How should raised intracranial pressure be evaluated and managed?

Evaluation and Management of Raised Intracranial Pressure

Raised intracranial pressure (ICP >20 mmHg) requires immediate recognition and aggressive treatment to prevent herniation and death, with management prioritizing surgical decompression when indicated, followed by medical therapies including head elevation, hyperosmolar agents (mannitol or hypertonic saline), and external ventricular drainage. 1, 2, 3

Initial Evaluation and Monitoring

Clinical Assessment

• Assess for signs of intracranial hypertension: declining Glasgow Coma Scale score (particularly ≤8), pupillary changes indicating transtentorial herniation, and acute deterioration in mental status 4, 2, 5
• Identify the underlying cause immediately: CT imaging is essential to detect surgically treatable lesions including hematoma (subdural, epidural, intracerebral), tumor, hydrocephalus, or large cerebellar infarction 4, 6, 7
• Look for specific CT signs of elevated ICP: sulcal obliteration, third ventricular compression, lateral ventricle compression, midline shift, and herniation—the presence of all five signs dramatically increases mortality risk (OR = 4.44) 8

ICP Monitoring

• Consider invasive ICP monitoring for patients listed for transplantation or with severe neurological injury (GCS ≤8), though routine monitoring is not universally recommended across all conditions 4, 1
• External ventricular drain (EVD) is preferred when monitoring is indicated as it allows both pressure measurement and therapeutic CSF drainage 1
• Use bolted catheters with antibiotic coating rather than tunneled or uncoated catheters to reduce infection risk (OR 0.60) 1

Immediate General Measures

Positioning and Basic Management

• Elevate head of bed to 20-30 degrees to improve venous drainage and reduce ICP 4, 2, 6
• Keep neck in neutral position—any rotation, flexion, or extension significantly increases ICP 9
• Intubate patients with grade III-IV encephalopathy (marked confusion/coma) for airway protection 4

Physiologic Optimization

• Maintain euvolemia with isotonic crystalloids (0.9% NaCl or balanced solutions); avoid hypotonic fluids which worsen cerebral edema 4, 10
• Prevent and treat factors that exacerbate ICP: hypoxia, hypercarbia (maintain normocapnia unless acute crisis), hyperthermia, and hyponatremia 4, 6
• Target mean arterial pressure ≥65 mmHg to maintain cerebral perfusion pressure, though this may need adjustment to 70 mmHg in older patients with cerebral edema 4
• Use norepinephrine as first-line vasopressor after volume resuscitation 4

Surgical Management

Surgical intervention is the definitive treatment when ICP elevation is caused by mass lesions including hematoma, contusion, tumor, or obstructive hydrocephalus 6, 7

External Ventricular Drainage

• EVD placement is indicated for intraventricular hemorrhage with hydrocephalus and traumatic brain injury with refractory ICP elevation 1
• CSF drainage via EVD is the most effective first-tier intervention for controlling ICP when medical measures fail 6
• Remove catheters as soon as clinically possible—infection risk increases significantly after 5-7 days of drainage 1
• Consider intraventricular fibrinolysis to reduce catheter occlusion (from 37.3% to 10.6%) and mortality (from 40.9% to 22.4%) in patients with intraventricular hemorrhage 1

Decompressive Craniectomy

• Bilateral decompressive craniectomy is the last resort for refractory intracranial hypertension and should be performed without delay once considered 6

Medical Management

First-Tier Hyperosmolar Therapy

Mannitol (FDA-approved):

• Dose: 0.25-2 g/kg IV as 15-25% solution over 30-60 minutes for reduction of intracranial pressure 3
• In small or debilitated patients, 500 mg/kg may be sufficient 3
• Evidence of reduced ICP should be observed within 15 minutes 3
• Monitor circulatory and renal function closely, particularly at higher doses and rapid infusion rates 3

Hypertonic Saline (3%):

• Preferred over mannitol in intracerebral hemorrhage as it provides more rapid ICP reduction, greater increases in cerebral perfusion pressure, longer duration of action, and is safer in hypovolemia 2
• For acute ICP crisis: 2 mL/kg bolus over 15-20 minutes, with maximum effect at 10-15 minutes lasting 2-4 hours 2
• For sustained control: continuous infusion targeting serum sodium 145-155 mmol/L 2
• Monitor serum sodium within 6 hours of initiation and every 6 hours thereafter; do not exceed 155-160 mmol/L 2
• Critical caveat: Despite proven ICP reduction, hypertonic saline does not improve neurological outcomes or survival 2

