How to approach hydrocephalus in adults?

Management of Hydrocephalus in Adults

The management of adult hydrocephalus requires a systematic approach with cerebrospinal fluid (CSF) diversion via external ventricular drainage (EVD) or permanent shunting as the primary intervention for patients with clinical or radiological signs of hydrocephalus. 1, 2

Diagnosis and Assessment

• Hydrocephalus results from an imbalance between CSF production and absorption or obstruction of CSF pathways, leading to ventricular dilatation and increased intracranial pressure 3
• Magnetic resonance imaging (MRI) is the first-line imaging modality for diagnosis, with computed tomography (CT) often used initially in emergency settings 3
• MRI protocol should include sagittal high-resolution T2-weighted images to evaluate CSF pathways 3
• When inflammatory etiology is suspected, contrast-enhanced imaging is necessary 3

Classification and Etiology

• Occlusive (obstructive) hydrocephalus: caused by blockage of CSF pathways 3
• Malabsorptive hydrocephalus: caused by impaired CSF absorption 3
• Common causes in adults include:
  • Intracerebral hemorrhage (ICH) with intraventricular extension (occurs in ~55% of ICH patients with IVH) 2
  • Subarachnoid hemorrhage (SAH) (occurs in 8.9-48% of patients) 2
  • Traumatic brain injury (TBI) 2
  • Tumors obstructing CSF pathways 1
  • Post-infectious conditions 3

Indications for Intervention

• Clinical or radiological signs of hydrocephalus 1
• Glasgow Coma Scale (GCS) score of 8 or less 2
• Evidence of transtentorial herniation 2
• Significant intraventricular hemorrhage 2
• Decreased level of consciousness 2

Treatment Approach

Surgical Management

• External ventricular drainage (EVD) is the first-line intervention for acute hydrocephalus 1, 2

  • Allows both ICP monitoring and CSF drainage 2
  • Before insertion, evaluate coagulation status and correct any abnormalities 2
  • Consider platelet transfusion for patients on antiplatelet therapy 2
  • Reverse coagulopathy in patients on warfarin before device insertion 2

• Permanent CSF diversion (shunting) for persistent hydrocephalus 2

  • Improves neurological outcomes in appropriate candidates 2
  • Risk factors for shunt dependency include poor admission neurological grade, increased age, and high Fisher grades in SAH patients 2

• Endoscopic third ventriculostomy (ETV) may be considered as an alternative to shunting in selected cases 4

Management of Intracranial Pressure (ICP)

• Target cerebral perfusion pressure (CPP) of 50-70 mmHg, depending on cerebral autoregulation status 2
• For refractory elevated ICP, consider osmotic therapy with hypertonic saline (3%) 1, 2
• Avoid corticosteroids as they are not recommended for treatment of elevated ICP in ICH 2

Monitoring and Follow-up

• Regular clinical assessment for signs of increased ICP 2
• Follow-up imaging to evaluate ventricular size and shunt function 3
• Monitor for complications including infection (approximately 4% risk with ventricular catheters) and intracranial hemorrhage (approximately 3% risk, higher in patients with coagulopathies at 15.3%) 2

Special Considerations

• Electromagnetic image guidance can be used as a technical adjuvant for ventricular catheter placement, especially in patients with difficult anatomy (small or slit ventricles) 1
• Ultrasound-assisted catheter placement is an option, particularly for accurate positioning away from choroid plexus 1
• Avoid medications that alter cerebral blood flow or cause fluid retention, such as minoxidil, which could disrupt the delicate balance of CSF production and absorption 5
• For patients requiring antihypertensive therapy, consider agents with more predictable effects on cerebral hemodynamics rather than direct vasodilators 5

Prognosis

• Outcomes vary widely and depend on underlying etiology, timing of intervention, and complications 6, 4
• Early intervention is associated with better outcomes 2
• Gross total resection of tumors causing obstructive hydrocephalus improves outcomes in cases of tumor-related hydrocephalus 1

Complications and Pitfalls

• Shunt failure is a common complication requiring revision 6
• Infection risk increases with prolonged external ventricular drainage 2
• Overdrainage can lead to subdural collections or slit ventricle syndrome 4
• Underdrainage may result in persistent symptoms of increased ICP 2