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VP shunts


Rhiannon is a 2-year-old with spina bifida who had a VP shunt inserted during the first month of life.  It was revised because of a “blockage” at 18 months.  She had not been herself for the last 24 hours, more lethargic than usual- especially this morning when she woke up, where she also felt hot.  She vomited in the car on the way to the Emergency Department. She has had previous urinary tract infections.

Rhiannon was afebrile on presentation in ED.  In triage, she was observed awake and drinking from a bottle but wasn’t perturbed by having her observations taken or finger-prick glucose.  Overall, she was a little quiet in the ED, and her mum was concerned that this differed from her baseline. 

Her urine microscopy was not concerning.  She had mild neutrophilia and a normal CRP.  Subcutaneous examination of her shunt, from her skull to the right clavicle, was normal.  She vomited once in the ED.

This is a common presentation and one that can be challenging to manage. However, missing a shunt problem can have catastrophic consequences. This post will take you through some pearls and pitfalls of managing children with VP shunts presenting to the ED.

What is a VP shunt?

A ventriculoperitoneal (VP) shunt is a medical device used to drain fluid via a pressure gradient away from the brain for excessive cerebrospinal fluid (CSF) conditions.  The intention is to shunt fluid away and avoid undue pressure on the brain.  It is one of the most commonly performed neurosurgical procedures and is the treatment of choice for most patients with hydrocephalus.

Black and white image of the parts of a VP shunt

Shunts drain according to the differential pressure gradient between the ventricle and the tip of the distal catheter.  The ventricular end of the catheter is inserted through a burr hole in the right parieto-occipital region, and the valve often sits behind the right ear.  The distal portion is subcutaneously tunnelled into the abdomen, positioned inside the peritoneal cavity.

The diagnosis of raised intracranial pressure in children with VP shunts is challenging.  The symptoms are non-specific, and the commonest causes are often benign.  Rhiannon could easily have a simple viral illness, or her symptoms could be associated with rising intracranial pressure. Missing a shunt malfunction in these patients can be catastrophic.

Physiology of CSF circulation and drainage

  • CSF  is produced at a rate of approximately 20ml/h in children and adults. In normal circumstances, the average adult recycles CSF three times a day. The average adult volume of CSF (about 150mls) is reached by age 5.  The volume in a neonate can be estimated at  2ml/kg.
  • Around 50% of CSF is created by the choroid plexus of the lateral, third and fourth ventricles.  The rest of the CSF arises from the extracellular fluid of the brain.  CSF travels out of the foramen of Lushka and foramen of Magendie (at the level of the fourth ventricle) and heads through to the subarachnoid spaces, along the spinal cord to the cerebral hemispheres.  Over the cerebral hemispheres, the CSF is reabsorbed by arachnoid villi and then into the venous sinuses, which drain into the jugular (internal) veins.
  • Intracranial pressure (ICP) rises when CSF production exceeds absorption.
  • Hydrocephalus is the consequence of excessive CSF accumulation, which could be caused by disruptions in formation, flow, or absorption.
  • As hydrocephalus worsens and intracranial pressure increases, the temporal and frontal horns dilate, sometimes asymmetrically; there’s elevation of the corpus callosum and stretching of white matter tracts.
Diagram of the flow of CSF through the ventricles
Lateral = Lushka — Median = Magendie

Shunting CSF is an effective way to avoid the neurological damage that ensues if the build-up of CSF is left untreated.

Three shunt types are mainly used to shunt CSF: Ventriculoperitoneal (VP), ventriculopleural (VPL), and ventriculoatrial (VA). By far, the commonest are VP shunts.

Reasons for VP shunt placement

There are many reasons why a VP shunt may be placed.  They can be categorized into congenital or acquired causes.

A table displaying the potential reasons for VP shunt placement. It is broken down into congenital and acquired causes

Having a VP shunt is a cause for concern for patients and caregivers.  Common areas for consideration in paediatric patients include:

  • Flying and travel: there is no evidence that flying is dangerous, but patients have concerns over access to neurosurgical help should they need it. Shunt alert cards displaying the type of shunt are available.  The need for extra travel insurance is also an area of concern.
  • Sports: Contact sports such as boxing are contraindicated, and the US paediatric neurosurgeons named wrestling and football (soccer) as the commonest sports with adverse events.  Neurosurgeons in the UK advise that in football and rugby, wearing a skullcap is acceptable.  You can still go scuba diving.
  • Future employment: in the UK, the Royal Air Force, Royal Navy and Police Force are the only services that preclude entry.
  • Programmable shunts and magnets: Background magnetic fields of household objects, such as microwaves, are safe, as are walk-through metal detectors.  A post-MRI check is advised with some programmable shunts, but all are MRI-safe.  The iPad2 has a strong magnetic field and can re-program some shunt valves; it’s important to keep them at safe distances.
  • Shunt length: reassurance that placing sufficient length inside the abdomen will suffice and allow for growth.
  • Weight: Obesity is a risk factor for failure or dislodgement of VP shunts.

