THE DIAGNOSIS OF BLOCKED CEREBROSPINAL-FLUID SHUNTS - A PROSPECTIVE-STUDY OF REFERRAL TO A PEDIATRIC NEUROSURGICAL UNIT

A prospective study was undertaken of all children referred to the Hos pital for Sick Children with a provisional diagnosis of shunt blockage over a 5-month period. Fifty-two admissions were recorded, relating t o 45 children, 5 of whom had multiple admissions. Only 19 of the 52 ad missions led to a final diagnosis of shunt malfunction. No source of r eferral, whether by the child's general practitioner or from another h ospital, was found to be more accurate than direct referral by the par ents to the neurosurgical ward. Headache, vomiting and irritability we re not significant indicators as to whether the child's shunt was actu ally blocked, and nor was the duration of the symptoms. Drowsiness was a significant, but not definite, indicator of shunt blockage, while p yrexia made it more likely that the patient had an alternative diagnos is. In 35 of the admissions a computed tomographic scan was performed: a normal scan, unchanged from previous scans, did not reliably exclud e the diagnosis of shunt blockage. Percutaneous manometry via the rese rvoir of the shunt system was performed during 26 admissions: this inv estigation produced no false positives nor false negatives, but was eq uivocal in 5 cases, all of which were found at surgery to have a defin ite shunt blockage. The accuracy of the diagnosis of shunt blockage ma de prior to referral to a neurosurgical unit is discussed, together wi th the implications for resource use.