 599-609.
    • GiACTA trial (Tocilizumab in GCA): Stone, J. H., et al. (2017). Trial of Tocilizumab in Giant-Cell Arteritis. New England Journal of Medicine, 377(4), 317-328.
    • RAVE trial (Rituximab in AAV): Stone, J. H., et al. (2010). Rituximab versus cyclophosphamide for ANCA-associated vasculitis. New England Journal of Medicine, 363(3), 221-232.
    • PEXIVAS trial (Plasma Exchange in AAV): Walsh, M., et al. (2020). Plasma Exchange and Glucocorticoids in Severe ANCA-Associated Vasculitis. New England Journal of Medicine, 382(7), 622-631.
    • MAINRITSAN trials (Rituximab Maintenance in AAV): Charles, P., et al. (2012). Comparison of Azathioprine and Rituximab for Maintenance of Remission in ANCA-Associated Vasculitis. Annals of the Rheumatic Diseases, 71(12), 1957-1963; and PuĂŠchal, X., et al. (2019). Long-term remission with rituximab in ANCA-associated vasculitis. Annals of the Rheumatic Diseases, 78(3), 364-370.
  • Reviews:
    • Watts, R. A., et al. (2022). Vasculitis. The Lancet, 399(10332), 1251-1262.
    • Kitching, A. R., et al. (2020). ANCA-associated vasculitis. Nature Reviews Disease Primers, 6(1), 71.

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