Neuroscience · Year 2 · from Neuroscience
Case 3: Cerebellar Lesion (Cerebellar Stroke)
Patient Presentation
Demographics: 58-year-old male
Chief Complaint: Sudden dizziness and inability to walk for 2 hours
History of Present Illness: The patient was eating lunch when he suddenly felt the room was spinning. He vomited twice and noted that he could not walk straight, veering to the left. He has no arm or leg weakness. He has a history of atrial fibrillation (on anticoagulation) and hypertension.
Systematic Neurological Examination:
Mental Status:
- Alert and oriented; cognition intact
- Speech: Scanning dysarthria (staccato, irregular rhythm)
Cranial Nerves:
- II-V: Intact
- VI: Nystagmus present - horizontal, gaze-evoked (worse on left lateral gaze), with rotatory component
- VII-XII: Intact (no facial weakness, tongue midline)
Motor Examination:
- Tone: DECREASED on left (hypotonia is a cerebellar sign)
- Strength: 5/5 in all extremities (NO weakness)
Sensory Examination:
- Completely normal throughout
Reflexes:
- 2+ and symmetric throughout; may be slightly decreased on left
- Babinski: Absent bilaterally (flexor response)
Coordination (KEY FINDINGS):
- Finger-to-nose (RIGHT): Normal, accurate
- Finger-to-nose (LEFT): Dysmetria (overshoots target), intention tremor (oscillation increasing as finger approaches target)
- Heel-to-shin (RIGHT): Normal
- Heel-to-shin (LEFT): Ataxic, irregular, falls off shin
- Rapid alternating movements: Dysdiadochokinesia on LEFT (irregular rhythm and amplitude when tapping hand on thigh)
- Rebound phenomenon: Present on left (arm overshoots when resistance suddenly released)
Romberg Test:
- Stands with feet together - unsteady with eyes OPEN
- Still unsteady with eyes CLOSED (does not significantly worsen)
- NEGATIVE Romberg (unsteadiness is not dependent on vision) - indicates cerebellar, not sensory, ataxia
Gait:
- Wide-based
- Veers to the LEFT (toward the side of the lesion)
- Cannot perform tandem walking
- Unable to stand on left foot alone
Summary of Cerebellar Findings (DANISH mnemonic):
- Dysdiadochokinesia (left)
- Ataxia (limb and gait)
- Nystagmus (gaze-evoked)
- Intention tremor (left)
- Slurred/Scanning speech
- Hypotonia (left)
- ALL IPSILATERAL to the lesion (cerebellum exerts ipsilateral control)
Imaging:
- CT head: Hypodense region in left cerebellar hemisphere
- MRI: Acute infarction in left PICA territory
Diagnosis: Left cerebellar stroke (PICA territory) with ipsilateral cerebellar signs
Clinical Pearl: Cerebellar lesions produce ipsilateral ataxia without weakness. The Romberg test helps distinguish cerebellar from sensory ataxia: in sensory ataxia, the patient is stable with eyes open but falls when eyes close (positive Romberg) because they lose visual compensation for proprioceptive loss. In cerebellar ataxia, the patient is unsteady regardless of eye opening. The cerebellar stroke patient has normal strength because pyramidal tracts are intact - coordination, not power, is the problem.
Clinical Image
Image Description: Illustration or photograph demonstrating key components of the neurological examination, including reflex testing with a reflex hammer, the Babinski sign test (stroking the lateral plantar surface), and pronator drift assessment with arms extended and eyes closed. These techniques help distinguish upper motor neuron from lower motor neuron pathology.
Attribution: Image from Radiopaedia (https://radiopaedia.org/), Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license.