Ventriculoperitoneal shunt problems

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Background

Diagram showing a brain shunt CRUK 052.svg.png
  • Also called a cerebral sinus fluid (CSF), VP, or cerebral shunt
  • Highest incidence of postoperative complications of any neurosurgical procedure
    • Majority in the first 2 years (40% in the first year[1])
  • May drain into peritoneal cavity or less commonly the right atrium, pleural cavity, ureter, gallbladder
Vpvalve.png

Clinical Features

  • Develop over several days

Adults

Infants

  • Vomiting, irritability, bulging fontanelle
    • Often very subtle: a caregiver-reported change in behavior predicts malfunction

Differential Diagnosis

Ventriculoperitoneal shunt problems

Loculation of Ventricles

  • Separate, noncommunicating CSF accumulations may develop within a ventricle
    • Shunt device unable to drain entire ventricular system leading to increased ICP

Abdominal Complications

  • Pseudocyst may form around the peritoneal catheter
    • Can lead to occlusion and/or abdominal pain (depending on size)

Evaluation

  • Physical Exam
    • Neither Sn nor Sp
    • Decreased level of consciousness, erythema along shunt tract, buldging fontanel, nausea/vomiting, irritability should raise suspicion
  • Valve chamber abnormality
    • Gently compress chamber and observe for refill
    • Difficulty compressing chamber indicates distal flow obstruction
    • Slow refill (>3s) indicates proximal obstruction

Work Up

  • CBC, Chem7, coags
  • Blood cultures
  • Shunt tap if concerned for infection (this is usually done by or in consultation with neurosurgery)
    • A normal lumbar puncture does not rule out ventriculitis (shunt infection)
  • Imaging
    • Shunt series
      • AP and lateral skull, AP chest and abdomen
      • Identifies kinking, migration, or disconnection
    • CT
      • Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
      • Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
      • One-third of patients with shunt malfunction will have normal head CT[citation needed]
    • US
      • If the baby has an open fontanelle, you may use US
      • Some literature for ultrasound of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP)[citation needed]

Management

  • Assume shunt malfunction in patients with suggestive features regardless of findings on imaging
  • Revisions are extremely common, low threshold to contact Neurosurgery
  • Ventriculoperitoneal shunt drainage

Disposition

See Also

References

  1. Drake JM, Kestle JRW, Tuli S. CSF shunts 50 years on past, present and future. Child’s Nerv Syst. 2000; 16:800–804.