Ventriculoperitoneal shunt complications

Background

• Also called a cerebral sinus fluid (CSF), VP, or cerebral shunt
• Highest incidence of postoperative complications of any neurosurgical procedure
• May drain into peritoneal cavity or less commonly the R atrium, pleural cavity, ureter, GB

Clinical Features

• Develop over several days
• Adults
  • Cephalgia, N/V, lethargy, ataxia, altered mental status
  • Paralysis of upward gaze, dilated pupilsCN palsies
• Infants
  • Vomiting, irritability, bulging fontanelle

Differential Diagnosis

Ventriculoperitoneal shunt problems

• Ventriculoperitoneal shunt obstruction
• Ventriculoperitoneal shunt overdrainage (Slit Ventricle Syndrome)
• Ventriculoperitoneal shunt infection
• Ventriculoperitoneal shunt mechanical failure

Mechanical Failure

• Causes
  • Fracture of tubing
    • Occurs many years after shunt placement in distal tubing
    • May present w/ mild symptoms of incr ICP and local symptoms of pain, erythema, edema
  • Disconnection
    • Occurs shortly after insertion
  • Migration
  • Misplacement
    • Usually manifests postoperatively

Loculation of Ventricles

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

Abdominal Complications

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

Work-Up

• Physical Exam
  • Neither Sn nor Sp
  • Locate valve chamber
    • Gently compress chamber and observe for refill
    • Difficulty compressing chamber indicates distal flow obstruction
    • Slow refill (>3s) indicates proximal obstruction
• Imaging
  • Shunt series
    • AP and lateral skull, AP chest and abdomen
    • Identifies kinking, migration, or disconnection
  • CT
    • Needed to evaluate ventricular size
    • Very helpful to compare to previous study (many pts w/ shunts have abnormal baseline)

Management

• Assume shunt malfunction in pts w/ suggestive features regardless of findings on imaging
• Shunt Tap
  • Should only be performed by emergency physician in an emergency
  • Alleviates incr ICP and helps make definitive diagnosis
  • Procedure
    • Prepare tap site in sterile manner
    • 23ga needle or butterfly attached to a manometer is inserted into the reservoir
      • If no fluid returns or flow ceases, a proximal obstruction is likely
    • Measure opening pressure (nl = 12 +/- 2)
      • Measure while reservoir outflow is occluded
      • Opening pressure >20 indicates distal obstruction; low pressure indicates proximal
    • Fluid removal (for incr ICP)
      • Remove slowly to avoid choroid plexus bleeding
      • Remove until pressure is 10-20

See Also

CSF Studies

Source

Tintinalli