A unique pediatric case of radiation-induced parkinsonism

Abstract

We wish to report a pediatric case of parkinsonism secondary to radiation therapy. The patient was diagnosed at the age of 16 years with a thalamic and midbrain dysgerminoma. After partial tumor resection, the patient received chemotherapy followed by radiation therapy. Two months after the initiation of the radiation therapy, without any evidence of tumor progression on imaging, the patient developed severe parkinsonism and encephalopathy requiring intensive care unit admission. With supporting measures, his level of consciousness gradually improved but did not return to baseline. His parkinsonism remained severe despite high doses of levodopa-carbidopa and benztropine. Ten months later, without any significant modification of his medication, the patient's parkinsonism started to improve. Over the following 8 months, the improvement was so dramatic that the anti-parkinsonism medications could be weaned then stopped. Radiation-induced parkinsonism has been described on rare occasions in both the pediatric and adult populations. Our patient is the first case of early-delayed radiation-induced parkinsonism in the pediatric population. The evolution of his neurological status is surprising; after 10 months of static post radiation encephalopathy and severe parkinsonism, we would not have expected such good neurological improvement.