Secondary parkinsonism caused by chronic subdural hematomas owing to compressed cortex and a disturbed cortico–basal ganglia–thalamocortical circuit: illustrative case

BACKGROUND: Chronic subdural hematoma (CSDH) is a commonly encountered condition in neurological and neurosurgical practice, but the presence of concomitant parkinsonism is extremely rare. Basal ganglia disturbance is a well-known underlying mechanism; however, few cases present with cerebral cortex compression as the cause of symptoms. OBSERVATIONS: A 52-year-old man was referred to the authors’ hospital with a 5-week history of gait disturbance and suspected Parkinson’s disease. Neurological examination revealed a mask-like face, stooped posture, left-predominant rigidity, and postural instability. The authors initiated dopamine agonist administration, and brain magnetic resonance imaging (MRI) was scheduled. One week later, MRI showed bilateral CSDHs. The hematomas markedly compressed the bilateral cerebral cortex, whereas the midbrain and basal ganglia structures were intact. The patient underwent burr hole drainage and was discharged after 9 days without sequelae. LESSONS: CSDH can cause parkinsonism by compressing the cerebral cortex, which is a part of the cortico–basal ganglia–thalamocortical circuit. Surgery leads to positive outcomes, as illustrated by this case, in which cerebral cortex compression caused parkinsonism.