Pituitary apoplexy, the Houssay phenomenon, and accelerated proliferative retinopathy

A 42-year-old man with diabetes mellitus and probably acromegaly had a pituitary apoplexy with left-sided oculomotor palsy. There was an immediate fall in blood glucose concentration. Pituitary insufficiency promptly developed. Blood glucose levels remained normal for the next two years. During the first year after the pituitary apoplexy, severe proliferative retinopathy developed in the left eye, which became almost blind. Only mild retinopathy was present on the right side. Plasma concentrations of growth hormone remained low after the apoplexy, and the acromegalic features subsided. The explanation of these findings may be that the proliferative retinal angiopathy was caused by compression of the cavernous sinus at the time of the apoplexy. This would lead to impaired venous drainage, thus resembling occlusion of the central retinal vein, which may cause retinopathy similar to that seen in diabetes mellitus.