Ventricular Peritoneal Shunts

Basics

Description

  • Ventricular peritoneal (VP) shunts are usually placed for hydrocephalus:
    • Conduit between excess CSF and peritoneal cavity (or right atrium–VA shunt and pleura or rarely into the ureter or bladder)
  • Complications requiring revision are common, especially in the 1st 6 mo after placement
  • Obstruction: Shunt malfunction impairs drainage of CSF: Also known as obstructive hydrocephalus:
    • Increases intracranial pressure (ICP)
    • Rate of increase in ICP determines severity
    • 30–40% mechanical malfunction rate in 1st year
  • Overdrainage syndrome:
    • Multiple causes including:
      • Low-pressure shunt settings
      • Change in body position
      • Excessive length of shunt catheter
      • Increased intrathoracic pressure
      • Improper shunt placement
    • Decreases ICP
    • Produces postural headache and nausea (as after lumbar puncture)
  • Infection:
    • Mostly occur soon after placement
    • Shunt is a foreign body, removal usually required
    • Staphylococcus epidermidis and other Staphylococcus species in 75% of infections enter through skin flora
    • Gram-negative organisms also implicated
    • Multidrug-resistant Staphylococcus aureus (MRSA) has been reported
    • Delayed shunt infections – due to spread of infection from other sites
  • Malposition:
    • Disconnection, obstruction, breakage, erosion of skin with exposure of system
    • Subdural hematomas, intracerebral or intraventricular hemorrhage
    • Abdominal pseudocyst or CSFoma, perforation of viscera
  • Slit ventricle syndrome:
    • Prolonged overdrainage causes decreased ventricular size
    • Intermittent increases in ICP occur owing to proximal obstruction

Pediatric Considerations

  • 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)
    • Normal-pressure hydrocephalus
    • Post-CVA
    • Tumor or other mass lesions
    • Communicating hydrocephalus secondary to meningitis or subarachnoid hemorrhage

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