Posterior Fossa Shunt Malfunction Presenting as Essential Hypertension: Case Report

Holly Gilmer-Hill, MD; Kristin Strother, MSN, RN

Introduction

Hypertension with bradycardia commonly occurs in association with high intracranial pressure. Essential hypertension without bradycardia may occur in association with posterior fossa pathology such as vascular medullary compression. To our knowledge, posterior fossa shunt malfunction presenting as essential hypertension without bradycardia has not been previously described in the literature.

Methods

The patient is an 8 yo boy with Dandy-Walker malformation and hydrocephalus. He has a shunt with two catheters, one to the lateral ventricle and one to the posterior fossa. He presented to our hospital after elevated blood pressures, ranging from 180/100 to 200/120, were measured. His heart rate remained stable in the 80ís. He had some headaches at home, but did not have headache, vomiting, seizures, or ataxia on presentation. Head CT showed generous ventricles that were unchanged from his baseline studies. Shunt tap showed good CSF flow and dynamics, with an intracranial pressure of 10. During the next 48 hours, he continued to exhibit elevated blood pressures ranging from 143/94 to 160/110 despite treatment with antihypertensive medications. Diagnostic workup including laboratory studies, renal ultrasound, and echocardiogram was normal.


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Results

Due to the patientís continued hypertension despite medical treatment and recurrence of headaches, a shunt exploration was performed. The ventricular catheter was patent with an opening pressure of 10. The posterior fossa catheter was occluded and was revised. The posterior fossa opening pressure was 20. Immediately postoperatively, the patientís blood pressure was 106/70. He remained normotensive for the rest of his hospital stay and was discharged home without antihypertensive medication.


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Head CT images at the time of the posterior fossa shunt malfunction. Note the 2 shunt catheters, one ending in the third ventricle and the other ending in the posterior fossa. The lateral ventricles are decompressed, and the ventricular shunt was found to be functional at surgery.

Learning Objectives

Recognize this unusual presentation of posterior fossa shunt malfunction, even when diagnostic studies such as brain CT and shunt tap are unremarkable.

Conclusions

Posterior fossa shunt malfunction may present with isolated hypertension, without typical shunt malfunction symptoms and even with a functioning ventricular shunt.