Priapism in a patient treated with total parenteral nutrition

Venous thrombosis is a common complication of total parenteral nutrition. We report a case of priapism in a 40-year-old man after administration of total parenteral nutrition for chronic idiopathic intestinal pseudo-obstruction. The patient received glucose, amino acids, and 20% fat emulsion; 12 hours after administration, the patient complained of a persistent, painful penile erection lasting 5 hours. Bilateral corpora cavernosa spongiosum shunts achieved immediate and sustained detumescence, but the patient remained impotent. There was no history of penile or pelvic trauma, hemoglobinopathy, coagulopathy, venous thrombosis, or leukemia. The medical literature describes seven other cases of priapism related to total parenteral nutrition. All of the patients received 20% fat emulsion; two patients developed priapism during the weekly infusion of fat emulsion. Among the multiple factors that can favor thrombosis and therefore priapism during total parenteral nutrition, fat infusion appears to be the most important. Three different mechanisms have been postulated: increase in blood coagulability, effects on red blood cells, and fat embolism. In this patient, platelet function was estimated in vivo by the levels of antiheparin platelet factor 4 and beta-thromboglobulin. These two parameters were both elevated before 20% lipid emulsion and were even higher after the 20% fat-emulsion infusion. Therefore, even if a direct thromboplastic effect is possible, 20% fat emulsion increases platelet activity, which was already high in our patient, and thereby favors priapism.