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Hydrocephalus, CSF shunts and ETV

Hydrocephalus is treated by diverting cerebrospinal fluid — with a ventriculoperitoneal (VP) shunt, which fails often, mostly by proximal obstruction, or with endoscopic third ventriculostomy (ETV), which suits mainly aqueductal obstruction in a child over one year.

לקריאה בעברית

Why it matters in the exam

Questions centre on a child with a shunt who arrives with headache, vomiting and drowsiness, and on the numbers: about 40% of shunts fail in the first year and about half within two years, and the commonest cause of failure is obstruction of the proximal catheter. Infection follows 5 to 10% of operations, mostly in the first months after implantation, mainly Staphylococcus epidermidis and S. aureus from the patient's skin. Work-up: CT or fast MRI to compare ventricular size and a shunt series to look for disconnection or catheter fracture. Unchanged ventricles do not exclude failure.

Mechanisms: obstructive (non-communicating) hydrocephalus — a block within the ventricular system, such as aqueductal stenosis or a posterior fossa tumour; communicating — impaired absorption at the arachnoid granulations, for example after haemorrhage or meningitis. An infant with open sutures shows a growing head circumference, a bulging fontanelle and "sunsetting" eyes; an older child has morning headache, vomiting and papilloedema. In ETV the floor of the third ventricle is opened in the midline, in front of the mammillary bodies and behind the infundibular recess, above the basilar artery — the main hazard of the operation. Success is predicted by the ETV Success Score from age, cause and previous shunt; it is low in infants under 6 months and in post-haemorrhagic or post-infectious hydrocephalus.

Key points

About 40% fail in the first year; commonest cause — proximal obstruction.
Infection 5 to 10%, mostly early, Staphylococcus epidermidis.
Work-up: CT or fast MRI and a shunt series.
ETV — floor of the third ventricle, in front of the mammillary bodies.
ETV suits aqueductal stenosis over one year of age.

Summary table

Situation	Sign or mechanism	Work-up	Treatment
Obstructive shunt failure	Headache, vomiting, drowsiness; usually proximal	CT or fast MRI, shunt series	Urgent revision
Shunt infection	Fever, redness along the track, abdominal pain	Fluid sample from the shunt	Remove the shunt, external drain, antibiotics, re-implant
Overdrainage	Postural headache, slit ventricles, subdural collections	MRI	Change valve or add an anti-siphon device
Aqueductal stenosis	Dilated lateral and third ventricles, normal fourth	MRI	ETV first choice over one year of age
Post-haemorrhagic hydrocephalus of prematurity	Intraventricular haemorrhage, rising head circumference	Cranial ultrasound through the fontanelle	Taps, reservoir, then shunt

A free exam question

רופא ילדים מתייעץ לגבי ילד שמוגדר כ- MALFORMATION TYPE II CHIARI . מה נכון לגבי תיסמונת זו? (the question as examined, in Hebrew)

א. סביר שלא יהיה הידרוצפלוס
ב. שכיח שיהיה הידרוצפלוס וגם. אנומליות סופראטנטוריאליות
ג. לא שכיח שיהיה הידרוצפלוס, אבל כן שכיח למצוא אנומליות סופראטנטוריאליות
ד. לא שכיח שיהיה הידרוצפלוס ולא שכיח שיהיו אנומליות סופראטנטוריאליות

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Sources

Congress of Neurological Surgeons: Pediatric Hydrocephalus Systematic Review and Evidence-Based Guidelines, 2014 (update 2020) — Shunt implantation, infection prevention, ETV
Youmans and Winn Neurological Surgery, 8th edition (2022) — Hydrocephalus in children; Cerebrospinal fluid shunts
Israeli Ministry of Health guidance on neurosurgical implant infection prevention, current — Surgical site infection bundle

Sources are given for further reading; the text is written afresh and not copied from them.

Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.