Makindo Medical Notes

Related Subjects: |Brain Herniation syndromes |Haemorrhagic stroke |Traumatic Head/Brain Injury |Acute Hydrocephalus |Epidural Haematoma |Subdural Haematoma

Introduction

• The brain is encased within a rigid skull, with additional internal structures that help maintain its position and protect it against shifts due to rapid movements.
• The falx cerebri separates the cerebral hemispheres, while the tentorium cerebelli acts as a barrier between the cerebrum and the brainstem/cerebellum. These structures help to localize brain shifts but can become critical barriers during increased intracranial pressure (ICP).
• Brain herniation occurs when a mass effect or elevated ICP pushes brain tissue past these structures, leading to compression and displacement of brain structures—a condition that is often life-threatening and demands immediate intervention.
• Brain herniation is typically seen in the context of rising ICP in comatose patients and is a neurosurgical emergency. There are six primary types of herniation syndromes.

Herniation Syndromes

Uncal Herniation with Duret Hemorrhages

Transcalvarial Herniation

Clinical Signs of Raised ICP

• Dilated, non-reactive pupil (often ipsilateral to the lesion in uncal herniation)
• Severe headache, confusion, and progressive drowsiness
• Depressed consciousness or coma
• Third nerve palsy presenting as ptosis and "down and out" gaze
• Contralateral hemiparesis or hemiplegia
• Bradycardia, hypertension, and irregular respiration (Cushing's triad)
• Respiratory depression or arrest, indicating brainstem involvement

Investigations

• Urgent CT head or MRI to identify herniation and the underlying cause.

Management

• These conditions are often fatal if not managed urgently, with a remote possibility of recovery in cases of severe uncal herniation.
• Key management strategies include:
  • Neurosurgical intervention: Decompressive craniectomy or other procedures to relieve pressure.
  • Mannitol or hypertonic saline: To reduce ICP temporarily while awaiting definitive intervention.
  • Emergency ventriculostomy: For acute hydrocephalus or to drain CSF and relieve pressure.
  • Palliation: May be considered in cases with irreversible brain damage and poor prognosis.