What is the treatment for uncal herniation?

Treatment of Uncal Herniation

Immediate administration of hyperosmolar therapy (mannitol 0.5 g/kg IV or hypertonic saline 2-3 ml/kg of 3% saline) combined with brief hyperventilation (target PaCO2 4.0-4.5 kPa) and urgent neurosurgical consultation for definitive decompressive surgery is the treatment for uncal herniation. 1

Immediate Medical Management

Hyperosmolar Therapy (First-Line)

• Administer mannitol 0.5 g/kg IV bolus immediately when clinical or radiological evidence of raised ICP with impending uncal herniation is present 1
• Alternatively, use hypertonic saline 2 ml/kg of 3% saline as a bolus 1
• Mannitol works by increasing osmotic pressure of plasma and extracellular space, inducing movement of intracellular water to vascular spaces, thereby reducing intracranial pressure 2
• Mannitol is freely filtered by glomeruli with elimination half-life of 0.5-2.5 hours in patients with normal renal function 2

Controlled Hyperventilation (Temporizing Measure Only)

• Hyperventilation is justified for short-term use only with target PaCO2 of 4.0-4.5 kPa (not less than 4 kPa) 1
• This is specifically indicated for impending uncal herniation as a bridge to definitive treatment 1
• Effects are short-lived due to rapid restoration of cerebral blood flow autoregulation 1
• Do not use prophylactic continuous hyperventilation - randomized trials show no reduction in cerebral edema incidence and no survival benefit 1
• Hyperventilation may worsen cerebral edema by causing cerebral hypoxia through vasoconstriction 1

Airway and Ventilation Management

• Intubate immediately if not already done - GCS ≤8 or significantly deteriorating conscious level are absolute indications 1
• Target PaO2 ≥13 kPa while avoiding hyperoxia 1
• Maintain PaCO2 between 4.5-5.0 kPa under normal circumstances 1
• Use minimum 5 cmH2O PEEP to prevent atelectasis; PEEP up to 10 cmH2O does not adversely affect cerebral perfusion 1

Positioning and Sedation

• Position patient with 20-30° head-up tilt to facilitate venous drainage 1
• Maintain adequate sedation with propofol or midazolam infusions 1
• Add neuromuscular blockade to prevent increases in intracranial pressure from coughing or agitation 1
• Administer bolus sedative drugs as part of ICP reduction strategy 1

Blood Pressure Management

Target Parameters

• Maintain systolic BP >110 mmHg and MAP >90 mmHg in traumatic brain injury 1
• Measure all invasive arterial pressures with transducer at level of tragus, including when patient is head-up 1
• Avoid hypotension as it adversely affects neurological outcome 1

Fluid Management

• Use 0.9% saline exclusively - it is the only commonly available isotonic crystalloid appropriate for brain injury 1
• Avoid Ringer's lactate, Ringer's acetate, gelatins, albumin, and synthetic colloids as they are hypotonic and can worsen cerebral edema 1
• Reverse hypovolaemia promptly to maintain cerebral blood flow 1

Hypertension Management

• Increase sedation first for elevated blood pressure 1
• Use small boluses of labetalol if sedation inadequate 1

Definitive Treatment

Urgent Neurosurgical Intervention

• Obtain immediate neurosurgical consultation - uncal herniation is uniformly fatal without intervention 1
• Surgical decompression (decompressive craniectomy) is the definitive treatment for herniation with mass effect 1
• In traumatic cases with temporal lobe contusion, aggressive temporal lobectomy may be required - complete temporal lobectomy shows better outcomes than subtemporal decompression alone 3

ICP Monitoring

• Consider placement of ICP monitoring device in grade III/IV encephalopathy patients listed for transplantation (in acute liver failure context) 1
• Frequent evaluation for signs of intracranial hypertension needed when ICP monitoring not available 1

Additional Pharmacologic Measures

Seizure Management

• Treat seizures immediately with benzodiazepines and phenytoin or levetiracetam 1
• Prophylactic anticonvulsants have unclear value 1

Refractory Intracranial Hypertension

• Short-acting barbiturates (thiopentone) may be considered for refractory ICP elevation not controlled by mannitol 1
• Do not use corticosteroids - they are ineffective for controlling elevated ICP in acute brain injury 1

Critical Pitfalls to Avoid

• Never delay definitive neurosurgical intervention - medical management is temporizing only 1
• Do not use prophylactic hyperventilation - reserve for acute herniation crisis only 1
• Avoid hypotonic fluids (Ringer's lactate, colloids) which worsen cerebral edema 1
• Do not allow hypotension or hypoxia even briefly - both worsen outcomes 1
• Recognize that uncal herniation represents a neurosurgical emergency requiring immediate operative decompression for survival 1