VP Shunts
Division of Child Neurology
Department of Pediatrics
Goryeb Children’s Hospital
Atlantic Health System
Cerebral Shunts

To treat hydrocephalus / reduce ICP

Proximal end inserted into a CSF source (usually blocked)
 Ventricle
 Lumbar cistern of the spinal cord

Distal end inserted near absorptive epithelial surface or
directly into the blood stream:
 Peritoneal cavity of the abdomen (most common)
 VP shunt = ventriculo-peritoneal shunt
 LP shunt = lumbar-peritoneal shunt
 Right Atrium of the heart (VA shunt)

Pleural cavity of the lung (VPL shunt)
VP SHUNT
VA SHUNT
LP SHUNT
Cerebral Shunts
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May also insert distal end into:
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gallbladder (mixes with bile)
ureter (mixes with urine)
Variety of forms:
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made of different materials (silicone)
different types of pumps and uni-directional valves
+/- programmable
Shunt Complications
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More common in childhood
May require immediate shunt revision or shunt
re-programming
Shunt complications often mimic the symptoms that
prompted initial shunting
 headache
 double vision
 nausea / vomiting
 altered mentation (lethargy / irritability)
 bulging fontanelle
Shunt failure rate 2 years after insertion - up to 50%
“Sunsetting Eyes”: clinical sign of
increased intracranial pressure
Infection
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Incidence 1-20 %, average 10 %
Usually intra-operative contamination of surgical wound
by skin flora
Common microbial agents
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Staph epi (coagulase negative staph) > 50%
Staph aureus 20 %
Gram negative bacilli 15 %
Candida
Symptoms – ICP, fever, WBC
No correlation with shunt type
Risk factors for shunt infection

age < 6 months
4 Distinct Clinical Syndromes
of Shunt Infection
1. Colonization of the shunt - most common
2. Wound infection
3. Peritonitis / distal infection
4. Meningitis
1. Colonization of the Shunt

MOST COMMON
 Symptoms of shunt malfunction > infection
 Lethargy, headache, vomiting, full fontanelle
 Low grade fever
 Within months of shunt insertion
 CSF from ventricle or lumbar puncture STERILE
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Unusual to see signs of meningitis / ventriculitis
CSF minimally abnormal
Infecting organism in SHUNT RESERVOIR
Blood cultures negative unless VA Shunt
colonization

If VA shunt, more severe systemic symptoms
 Septic pulmonary emboli
 Pulmonary hypertension
 Infective endocarditis

For more chronic VA shunt colonization
 hypo-complementemic glomerulonephritis =
Ag-Ab complex deposition in glomeruli
 “Shunt Nephritis”
 hypertension, microscopic hematuria, elevated BUN
and creatinine, anemia
2. Wound Infection
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Obvious infection or dehiscence along the shunt
tract
Within days-to-weeks of shunt procedure
Staph aureus - most common isolate
Fever common
Symptoms of shunt malfunction follow
3. Distal Infection / Peritonitis
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
Abdominal symptoms without signs of shunt
malfunction common
Pathogenesis:
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perforation of bowel at time of insertion
translocation of bacteria across the bowel wall
Gram negative isolates, mixed flora cultured from
distal portion of shunt catheter
4. Meningitis
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Pathogens:
 Strep pneumo
 N. meningitidis
 Hib
Presentation typical of acute bacterial meningitis
Treatment of Shunt Infection
1. IV anti-staph PCN (if resistant, IV vancomycin)
2. intra-shunt vancomycin (monitoring CSF levels to avoid
toxicity)

due to poor penetration of most abx into CSF across inflamed
meninges
3. externalize the distal shunt
For gram negative infections :
 3rd generation IV cephalosporin
 Intra-shunt aminoglycoside
Treatment of Shunt Infection
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Often need to remove shunt
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colonization, wound infection, distal peritonitis
for meningitis, IV abx without shunt removal
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After reservoir CSF sterile x 48 hour, can insert new
shunt on other side
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High rate of infection relapse due to:
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Abx therapy alone (no shunt externalization or removal)
Abx therapy + partial shunt revision
Prevention of Shunt Infection
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Meticulous cutaneous preparation and surgical
technique
?? perioperative IV abx, intra-ventricular abx, abx
impregnated shunt tubing, soaking the shunt in abx
Other Shunt Complications

Obstruction
 Proximal – build-up of excess protein in CSF, slowly clogs
the valve
 Distal – build-up of excess peritoneal protein blocks distal
tip
 Over-drainage (see below)
 Slit Ventricle Syndrome (see below)

Over-drainage
 Intraventricular CSF drains too rapidly  brain collapses
on itself  extra-axial fluid (CSF or blood) collects to fill
the spatial void  external compression of brain  brain
damage, stretching of bridging veins  subdural
hemorrhage
Over-drainage
Other Shunt Complications

Slit Ventricle Syndrome
 CSF slowly over-drains over several years after shunt
procedure
 uncommon, but results in need for many shunt revisions
 symptoms similar to typical shunt malfunction BUT
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cyclical (appear, subside, appear, subside…, over years)
symptoms alleviated by lying prone
due to:
 overdrainage simultaneous with brain growth (brain growth
fills the intraventricular space, leaving the ventricles collapsed)
 compliance of brain decreases, preventing ventricles from
enlarging
 collapsed ventricles can also block shunt valve (a form of
obstruction)
Slit Ventricle
Syndrome
Other Shunt Complications

Intra-ventricular hemorrhage
 occurs at any time during or after a shunt insertion or
revision
 can occur in nearly 31% of shunt revisions
A large dural hole around the ventricular catheter
may predispose to CSF flow through the dural
opening leading to the formation of subcutaneous
tract
Distal VP shunt catheter protruding from anus
Conditions requiring shunting
Obstructive / Non-communicating Hydrocephalus
due to Aqueductal Stenosis
CT of the brain:
3rd
- large frontal and
temporal horns of
lateral ventricles
- large third ventricle
4th
- 4th ventricle small
Obstructive / Non-communicating Hydrocephalus
due to Chiari Malformation
low lying tonsils alone (Chiari I) – usually asymptomatic
low lying tonsils + hydrocephalus (Chiari II) – diffuse headache
Chiari I
Chiari II (+ lumbosacral myelomeningocele)
Non-Obstructive / Communicating Hydrocephalus
as a complication of prior Meningitis
3rd
4th
CT of the brain
reveals enlarged frontal
and temporal horns of
the lateral ventricles and
enlarged 3rd and 4th
ventricles.
Dandy-Walker Malformation:
aplasia / hypoplasia of cerebellar vermis
(midline cerebellum missing or underdeveloped)
Hydrocephalus due to
Choroid Plexus Papilloma
(CSF secreting intraventricular tumor
which obstructs ventricular system)
Conditions with enlarged CSF
spaces that usually do NOT
require shunting
Benign External Hydrocephalus
Porencephaly
Holoprosencephaly
Lissencephaly “smooth brain”
- achieve maximum 3-5 month dev milestones
- may be caused by LIS-1 gene mutation (Miller-Diecker
lissencephaly)
- microcephaly, MR, seizures
Schizencephaly: “clefted brain”
Multifocal Cystic Encephalomalacia
(hx of neonatal meningitis)