In the paediatric cohort, failure rates are quoted as 30-40% at one year and 50% at two years. A patient can expect to have 2-3 shunt revisions over the course of 20 years, and the median time to shunt failure is just one and a half years. Paediatric revisions are more commonplace than adult revisions.

A list of the possible causes of VP shunt failure. Proximal occlusion is the most common

Risk factors for shunt failure include:

  • Younger patients (<6months), particularly neonates
  • Complex comorbidities, for example, cardiac, myelomeningocele, IVH’s, tumour and post-meningitic hydrocephalus, spinal dysraphism, and congenital hydrocephalus
  • Prior shunt failure and short time intervals between revisions
  • Male sex
  • Low socioeconomic status

Causes of VP shunt failure

Obstruction, blockage or occlusion

The commonest cause of shunt malfunction is proximal occlusion. There’s no clear data on whether programmable or non-programmable shunts are less likely to occur.

It’s hypothesised that when inserted near the foramen of Monroe, the lumen can be obstructed with brain parenchyma from the cerebral cortex before reaching the ventricle or choroid plexus. It can also be occluded with blood following choroid plexus haemorrhage, along with other cellular matter such as macrophages, giant cells, connective tissue, fibrin networks, debris, and neoplastic cells.

Distal catheter blockage tends to occur later, and when it happens, it should raise suspicion for an intra-abdominal pseudocyst or adhesions, which may affect future peritoneal catheter placements.

Shunt infection

Shunt infection is the second most common reason for malfunction. The data is mixed, particularly as some older papers use data from before antibiotic-impregnated catheters, skewing the data. Risk factors include young age (including neonates), post-op CSF leak, previous shunt infections, and the presence of a gastrostomy tube.

The vast majority of shunt infections are acute.  Far fewer late-onset infections have been reported. They can be attributed mostly to peritonitis, abdominal pseudocyst, bowel perforation, and haematogenous inoculation.

Shunt infection is associated with an increased risk of seizure disorder, decreased intellectual performance, and a two-fold increase in long-term mortality. Re-infection occurs in one-quarter of children.

The proportion of shunt infections falls off rapidly after the first several months following implantation. The vast majority occur during the first six months. Children will present with signs of shunt failure and systemic infection. Fever is common, and if we were to sample CSF (which is not often done in the ED), the presence of >10% neutrophils in the ventricular fluid is highly specific and sensitive to infection.

The commonest organisms are skin flora, including Staphylococcus epidermidis and Staph. aureus and gram-negative rods.  Infections with Staph. aureus and epidermidis are associated with an earlier onset as they are skin commensals. Infections with Staph. aureus are associated with a significantly increased likelihood of subsequent shunt infection.

Shunt fracture

This is often a late complication and almost always occurs along the distal portion between the valve and peritoneum.  Fibrous tissue becomes calcified with age and does not slide freely within the subcutaneous tissue; the tubing can crack.  This is more likely to happen in the neck, where most movement occurs.

Tension can also form along areas of calcification, causing tethering and stretching as the child grows.  It is important to note that early shunt fracture can occur, and this could be a consequence of trauma to the tubing during surgery.

CSF can still drain, resulting in an insidious duration of symptoms, clouding and confusing the diagnostic process.

Shunt series radiographs should always be sought in this cohort, though frequent fractures and disconnections are incidental findings during surveillance exams.

An x-ray of a fractured VP shunt
VP shunt fracture. Reused with permission from Education and Practice, Archives of Disease of Childhood

Shunt disconnections

Catheters are generally multi-component and hubbed together so that disconnections can occur soon after surgery. The disconnection impedes the flow of CSF, and it may still leak.  Therefore, the onset of these symptoms may be slow.  Disconnections can happen at either the proximal or distal aspect of the valve.

A neck x-ray showing a disconnected VP shunt
Case courtesy of Dr Adam Eid Ramsey, From the case rID: 71794

Abdominal pseudocyst

This is a rare complication of VP shunts and is usually a late complication occurring years after initial placement. A pseudocyst is a fluid-filled sac that collects at the distal tip of the catheter.  They are thought to form because of inflammation or abdominal adhesions.  It can present with abdominal pain or distention with or without a palpable abdominal mass.  Neurological symptoms occur when there is elevated ICP.

