A rare form of necrotising small vessel vasculitis of the upper and lower respiratory tract and the kidneys associated with granuloma formation.
More common over the age of 40 years.
M > F (2:1)
The aetiology is unknown, but it responds to immuno-suppression. The small vessel vasculitis in the kidney causes reduced glomerular filtration rate and ischaemia of the glomeruli and hence acute or chronic renal failure.
General malaise is common. In the upper respiratory tract it causes ulceration and granulomas in the nose and sinuses leading to sinusitis, rhinorrhea and epistaxis. It may be very deforming. In the lungs it causes nodular masses, which may cavitate or infiltrations which can lead to cough, dyspnoea, pleuritic pain and haemoptysis. It affects the kidneys in 90% of cases, manifesting as oliguria, haematuria and uraemia.
An inflammatory small vessel arteritis with predominantly mononuclear infiltrates. There are necrotising granulomata of the respiratory tract. Kidney biopsy reveals a focal necrotising glomerulonephritis.
i. 1 Full blood count: anaemia of chronic disease, neutrophilia.
ii. The ESR is usually very high.
iii. U&Es to assess renal function.
iv. Urine microscopy shows red cell casts.
v. Lung function testing.
vi. The finding of anti neutrophil cytoplasmic antibodies (cANCA) – PR3 (directed against a serine protease termed proteinase C) has a specificity of 90% and a sensitivity of 50% in early disease but closer to 100% in established disease. Finding pANCA (anti-myeloperoxidase) is less specific of Wegener’s, i.e. it is found in other inflammatory conditions.
vii. Transbronchial or open lung biopsy.
viii. Renal biopsy to assess the pattern and severity of glomerulonephritis.
Cyclophosphamide and high-dose steroids to induce remission. Relapse is prevented by long-term low-dose immunosuppression. In pulmonary haemorrhage or severe acute renal failure, plasma exchange may be used. Oral co-trimoxazole is used for nasal involvement.
Once fatal in 1–2 years now much improved due to the use of cyclophosphamide and other immunosuppressive agents.