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Henoch-Schonlein purpura (HSP) is a vasculitis with IgA dominant immune complexes.1 The small vessel vasculitis is characterised by inflammation and necrosis. We report a case of granulomatous HSP nephritis (HSPN) in association with keratitis and bilateral anterior granulomatous uveitis.
A 42 year old man presented to the casualty department with acute polyarthropathy, purpura, and nephritic syndrome. The urinalysis demonstrated 3+ blood and protein, blood pressure was 152/96, serum creatinine was 130 μmol/l, complement C3 titre was 0.78 g/l (normal 0.88–1.82), and immunoglobulin IgA titre was 4.6 g/litre (normal 0.80–2.80).
He underwent a left native kidney needle biopsy. Light microscopy demonstrated mesangial proliferative glomerulonephritis with no signs of interstitial nephritis. There was prominent vasculitis with a granulomatous response and fibrinoid necrosis (fig 1), mainly affecting the glomerular arterioles. Immunofluorescence studies demonstrated a predominantly granular staining for IgA and C3. Electron microscopy of the glomerulus demonstrated prominent endocapillary cellularity and neutrophil populations, with a number of subepithelial immune complexes.
The clinical and immunopathological findings were consistent with HSPN. His condition responded to oral prednisolone (1 mg/kg), and the laboratory parameters normalised within a 5 month period. The steroid therapy was discontinued and the patient remained systemically well with normal renal function.
One month after remission of the HSPN, he attended the ophthalmic casualty department with a painful right eye. He was treated for a punctate keratitis and corneal epithelial erosion with topical antibiotics and ocular lubricants. This developed into an epithelial defect, but soon resolved. Corneal sensation was intact. One month later, he represented with blurred vision in the right eye. Examination of the left eye was normal. Vision was 6/24, with severe scleral hyperaemia, corneal oedema, mutton-fat keratic precipitates, fibrinous anterior chamber reaction, posterior synechiae, and 2+ anterior vitreal cells. Intraocular pressure was 32 mm Hg and fundal examination was unremarkable.
Routine blood tests and a vasculitis screen, including antinuclear antibodies, antineutrophil cytoplasmic antibody (ANCA), rheumatoid factor, viral serology, autoantibody titres, antistreptolysin O titre, VDRL, and serum angiotensin converting enzyme levels were all normal. The erythrocyte sedimentation rate, C reactive protein, chest x ray, complement titre, urinalysis, and renal function were normal.
The granulomatous anterior uveitis and trabeculitis were treated with dexamethasone 1% eye drops, cyclopentolate 1% eye drops, and oral acetozolamide. After 1 week, he developed bilateral granulomatous anterior uveitis and was treated with topical steroids. After 2 months, the uveitis resolved completely and the intraocular pressure normalised. He reported no recurrence of HSP symptoms during this period.
The relation between idiopathic acute interstitial nephritis and uveitis is well established in the literature.2 There is only a single report of ocular inflammatory disease associated with classic HSP.3 Our patient fulfilled the American College of Rheumatology diagnostic criteria for HSP4; however, the histopathological features demonstrated an unusual type of HSPN.
The differential diagnosis in this case included sarcoidosis, tubulointerstitial nephritis syndrome, ANCA associated granulomatous nephritis, post-streptococcal nephritis, herpetic infections, syphilis, tuberculosis, and Wegener’s granulomatosis. The clinical and immunopathological findings in our patient were consistent with HSPN. The laboratory investigations excluded the other potential aetiologies.
There are anatomic and haemodynamic relations between uveal and renal vasculature, which are important determinants for the site of immune complex deposition. Plasma passes through at high hydrostatic pressure and in large volumes through both the capillaries in the renal glomerulus and uveal tissue, and both vessels contain endothelial fenestrations.5
In classic HSP, there is alternative complement pathway activation with elevated levels of abnormally glycosylated serum IgA1. This is not sufficiently cleared by the liver and leads to increased levels of IgA1 containing circulating immune complexes.6 The immune complexes may reach the eye in the circulation and then deposit in the uveal tissue. The sites of immune complex deposition are ocular resident cells—namely, vascular endothelial cells, pigmented epithelial cells, and corneal endothelial cells.7 There is expression of adhesion molecules on the ocular resident cells, which allows leucocytes to migrate to the uveal tissue and cornea and cause tissue injury—namely, uveitis and keratitis.
In our patient, the finding of a granulomatous vasculitis is highly unusual. Activation of MHC restricted autoreactive CD4+ T cells in renal and uveal tissue may lead to strong macrophage responses, with the formation of granulomas. However, overlap syndromes with other forms of granulomatous vasculitis may occur.8 This expression of MHC class II markers on ocular resident cells has been observed in various experimental uveitides,9,10 and may explain the later presentation of uveitis in this case following remission of the HSPN.
We report an unusual case of a granulomatous HSPN in association with bilateral granulomatous anterior uveitis and keratitis. The inflammatory eye disease may be insidious in onset with an aggressive clinical course.
We thank Dr George Lindrop for help in interpreting the renal biopsy.