What is the management approach for patients with motor neuron disease (MND), including amyotrophic lateral sclerosis (ALS)?

Management Approach for Motor Neuron Disease (MND)/Amyotrophic Lateral Sclerosis (ALS)

A comprehensive multidisciplinary approach focusing on nutritional support, respiratory management, and riluzole treatment is essential for optimal management of patients with motor neuron disease to improve survival and quality of life.

Disease Overview and Progression

• MND/ALS typically progresses with an average life expectancy of 2-5 years from symptom onset, though approximately 5% of patients survive beyond a decade 1
• Bulbar onset has a poorer prognosis with faster progression compared to spinal onset 1
• Regular monitoring is recommended every 3 months due to the progressive nature of the disease 2, 1

Pharmacological Management

Disease-Modifying Therapy

• Riluzole 50mg twice daily is the primary disease-modifying treatment for ALS 3
• Riluzole has been shown to prolong survival by approximately 2-3 months in clinical trials 3, 4
• Riluzole should be taken at least 1 hour before or 2 hours after meals 3
• Monitor serum aminotransferases before and during treatment 3
• Discontinue riluzole if there is evidence of liver dysfunction 3

Symptom Management

• For patients with sialorrhea (excessive saliva):
  1. First-line: Trial of anticholinergic medication 2
  2. Second-line: Consider botulinum toxin therapy to salivary glands if anticholinergics fail or cause intolerable side effects 2

Nutritional Management

Assessment and Monitoring

• Screen for dysphagia in all patients at diagnosis and during follow-up 2
• Monitor weight, BMI, and nutritional status every 3 months 2, 1
• Malnutrition is present in 0-21% of patients at diagnosis and 7.5-53% during follow-up 2

Interventions

• For patients with dysphagia or weight loss >5-10% of habitual weight:
  1. Provide nutritional supplementation when dietary intake is insufficient 2
  2. Consider gastrostomy placement before weight loss exceeds 10% of baseline 2
  3. Energy requirements should be estimated at approximately 30 kcal/kg body weight 2

Clinical Significance

• Each weight loss of 5% is associated with a 34% increased risk of death 2
• Each loss of 1 point of BMI is associated with a 24% increased risk of death 2
• Weight gain of 1 BMI point reduces death risk by 14% 2

Respiratory Management

Assessment and Monitoring

• Perform pulmonary function tests (PFTs) at minimum every 6 months 2
• Tests should include:
  • Vital capacity (FVC or SVC)
  • Maximum inspiratory/expiratory pressures (MIP/MEP)
  • Sniff nasal inspiratory pressure (SNIP)
  • Peak cough flow (PCF) 2

Non-invasive Ventilation (NIV)

• Initiate NIV based on:
  • Abnormal pulmonary function tests
  • Evidence of sleep-disordered breathing
  • Signs of hypoventilation 2
• For daytime ventilatory support, consider mouthpiece ventilation (MPV) as an adjunct to nocturnal mask NIV in patients with preserved bulbar function 2

Invasive Ventilation

• Consider invasive home mechanical ventilation via tracheostomy when:
  • NIV fails or is not tolerated
  • Bulbar function worsens
  • Frequent aspiration occurs
  • Insufficient cough or declining lung function persists despite adequate secretion management 2
• Early discussion about ventilation options is essential 2

Airway Clearance

• For patients with reduced lung function or cough effectiveness, use lung volume recruitment (breath stacking) techniques 2

Diagnostic Imaging

• MRI head without IV contrast is the appropriate initial imaging for patients with suspected motor neuron disease 2
• MRI spine without IV contrast may be appropriate for certain patients to exclude structural, infectious, or neoplastic mimics 2
• Common MRI findings in ALS include:
  • Abnormal T2/FLAIR signal in corticospinal tracts
  • Abnormal hypointensity in the precentral gyrus on T2*/SWI sequences
  • "Snake eyes" appearance in the anterior horns of the spinal cord 2

Follow-up Schedule

• Clinical evaluations should be performed every 3 months, including:
  • Weight and BMI monitoring
  • Respiratory function tests
  • Swallowing capacity evaluation
  • ALSFRS-R scoring 2, 1
• Adjust testing frequency based on individual disease progression rate 2

Common Pitfalls and Caveats

• Delayed diagnosis may occur due to variable and complex features of MND
• Bulbar dysfunction may limit tolerance of NIV and effectiveness of cough techniques
• Discussions regarding invasive ventilation should begin early in the disease course
• Riluzole may cause liver enzyme elevations, requiring regular monitoring
• Nutritional interventions should be implemented before significant weight loss occurs

By implementing this comprehensive management approach with regular monitoring and timely interventions, clinicians can optimize quality of life and potentially extend survival for patients with MND/ALS.