Changes in platelet function and excessive bruising were investigated by chart review and prospective screening in 51 patients treated with the ketogenic diet for epilepsy at RUSH-Presbyterian-St Luke’s Medical Center, Chicago, IL A significant increase in bruising or other minor bleeding was reported and/or observed in 16 (31%) patients. The complication was more frequent in younger patients but was independent of sex and number of concurrent anticonvulsants (AED). The average age of patients with bleeding was 5 years compared to 8 years for patients without bleeding. The possibility of an interaction with a specific AED was suggested by a 25% use of lamotrigine in patients with bruises compared to 8% use in the nonbruising group (not significant p=.ll). Five of 6 patients tested had prolonged bleeding times and all had diminished response to platelet aggregating agents. One had a latent von Willebrand disease. The mechanism of the diet-induced bruising may be complex, involving interaction between the diet and individual platelet dysfunction. A possible bleeding tendency should be evaluated in patients on the ketogenic diet who are candidates for surgery or anticoagulant therapy. [1]

COMMENT. Despite the absence of serious bleeding in this series of patients treated with the ketogenic diet, a 30% incidence of diet-induced bruising deserves further study and evaluation. A possible interaction with lamotrigine is suggested in some patients receiving concurrent drug and diet.

This is not the first observation of platelet dysfunction and anemia as a complication of the ketogenic diet. Complications in 10% of 52 children treated by Ballaban-Gil et al, 1998 (see Ped Neur Briefs August 1998;12:60) included thrombocytopenia and hemolytic anemia. Valproate interaction could not be excluded in 29 (56%). The proportion of ketogenic/antiketogenic foods was 4:1 in this study but was not specified in the above Pres St Luke’s study. This report of diet-induced bruising is another reason to endorse the Mayo Clinic method of slow initiation of the diet with lower ratios, in place of the Hopkins recommended ratio of 4:1. Using the Mayo Clinic method, I have not encountered this or other serious complication as reported with the Hopkins regimen (Ped Neur Briefs 1998; 12:61).

A fat-overload syndrome with neurologic complications is reported in 2 children receiving fat emulsion therapy. Both patients died and autopsy showed cerebral intravascular lipid deposition and areas of necrosis and hemorrhage. (Progress in Pediatric Neurology III, PNB Publ, 1997;p98) [2]. A rapid rise in triglyceride levels was invoked as a factor in this complication.