Neuroscience · Year 2 · from Neuroscience
Case 1: Upper Motor Neuron Lesion (Hemispheric Stroke)
Patient Presentation
Demographics: 68-year-old right-handed male
Chief Complaint: Left arm and leg weakness
History of Present Illness: The patient was found by his wife with weakness on his left side. She last saw him normal 3 hours ago when she left to run errands. Upon return, he was sitting in his chair but could not lift his left arm and had slurred speech. He has a history of hypertension (poorly controlled), type 2 diabetes, and former smoking.
Systematic Neurological Examination:
Mental Status:
- Level of consciousness: Alert
- Attention: Intact; follows commands appropriately
- Orientation: Oriented to person, place, and time
- Language: Speech slightly dysarthric; naming, repetition, and comprehension intact
- Neglect testing: When asked to identify objects in left visual field, patient occasionally misses items; extinction to double simultaneous stimulation (extinguishes left side)
Cranial Nerves:
- II: Visual acuity grossly intact; left homonymous hemianopia on confrontation (misses fingers in left visual fields of both eyes)
- III, IV, VI: Pupils equal and reactive; eyes deviate to the RIGHT (toward the lesion); full range of motion when tested
- V: Sensation intact bilaterally
- VII: Left lower facial weakness (flattened nasolabial fold, droop of mouth corner); able to wrinkle forehead bilaterally (forehead SPARED - UMN pattern)
- VIII-XII: Intact
Motor Examination:
- Inspection: No atrophy; no fasciculations
- Tone: Left arm and leg have increased tone with spasticity (velocity-dependent catch)
- Strength (MRC scale):
- Right upper extremity: 5/5
- Right lower extremity: 5/5
- Left upper extremity: 2/5 (deltoid, biceps, triceps, wrist extensors, grip)
- Left lower extremity: 3/5 (hip flexion, knee extension, ankle dorsiflexion)
- Pronator drift: Left arm pronates and drifts downward when arms extended with eyes closed
Sensory Examination:
- Light touch: Decreased on left face, arm, and leg
- Proprioception: Impaired in left fingers and toes
- Pain/temperature: Decreased on left hemibody
Reflexes:
- Right biceps 2+, triceps 2+, brachioradialis 2+, patellar 2+, Achilles 2+
- Left biceps 3+, triceps 3+, brachioradialis 3+, patellar 4+ with clonus, Achilles 3+
- Babinski: Extensor response (upgoing toe) on LEFT; flexor (normal) on right
- Hoffman's sign: Present on left
Coordination:
- Right: Normal finger-to-nose, normal heel-to-shin
- Left: Unable to assess adequately due to weakness
Gait:
- Unable to walk independently; when supported, demonstrates circumduction of left leg (swings leg in arc due to stiffness)
Summary of UMN Findings:
- Weakness with spasticity (not flaccidity)
- Hyperreflexia with clonus
- Positive Babinski sign
- Forehead-sparing facial weakness
- NO atrophy, NO fasciculations
Diagnosis: Right MCA territory stroke with left hemiparesis (UMN pattern)
Clinical Pearl: Upper motor neuron lesions produce a characteristic pattern: weakness with increased tone (spasticity), hyperactive reflexes, and pathological reflexes (Babinski, Hoffmann). The weakness affects extensors more than flexors in the arm and flexors more than extensors in the leg. Forehead sparing in facial weakness indicates UMN localization because the upper face has bilateral cortical representation. The eyes "look toward the lesion" in acute cortical strokes.