Parkinsonism Improved With Levodopa After Endoscopic Third Ventriculostomy in Shunted Hydrocephalus Due to Aqueductal Stenosis.

INTRODUCTION: Levodopa-responsive parkinsonism has been reported following ventriculoperitoneal (VP) shunt in patients with obstructive hydrocephalus due to aqueductal stenosis. It has been thought to arise from injury to the global rostral midbrain including the nigrostriatal pathway by a transtentorial pressure gradient. We present a similar patient, but his parkinsonism resisted levodopa administration during the initial therapy. CASE REPORT: A 51-year-old man suffered from hydrocephalus due to secondary aqueductal stenosis presumably attributed to massive bleeding during surgery for a fourth ventricle hemangioblastoma. After resolution of the hydrocephalus with VP shunt, he developed severe parkinsonism, Parinaud syndrome, and hyperreflexia, suggesting global rostral midbrain dysfunction, but high-dosage levodopa therapy was not effective. An inverted transtentorial pressure gradient suggested by his unilateral slit-like ventricle was assumed to be the cause of the levodopa resistance. Also based on an assumption that the absorption of cerebrospinal fluid was impaired due to the intraoperative bleeding, a lumbar peritoneal shunt was added to the preexisting VP shunt, but it failed to control the ventricular size. Instead, endoscopic third ventriculostomy stabilized it, characteristically inducing levodopa responsiveness in our patient. An increase of the levodopa dosage led to clinical improvement, which needed a maintenance dosage because of dependency.
CONCLUSION: The details of this patient suggest that a transtentorial pressure gradient may have impaired more distal basal ganglia connections over a global rostral midbrain including the nigrostriatal pathway, and that aggressive levodopa therapy after endoscopic third ventriculostomy can be effective for refractory parkinsonism.