Retinal vein thrombosis associated with a herbal phytoestrogen preparation in a susceptible patient

A 55 year old woman, known to have systemic lupus erythematosus and protein S deficiency, presented with sudden onset of visual loss in the left eye. Three days previously, she took a herbal phytoestrogen preparation for relief of her menopausal symptoms. Ophthalmological assessment showed a left inferior hemiretinal vein thrombosis. The temporal relation between the onset of visual symptoms and ingestion of this herbal preparation suggested that in this patient with a prior non-manifest prothrombotic tendency, there may be an association between the development of retinal vein thrombosis and herbal phytoestrogen use.