Ventriculoperitoneal shunt block: what are the best predictive clinical indicators?
OBJECTIVE
To evaluate the predictive value of symptoms, signs, and radiographic findings accompanying presumed ventriculoperitoneal (VP) shunt malfunction, by comparing presentation with operative findings and subsequent clinical course.


METHODS
Prospective study of all 53 patient referrals to a paediatric neurosurgical centre between April and November 1999 with a diagnosis of presumed shunt malfunction. Referral pattern, presenting symptoms and signs, results of computed tomography (CT) scanning, operative findings, and clinical outcome were recorded. Two patient groups were defined, one with proven shunt block, the other with presumed normal shunt function. Symptomatology, CT scan findings, and the subsequent clinical course for each group were then compared.


RESULTS
Common presenting features were headache, drowsiness, and vomiting. CT scans were performed in all patients. Thirty seven had operatively proven shunt malfunction, of whom 34 had shunt block and three shunt infection; 84% with shunt block had increased ventricle size when compared with previous imaging. For the two patient groups (with and without shunt block), odds ratios with 95% confidence intervals on their presenting symptoms were headache 1.5 (0.27 to 10.9), vomiting 0.9 (0.25 to 3.65), drowsiness 10 (0.69 to 10.7), and fever 0.19 (0.03 to 6.95). Every patient with ventricular enlargement greater than their known baseline had a proven blocked shunt.


CONCLUSIONS
Drowsiness is by far the best clinical predictor of VP shunt block. Headache and vomiting were less predictive of acute shunt block in this study. Wherever possible CT scan findings should be interpreted in the context of previous imaging. We would caution that not all cases of proven shunt blockage present with an increase in ventricle size.
Department of Neurosurgery, Great Ormond Street Hospital for Children, London WC1N 3JH, UK.
N P
NP
Barnes
S J
SJ
Jones
R D
RD
Hayward
W J
WJ
Harkness
D
D
Thompson
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004868:Equipment Failure; D006261:Headache / Q000209:etiology; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000601:surgery; D007223:Infant; D016134:Organizational Policy; D010343:Patient Admission / Q000706:statistics & numerical data; D011446:Prospective Studies; D012017:Referral and Consultation; D012086:Reoperation / Q000706:statistics & numerical data; D012894:Sleep Stages; D017287:Ventriculoperitoneal Shunt / Q000009:adverse effects*; D014839:Vomiting / Q000209:etiology