Ventriculoperitoneal shunt complications: Difference between revisions

m (Rossdonaldson1 moved page CSF Shunt to Ventriculoperitoneal shunt problems)
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==Background==
==Background==
*Also called a cerebral sinus fluid (CSF), VP, or cerebral shunt
*Highest incidence of postoperative complications of any neurosurgical procedure
*Highest incidence of postoperative complications of any neurosurgical procedure
*May drain into peritoneal cavity or less commonly the R atrium, pleural cavity, ureter, GB
*May drain into peritoneal cavity or less commonly the R atrium, pleural cavity, ureter, GB

Revision as of 13:44, 18 July 2015

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

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

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

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

Overdrainage (Slit Ventricle Syndrome)

  • Overdrainage -> tissue occluding the orifices of the proximal shunt apparatus
    • As pressure increases the occluding tissue diesengages allowing drainage to resume
    • Leads to cyclic incr ICP complaints that worsen when pt stands

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

Infection

Background

  • Occurrence
    • 50% within first 2 weeks of placement
    • 70% within 2 months of placement
    • 80% within 6 months of placement
    • 10% present >1 year after surgery

Types

  • External Infection
    • Involve the subcutaneous tract around the shunt
  • Internal Infection
    • Involves the shunt and CSF contained within the shunt

Bacteriology

  • 50% of cases caused by S. epidermidis
  • Also caused by S. aureus, Gram-negatives, anaerobes

Clinical Features

  • Internal Infection
    • Mental status changes, HA, N/V, irritability
    • Neck stiffness (33% of pts)
    • Fever is often absent
    • Abdominal pain (VP shunt)
  • External Infection
    • Swelling, erythema, tenderness along site of shunt tubing

Management

  • Emergent neurosurgical consultation and admission
  • Shunt tap
    • LP often misses CSF shunt infections and has no role when shunt infection is suspected
  • Imaging
    • Useful to exclude mechanical shunt malfunction (often coexists w/ infection)
  • Abx

See Also

CSF Studies

Source

Tintinalli