Ocular involvement in hemolytic uremic syndrome due to factor H deficiency—are there therapeutic consequences?

Factor H deficiency is responsible for thrombotic microangiopathy (TMA) via uncontrolled activation of the alternative pathway of the complement system. Ocular TMA has never been reported in patients with factor H abnormalities. A male patient with congenital homozygote factor H deficiency reached end-stage renal disease at the age of 10 years. Hemodialysis was uneventful for 3 years, when, suddenly, unilateral ocular pain and blurred vision occurred while he had febrile pharyngitis. Ophthalmologic examination found vitreous bleeding, elevated ocular pressure, choroidal hemorrhage (ultrasound biomicroscopy) and retinal ischemia (fluorescein angiography). C-reactive protein concentration was increased, while haptoglobin levels remained normal. We suspected that TMA due to factor H deficiency was responsible for the ocular manifestations and immediately initiated daily plasma exchanges (PEs) with fresh frozen plasma (FFP) for 10 days followed by three sessions per week. Factor H serum level increased from 6% to 82%, and C3 level normalized. Progressively, ocular pain decreased, and visual acuity and ophthalmologic findings showed improvement. When there is permanent activation of the alternative pathway in patients with end-stage renal disease (ESRD), the search for secondary targets might be of interest. In nephrectomized patients, no biological parameter can predict isolated ocular TMA. Early ophthalmologic investigation and substitution of factor H via FFP may avoid irreversible damage.