What are the symptoms and treatment options for Amyotrophic Lateral Sclerosis (ALS)?

Symptoms and Treatment Options for Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by degeneration of upper and lower motor neurons in the brain and spinal cord, leading to paralysis and ultimately death due to respiratory failure within 2-5 years.1

Clinical Presentation and Symptoms

Initial Presentation

• ALS typically presents in two main forms: bulbar onset (25-35% of patients) or spinal/limb onset (65-75% of patients) 2
• Mean age of onset for sporadic ALS is approximately 60 years, with a slight male predominance (M:F ratio 1.5:1) 1
• Patients with bulbar onset have shorter life expectancy compared to those with limb onset 2

Motor Symptoms

• Limb onset: Focal muscle weakness and wasting, which may start distally or proximally in upper and lower limbs 1
• Bulbar onset: Dysarthria (speech difficulties) and dysphagia (swallowing problems) for solids or liquids 1
• Progressive development of spasticity in weakened limbs, affecting manual dexterity and gait 1
• Hyperreflexia, muscle fasciculations, and progressive muscle atrophy leading to functional quadriplegia 3

Bulbar Symptoms

• Dysphagia affects food intake, increases meal time, and causes fatigue during and after eating 2
• Swallowing disorders progress through 5 stages: normal eating habits → early eating problems → dietary consistency changes → need for tube feeding → nothing by mouth 2
• Speech deterioration occurs rapidly after bulbar symptom onset, with speech remaining adequate for only about 18 months after the first bulbar symptom 4
• Difficulty managing saliva and increased risk of aspiration 5

Respiratory Symptoms

• Respiratory complications are the most common cause of death in ALS 3
• Symptoms include shortness of breath, orthopnea, sleep disturbances, morning headaches, and fatigue 3
• Respiratory failure typically occurs within 3-5 years of diagnosis 3

Nutritional Impact

• Malnutrition is common due to multiple factors 2:
  • Difficulty chewing and swallowing
  • Increased time required to complete meals
  • Anorexia related to psychosocial distress and depression
  • Constipation due to weakness of abdominal muscles and limited physical activity
  • Increased energy requirements due to respiratory effort and infections 2

Diagnostic Approach

Clinical Evaluation

• Diagnosis based on clinical history, examination, electromyography, and exclusion of "ALS-mimics" 1
• Signs of both upper motor neuron and lower motor neuron damage not explained by other disease processes 1

Imaging

• MRI head without IV contrast is usually appropriate for initial imaging to exclude other conditions 2
• MRI spine without IV contrast may be appropriate for certain patients 2
• The most common MRI finding in ALS is abnormal T2/FLAIR signal in the corticospinal tracts 2

Swallowing Assessment

• Videofluoroscopy (VFS) is recommended for clinical evaluation of dysphagia at diagnosis 2
• VFS can detect early signs of dysphagia even in asymptomatic ALS patients 2
• Common VFS findings include delayed bolus transport from oral cavity to pharynx and decreased pharyngeal contraction 2

Treatment Options

Pharmacological Treatment

• Riluzole is the only FDA-approved drug shown to extend survival in ALS patients 6
• Recommended dosage: 50 mg twice daily, taken at least 1 hour before or 2 hours after meals 6
• Monitor serum aminotransferases before and during treatment due to risk of hepatic injury 6

Nutritional Management

• Regular nutritional status assessment (BMI, weight loss) every 3 months to detect early malnutrition 2
• For patients with weight loss:
  • BMI <25 kg/m²: weight gain recommended
  • BMI 25-35 kg/m²: weight stabilization recommended 2
• For patients with dysphagia:
  • Adapt food texture (soft, semisolid, or semiliquid) to facilitate swallowing 7
  • Implement postural maneuvers, particularly chin-tuck posture, to protect airway during swallowing 7
  • For delayed swallowing, use thicker liquids and semisolid foods with high water content instead of thin liquids 7

Advanced Nutritional Support

• Enteral nutrition via feeding tubes (preferably gastrostomy) is recommended when oral intake becomes insufficient 7
• Percutaneous Endoscopic Gastrostomy (PEG) placement should be considered before respiratory function significantly deteriorates 2

Respiratory Support

• Non-invasive ventilation prolongs survival and improves quality of life 1, 8
• Early initiation of non-invasive ventilation and airway clearance techniques can prevent respiratory infections 8

Physical Activity

• Low to moderate physical activity is advised as long as it doesn't worsen the patient's condition 7
• Avoid excessive physical exertion that could lead to fatigue and worsen symptoms 7

Palliative Care

• A palliative care approach should be adopted from the time of diagnosis 2
• Early referral to palliative services is recommended to establish relationships with staff and address end-of-life issues 2
• Structured caregiver support, including counseling and support groups, should be available 2

Common Pitfalls and Caveats

• Dysphagia management techniques that work for other conditions may not be effective in ALS due to the specific pathophysiology of muscle atrophy and fatigue 7
• Despite limited evidence for efficacy, nutritional interventions are crucial for maintaining quality of life and preventing complications 7
• Initiation of hospice care should not limit availability of supportive treatments such as gastrostomy and non-invasive ventilation 2
• Advance directives should be discussed early while communication abilities are preserved 2