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Definition, classification and epidemiologic characteristics of vasculitis. Athol Wells Royal Brompton Hospital London, UK . The pulmonary vessels are the new “silent zone” of the lungs . Pulmonary vascular disease. non-vasculitic antiphospholipid syndrome coagulopathies
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Definition, classification and epidemiologic characteristics of vasculitis Athol Wells Royal Brompton Hospital London, UK
The pulmonary vessels are the new “silent zone” of the lungs
Pulmonary vascular disease • non-vasculitic • antiphospholipid syndrome • coagulopathies • systemic sclerosis • A-V malformations • PPH • Behcet’s syndrome • idiopathic pulmonary haemosiderosis • vasculitis • systemic • rheumatological • pulmonary-renal • capillaritis • Behcet’s syndrome • drugs
This talk is fundamentally about the systemic vasculitides and their effect on the lungs
Definition problems • Heterogeneity of pathogenesis (immune complexes, alterations in cell mediated immunity) • Systemic versus lung involvement • Clinical profiles vary widely • Size of vessel involved highly variable • A need for a logical classification
Classification dilemmas • A fundamental division between histological definition and definition based on clinical criteria • Histologic definition: Chapel Hill • Clinical definition: ACR criteria • In addition, pulmonologists need to know pulmonary manifestations
Histologic definitions • Constriction of available information • A histological diagnosis not always possible • In some cases, histologic appearances lie somewhere between entities. Classic problem of granulomatous disease in suspected Wegener’s granulomatosis
Clinical definitions • Rely on formulated criteria • Diseases do not read text books • Many patients fall between entities • No two patients with CSS alike • The concept of the Cheshire cat syndrome: patients who do not meet formal criteria and are unclassifiable
The key question Based on clinical features, or on histologic appearances, which classical vasculitis does my patient most closely resemble?
Therefore, we need the classification framework that follows
Plan of this review • Review of Chapel Hill definitions • Review of ACR criteria and epidemiology for systemic vasculitides affecting the lungs • Brief review of classical pulmonary features in main syndromes (without undue overlap with the next presentation)
Chapel Hill International Consensus nomenclature of systemic vasculitis (1992)
CH: Large vessel vasculitis • Divided into Giant cell arteritis and Takayasu’s arteritis • GCA has predilection for temporal and carotid arteries, sometimes associated with PMR • Takayasu’s: granulomatous inflammation of aorta and major branches • Lung disease rare
CH: medium vesel vasculitis • PAN, Kawasaki disease • PAN: necrotizing inflammation of medium/small arteries without GN or vasculitis within the arterioles, capillaries or venules • Kawasaki: large/medium small vessel arteritis associated with mucocutaneous lymph node syndrome • Neither associated with lung disease
CH: small vessel vasculitis • Wegener’s granulomatosis • Microscopic polyangitis • Churg-Strauss syndrome • Henoch-Schonlein purpura • Essential cryoglobulinaemic vasculitis • Cutaneous leukocytoclastic vasculitis
Giant cell arteritis • Most common systemic vasculitis • Incidence: 120-200/million in Europe • Less frequent in black, Asian, South American populations • Mean age 70 years • Definition requires age over 50 years • Lung involvement exceedingly rare
Takayasu’s arteritis • Most prevalent in Eastern Asia • Incidence in Japan: 150/year • Increasingly recognised in other regions • Peak onset third decade • 70-90% of cases occur in females • Lung involvement not uncommon
Takayasu’s: ACR criteria • Age <40 • Limb claudication • Diminished pulses • BP>10mm Hg difference between arms • Bruits • Abnormal arteriogram Three criteria: 91% sensitivity, 98% specificity
PAN/microscopic polyangiitis • Viewed as same disorder until Chapel Hill consensus conference • Therefore, statements on relative incidence need to be viewed with caution • MP>PAN (MP incidence >8/million in UK, classic PAN: very few cases) • Geographic variation in MP: Kuwait, Spain have higher incidence than Norway • PAN, no gender difference; MP male>female
Clinical features of MP • Cardinal sites lungs and kidneys • No granulomatous component but similar clinical features to WG • No formal ACR criteria • Classical pulmonary presentation is diffuse alveolar haemorrhage
MICROSCOPIC POLYANGIITIS Pathology pulmonary haemorrhage (red cells, fibrin in alveolar spaces) neutrophilic capillaritis with healing, polypoid plugs of organising fibrosis
DIFFERENTIAL DIAGNOSIS OF MICROSCOPIC POLYANGIITIS FeatureMicroscopic PolyangiitisWegener's GranulomatosisPAN Size of vessels: Medium sized arteries Yes or no Yes or no Yes (bronchial arteries) Arterioles, venules, capillaries Yes Yes No Granulomatous inflammation No Yes No Lung involvement Common Common Uncommon ANCAa Mostly P-ANCA Mostly C-ANCA Mostly P-ANCA aANCA = Antineutrophil cytoplasmic antibody.
