OFFICIAL ABP TOPIC:

Understand the management of a patient with hydrocephalus/ventriculoperitoneal shunt

BACKGROUND

Hydrocephalus is the abnormal accumulation of CSF within the cerebral ventricles, leading to increased intracranial pressure. The most common treatment is surgical placement of a ventriculoperitoneal (VP) shunt to divert excess CSF. Monitoring for complications is essential for children with VP shunts.

EVALUATING HYDROCEPHALUS AND VP SHUNTS

Common causes of hydrocephalus include:

• Congenital: Chiari malformations, primary aqueductal stenosis, intraventricular cysts or masses
• Acquired: Brain tumors, posthemorrhagic hydrocephalus (esp. in premature infants), infections

Hydrocephalus may cause different signs and symptoms according to age:

• Neonates: Macrocephaly, bulging or tense fontanelles, splayed cranial sutures, apnea and bradycardia (late signs)
• Infants: Irritability, vomiting, poor feeding and weight loss, developmental delays
• Children: Headaches, especially in the morning, visual changes, diplopia, lethargy, altered mental status, focal neurologic deficits

Physical exam findings of hydrocephalus include increased head circumference, tense and bulging fontanelles, upgaze palsy (sun-setting sign), papilledema, and focal neurologic deficits. Head circumference should be measured serially at every well-child visit until 36 months of age.

Diagnostic testing to evaluate for hydrocephalus or shunt malfunction:

• Brain MRI: Preferred study to assess ventricular size and detect underlying causes.
  • Fast-sequence protocols can be done without sedation.
• Head CT: Used if MRI is unavailable or in emergencies.
• Ultrasonography: Limited to infants with open fontanelles.
• Shunt series X-rays:
  • Evaluate catheter integrity and continuity.
  • Rule out disconnection or migration.
• Shunt tap:
  • Assess CSF flow and intracranial pressure.
  • Obtain CSF for cell counts, culture, and chemistries if infection suspected.

MANAGEMENT OF HYDROCEPHALUS AND VP SHUNT COMPLICATIONS

ACUTE MANAGEMENT

Acute hydrocephalus causing neurologic compromise is a neurosurgical emergency.

• Consult neurosurgery immediately.
• Temporizing measures while awaiting definitive surgery:
  • Placement of external ventricular drain.
  • Placement of temporary intraventricular reservoirs in neonates.
• Definitive management options:
  • VP shunt placement (most common treatment): CSF is diverted to the abdominal cavity, where it mixes with peritoneal fluid and is absorbed.
  • Endoscopic third ventriculostomy: Holes are placed in the third ventricle so that CSF can bypass obstructions distal to the third ventricle.

CHRONIC MANAGEMENT

Children with VP shunts require lifelong surveillance for shunt complications. About half of children with VP shunts require at least one shunt revision.

• Rule of 2s:
  • First 2 days: Monitor for surgical complications (hemorrhage, infection, malposition).
  • First 2 months: Highest-risk period for shunt infection.
  • First 2 years: Highest-risk period for shunt malfunction.
• Shunt malfunction:
  • Proximal obstruction (e.g., choroid plexus, debris).
  • Valve failure (over- or underdrainage).
  • Distal catheter problems (e.g., disconnection, migration, kinking, pseudocyst).
  • Symptoms: Headache, vomiting, lethargy, rapidly increasing head circumference (infants).
  • Obtain shunt series XR and emergent neurosurgical evaluation (possible shunt revision).
• Shunt infection (usually due to Staphylococcus species):
  • Typically presents within the first few months post-op.
  • Symptoms: Fever, vomiting, irritability, meningismus, erythema along shunt tract.
  • Diagnosis: CSF pleocytosis and culture from shunt tap.
  • Treatment: Complete shunt removal, temporary external ventricular drain, IV antibiotics, delayed shunt replacement.
• Overdrainage: Shunt draining too much CSF.
  • Can cause intracranial hypotension and chronic positional headaches.
  • Possible subdural hematomas and cranial vault collapse.
  • Treat with shunt valve adjustment or replacement.

CAREGIVER EDUCATION

Instruct parents/caregivers to watch for signs of shunt malfunction or infection:

• Headache, vomiting, lethargy.
• Fever, irritability.
• Redness/swelling along shunt tract.
• Rapidly increasing head size (infants).

WHEN TO REFER

Urgent neurosurgical referral for:

• Suspected acute hydrocephalus.
• Possible shunt malfunction or infection.
• Rapidly progressive macrocephaly.

REFERENCES

https://publications.aap.org/pediatricsinreview/article/37/11/478/34935/Pediatric-Hydrocephalus-Current-State-of-Diagnosis