What are the diagnostic steps and treatment options for a patient suspected of having Amyotrophic Lateral Sclerosis (ALS)?

Diagnostic Steps and Treatment Options for Amyotrophic Lateral Sclerosis (ALS)

The diagnosis of ALS requires comprehensive neurological evaluation including clinical examination for both upper and lower motor neuron signs, electromyography (EMG) with nerve conduction studies, and exclusion of other conditions through MRI and laboratory testing, while treatment should focus on riluzole as the primary disease-modifying therapy along with multidisciplinary supportive care. 1, 2, 3

Diagnostic Steps

Clinical Examination

• Assess for signs of both upper and lower motor neuron dysfunction:
  • Upper motor neuron signs: hyperreflexia, spasticity, Babinski sign
  • Lower motor neuron signs: weakness, atrophy, fasciculations
• Evaluate for bulbar symptoms: dysarthria, dysphagia, tongue atrophy, fasciculations
• Document pattern of weakness (limb vs. bulbar onset)
• Monitor for respiratory function

Diagnostic Testing

1. Electrophysiologic Studies (essential for diagnosis):

   • EMG and nerve conduction studies to detect:
     • Denervation in multiple body regions
     • Fasciculations in multiple regions
     • Evidence of reinnervation 1, 4

2. Neuroimaging:

   • MRI of brain and spinal cord to exclude other conditions
   • May show characteristic findings:
     • Abnormal T2/FLAIR signal in corticospinal tracts
     • "Snake eyes" appearance in anterior horns of spinal cord
     • Abnormal hypointensity in precentral gyrus on T2*-weighted imaging 1

3. Laboratory Testing:

   • Complete blood count
   • Comprehensive metabolic panel with liver function tests
   • Thyroid function tests
   • Cerebrospinal fluid analysis (if indicated)
   • Genetic testing for familial ALS cases 1, 5

4. Dysphagia Assessment:

   • Screening with structured questionnaires (EAT-10)
   • Volume-Viscosity Swallow Test (V-VST)
   • Videofluoroscopy (VFS) - recommended for all ALS patients even without bulbar symptoms
   • Fiberoptic Endoscopic Evaluation of Swallowing (FEES) 6, 1

Diagnostic Criteria

The diagnosis is based on:

• Progressive upper and lower motor neuron signs
• Spread of symptoms to multiple body regions
• Absence of evidence for other conditions
• Supportive EMG findings 3, 7

Treatment Options

Disease-Modifying Therapy

• Riluzole (50 mg twice daily):
  • Only FDA-approved medication shown to extend survival
  • Prolongs median survival by approximately 60-90 days
  • Take at least 1 hour before or 2 hours after meals
  • Monitor liver function tests before and during treatment
  • Does not improve muscle strength or neurological function 2

Supportive Care

1. Respiratory Management:

   • Regular assessment of respiratory function
   • Non-invasive ventilation when indicated
   • Discussion about invasive ventilation options 1, 8

2. Nutritional Support:

   • For patients with dysphagia:
     • Fractionate and enrich meals with energy or deficient nutrients
     • Adapt texture of solids and liquids based on swallowing ability
     • Consider oral nutritional supplements if weight loss progresses
     • Gastrostomy tube placement when oral intake becomes insufficient 6

3. Dysphagia Management:

   • Dietetic counseling for texture modification
   • Postural maneuvers (such as chin-tuck posture) to protect airway
   • Use of thicker liquids and semisolid foods
   • Consider instrumental swallowing studies to guide recommendations 6, 1

4. Symptomatic Treatment:

   • Manage spasticity, cramps, pain, excessive salivation, emotional lability
   • Physical therapy to maintain mobility and prevent contractures
   • Occupational therapy for adaptive equipment 8

5. Palliative Care:

   • Early referral to palliative care services
   • Advance care planning before communication becomes limited
   • Focus on quality of life and symptom management 1

Monitoring and Follow-up

• Regular follow-up every 3 months
• More frequent evaluation based on:
  • Presence of bulbar symptoms
  • Rate of disease progression
  • Changes in nutritional status
• Dysphagia screening at diagnosis and during follow-up 1

Prognosis

• Median survival: 2-5 years from symptom onset
• Prognostic factors:
  • Age at onset (older age = worse prognosis)
  • Site of onset (bulbar onset = worse prognosis)
  • Weight loss and BMI changes
  • Rate of respiratory function decline 1, 8

Common Pitfalls to Avoid

• Delaying diagnosis with unnecessary tests
• Missing silent aspirations in patients without obvious bulbar symptoms
• Overlooking dysphagia in patients with "normal eating habits"
• Failing to monitor liver function in patients on riluzole
• Neglecting to screen for respiratory insufficiency
• Delaying discussions about end-of-life care 6, 1, 2