Shunt migration

The proximal or distal catheter tip may migrate.  With growth, the proximal catheter can withdraw from the ventricle (extremely rare), or the distal catheter can shift away from the peritoneum.  The distal tubing can become tethered and cause traction on some components, causing a disconnection.  Distal migration occurs as the child grows.


It is possible that a VP shunt can over-drain and ‘under-drain’.  The dura can be stressed with rapid over-drainage, and subdural haematomas and/or extra-axial fluid collections can form.

A slit ventricular syndrome occurs when gravitational forces exert a siphoning effect on the ventricles.  This effect is generally amplified by pressure.

Clinical presentation of VP shunt malfunction

Children with a blocked shunt can present with a myriad of symptoms, including:

  • headache
  • nausea
  • vomiting
  • fever
  • irritability
  • abnormal level of consciousness

Infants and older children may present differently.


  • difficulty feeding
  • bulging fontanelle

Older children may present more specifically with

  • Nausea, somnolence, lethargy, cognitive difficulties, or eye pain.

Predictably, fever is commoner in children with shunt infections. Those with shunts because of myelomeningoceles may present with symptoms such as:-

  • weakness,
  • difficulty walking
  • bowel/bladder dysfunction
  • lower cranial nerve palsies.

Children present with these symptoms all the time to the ED. They are clearly not specific to a shunt problem.  Consequently, diagnosing shunt malfunction on clinical grounds alone is incredibly difficult. Patients with shunt fracture or disconnection can present with a slow onset of symptoms.  They may have pain/tenderness localized to the area of fracture/disconnection or an area of calcification of an area of fluctuant swelling.

Diagnosis, evaluation, and imaging

Diagnosing a shunt malfunction requires a combination of CT, shunt series radiographs, and occasionally (though seldom in the ED), CSF sampling.

A CT will likely show an increase in ventricular size and, occasionally, periventricular lucency, representing oedema.  There may be increasing ventricular size on cross-sectional imaging. Still, up to 15% will have “such profound alterations on brain compliance that their ventricles will not enlarge in the face of shunt failure and increased ICP”.  Ventricular size doesn’t appear to reach a plateau until approximately 14 months after placement of the shunt (regardless of type implanted).

A lumbar puncture (LP) may demonstrate increased opening pressures, but not always.  It is also used for evidence of infection.  This is not performed commonly in the ED in the context of possible shunt malfunction.

Shunt series (SS) radiographs are used to check the overall course of the catheter, looking for disconnection or disruption.  The series will not show obstructions, only damage to the catheter. It can rarely demonstrate complications such as a CSF pseudocyst (abnormal separation of bowel loops near the catheter tip) but shouldn’t be relied upon for this.

The number of radiographs needed varies according to the child’s size. It is usually 3-4 radiographs, including two views of the skull and the continuous trajectory of the shunt tubing down the neck and chest and then looping into the abdomen.

If a series is performed after the scan, theoretically, a two-view skull radiograph can be eliminated, provided that the chest x-ray includes the base of the neck. Unnecessary radiation may then be avoided.

Ultrasound use is an area of ongoing research and has been largely unvalidated in children with VP shunts.

No clear cause for Rhiannon’s symptoms was found following a thorough examination.  A CT was performed because of concern over shunt failure. Her ventricles were noted to be slightly larger than a CT performed previously.  Shunt series radiographs showed continuous, non-kinked tubing.  She was admitted under the care of the Neurosurgeons, and her shunt was revised.  No physical reason for shunt obstruction was found.

Selected references

Berry JG, Hall MA, Ph D. A multi-institutional 5 year analysis of Initial and multiple ventricular shunt revisions in children. Neurosurgery. 2008;62(2):445–54.

Boyle TP, Kimia AA, Nigrovic LE. Validating a clinical prediction rule for ventricular shunt malfunction. Pediatr Emerg Care. 2018;34(11):751–6.

Brian W. Hanak et al. Cerebrospinal fluid shunting compliations in children. Pediatr Neur. 2017;52(6):381–400.

Brinker T, Stopa E, Morrison J, Klinge P. A new look at cerebrospinal fluid circulation. Fluids Barriers CNS. 2014;11(1):1–16.

Buster BE, Bonney PA, Cheema AA, Glenn CA, Conner AK, Safavi-Abbasi S, et al. Proximal ventricular shunt malfunctions in children: Factors associated with failure. J Clin Neurosci [Internet]. 2016;24:94–8. Available from:

Dabdoub CB, Dabdoub CF, Chavez M, Villarroel J, Ferrufino JL, Coimbra A, et al. Abdominal cerebrospinal fluid pseudocyst: A comparative analysis between children and adults. Child’s Nerv Syst. 2014;30(4):579–89.

