Neuroscience · Year 2 · from Neuroscience
Case 1: Cerebellar Stroke with Herniation Risk
Patient Presentation
Demographics: 72-year-old male
Chief Complaint: Sudden severe dizziness, vomiting, and inability to walk
History of Present Illness: A 72-year-old man with a history of hypertension and atrial fibrillation (on aspirin, not anticoagulated) suddenly developed severe vertigo and vomiting while getting out of bed. He is unable to stand or walk without falling. He describes the room as spinning constantly and has vomited six times. He also reports a severe headache in the back of his head. His wife notes that his speech seems slightly slurred. He denies limb weakness, numbness, or visual changes.
Physical Examination:
- Vital signs: BP 185/105, HR 88 (irregular), RR 18
- General: In distress, vomiting, eyes closed, holding head
- Neurological:
- Mental status: Alert but drowsy; oriented to person and place
- Cranial nerves: Bilateral nystagmus (direction-changing); no facial weakness; gag intact
- Motor: 5/5 strength all extremities when tested in bed
- Coordination: Severe bilateral limb ataxia - cannot perform finger-to-nose or heel-to-shin
- Speech: Dysarthric with scanning quality
- Gait: Unable to stand - truncal ataxia and falling backward
- Reflexes: 2+ and symmetric; no Babinski
Workup:
- CT head without contrast: Hypodensity in right cerebellar hemisphere with early mass effect; compressed fourth ventricle; early hydrocephalus
- CT angiography: Occluded right posterior inferior cerebellar artery (PICA)
- Repeat CT (4 hours later for worsening drowsiness): Increased cerebellar edema with complete effacement of fourth ventricle; progressive hydrocephalus
Diagnosis: Right cerebellar infarct (PICA territory) with obstructive hydrocephalus and impending herniation
Treatment:
- Emergent neurosurgical consultation
- External ventricular drain (EVD) placement for hydrocephalus
- Suboccipital decompressive craniectomy with resection of infarcted cerebellar tissue
- ICU monitoring
- ICP monitoring post-operatively
- Gradual neurological improvement after surgery
- Anticoagulation started after appropriate interval for atrial fibrillation
- Intensive physical therapy for ataxia
- Walking with walker at discharge; independent ambulation at 3 months with mild residual ataxia
Clinical Pearl: Cerebellar stroke is a neurosurgical emergency because the posterior fossa is a closed space. Unlike supratentorial strokes, even moderate cerebellar infarcts can cause rapid deterioration from: (1) obstructive hydrocephalus from fourth ventricle compression, and (2) direct brainstem compression as the swollen cerebellum herniates through the foramen magnum (tonsillar herniation) or upward through the tentorial incisura. Warning signs include decreasing level of consciousness, worsening headache, and new brainstem signs. Emergency decompression can be life-saving and often results in good functional outcomes because the brainstem itself may be spared.