Reversible istradefylline-induced pleurothotonus in a patient with Parkinson's disease: A case report and literature review

Pleurothotonus, commonly known as Pisa syndrome (PS), is characterized by abnormal lateral flexion of the trunk. The precise mechanism of this disease is unknown. Istradefylline was administered to a 68-year-old male patient with Parkinson's disease (PD) to treat wearing-off; however, PS appeared 4 months after the first istradefylline treatment. Despite drug adjustments for 9 months, no improvement was observed. Finally, istradefylline was discontinued, and PS symptoms gradually improved over the subsequent 4 months and eventually disappeared. From 2005 to 2014, six studies appeared in the literature on dopaminergic therapy for PS patients with PD. The period between PS appearance after drug introduction until PS recovery with appropriate treatment differs among drugs. This study aimed to identify the drugs that initiate PS and assess the period between PS appearance and disappearance, respectively, after the drug is first administered and later discontinued.