Amyotrophic Lateral Sclerosis (ALS) for USMLE Step 3 & COMLEX-USA Level 3

Amyotrophic Lateral Sclerosis (ALS) for USMLE Step 3 & COMLEX-USA Level 3 emphasizes clinical decision-making, long-term management, and prognosis, including addressing complications and palliative care. Clinical Diagnosis

• Progressive Weakness: Focus on the pattern of muscle weakness (asymmetric, distal ? proximal progression).
• Upper Motor Neuron (UMN) Signs: Spasticity, hyperreflexia, and positive Babinski sign.
• Lower Motor Neuron (LMN) Signs: Fasciculations, muscle atrophy, and flaccid paralysis.
• Bulbar Symptoms: Dysarthria, dysphagia, and tongue atrophy; these symptoms significantly affect quality of life and prognosis.

Diagnosis and Monitoring

• Electromyography (EMG) and Nerve Conduction Studies (NCS): Routine for confirming ALS and assessing disease progression.
• Pulmonary Function Tests (PFTs): Monitor for respiratory muscle weakness, with reduced forced vital capacity (FVC) indicating a need for ventilatory support.

Multidisciplinary Management

• Neurologist: Manages disease-modifying therapies and coordination of care.
• Pulmonologist: Focus on respiratory status; initiate non-invasive ventilation (BiPAP) as FVC declines. Monitor for respiratory failure.
• Physical/Occupational Therapy: Helps maintain mobility, manage contractures, and improve activities of daily living (ADLs).
• Speech Therapy: For dysarthria and swallowing difficulties; may recommend feeding tubes (gastrostomy) as dysphagia worsens.

Pharmacologic Treatment

• Riluzole: Prolongs survival by a few months; reduces glutamate-mediated excitotoxicity.
• Edaravone: Can slow disease progression in early-stage ALS in some patients.
• Symptom Management:
• Spasticity: Baclofen or tizanidine.
• Sialorrhea: Glycopyrrolate, atropine, or botulinum toxin injections.
• Pain: Opioids or NSAIDs for managing painful muscle cramps or contractures.
• Depression/Anxiety: Common in ALS; consider SSRIs or counseling.

Respiratory Support

• Non-invasive ventilation (e.g., BiPAP) to address hypoventilation, especially during sleep.
• Invasive ventilation (tracheostomy) is considered for advanced disease, but this is often a patient-centered decision.

Feeding Support

• Dysphagia: PEG (percutaneous endoscopic gastrostomy) for nutritional support as oral feeding becomes difficult.

End-of-Life and Palliative Care

• Advance Directives: Discuss early in disease progression, particularly decisions about invasive ventilation, feeding tubes, and resuscitation status.
• Palliative Care: Focus on managing symptoms like pain, dyspnea, and psychological distress. Ensure a multidisciplinary approach to improve comfort in end stages.
• Hospice Care: Introduced when life expectancy is under 6 months and when aggressive interventions are no longer desired.

Prognosis

• Median survival is 3 years from diagnosis, typically due to respiratory failure.
• Bulbar-Onset ALS: Shorter survival than limb-onset ALS, primarily due to early respiratory and swallowing involvement.

Patient Education

• Regular counseling about disease progression, symptom management, and advance care planning.
• Discussions about quality of life and end-of-life care should be ongoing, with a focus on patient preferences and values.

For Step 3, the focus is on integrated, long-term patient management, including the coordination of care across specialties and addressing critical issues like respiratory decline and palliative care planning.