Hyperventilation

• Prophylactic hyperventilation is not recommended and shows no survival benefit 4, 6
• Reserve hyperventilation (target PaCO₂ <35 mmHg) only for life-threatening ICP elevation not controlled by mannitol as a temporary bridge to prevent imminent herniation 4, 6
• Forced hyperventilation (PaCO₂ <25 mmHg) is a second-tier option for refractory cases 6
• Concern exists that excessive cerebral vasoconstriction may worsen edema through cerebral hypoxia 4

Seizure Management

• Treat seizures immediately with phenytoin and low-dose benzodiazepines as seizure activity acutely elevates ICP and causes cerebral hypoxia 4
• Use minimal benzodiazepine doses due to delayed hepatic clearance in liver failure patients 4
• Prophylactic phenytoin is not currently recommended despite some evidence of reduced cerebral edema at autopsy 4
• Monitor with EEG in patients with fluctuating consciousness or subtle movements to detect non-convulsive status epilepticus 4

Sedation Considerations

• Avoid sedation in early encephalopathy (grades I-II) to allow neurological assessment 4
• For intubated patients, use short-acting agents: propofol may reduce cerebral blood flow but lacks controlled evidence of efficacy; use minimal doses given prolonged half-life in hepatic failure 4
• Use endotracheal lidocaine before suctioning to prevent ICP spikes from Valsalva-like maneuvers 4

Second-Tier Therapies for Refractory ICP

• Short-acting barbiturates (e.g., pentobarbital) may be considered for refractory intracranial hypertension 4, 6
• Barbiturate coma is a second-tier option when first-tier measures fail 6
• Induced hypothermia remains experimental and should not be used routinely—a recent trial was stopped early due to excess mortality 4

Specific Contraindications and Pitfalls

What NOT to Do

• Never use corticosteroids to control elevated ICP in acute liver failure—they are ineffective and potentially harmful 4
• Do not restrict fluids in an attempt to reduce cerebral edema; this worsens outcomes 4
• Never flush an EVD system with a transducer-flush device—this can generate fatal air emboli 1
• Do not use hypertonic saline for volume resuscitation in hemorrhagic shock unless combined with severe head trauma and focal neurological signs 2
• Avoid hypotonic fluids (osmolarity <280 mOsm/L) as they worsen cerebral edema 10
• Do not use prophylactic antibiotics or lactulose routinely in acute liver failure—no survival benefit has been demonstrated, though lactulose may cause problematic bowel distension before transplant 4

Critical Monitoring Parameters

• Verify EVD function immediately if: acute mental status change occurs, ICP rises above 20-22 mmHg, or CSF stops draining without visible blockage—notify the provider immediately before troubleshooting 1
• Check coagulation status before any EVD manipulation to prevent intracranial bleeding 1
• Monitor for infection vigilantly: CSF leakage >1 day increases ventriculitis risk to 21.1% versus 0% for <1 day 1

Condition-Specific Considerations

Acute Liver Failure

• ICP monitoring is mainly considered for transplant candidates 4
• Arterial ammonia >200 μg/dL is strongly associated with cerebral herniation 4
• Infection and systemic inflammatory response syndrome are associated with progression to deeper encephalopathy 4

Ischemic Stroke

• Brain edema typically peaks at 3-5 days after stroke; less than 10-20% develop clinically significant edema requiring intervention 4
• Large cerebellar infarctions may cause problems within the first 24 hours due to acute hydrocephalus 4
• Avoid antihypertensive agents that induce cerebral vasodilation in patients with elevated ICP 4

Bacterial Meningitis

• Maintain euvolemia rather than restricting fluids 4
• Basic measures to control ICP and maintain cerebral perfusion pressure are recommended, but routine ICP monitoring is not 4
• Glycerol is not recommended—trials showed increased mortality in adults 4

Idiopathic Intracranial Hypertension

• CSF diversion and neurovascular stenting are not treatments for headache alone in IIH 4
• These procedures should only be considered in multidisciplinary settings with ICP monitoring for patients with visual loss 4

4, 1, 2, 3, 6