What are the features and management of raised intracranial pressure (ICP)?

Raised Intracranial Pressure: Clinical Features and Management

Clinical Features

Raised ICP presents with a predictable progression from early warning signs to life-threatening neurological emergency, requiring immediate recognition and intervention. 1

Early Signs and Symptoms

• Headache is typically severe and worsens with Valsalva maneuvers (coughing, straining, bending forward). 1
• Nausea and vomiting occur commonly, with projectile vomiting without preceding nausea being particularly characteristic. 1
• Visual disturbances including blurred vision, diplopia, and visual field defects develop as pressure increases. 1
• Papilledema (optic disc swelling on fundoscopic examination) is a notable sign, though it may be absent in acute onset despite significantly elevated ICP. 1
• Sixth nerve palsy causing incomitant esotropia (worse at distance) can indicate elevated ICP. 1

Late/Critical Signs

• Declining consciousness ranging from mild confusion to progressive obtundation and coma represents advanced ICP elevation. 1
• Focal neurological deficits including hemiparesis or quadriparesis develop as herniation threatens. 2
• Abnormal pupillary responses signal impending herniation. 1
• Abnormal posturing (decorticate or decerebrate) indicates severe brainstem compression. 1, 2
• Respiratory abnormalities and eventual cardiopulmonary arrest occur in terminal stages. 2

Pediatric-Specific Features

• Bulging fontanelle in infants with open fontanelles is a key early sign. 1
• Increased head circumference and separation of cranial sutures indicate chronic pressure elevation. 1

Diagnostic Thresholds

• ICP >20-25 mmHg is generally considered elevated and warrants treatment. 1, 3
• ICP 20-40 mmHg is associated with 3.95 times higher risk of mortality and poor neurological outcome. 1
• ICP >40 mmHg increases mortality risk 6.9 times and is almost universally associated with severe consciousness impairment or coma. 1
• Lumbar puncture opening pressure >200 mm H₂O indicates elevated ICP (though LP is contraindicated if mass effect is suspected). 1

Management Approach

Begin with simple, less aggressive measures and escalate systematically based on ICP response, always maintaining cerebral perfusion pressure (CPP) between 60-70 mmHg. 4, 5

Immediate First-Line Interventions

Positioning and Basic Measures

• Elevate head of bed to 20-30 degrees with neck in neutral midline position to promote jugular venous outflow. 4, 5, 6
• Ensure patient is not hypovolemic before head elevation, as this can drop blood pressure and worsen CPP. 4
• Secure airway and provide adequate oxygenation to prevent hypoxemia which exacerbates cerebral edema. 5, 6
• Avoid hypercarbia through proper ventilation, as elevated CO₂ causes cerebral vasodilation and worsens ICP. 5, 6
• Correct hyperthermia aggressively, as fever increases cerebral metabolic demand and ICP. 5, 6

Fluid Management

• Restrict free water and avoid hypotonic fluids that worsen cerebral edema. 5, 6
• Maintain euvolemia with isotonic crystalloids. 6
• Avoid antihypertensive agents that cause cerebral vasodilation (nitroprusside, nitroglycerin, hydralazine). 5

Second-Line Medical Therapy

Osmotic Therapy

• Mannitol 0.5-1 g/kg IV infused rapidly over 5-10 minutes is first-line osmotic therapy. 4, 5
• Maximum effect occurs within 10-15 minutes with duration of 2-4 hours. 5
• Maximum cumulative dose is 2 g/kg. 6, 7
• Monitor for complications: intravascular volume depletion, renal failure, and rebound intracranial hypertension with repeated dosing. 4
• Hypertonic saline (3%) is an alternative osmotic agent that may be superior in some cases and does not cause diuresis. 6, 2

Cerebral Perfusion Pressure Management

• Maintain CPP 60-70 mmHg (CPP = Mean Arterial Pressure - ICP). 5, 8
• Avoid CPP <60 mmHg which is associated with worse outcomes and cerebral ischemia. 5, 8
• Avoid CPP >90 mmHg which may worsen vasogenic edema and paradoxically increase ICP. 5, 8

Monitoring Considerations

• Fiberoptic ICP monitors (intraparenchymal) or ventricular catheters (external ventricular drains) are used in patients with high suspicion of elevated ICP or clinical deterioration. 4
• Ventricular catheters allow both monitoring and therapeutic CSF drainage, making them preferred when hydrocephalus is present. 1, 6
• ICP monitoring is recommended for patients with GCS ≤8 or clinical evidence of herniation. 6
• Transcranial Doppler shows decreased diastolic velocity and increased pulsatility index with elevated ICP, though this requires confirmation by other means. 4

Third-Line/Refractory Measures

Sedation and Analgesia

• Provide adequate sedation to prevent agitation and straining which spike ICP. 4, 9
• Consider neuromuscular paralysis if ICP remains refractory despite sedation. 2

Hyperventilation

• Moderate hyperventilation (PaCO₂ 26-30 mmHg) can be used temporarily for acute ICP crises. 9, 10
• Avoid prophylactic or prolonged hyperventilation as excessive hypocapnia causes cerebral vasoconstriction and may worsen ischemia. 4, 6
• Never hyperventilate below PaCO₂ 25 mmHg except as a last resort. 10

Advanced Therapies

• Barbiturate coma (high-dose pentobarbital) for refractory ICP, though associated with cardiovascular/respiratory depression and prolonged coma. 4, 9
• Systemic cooling to 32-34°C can lower refractory ICP but carries high complication rates (pulmonary, infectious, coagulation, electrolyte problems) and significant rebound ICP when reversed. 4, 3

Surgical Interventions

• CSF drainage via external ventricular drain is highly effective when hydrocephalus is present. 6, 10
• Evacuation of mass lesions (hematoma, tumor, large infarct) when surgically accessible and patient condition is salvageable. 2, 10
• Decompressive craniectomy may be life-saving for malignant cerebral edema refractory to medical management. 6, 3

Critical Pitfalls to Avoid

• Never perform lumbar puncture before neuroimaging in patients with suspected elevated ICP, as this can precipitate herniation. 6
• Avoid corticosteroids for ICP management in intracerebral hemorrhage or ischemic stroke—they are ineffective and potentially harmful. 4, 5, 6
• Do not use 25% mannitol if the flip-top vial seal is not intact, and never place mannitol in PVC bags as white precipitate may form. 7
• Recognize that mannitol effects are temporary—repeated doses may be necessary but carry risk of rebound ICP and renal complications. 4, 5
• Avoid excessive blood pressure elevation to maintain CPP, as this can paradoxically increase ICP in patients with impaired autoregulation. 4