[A case of impending neuroleptic malignant syndrome associated with Shy-Drager syndrome].

We report a 55-year-old man with impending neuroleptic malignant syndrome who showed a remarkable dysautonomia such as dysuria and was treated with L-dopa under the diagnosis of Shy-Drager syndrome. The patient demonstrated fever, leukocytosis and elevated serum creatine kinase by a decrease in L-dopa dose. Probably, he developed impending neuroleptic malignant syndrome, induced by urinary tract infection as well as decrease in L-dopa dose. Since Shy-Drager syndrome is often treated with antiparkinsonian drugs, neuroleptic malignant syndrome can possibly develop after the change in dosage of catecholaminergic drugs. The imbalance of neurotransmitters and receptors in the central autonomic nervous system may participate in the development of neuroleptic malignant syndrome. Accordingly, Shy-Drager syndrome can easily be associated with neuroleptic malignant syndrome because of its severe disturbance in the autonomic nervous system. However, autonomic nervous dysfunction, a major sign of neuroleptic malignant syndrome, might be masked by symptoms of Shy-Drager syndrome. Therefore, diagnosis of neuroleptic malignant syndrome is often delayed. Careful observations of patients with Shy-Drager syndrome related with an antiparkinsonian drug are necessary, especially when the dose of drugs is changed or the general condition deteriorates.