Test characteristics of neuroimaging in the emergency department evaluation of children for cerebrospinal fluid shunt malfunction.
OBJECTIVE
Cerebrospinal fluid (CSF) shunt malfunction is one of the most common life-threatening neurosurgical conditions. In the emergency department (ED), imaging techniques to identify shunt malfunction include the shunt series (SS) and CT scanning of the head. We sought to determine the test characteristics of the SS and CT scan for identifying children with shunt malfunction.


METHODS
We retrospectively reviewed the medical records of children with a CSF shunt who presented to our tertiary care pediatric emergency department and received an SS during a 2-year period from Jan. 1, 2001, to Dec. 31, 2002. A pediatric neuroradiologist reviewed all SS and CT scans. We defined shunt malfunction as present if the child underwent operative shunt revision.


RESULTS
We identified 437 ED visits by 280 children. Forty-seven SS were read as abnormal. A CT scan was performed in 386 (88.3%) cases and 80 were abnormal. Shunt malfunction was identified in 131 (30.0%) children. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of the SS for identifying cases of shunt malfunction were 30.0%, 95.8%, 72.3%, 75.1%, 7.1 and 0.7, respectively; for the CT scan, they were 61.0%, 82.7%, 64.5%, 80.5%, 3.5 and 0.5, respectively.


CONCLUSIONS
Neuroimaging has a low sensitivity for identifying shunt malfunction. Neurosurgical consultation should be sought if shunt malfunction is clinically suspected, despite normal imaging.
Mater
Ahmed
A
Division of Pediatric Emergency Medicine, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.
Shroff
Manohar
M
Al-Farsi
Sami
S
Drake
James
J
Goldman
Ran D
RD
D000293:Adolescent; D001927:Brain Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D002557:Cerebrospinal Fluid Shunts / Q000009:adverse effects* / Q000295:instrumentation; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007223:Infant; D015278:Intensive Care Units, Pediatric / Q000706:statistics & numerical data*; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*