Description

• Ventricular peritoneal (VP) shunts are usually placed for hydrocephalus:
  • Conduit between CSF and peritoneal cavity (or right atrium-VA shunt))
• Complications requiring revision are common, especially in the first 6 mo after placement
• Obstruction: Shunt malfunction impairs drainage of CSF:
  • Increases intracranial pressure (ICP)
  • Rate of increase in ICP determines severity
  • 30–40% mechanical malfunction rate in first year
• Overdrainage syndrome:
  • Upright posture increases CSF outflow
  • Decreases ICP
  • Produces postural headache and nausea (as after lumbar puncture)
• Infection:
  • Shunt is a foreign body
  • Staphylococcus epidermidis and other Staphylococcus species in 75% of infections
  • Gram-negative organisms also implicated
  • Multidrug-resistant Staphylococcus aureus (MRSA) has been reported
  • Most occur soon after placement
  • Shunt removal usually required
• Slit ventricle syndrome:
  • Prolonged overdrainage causes decreased ventricular size
  • Intermittent increases in ICP occur owing to proximal obstruction

• Complications more common in children, especially neonates
• If cranial sutures are open, CSF may accumulate without much ICP increase
• Produces relatively nonspecific signs and symptoms:
  • Drowsy
  • Headache
  • Nausea and vomiting

Etiology

• Shunt may be needed to treat increased ICP due to:
  • Congenital malformations
  • Idiopathic intracranial hypertension (pseudotumor cerebri)
  • Post CVA
  • Tumor or other mass lesions
  • Post head trauma
  • Subarachnoid hemorrhage
  • Scarring at base of brain after bacterial meningitis