Case report: Rapid-onset parkinsonism after a hornet sting

Neurological manifestations with basal ganglia involvement following Hymenoptera stings are rare and clinically ill-defined conditions. We present a patient with acute parkinsonism non-responsive to levodopa, who developed striatal lesions after a hornet sting. We report his response to immunomodulatory treatment and subsequent clinical and brain magnetic resonance imaging (MRI) follow-up. We also searched the literature for patients with acute extrapyramidal syndromes following an insect sting. Fourteen cases have been published; 12 of them are reviewed here. The majority of cases presented with symmetric akinetic syndrome with axial rigidity and/or gait impairment. Six patients were treated with levodopa and only two of these had a modest response to therapy. Brain MRI/computed tomography scan revealed lesions of the basal ganglia, which resulted in fatal outcome in four patients, whereas only one achieved complete recovery. Clinicians should be aware of this rare but devastating cause of acute-onset parkinsonism and specific clinical presentation of this condition, and should consider prompt and prolonged immunomodulatory treatment to prevent irreversible basal ganglia damage.