Suspected Low-Pressure Hydrocephalus Caused by Spinal Drainage after Subarachnoid Hemorrhage

Hydrocephalus induced by low cerebrospinal fluid (CSF) pressure is extremely rare and sporadically re-ported. Subarachnoid hemorrhage, head trauma, and spinal drainage were reported to be causative fac-tors for surgical treatment. A 33-year-old man with subarachnoid hemorrhage caused by right vertebral artery aneurysm rupture developed headache. Trapping surgery was performed, and a spinal drain was inserted from L4/5 for subarachnoid hemorrhage washout. On postoperative day 3, subdural fluid ac-cumulation had increased at the posterior fossa craniotomy site and the cerebellar sulci had narrowed; the ventricles were slightly enlarged. The patient reported headache during head elevation. Low-pressure hydrocephalus (LPH) was suspected. After the spinal drain was removed, headache resolved, and cerebral ventriculomegaly disappeared. The subsequent clinical course was good. The patient was discharged 3 weeks after surgery. LPH is a rare disease caused by various factors and is treated by cor-recting liquorrhea or overdrainage, when present. Otherwise, drainage at negative CSF pressure is nec-essary. The symptoms and image findings for LPH are similar to those for intracranial hypertension and normal-pressure hydrocephalus. This report describes a suspected case of LPH caused by spinal drainage after subarachnoid hemorrhage and reviews the literature. (J Nippon Med Sch 2022; 89: 238?243)