Vasculitis

Introduction

• Defined by inflammatory leukocytes in vessel walls leading to bleeding and compromise of lumen
• Categorised by vessel size

Large vessel vasculitis

• Takayasu arteritis
  • Aorta and major branches with median age of onset of 35
  • Female:Male = 6:1
  • Mostly aorta + major branches
• Giant cell arteritis (temporal arteritis/GCA)
  • Aorta, major branches and predilection for carotid including superficial temporal artery. Usually >50
  • ~50% of patients have aortic involvement
  • Categorisation
    • Cranial GCA
    • Large-vessel GCA
    • Cranial GCA with large vessel involvement
  • Female:Male = 3:1
  • Aortic involvement usually heralded by fever, weight loss, lethargy
• Clinically isolated aortitis (CIA)
  • Female predominance and peaks in 7th decade
  • May well be a subtype of GCA given the above similarities
• Periaortitis
  • Inflammation spreads beyond the aortic wall
  • May present with constitutional symptoms, chest pain or abdominal/back pain
  • Clinical manifestations due to obstruction of adjacent structures are common e.g. lymphatics, retroperitoneal vasculature or ureters

Medium vessel vasculitis

• Polyarteritis nodosa
  • Can affect any organ and typically present with systemic symptoms
  • Striking tendency to spare the lungs
  • Cutaneous-only variant exists
  • Skin involvement often resembles erythema nodosum, palpable purpura, ulcers or vesicular eruptions
• Kawasaki disease

Small vessel vasculitis

• ANCA-associated vasculitis
  • Anti-neutrophil cytoplasmic antibody
  • Microscopic polyangiitis
    • ANCA positive in >90%
    • Mostly glomerulonephritis and pulmonary capillaritis
  • Granulomatosis with polyangiitis (Wegener’s)
    • Upper and lower respiratory tract granulomatous inflammation + necrotising pauci-immune glomerulonephritis
    • ANCA positive in >80%
  • Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)
    • Chronic rhinosinusitis, asthma and eosinophilia
    • ANCA positive in 40%

• Immune complex small-vessel vasculitis
  • Anti-GBM disease
    • Glomerular and pulmonary capillaries
  • Cryoglobulinaemic vasculitis
    • Cryoglobulins (serum proteins that precipitate in cold and dissolve upon rewarming) seen with Hepatitis C infection
    • Skin, glomeruli and peripheral nerves often involved
  • IgA vasculitis (Henoch-Schonlein purpura)
    • Skin, GI tract and glomerulonephritis are all possible

Clinical features suggestive of systemic vasculitis

• Systemic fevers, fatigue, weight loss, arthralgias are often present
• Hx of eye inflammation (particularly scleritis)
• Acute foot or wrist drop may be due motor neuropathy from ischaemia
• Unexplained haemoptysis should raise concern for alveolar haemorrhage and ANCA-associated vasculitis
• Any patient with glomerulonephritis
• History of autoimmune condition, hepatitis virus, drug use

Clinical features

• Examination
  • Sensory and/or motor neuropathy
  • Palpable purpura – Strongly suggestive of cutaneous leukocytoclastic vasculitis and is common in small-vessel vasculitis and PAN
  • Absent or diminished pulses/BP differentials
• Labs
  • ANA – Positive suggests underlying rheumatic disease e.g. SLE
  • Low complement – Low C4 in particular suggests mixed cryoglobulinaemia or SLE
  • ANCA – Highly specific for ANCA-associated vasculitis if suspicion exists
  • Biopsies of skin or temporal artery

Aortitis

Aetiology

Infectious

• Salmonella, Staphylocococcus, Streptococcus, Treponema pallidum
• Fungal
• Mycobacterial

Non-infectious

• Large vessel vasculitis – Giant cell, Takayasu
• Clinically isolated aortitis
• Secondary: AS, Behcet’s, Granulomatosis with polyangiitis, IgG4-related disease, RA, Sarcoidosis, SLE
• Periaortitis: Histiocytosis, inflammatory AAA, retroperitoneal fibrosis, IgG4-related disease, neoplastic, radiation-induced

Lab markers

Studies on patients with GCA-related aortitis have shown universally elevated CRP/ESR

Conversely, studies on those with CIA who have undergone aneurysm repair showed median CRP/ESR levels in the normal range

CRP and ESR are also less likely to be elevated in Takayasu arteritis

Imaging

CT

• May show aortic wall thickening
• Angiography may show luminal irregularities including dilatations and stenosis

MR

• May show wall thickening
• Angiography may show luminal irregularities and mural enhancement, a marker of aortic inflammation with sensitivity of 90% in Takayasu arteritis
• Vessel wall oedema is almost always present in active aortitis and is more sensitively identified on MR than on CT and does not require MR contrast
• Both mural enhancement and oedema may help distinguish atherosclerosis from aortitis

PET

• MR or CT-PET can show increased FDG uptake to help identify inflammation otherwise not visible on plain imaging above
• Patchy uptake may be seen in atherosclerosis however circumferential increased uptake is highly specific for aortitis

Prognosis

Ferfar et al. followed patients diagnosed with aortitis either radiologically or histologically for 52 months

• Aortic aneurysm
  • GCA – 21%
  • TAK – 25%
  • CIA – 43%
• Aortic dissection
  • GCA – 5%
  • TAK – 2%
  • CIA – 10%

Treatment

Immunosuppression the mainstay of active inflammatory conditions.

Treatment of clinically isolated aortitis is more controversial. Immunosuppression may play a role as may elective surgical treatment of aneurysm, ideally during disease remission.

Last Updated on November 9, 2021 by Andrew Crofton