Neuroscience · Year 2 · from Neuroscience
Case 3: Uncal Herniation
Patient Presentation
Demographics: 45-year-old female
Chief Complaint: Found unresponsive at home
History of Present Illness: Emergency medical services were called when the patient's husband found her unresponsive in bed. He reported she had complained of "the worst headache of her life" approximately 2 hours earlier while they were watching television. She took ibuprofen and went to lie down. When he checked on her 30 minutes later, she was difficult to arouse. By the time EMS arrived, she was completely unresponsive. She has a history of hypertension and smokes one pack of cigarettes daily.
Physical Examination:
- Vital signs: BP 185/110, HR 58, RR irregular, T 37.2C
- General: Unresponsive, GCS 6 (E1V2M3)
- Neurological:
- Right pupil 6 mm fixed and dilated; left pupil 3 mm reactive
- No response to verbal commands
- Withdraws left side to pain; right side extensor posturing (decerebrate response)
- Corneal reflexes absent on right, present on left
- No gag reflex
Workup:
- CT head without contrast: Diffuse subarachnoid hemorrhage concentrated in basal cisterns; 3 cm left temporal intracerebral hematoma with uncal herniation and effacement of perimesencephalic cistern; early hydrocephalus
- CT angiography: 8 mm saccular aneurysm at left posterior communicating artery origin
Diagnosis: Aneurysmal subarachnoid hemorrhage with intracerebral hematoma, uncal herniation, and CN III palsy
Treatment:
- Immediate intubation for airway protection
- External ventricular drain (EVD) placement for ICP monitoring and CSF drainage
- Osmotic therapy with mannitol 1 g/kg IV bolus
- Emergency craniotomy with aneurysm clipping and hematoma evacuation
- Post-operative care in neurocritical care unit with nimodipine for vasospasm prophylaxis
- Gradual weaning from sedation; right pupil reactivity returned after decompression
- Prolonged rehabilitation required; at 6-month follow-up, Modified Rankin Scale 3
Clinical Pearl: Uncal herniation occurs when increased intracranial pressure forces the medial temporal lobe (uncus) through the tentorial notch. This compresses the ipsilateral CN III (causing pupil dilation and ptosis), the cerebral peduncle (causing contralateral hemiparesis), and the posterior cerebral artery (causing visual field deficits). The classic triad of CN III palsy, contralateral hemiparesis, and decreased consciousness requires emergent intervention.
Clinical Image
Image Description: Axial CT scan of the head demonstrating a crescent-shaped subdural hematoma along the right cerebral convexity, a characteristic finding in subdural hemorrhage resulting from torn bridging veins in the subdural space.
Attribution: Image from Radiopaedia (https://radiopaedia.org/), Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license.