Neuroscience · Year 2 · from Neuroscience
Case 1: Amyotrophic Lateral Sclerosis (ALS)
Patient Presentation
Demographics: 62-year-old male
Chief Complaint: Progressive weakness in right hand and arm for 6 months
History of Present Illness: A 62-year-old right-handed man presents with gradually worsening weakness that began in his right hand. He first noticed difficulty turning keys and buttoning shirts. Over the past 3 months, weakness has spread to his right arm and he has developed cramping and twitching throughout both arms. He has also noticed difficulty speaking clearly, with occasional slurring, and his wife reports he has been choking on liquids. He denies numbness, tingling, visual changes, or cognitive difficulties. He has lost 15 pounds due to difficulty eating.
Physical Examination:
- Vital signs: Normal
- General: Thin male with visible muscle twitching in upper extremities
- Neurological:
- Mental status: Alert, oriented, cognition intact
- Speech: Mildly dysarthric with spastic quality
- Cranial nerves: Tongue atrophy with fasciculations; brisk jaw jerk; reduced palate elevation
- Motor:
- Upper extremities: Atrophy of intrinsic hand muscles bilaterally, worse on right; fasciculations visible in deltoids, biceps, and forearms; strength 3/5 right hand, 4/5 left hand, 4/5 bilateral proximal arms
- Lower extremities: Mild weakness hip flexors bilaterally (4+/5); no atrophy yet
- Tone: Spasticity in all extremities
- Reflexes: 3+ throughout; bilateral Hoffman signs; bilateral upgoing Babinski responses
- Sensory: Completely intact to all modalities
- Coordination: Intact but limited by weakness
Workup:
- EMG/Nerve conduction studies: Widespread acute and chronic denervation in cervical, thoracic, and lumbosacral segments; normal sensory nerve action potentials; fasciculation potentials in multiple muscles
- MRI brain and cervical spine: Normal (excludes structural lesions)
- Laboratory studies: Normal (creatine kinase mildly elevated; normal B12, thyroid, paraneoplastic panel)
- Pulmonary function tests: FVC 72% predicted; early restrictive pattern
Diagnosis: Amyotrophic lateral sclerosis (ALS) - clinically definite
Treatment:
- Riluzole 50 mg twice daily (glutamate antagonist; modest survival benefit)
- Edaravone IV infusions (antioxidant; slows functional decline)
- Speech therapy for dysarthria and dysphagia evaluation
- Modified diet and eventual discussion of PEG tube placement
- Pulmonary follow-up with serial PFTs; noninvasive ventilation when indicated
- Physical and occupational therapy
- Multidisciplinary ALS clinic enrollment
- Palliative care and advance directive discussions
Clinical Pearl: ALS is defined by the combination of upper motor neuron (UMN) and lower motor neuron (LMN) signs in the same body region. UMN signs include spasticity, hyperreflexia, and Babinski signs; LMN signs include weakness, atrophy, and fasciculations. The coexistence of these apparently contradictory findings (spastic atrophic weakness) is the clinical hallmark. Sensory function is preserved, distinguishing ALS from conditions affecting the entire spinal cord. The El Escorial criteria require UMN and LMN signs in multiple regions (bulbar, cervical, thoracic, lumbosacral) for definite diagnosis.