DeFlorio RM, Shah CC. Techniques that decrease or eliminate ionizing radiation for evaluation of ventricular shunts in children with hydrocephalus. Semin Ultrasound, CT MRI [Internet]. 2014;35(4):365–73. Available from:

Desai KR, Babb JS, Amodio JB. The utility of the plain radiograph “shunt series” in the evaluation of suspected ventriculoperitoneal shunt failure in pediatric patients. Pediatr Radiol. 2007;37(5):452–6.

Erol FS, Ozturk S, Akgun B, Kaplan M. Ventriculoperitoneal shunt malfunction caused by fractures and disconnections over 10 years of follow-up. Child’s Nerv Syst. 2017;33(3):475–81.

Gonzalez DO, Mahida JB, Asti L, Ambeba EJ, Kenney B, Governale L, et al. Predictors of Ventriculoperitoneal Shunt Failure in Children Undergoing Initial Placement or Revision. Pediatr Neurosurg. 2016;52(1):6–12.

Hanak BW, Ross EF, Harris CA, Browd SR, Shain W. Toward a better understanding of the cellular basis for cerebrospinal fluid shunt obstruction: Report on the construction of a bank of explanted hydrocephalus devices. J Neurosurg Pediatr. 2016;18(2):213–23.

Khan F, Shamim MS, Rehman A, Bari ME. Analysis of factors affecting ventriculoperitoneal shunt survival in pediatric patients. Child’s Nerv Syst. 2013;29(5):791–802.

Mansson PK, Johansson S, Ziebell M, Juhler M. Forty years of shunt surgery at Rigshospitalet, Denmark: A retrospective study comparing past and present rates and causes of revision and infection. BMJ Open. 2017;7(1).

Mcclinton D, Carraccio C, Englander R. Predictors of ventriculoperitoneal shunt pathology. Pediatr Infect Dis J. 2001;20(6):593–7.

Mcgirt MJ, Zaas A, Fuchs HE, George TM, Kaye K, Sexton DJ. Factors Infecton for Pediatrc and Venticulopertoneal of Shunlt Predictors Infectous Patiogens. 2014;36(7):858–62.

Paff M, Alexandru-Abrams D, Muhonen M, Loudon W. Ventriculoperitoneal shunt complications: A review. Interdiscip Neurosurg Adv Tech Case Manag. 2018;13(June 2017):66–70.

Pople IK. Hydrocephalus and shunts: What the neurologist should know. Neurol Pract. 2002;73(1).

Rochette A, Malenfant Rancourt MP, Sola C, Prodhomme O, Saguintaah M, Schaub R, et al. Cerebrospinal fluid volume in neonates undergoing spinal anaesthesia: A descriptive magnetic resonance imaging study. Br J Anaesth [Internet]. 2016;117(2):214–9. Available from:

Shastin D, Zaben M, Leach P. Life with a cerebrospinal fluid (CSF) shunt. BMJ [Internet]. 2016;355(October):1–5. Available from:

Simon TD, Butler J, Whitlock KB, Browd SR, Holubkov R, Kestle JRW, et al. Risk factors for first cerebrospinal fluid shunt infection: Findings from a multi-center prospective cohort study. J Pediatr [Internet]. 2014;164(6):1462-1468.e2. Available from:

Smyth MD, Narayan P, Tubbs RS, Leonard JR, Park TS, Loukas M, et al. Cumulative diagnostic radiation exposure in children with ventriculoperitoneal shunts: A review. Child’s Nerv Syst. 2008;24(4):493–7.

Stone JJ, Walker CT, Jacobson M, Phillips V, Silberstein HJ. Revision rate of pediatric ventriculoperitoneal shunts after 15 years: Clinical article. J Neurosurg Pediatr. 2013;11(1):15–9.

Tuli S, O’Hayon B, Drake J, Clarke M, Kestle J. Change in ventricular size and effect of ventricular catheter placement in pediatric patients with shunted hydrocephalus. Neurosurgery. 1999;45(6):1329–35.

Wu Y. V Entriculoperitoneal S Hunt C Omplications in C Alifornia : 1990 To 2000. 2007;61(3):557–63.


  • Angharad Griffiths is a General Paediatric trainee in Ireland, with a special interest in PEM. Welsh-speaker from the Valleys. Enjoys being outdoors, sports fan, Hockey International many years ago. Dodgy knees.

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