Ventriculoperitoneal shunt complications: Difference between revisions
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==Background==
==Background==
[[File:Diagram showing a brain shunt CRUK 052.svg.png|thumb]]
*Also called a cerebral sinus fluid (CSF), VP, or cerebral shunt
*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
**Majority in the first 2 years (40% in the first year<ref>Drake JM, Kestle JRW, Tuli S. CSF shunts 50 years on past, present and future. Child’s Nerv Syst. 2000; 16:800–804. </ref>)
*May drain into peritoneal cavity or less commonly the right atrium, pleural cavity, ureter, gallbladder
 
[[File:vpvalve.png|thumb]]


==Clinical Features==
==Clinical Features==
*Develop over several days
*Develop over several days
*Adults
 
**Cephalgia, N/V, lethargy, ataxia, altered mental status
===Adults===
**Paralysis of upward gaze, dilated pupilsCN palsies
*[[headache|Cephalgia]], [[nausea and vomiting]], [[lethargy]], [[ataxia]], [[altered mental status]]
*Infants
*Paralysis of upward gaze ("sunset eyes"), dilated pupils, [[cranial nerve palsies]]
**Vomiting, irritability, bulging fontanelle
 
===Infants===
*[[nausea and vomiting (peds)|Vomiting]], irritability, [[bulging fontanelle]]
**Often '''very subtle''': a caregiver-reported change in behavior predicts malfunction
 
 
===Physical Exam===
*Neither sensitive nor specific
*[[AMS|Decreased level of consciousness]], erythema along shunt tract, [[bulging fontanelle]], [[nausea/vomiting]], irritability should raise suspicion
*Valve chamber abnormality
**Gently compress chamber and observe for refill
**Difficulty compressing chamber indicates distal flow obstruction
**Slow refill (>3s) indicates proximal obstruction


==Differential Diagnosis==
==Differential Diagnosis==
{{VP shunt prob DDX}}
{{VP shunt prob DDX}}


==Mechanical Failure==
===Loculation of Ventricles===
*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
*Separate, noncommunicating CSF accumulations may develop within a ventricle
**Shunt device unable to drain entire ventricular system -> incr ICP
**Shunt device unable to drain entire ventricular system leading to increased ICP


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


==Work-Up==
==Evaluation==
*Physical Exam
*CBC, Chem7, coags
**Neither Sn nor Sp
*Blood cultures
**Locate valve chamber
*Shunt tap if concerned for infection (this is usually done by or in consultation with neurosurgery)
***Gently compress chamber and observe for refill
**A normal lumbar puncture does not rule out ventriculitis (shunt infection)
***Difficulty compressing chamber indicates distal flow obstruction
***Slow refill (>3s) indicates proximal obstruction
*Imaging
*Imaging
**Shunt series
**Shunt series
***AP and lateral skull, AP chest and abdomen
***AP and lateral skull, AP chest and abdomen
***Identifies kinking, migration, or disconnection
***Identifies kinking, migration, or disconnection
**CT
**[[head CT|CT]]
***Needed to evaluate ventricular size
***Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
***Very helpful to compare to previous study (many pts w/ shunts have abnormal baseline)
***Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
***One-third of patients with shunt malfunction will have normal head CT{{Citation needed|reason=Reliable source needed|date=March 2016}}
**[[Ultrasound]]
***If the baby has an open fontanelle, you may use US
***Some literature for [[ultrasound]] of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP){{Citation needed|reason=Reliable source needed|date=March 2016}}


==Management==
==Management==
*Assume shunt malfunction in pts w/ suggestive features regardless of findings on imaging
*Assume shunt malfunction in patients with suggestive features regardless of findings on imaging
*Shunt Tap
*Revisions are extremely common, low threshold to contact Neurosurgery
**Should only be performed by emergency physician in an emergency
*[[Ventriculoperitoneal shunt drainage]]
**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===
==Disposition==
*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
**Cefepime/Ceftazidime or [[carbapenem]] + [[vancomycin]]


==See Also==
==See Also==
[[CSF Studies]]
*[[CSF Studies]]


==Source==
==References==
Tintinalli
<references/>


[[Category:Neuro]]
[[Category:Neurology]]

Revision as of 23:51, 1 October 2019

Background

Diagram showing a brain shunt CRUK 052.svg.png
  • Also called a cerebral sinus fluid (CSF), VP, or cerebral shunt
  • Highest incidence of postoperative complications of any neurosurgical procedure
    • Majority in the first 2 years (40% in the first year[1])
  • May drain into peritoneal cavity or less commonly the right atrium, pleural cavity, ureter, gallbladder
Vpvalve.png

Clinical Features

  • Develop over several days

Adults

Infants


Physical Exam

  • Neither sensitive nor specific
  • Decreased level of consciousness, erythema along shunt tract, bulging fontanelle, nausea/vomiting, irritability should raise suspicion
  • Valve chamber abnormality
    • Gently compress chamber and observe for refill
    • Difficulty compressing chamber indicates distal flow obstruction
    • Slow refill (>3s) indicates proximal obstruction

Differential Diagnosis

Ventriculoperitoneal shunt problems

Loculation of Ventricles

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

Abdominal Complications

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

Evaluation

  • CBC, Chem7, coags
  • Blood cultures
  • Shunt tap if concerned for infection (this is usually done by or in consultation with neurosurgery)
    • A normal lumbar puncture does not rule out ventriculitis (shunt infection)
  • Imaging
    • Shunt series
      • AP and lateral skull, AP chest and abdomen
      • Identifies kinking, migration, or disconnection
    • CT
      • Needed to evaluate ventricular size (if larger, concerning for elevated ICP)
      • Very helpful to compare to previous study (many patients with shunts have abnormal baseline)
      • One-third of patients with shunt malfunction will have normal head CT[citation needed]
    • Ultrasound
      • If the baby has an open fontanelle, you may use US
      • Some literature for ultrasound of optic nerve diameter (if normal (3.3cm), lower chance of elevated ICP)[citation needed]

Management

  • Assume shunt malfunction in patients with suggestive features regardless of findings on imaging
  • Revisions are extremely common, low threshold to contact Neurosurgery
  • Ventriculoperitoneal shunt drainage

Disposition

See Also

References

  1. ↑ Drake JM, Kestle JRW, Tuli S. CSF shunts 50 years on past, present and future. Child’s Nerv Syst. 2000; 16:800–804.
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