[Pupillary reaction on tyramine- a parameter of uremic sympathicopathy (author's transl)].

Clinical tests, for instance pupillometry, Valsalvatest, and orthostatic tests show evidence of sympathicopathy in chronic renal failure (GFR: less than 30 ml/min). Hemodialysis does not improve the intensity or frequency of the alterations. Toxic effects of uremic toxins on the autonomic nervous system can be supposed.