Ventriculoperitoneal shunt obstruction

Background

• Most common type of shunt malfunction
  • Usually occurs at proximal tubing, followed by distal tubing followed by valve chamber
• Proximal obstructions usually occurs within first years of insertion
• Distal obstruction usually occurs only with shunts in place for >2yr
• 60% of children suffer malfunction within lifetime

Causes

• Proximal obstruction
  • Tissue debris
  • Choroid plexus
  • Clot
  • Infection
  • Catheter-tip migration
  • Localized immune response to the tubing
• Distal obstruction
  • Kinking or disconnection of the tube
  • Pseudocyst formation
  • Infection

Clinical Features

• Infants with bulging fontanels and suture diastasis
• Irritability
• Change in level of consciousness
• N/V, poor feeding
• Seizure
• Cushing's triad

Differential Diagnosis

Ventriculoperitoneal shunt problems

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

Diagnosis

• Shunt series
• CT scan with out contrast
• Ventricular tap
• MRI, unless patient has programmable shunt (Can be recalibrated by Neurosurgery if needed)
• Pumping shunt (institution dependent) - may pull choroid plexus into shunt or cause intraparenchymal bleed

Management

• Rapid deterioration and NSGY capability distant, may require shunt tap until pressure < 15 mmHg
• If pressure not relieved by shunt tap, obstruction likely proximal