Ventriculoperitoneal shunt complications: Difference between revisions
No edit summary |
m (Rossdonaldson1 moved page CSF Shunt to Ventriculoperitoneal shunt problems) |
(No difference)
|
Revision as of 13:43, 18 July 2015
Background
- 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
- Fracture of tubing
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)
- Shunt series
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
- Cefepime/Ceftazidime or carbapenem + vancomycin
See Also
Source
Tintinalli