Serotonin syndrome following levodopa treatment in diffuse Lewy body disease.

Serotonin syndrome results from an acute hyperserotonergic state. It is a rare and potentially fatal complication of drugs that affect the central nervous system serotonin levels. It is characterised by a triad of clinical features comprising altered sensorium, autonomic instability and neuromuscular hyperexcitability, in different combinations. We present an atypical case of serotonin syndrome related to levodopa use in a patient of probable Lewy body dementia. This case highlights the difficulty in diagnosis and management of cases with serotonin syndrome in the absence of history of a known serotonergic drug and the fact that levodopa can contribute to its occurrence.