Neuroscience · Year 2 · from Neuroscience
Case 3: Amyotrophic Lateral Sclerosis (ALS)
Patient Presentation
Demographics: 62-year-old male
Chief Complaint: Progressive weakness in right hand for 6 months
History of Present Illness: The patient first noticed weakness in his right hand 6 months ago, manifesting as difficulty turning keys and buttoning shirts. Over the past 3 months, the weakness has spread to involve his right arm more diffusely, and he has noticed his left hand becoming weak as well. He has also noticed "twitching" in his arm muscles and has lost weight (15 lbs) due to decreased appetite. His wife notes his speech has become slightly slurred in the past month. He denies numbness, tingling, or pain. He denies bladder or bowel problems.
Physical Examination:
- Vital signs: Normal; weight 72 kg (down from 87 kg)
- General: Thin male; visible muscle wasting in hands; fasciculations visible in upper arms
- Neurological:
- Mental status: Alert, oriented; cognition grossly intact; mildly dysarthric speech
- Cranial nerves:
- Tongue: Fasciculations visible; mild atrophy; deviates slightly right on protrusion
- Jaw jerk: BRISK (UMN sign)
- Facial sensation and strength: Normal
- Gag: Present
- Motor:
- Inspection: Atrophy of bilateral thenar and interosseous muscles; fasciculations in deltoids, biceps, and paraspinals
- Tone: Increased in lower extremities (spasticity)
- Strength:
- Right grip 3/5, finger abduction 3/5, wrist extension 4/5, shoulder abduction 4/5
- Left grip 4/5, finger abduction 4/5, wrist extension 4+/5, shoulder 5/5
- Bilateral hip flexion 4+/5, knee extension 5/5, ankle dorsiflexion 4+/5
- Sensory: INTACT throughout (no sensory involvement)
- Reflexes: 3+ throughout upper and lower extremities; bilateral Babinski signs present; jaw jerk brisk
- Gait: Slightly spastic
Key Findings:
- Combined upper motor neuron signs (spasticity, hyperreflexia, Babinski) AND lower motor neuron signs (atrophy, fasciculations) in the SAME regions
- Multiple body regions affected (bulbar, cervical, thoracic, lumbosacral)
- Sensory system SPARED
- Bladder/bowel function SPARED
Workup:
- EMG/Nerve conduction studies: Widespread denervation (fibrillations, positive sharp waves, large motor unit potentials) in multiple regions (tongue, cervical and lumbar myotomes, thoracic paraspinals); sensory nerve conductions NORMAL
- MRI brain and cervical spine: No structural lesions; no cervical cord compression
- Laboratory: CK mildly elevated (420 U/L); otherwise normal including normal glucose, thyroid, B12
- Pulmonary function tests: FVC 68% predicted (early respiratory muscle involvement)
Diagnosis: Amyotrophic lateral sclerosis (El Escorial criteria: Definite ALS - UMN and LMN signs in 3 regions)
Treatment:
- Riluzole 50 mg twice daily (modest survival benefit)
- Edaravone IV infusion cycles (slows functional decline)
- Multidisciplinary ALS clinic enrollment (neurology, pulmonology, nutrition, PT/OT, speech therapy, social work)
- Nutritional support (PEG tube discussed for future)
- Non-invasive ventilation (BiPAP) initiation given reduced FVC
- Advance care planning
Clinical Course: The patient's weakness progressed over the following months. He began using BiPAP at night when FVC dropped to 50%. A PEG tube was placed at 9 months when swallowing became unsafe. He participated actively in advance care planning, electing not to pursue tracheostomy and mechanical ventilation. He died peacefully at home 22 months after diagnosis, surrounded by family.
Clinical Pearl: ALS is characterized by the combination of upper motor neuron signs (spasticity, hyperreflexia, Babinski) and lower motor neuron signs (atrophy, fasciculations, weakness) WITHOUT sensory involvement. The presence of both UMN and LMN findings in the same myotome is the diagnostic hallmark - no other condition reliably produces this combination. Eye movements and bladder/bowel function are typically spared until late. Median survival is 3-5 years, with respiratory failure being the most common cause of death. Riluzole provides modest survival benefit; supportive care (nutrition, ventilation) significantly improves quality of life.
Clinical Image
Image Description: Axial FLAIR MRI of the brain demonstrating characteristic periventricular white matter lesions in multiple sclerosis. The ovoid lesions are oriented perpendicular to the lateral ventricles, forming the classic "Dawson's fingers" pattern that reflects perivenular demyelination along the medullary veins.
Attribution: Image from Radiopaedia (https://radiopaedia.org/), Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license.