Neurology · Year 3 · from Neurology

Case 3: Amyotrophic Lateral Sclerosis (ALS)

Patient Demographics

  • Age: 58 years
  • Sex: Male
  • Occupation: Attorney

Chief Complaint

"I'm tripping over my right foot and my arm keeps twitching."

History of Present Illness

The patient first noticed weakness in his right foot 6 months ago, causing him to trip. He has since developed weakness in his right hand, making it difficult to write and button his shirt. He has noticed involuntary twitching (fasciculations) in his arm and leg muscles. Over the past 2 months, his speech has become slurred. He has lost 15 lbs unintentionally. He denies sensory symptoms, bladder dysfunction, or double vision. No family history of similar illness. He has no pain. He is frightened because his symptoms continue to progress.

Neurological Examination Findings

Mental Status:

  • Alert, oriented, appropriately concerned
  • Cognition: Intact (frontotemporal dysfunction possible in ALS)
  • Pseudobulbar affect: Occasional inappropriate crying

Cranial Nerves:

  • Tongue: Atrophy with fasciculations (LMN sign)
  • Speech: Dysarthria (mixed spastic and flaccid)
  • Jaw jerk: Brisk (UMN sign)
  • Gag reflex: Present
  • No extraocular movement abnormalities (typically spared in ALS)

Motor Examination:

  • Mixed UMN and LMN signs in same regions:
  • Right upper extremity:
  • Weakness: Hand intrinsics 3/5, finger extensors 4/5
  • Atrophy: First dorsal interosseous, thenar eminence
  • Fasciculations: Visible in biceps and forearm
  • Left upper extremity: 5/5 but fasciculations present
  • Right lower extremity:
  • Foot dorsiflexion 3/5, hip flexion 4/5
  • Foot drop present
  • Atrophy of anterior tibial compartment
  • Left lower extremity: 4+/5 distally
  • Spasticity: Increased tone in all extremities (UMN)

Sensory Examination:

  • Normal throughout (key feature - rules out most mimics)

Reflexes:

  • Hyperreflexia throughout (3+ upper, 3+ lower) - UMN sign
  • Bilateral Babinski positive - UMN sign
  • Hoffman sign positive bilaterally
  • Despite atrophy, reflexes are brisk (pathognomonic combination)

Coordination:

  • Limited by weakness, no ataxia

Gait:

  • Spastic gait with right foot drop
  • Uses AFO (ankle-foot orthosis)

El Escorial Criteria Assessment

Revised El Escorial Criteria for ALS:

  • Evidence of LMN degeneration (atrophy, fasciculations, weakness): Present in bulbar, cervical, and lumbar regions
  • Evidence of UMN degeneration (hyperreflexia, spasticity, Babinski): Present in same regions
  • Progressive spread of symptoms
  • Absence of sensory, sphincter, visual, autonomic involvement, parkinsonian features
  • Classification: Clinically Probable ALS (UMN + LMN signs in ≥2 regions)

Neuro Workup

  • Electrodiagnostic Studies (EMG/NCS):
  • Active denervation (fibrillations, positive sharp waves) in 3 body regions
  • Chronic denervation (large polyphasic MUPs)
  • Fasciculation potentials
  • Motor NCS: Normal or low CMAP amplitudes
  • Sensory NCS: Normal (critical for diagnosis)
  • MRI Brain and Spine:
  • Rules out structural lesion (cervical myelopathy, syrinx)
  • May show corticospinal tract hyperintensity
  • Labs (to exclude mimics):
  • B12, TSH, PTH: Normal
  • HIV, Lyme: Negative
  • Serum protein electrophoresis: Normal
  • Creatine kinase: Mildly elevated (from denervation)
  • Heavy metals: Negative
  • Genetic testing: Consider SOD1 mutation if family history (10% familial ALS)
  • Pulmonary Function: FVC 72% predicted

Diagnosis

Amyotrophic Lateral Sclerosis (ALS) - sporadic, limb-onset with bulbar involvement

Management

Disease-Modifying Therapy:

  1. Riluzole 50 mg BID - glutamate release inhibitor
  • Modest survival benefit (2-3 months)
  • Monitor LFTs
  1. Edaravone (Radicava) - antioxidant, IV infusion
  • May slow functional decline in early ALS
  1. Tofersen - if SOD1 mutation positive (antisense oligonucleotide)
  2. AMX0035 (Relyvrio) - newer approval, mitochondrial/ER stress modulator

Symptomatic Management:

  1. Spasticity: Baclofen, tizanidine
  2. Sialorrhea (drooling): Glycopyrrolate, atropine drops, botulinum toxin to salivary glands
  3. Pseudobulbar affect: Dextromethorphan/quinidine (Nuedexta)
  4. Depression/anxiety: SSRIs
  5. Pain: Often from immobility, contractures - PT, NSAIDs, gabapentin
  6. Sleep: Non-invasive ventilation improves sleep

Nutritional Support:

  1. Swallowing evaluation
  2. Modified diet consistency
  3. PEG tube when oral intake insufficient (ideally before FVC <50%)
  4. Maintain weight (weight loss = poorer prognosis)

Respiratory Management:

  1. Serial FVC monitoring (every 3 months)
  2. Non-invasive ventilation (BiPAP) when FVC <50% or symptomatic
  • Improves survival by 7-10 months
  • Improves quality of life and sleep
  1. Cough assist device
  2. Discuss invasive ventilation preferences early

Multidisciplinary ALS Clinic:

  1. Neurology, pulmonology, nutrition, PT, OT, speech therapy, social work, palliative care
  2. Equipment: AFO for foot drop, wheelchair, communication devices
  3. Home modifications

Advance Care Planning:

  1. Goals of care discussion early
  2. Document preferences for intubation, tracheostomy
  3. Palliative care and hospice referral
  4. Average survival 2-5 years from diagnosis

Clinical Image

Image Description: Clinical photograph showing tongue atrophy and fasciculations in a patient with amyotrophic lateral sclerosis, demonstrating lower motor neuron involvement of the bulbar region.

Attribution: Image from Wikipedia Commons, public domain. Source: https://commons.wikimedia.org/wiki/File:Amyotrophic_lateral_sclerosis.jpg

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