Central retinal vein occlusion in Wegener's granulomatosis without retinal vasculitis

The classic type of Wegener's granulomatosis is characterised by necrotising granulomatous lesions of the upper and lower respiratory tracts, generalised focal necrotising vasculitis and glomerulonephritis, whereas the limited type has no renal involvement.¹ Ocular manifestations occur in 30–50% of the patients,¹ with retinal involvement less frequent and varying from 1 to 13% in the literature.²,³ We report a case of Wegener's granulomatosis presenting with a central retinal vein occlusion (RVO) without clinical evidence of intraocular inflammation or retinal vasculitis.

Case report

A 22‐year‐old white man presented with a 1‐week history of intermittent obscuration of vision in his right eye. His medical history was remarkable for classic Wegener's granulomatosis that had been in remission for the past year. His best‐corrected visual acuities were 20/25 in the right eye and 20/20 in the left eye. No relative afferent pupillary defect was evident. A slit‐lamp examination of the anterior segment was unremarkable. Fundus examination of the right eye showed a clear vitreous, hyperaemic optic disc, peripapillary retinal haemorrhages, cotton wool spots, and dilatation and tortuosity of the retinal venous system (fig 1A). Fluorescein angiography showed delayed and prolonged filling of the retinal vasculature, blocked fluorescence as a result of the retinal haemorrhages and mild vessel staining in a few areas in the late phases (fig 1B–D). Fundus examination of the left eye was normal. The patient was diagnosed as having a central RVO and was urgently referred to his rheumatologist for evaluation of a possible relapse of systemic Wegener's granulomatosis.

Figure 1 Fundus photography and fluorescein angiography of the patient with Wegener's granulomatosis. (A) Right eye fundus showing a hyperaemic optic disc, peripapillary retinal haemorrhage in the superotemporal sector with cotton wool spots along the edge, and dilatation and tortuosity of retinal veins. Fluorescein angiography showing (B) delayed and prolonged filling of the retinal vasculature, (C) blocked fluorescence as a result of the retinal haemorrhages and (D) mild vessel staining in a few areas in the late phases.

Comment

Retinal manifestations in Wegener's granulomatosis include chorioretinitis, macular oedema, retinitis with cotton wool spots, acute retinal necrosis, peripheral retinitis, central retinal artery occlusion and exudative retinal detachment.⁴ Five cases of RVO in Wegener's granulomatosis have been reported in the literature, all occurring in patients with classic Wegener's granulomatosis.¹,²,³ These patients also showed relatively good visual acuity (the worst was 20/60). RVO is believed to be caused by focal necrotising vasculitis.² However, all five patients failed to show any intraocular inflammation or retinal vasculitis at presentation. One of the eyes was enucleated owing to intractable neovascular glaucoma and was evaluated histopathologically, showing patchy areas of chronic choroiditis with no evidence of inflammation in the retinal vessels.² It was proposed that RVO may be due to inflammation occurring in the laminar or retrolaminar portion of the optic nerve that may not be clinically evident.³

The observation of RVO only in patients with classic Wegener's granulomatosis suggests that the mechanism may be similar to that of renal pathology in these patients. Pauci‐immune necrotising extracapillary granuloma formation is a common feature of glomerulonephritis in small vessel vasculitides, such as Wegener's granulomatosis, Churg–Strauss syndrome and microscopic polyangiitis.⁵,⁶ No cases of RVO have been reported in patients with microscopic polyangiitis, but the two reported cases of RVO in Churg–Strauss syndrome also did not show any evidence of vitritis or retinal vasculitis.⁷,⁸ In the first patient, a presumed hypercoagulable state and associated thromboembolism were purported to have led to RVO,⁷ whereas in the second patient, RVO occurred while the patient was adequately anticoagulated.⁸ Lack of granulomatous inflammation is the distinguishing feature of microscopic polyangiitis from both Wegener's granulomatosis and Churg–Strauss syndrome.⁶ We postulate that compression of the central retinal vein (in a laminar or retrolaminar location) by such extracapillary granulomatous lesions may be the mechanism of RVO in such patients. This pathogenic mechanism can also explain the lack of clinical evidence of retinal vasculitis in these patients.