Affiliations: CHUM, Hôpital Notre-Dame, André-Barbeau
Movement Disorders Unit, Montreal, Quebec, Canada | Department of Neurology and Neurosurgery, McGill
University, Montreal Children's Hospital, McGill University Health Center,
Montreal, Quebec, Canada
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.
Keywords: Secondary parkinsonism, radiation therapy, radiation-induced parkinsonism, post radiation encephalopathy and pediatric population
