Obstructive hydrocephalus-induced parkinsonism. I: Decreased basal ganglia regional blood flow.

A 17-year-old male developed acute parkinsonism after obstruction of a ventriculoperitoneal shunt with subsequent hydrocephalus. Following a previous shunt replacement, he developed florid parkinsonism which was associated with Parinaud syndrome. The initial single-photon emission computed tomography of the brain using 99mTc-hexamethylpropylenamine oxime demonstrated decreased cerebral blood flow in the regions of the left caudate and putamen. The patient underwent shunt revision with minimal improvement and therefore levodopa/carbidopa (Sinemet 100/25) was administered. Subsequently, he experienced almost complete recovery which may have been correlated with probable improvement of the basal ganglia regional cerebral blood flow. Parkinsonism associated with ventriculoperitoneal shunt obstruction is a rare but reversible disorder that is responsive to shunt replacement and antiparkinsonian drug administration. Cerebral perfusion studies may prove to be of value in delineating the pathophysiology of this complication.