How is intracranial hypertension (Increased Intracranial Pressure (ICP)) evaluated and managed?

Evaluation and Management of Intracranial Hypertension

Intracranial hypertension should be evaluated through urgent neuroimaging, lumbar puncture when safe, and managed using a stepwise approach including positioning, osmotic therapy, CSF drainage, and surgical interventions when necessary. 1

Diagnostic Evaluation

Initial Assessment

• Neurological examination: Look specifically for:
  • Papilloedema (key finding)
  • Sixth cranial nerve palsy (lateral rectus palsy)
  • Decreased consciousness (progressing to stupor and coma)
  • Cushing's triad (hypertension, bradycardia, irregular respiration)
  • Pupillary changes, abnormal posturing, and focal neurological deficits 2

Neuroimaging

• MRI brain with contrast within 24 hours (preferred first-line imaging) 1
• If MRI unavailable within 24 hours, perform urgent CT brain followed by MRI 1
• CT or MR venography is mandatory to exclude cerebral sinus thrombosis 1
• Look for signs of increased ICP:
  • No evidence of hydrocephalus, mass, structural or vascular lesion
  • No abnormal meningeal enhancement 1

Lumbar Puncture

• Perform after normal neuroimaging to:
  • Measure opening pressure (in lateral decubitus position)
  • Analyze CSF composition 1
• Normal ICP is <10 mmHg or <20 cmH2O
• Pathologically elevated ICP is ≥25 cmH2O in adults 1, 3

Management Principles

The three main principles of management are:

1. Treat the underlying disease
2. Protect vision
3. Minimize headache morbidity 1

First-Line Interventions

Positioning and General Measures

• Elevate head of bed by 20-30° to improve venous drainage 2
• Maintain normocapnia (PaCO₂ 35-40 mmHg) 2
• Ensure adequate analgesia and sedation to prevent ICP spikes 2
• Maintain normothermia and treat fever aggressively 2

Weight Management (for Idiopathic Intracranial Hypertension)

• For patients with BMI >30 kg/m², weight loss is the only disease-modifying therapy 1
• Refer to structured weight management program 1

Pharmacological Management

• Mannitol: First-line agent for acute ICP elevation

  • Dosage: 0.25-2 g/kg IV as 15-25% solution over 30-60 minutes
  • Pediatric dosage: 1-2 g/kg or 30-60 g/m² over 30-60 minutes
  • Small/debilitated patients: 500 mg/kg 4
  • Monitor for evidence of reduced ICP within 15 minutes of starting infusion 4
  • Contraindicated in anuria, severe pulmonary edema, active intracranial bleeding, severe dehydration 4

• Hypertonic saline: Alternative osmotic agent for refractory cases

  • Monitor electrolytes and renal function carefully 2

Second-Line Interventions

CSF Drainage

• External ventricular drainage is highly effective for reducing ICP, particularly in hydrocephalus 2
• Options include:
  • Intermittent drainage via intraventricular catheter
  • Continuous external ventricular drainage
  • Lumbar drainage (if no risk of herniation) 2

Controlled Hyperventilation

• Short-term hyperventilation (PaCO₂ 25-30 mmHg) may be used for acute, life-threatening ICP elevations
• Caution: prolonged hyperventilation can cause cerebral vasoconstriction and ischemia 2

Third-Line Interventions

Surgical Management

• Surgical evacuation for hematomas causing mass effect 2
• Decompressive craniectomy for refractory intracranial hypertension 1, 2
• For idiopathic intracranial hypertension with visual loss, CSF diversion procedures are preferred 1

Monitoring

ICP Monitoring

• Maintain ICP below 20-25 mmHg 2, 3
• Maintain cerebral perfusion pressure (CPP) above 60-70 mmHg 2
• Options include:
  • Intraventricular catheter (allows both monitoring and CSF drainage)
  • Intraparenchymal pressure monitor 1

Clinical Monitoring

• Frequent neurological assessments to detect early signs of herniation 2
• Monitor for complications of treatment:
  • Renal dysfunction from osmotic therapy
  • Electrolyte disturbances
  • Secondary ischemia 2

Special Considerations

Fulminant Intracranial Hypertension

• For rapid visual decline within 4 weeks of diagnosis:
  • Consider serial lumbar punctures as a temporizing measure
  • Implement longer-term measures such as CSF diversion or optic nerve sheath fenestration 1

Pregnant Patients

• Multidisciplinary approach involving obstetricians
• No specific mode of delivery recommended based on IIH diagnosis alone
• Careful risk-benefit assessment for headache medications during pregnancy 1

Common Pitfalls to Avoid

• Delaying neuroimaging in suspected increased ICP
• Performing lumbar puncture before excluding mass lesion
• Prolonged hyperventilation causing cerebral ischemia
• Excessive fluid restriction leading to hypotension and decreased CPP
• Overlooking medication overuse headache in chronic management
• Using steroids for IIH (not recommended unless associated with tumor) 1, 2

By following this structured approach to evaluation and management, patients with intracranial hypertension can receive timely intervention to prevent vision loss and reduce morbidity and mortality.