Treatment of Hydrocephalus

Overview

Hydrocephalus management depends on whether it is obstructive (non-communicating) or communicating, and on the acuity of presentation. Acute obstructive hydrocephalus is a neurosurgical emergency - rapid progression to coma and death ("hydrocephalic attack") can occur without prompt CSF diversion. - Bailey & Love's Short Practice of Surgery, 28th Ed.

1. Emergency / Temporary Measures

External Ventricular Drain (EVD)

The first-line bridge for acute or perioperative hydrocephalus.

Inserted through a burr hole at Kocher's point (right of midline, anterior to coronal suture), perpendicular to brain surface
Catheter tip sits at the foramen of Monro in the lateral ventricle
Can also deliver intrathecal antibiotics
Lumbar drains are an alternative for communicating hydrocephalus

Treating the Underlying Cause

When an obstructive tumour is resectable, surgery may resolve hydrocephalus directly without permanent CSF diversion.

2. Long-Term Surgical Treatment

A. Ventriculoperitoneal (VP) Shunt - The Mainstay

The VP shunt is the most widely used definitive treatment. It consists of:

Proximal (ventricular) catheter - inserted into the lateral ventricle
Shunt valve - regulates CSF flow by opening at a predetermined pressure; includes a CSF reservoir for percutaneous sampling
Distal catheter - tunnelled subcutaneously to the peritoneal cavity

Additional features:

Anti-siphon device - prevents excess drainage in the upright position
Programmable (adjustable) valves - opening pressure can be changed non-invasively using an external magnetic device

Examples of VP shunt valves showing different designs with reservoirs and catheters

Figure: Examples of ventriculoperitoneal shunt valves (Bailey & Love)

Alternative shunt sites (less common):

Type	Distal Location	Notes
Ventriculoatrial (VA)	Right atrium	Rare complications: pulmonary HTN, embolism, VA nephritis (Staph)
Ventriculopleural	Pleural space	Risk of pleural effusion
Lumboperitoneal	Peritoneum (lumbar)	For communicating hydrocephalus

B. Endoscopic Third Ventriculostomy (ETV)

Best for: obstructive hydrocephalus due to aqueduct stenosis - avoids indwelling hardware entirely.

Procedure:

Neuroendoscope inserted into the frontal horn of the lateral ventricle
Advanced into the third ventricle via the foramen of Monro
Floor of the third ventricle is fenestrated between the mammillary bodies and the pituitary recess
Creates free drainage into adjacent subarachnoid cisterns

Advantages: No implanted tubing, no infection risk from hardware

Limitations:

Re-blockage is common - many patients eventually require a shunt
Serious rare complications: basilar artery injury, fornix damage causing permanent memory impairment

ETV/CPC (ETV + Choroid Plexus Cauterization): Used particularly in infants under 2 years with non-communicating hydrocephalus (e.g., post-infectious, myelomeningocele-associated). Reduces CSF production by cauterizing the choroid plexus, improving ETV success rates.

ETV vs VP Shunt (current evidence): ETV shows lower infection rates and shunt dependency, especially in patients >1 year with obstructive hydrocephalus. A recent RCT (Surgical Neurology Int.) found ETV success 77% vs VPS 91%, though VPS had more complications overall. The ETV Success Score (ETVSS) helps predict who will benefit.

3. Shunt Complications (15-20% require revision within 3 years)

Complication	Features	Management
Infection	Fever, headache, meningism; 75% within 1 month of insertion	Remove shunt + EVD or serial LPs, antibiotics; reinsert shunt at new site when CSF clears
Blockage	Symptoms/signs of raised ICP; reservoir hard to compress or slow to refill	Emergency in obstructive hydrocephalus; CT confirms ventricular enlargement; shunt replacement
Overdrainage	Postural headaches (worse on standing), subdural hygroma/haematoma	Programmable valve adjustment, anti-siphon device
Slit ventricle syndrome	Children; tiny non-compliant ventricles; ICP spikes with coughing/straining	Raise valve opening pressure or add antisiphon device
VA-specific	Pulmonary HTN, pulmonary embolism, immune nephritis	Due to chronic Staph colonization

4. Special Conditions

Normal Pressure Hydrocephalus (NPH)

Classic triad: gait disturbance, urinary incontinence, cognitive decline in elderly patients.

Treatment of choice: VP shunt - ventricular size often normalises within weeks, gait improves fastest
Predicting responders is difficult; large-volume LP tap test (improvement in gait after removing ~40 mL CSF) helps select patients
Acetazolamide has been tried but clinical benefit is minimal
Goldman-Cecil Medicine, Bradley & Daroff's Neurology

Idiopathic Intracranial Hypertension (IIH / Pseudotumor Cerebri)

No true ventricular enlargement; raised ICP with normal CSF.

Weight loss (most effective long-term in obese patients)
Acetazolamide 250-500 mg twice daily, up to 4 g/day - reduces CSF production via carbonic anhydrase inhibition
Serial lumbar punctures - temporizing measure
CSF diversion (VP/LP shunt or optic nerve sheath fenestration) - reserved for visual loss or refractory cases
Bailey & Love; Tintinalli's Emergency Medicine

Post-Hemorrhagic Hydrocephalus (Neonatal/Preterm)

Early CSF removal may reduce need for VP shunt and attenuate neurodevelopmental impairment
Guidelines are locale-specific
Bradley & Daroff's Neurology

Childhood/Infantile Hydrocephalus

Catheter placed in anterior horn (avoids choroid plexus) to reduce blockage
Complications unique to children: peritoneal pseudocysts, slit ventricle syndrome, skull growth failure
Controversial whether to shunt all hydrocephalic infants immediately - outcomes for normal IQ (70-100) in ~72% of shunted children in one series
Adams & Victor's Principles of Neurology

Summary

Situation	Preferred Treatment
Acute obstructive hydrocephalus	EVD (emergency), then definitive treatment
Communicating / long-term	VP shunt (mainstay)
Obstructive (aqueduct stenosis, >1 yr)	ETV (first choice to avoid hardware)
Infants <2 yr with obstructive	ETV/CPC
NPH	VP shunt
IIH	Weight loss + acetazolamide; shunt/fenestration for refractory/visual loss
Shunt infection	Remove shunt + antibiotics, reinsert when CSF clear

Sources: Bailey & Love's Short Practice of Surgery 28th Ed. | Adams & Victor's Principles of Neurology 12th Ed. | Bradley & Daroff's Neurology in Clinical Practice | Goldman-Cecil Medicine | Tintinalli's Emergency Medicine

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