Pulmonary - renal syndrome algorithm haemoptysis and haematuria glomerulonephritis MSU; U/S; Bx alveolar haemorrhage CxR; CT; BAL Serology: ANCA; anti-GBM; ANA ANCA-associated Anti-GBM immune complex
Churg Strauss syndrome • Rare : annual incidence 3/million • Mean age 30-45 in various series • Very slight bias towards males • Make up <20% of “primary systemic vasculitis (Wegeners, CSS, PAN, microscopic polyangitis)
CSS: ACR criteria • Asthma • Eosinophilia • Neuropathy • Pulmonary infiltrates (not fixed) • Sinusitis • Positive biopsy • Four criteria: 85% sensitivity, 99.7% specificity
CHURG STRAUSS VASCULITIS • Tissue eosinophilia (including eosinophilic pneumonia) • Necrotising granulomatosis • Vasculitis
Wegener’s granulomatosis • Worldwide disease • Geographic variation: incidence 3-10/million, depending upon series • Actual incidence may be much higher as diagnosis often missed in limited disease • Peak incidence ages 30-50 • No gender predilection
WG: ACR criteria • Nasal or oral inflammation • CXR: nodules, fixed infiltrates or cavities • Microscopic haematuria or red cell casts • Granulomatous inflammation on biopsy Two criteria: 88% sensitivity and 92% specificity
WEGENER’S GRANULOMATOSIS Geographic areas of ‘basophilic’ necrosis or neutrophilic microabscesses
WEGENER’S GRANULOMATOSIS • Granulomatous inflammation
WEGENER’S GRANULOMATOSIS Vasculitis (lymphocytes, plasma cells, few eosinophils)
Henoch-Schonlein purpura • Incidence >130/million in children but <15/million in adults • Median age of onset 6 years • Involves skin, joints, GI tract, kidneys • Pulmonary involvement very rare but can be fatal
“Pulmonary capillaritis” • Not a diagnosis • A histopathologic finding: neutrophilic infiltration of interstitium, fibrinous thrombi occluding capillaries, necrosis of capillaries and alveolar walls • Seen in CSS, WG, MP, HSP and in many secondary vasculitides • Often associated with DAH and an active GN: the ”pulmonary-renal syndrome”
Other vasculitides • Rheumatologic disorders: SLE, RA, PM/DM • Behcets • Relapsing polychondritis • Leukocytoclastic vasculitis • Drugs:penicillamine, hydrallazine, nitrofurantoin, propylthiouracil • Lymphomatoid granulomatosis • Necrotizing sarcoid granulomatosis
ANCA positivity How should this be woven into classification and definition?
Immunofluorescence and ELISA • c-ANCA • PR3 • 29kD homologue to elastase and cathepsin G • Bacteriostatic • Inhibited by alpha-1 antitrypsin • Alpha-1 antitrypsin deficiency associated with increased risk of Wegener’s granulomatosis • p-ANCA • MPO • 140kD • Bacteriostatic • Involved in H202 generation
ANCA in diagnosis • An invaluable aide to diagnosis • Not formally incorporated in criteria • Many CSS and MP ANCA negative • In some series, WG ANCA negative in up to 30% • Problems of diagnostic review bias and severity bias • Never rely on ANCA in isolation
Conclusions • Classification and definition of vasculitis useful • Serves as a framework, but many patients lie somewhere in between • Satisfaction of full criteria should not be a sine qua non for a working diagnosis • ANCA an invaluable aide but not a requirement • In my patient, “clinical features most closely resemble which classic vasculitic syndrome”?