A reverse brain herniation (RBH) after ventriculoperitoneal shunt (VP) in posterior fossa tumour with obstructive hydrocephalus

The risk of hydrocephalus in posterior fossa tumour is quite high (71- 90%), cerebrospinal fluid (CSF) diversion procedures like ventriculoperitoneal (VP) shunt, Endoscopic third ventriculostomy (ETV) and external ventricular drainage (EVD) are emergency procedures and may improve symptoms like headache and vomiting. However, post-operative deterioration after CSF diversion should alert the clinician to the possibility of RBH which is rare (3%) and has a high mortality. We report a case of a 12-year female child with a left cerebellar lesion with hydrocephalus. VP shunt was done and her pupils revert back to normal size, two hours post-surgery her pupils become dilated and not reacting to light, an urgent CT was done which showed reverse brain herniation. Reverse brain herniation is a very rare complication after the CSF diversion procedure with a poor prognosis.