THERAPY OF COMPLEX-I DEFICIENCY - PERIPHERAL NEUROPATHY DURING DICHLOROACETATE THERAPY

A therapeutic trial with polyvitamins and dichloroacetate (DCA) in com bination with thiamine in a 13-year-old girl with complex I deficiency is reported. The polyvitamin therapy included thiamine. riboflavin, a scorbate, coenzyme Q 10 and carnitine. This therapeutic regine was use d over a period of 17 months without any effect. Although DCA lowered the lactate concentration in blood and CNS - measured by magnetic reso nance spectroscopy - no clinical benefit was achieved. After 20 weeks of DCA therapy a distal polyneuropathy with areflexia developed althou gh 100 mg thiamine daily as comedication was given from the beginning of DCA therapy. Nerve conduction velocity of the peroneal nerve was no t detectable, sensible evoked potentials of the tibialis posterious ne rve were normal. This side-effect resolved completely within 6 months after omission of DCA. Our observation suggests a direct toxic effect of DCA only on the peripheral nervous system in our patient since seve ral cerebral MRI and magnetic resonance spectroscopy studies showed no abnormalities. Conclusion DCA lowers the lactate concentration in chi ldren with complex I deficiency of the respiratory chain in a dose of 100 mg/kg body weight without clinical benefit. Reversible peripheral polyneuropathy may develop under DCA therapy despite thiamine medicati on.