Raised intracranial pressure (ICP)

The volume inside the cranium is fixed, so any increase in the contents can lead to raised ICP. This can be mass effect, edema, or obstruction to fluid outflow. Normal ICP in adults is <15mmHg.

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Investigations

• Urea & Creatinine
• Electrolytes
• CBC
• Liver Function Tests
• Glucose
• Serum osmolality
• Clotting
• Blood cultures
• Consider a toxicology screen if needed
• CXR: Check for infection (abscess)
• CT Head Scan: Crucial for identifying structural causes (e.g., mass lesions, hemorrhage)
• Lumbar Puncture (LP): Measure opening pressure, (if safe)

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Management

The goal is to reduce ICP and prevent secondary injury.

1. ABC
2. Correct hypotension, maintain MAP >90mmHg
3. Treat seizures
4. Brief examination; history if available
5. Elevate the head of the bed to 30–40°
6. If intubated, hyperventilate to reduce PaCO2 (aim 3.5–4kPa) (≈ 26–30 mmHg), This causes cerebral vasoconstriction and reduces ICP almost immediately.
7. Maintain PaO2 >90mmHg
8. Osmotic agents (e.g. mannitol) can be useful but may lead to rebound ICP after prolonged use (~12–24h)
9. Mannitol 20% solution 0.25–0.5g/kg IV over 10–20min (e.g. 5mL/kg)
   • Effect is seen after ~20min and lasts for 2–6h.
   • Follow serum osmolality—aim for about 300 mosmol/kg but don’t exceed 310
10. Corticosteroids are not effective in reducing ICP except for oedema surrounding tumours
    • Dexamethasone 10mg IV and follow with 4mg/6h IV/PO
11. Consider other measures, e.g. sedation, anti-epileptics, therapeutic hypothermia
12. Restrict fluid to <1.5L/d
13. Monitor the patient closely; consider monitoring ICP
14. Start to make a diagnosis
15. Treat cause or exacerbating factors, e.g. hyperglycemia, hyponatremia
16. Definitive treatment if possible
17. If focal causes (e.g. hematomas): Urgent neurosurgery is required for the definitive treatment of increased ICP.

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