Periarteritis nodosa and thrombotic thrombocytopenic purpura with serous retinal detachment in siblings

Periarteritis nodosa and thrombotic thrombocytopenic purpura in siblings is reported. In both patients a localised serous retinal detachment and lesions of the retinal pigment epithelium had developed owing to choroidal vascular obstruction. These cases support the suggested possible relationship between the two conditions.