How Many Shunt Malfunctions Do Children with Venticuloperitoneal Shunts Have?

Patient Presentation
A 25-month-old male came to the emergency room with increased somnolence and breaththrough seizures.
The patient had known congenital hydrocephalus secondary to neonatal meningitis, and usually had well-controlled generalized tonic-clonic seizures on Keppra®.
He had increasing somnolence for 24 hours and 2 seizures in the last 6 hours. He was able to eat and drink with no emesis, and his mother said that he would awaken but was more irritated. He did not complain of pain and had no infectious disease symptoms.
The past medical history showed no previous shunt revisions, but evaluations for possible shunt malfunction had happened 3 times in the past.

The pertinent physical exam showed a small but normal appearing male who was sleeping in his mothers lap. Heart rate was 130 beats per minute with a normal blood pressure and temperature. Growth parameters were 10-25%. HEENT showed 3 mm reactive pupils and a ventriculoperitoneal shunt on the right side. With palpation, no discontinuity of the shunt was noted in the head or neck. Abdomen showed a small scar in the mid right abdomen that was well healed. Abdomen was soft without obvious masses or distention. Neurological examination revealed cranial nerves 3-12 were intact, and deep tendon reflexes were slightly increased in upper and lower extremities with 2 beats of clonus in the feet, consistent with previous examinations. He was easy to arouse but very cranky and wanted to return to sleep. The diagnosis of probable shunt malfunction was made. The radiologic evaluation of a head computed tomography exam showed a discontinuous proximal shunt at the angle of the reservoir and ventriculomegaly. He was taken to the operating room and had the shunt replaced. He did well and was discharged home. The patient’s clinical course one week later revealed him returning to the emergency room with fever and increased somnolence. Head computed tomography at that time showed an intact shunt and he was diagnosed with a viral upper respiratory tract infection. He was well at his last follow-up appointment at 6 months.

Case Image

Figure 85 – AP radiograph of the skull demonstrates the tip of the VP shunt to be disconnected from its reservoir.

Case Image

Figure 86 – CT scan of the brain performed without intravenous contrast demonstrates marked dilation of the lateral, third and fourth ventricles in axial (top), coronal (middle), and sagittal (bottom) planes.

Discussion
Hydrocephalus can occur for many reasons including congenital anomalies (e.g. spina bifida, aqueductal stenosis, Arnold-Chiari or Dandy-Walker malformations), trauma, intraventricular hemorrhage and meningitis. The common pathway is cerebrospinal fluid accumulation causing pressure effects on the central nervous system. While not perfect, ventriculoperitoneal shunts allow many children with hydrocephalus to live symptom free lives and many others to have much improved quality of life. In the pre-shunt era, only 20% of children survived to adulthood and 50% had brain damage.
One major improvement was the development of the DWT pressure valve by Roald Dahl (the famous author), Stanley Wade (engineer particularly of hydraulic pumps) and Kenneth Till (first full-time pediatric neurosurgeon in Great Britain) valve (DWT)

Any medical device can have complications. For shunts these are divided into 3 categories, infective, overdrainage and mechanical.

  • Shunt infections occur in 5-10% of surgeries usually within the first 3 months after surgery and more commonly in younger patients. Staphylococcus is the most common organism, and common symptoms include abdominal pain, nuchal rigidity, and swelling, drainage or erythema of the shunt site.
  • Overdrainage of the ventricles can cause subdural hematomas and excessive siphoning can actually cause mechanical shunt obstruction.
  • Mechanical problems can be caused by disconnection of the parts of the shunt system, breakage of the tubing, and obstructions at either end of the tubing (especially glialependymal tissue in the brain).
    Children with acute mechanical shunt malfunctions can present in several ways including headache, emesis, personality changes, papilledema and cranial nerve palsies. New onset seizures or changes in the patients normal seizure pattern should also raise concerns. Chronic malfunction may present with loss of developmental milestones, abnormally increased head growth, papilledema or optic atrophy and again changes in seizure patterns.

Learning Point
Of the shunts placed about 80% will have a need for revision with 30% of these occurring in the first year. The average child over their childhood will have 2-3 operations for shunt revisions. This would come out to be 1-1.25 shunt revision surgeries per week for a large neurosurgical practice following 500 children. The number of evaluations for possible shunt malfunction because of seizures, headaches etc. to identify a child who needs a shunt revision is even higher.

Questions for Further Discussion
1. What is the role of a general pediatrician in shunt management and evaluation for possible shunt malfunctions?
2. What are the sports and activities limitations recommended for children with shunts?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Hydrocephalus

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Prusseit J, Simon M, von der Brelie C, Heep A, Molitor E, Volz S, Simon A. Epidemiology, prevention and management of ventriculoperitoneal shunt infections in children.
Pediatr Neurosurg. 2009;45(5):325-36.

Obituary of Kenneth Till. Guardian Newspaper. August 26, 2008. Available from the Internet at: http://www.guardian.co.uk/society/2008/aug/26/health

Conant, Jennet. The Irregulars. Roald Dahl and the British Spy Ring in Wartime Washington. Simon & Schuster. New York, NY. 2008;343.

Kramer LC, Azarow K, Schlifka BA. Management of Spina Bifida, Hydrocephalus and Shunts. eMedicine. Available from the Internet at http://emedicine.medscape.com/article/937979-overview (rev. 11/19/2009, cited 5/20/2010).

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    7. All medical and invasive procedures considered essential for the area of practice are competently performed.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

    Author

    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital