Learning objectives

• Describe the pathophysiology of Amyotrophic lateral sclerosis (ALS)
• Signs and symptoms of ALS
• Anesthetic management of ALS

Definition and mechanisms

• Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s Disease, is a rare and progressive nervous system disease that affects nerve cells in the brain and spinal cord
• Resulting in the progressive loss of motor neurons that control voluntary muscles
• ALS often begins with muscle twitching and weakness in a limb, or slurred speech
• Eventually, ALS affects the control of the muscles needed to move, speak, eat, and breathe
• The most common cause of death for patients with ALS is respiratory failure
• On average, patients die within 3-5 years after symptoms begin
• There is no cure for this fatal disease
• Most ALS cases are considered sporadic, about 5-10% of all ALS cases are familial

Signs and symptoms

• Difficulty walking or doing normal daily activities
• Tripping and falling
• Weakness in the legs, feet, or ankles
• Hand weakness or clumsiness
• Slurred speech or trouble swallowing
• Muscle cramps and twitching (fasciculations) in the arms, shoulders, and tongue
• Inappropriate crying, laughing, or yawning
• Cognitive and behavioral changes
• Pulmonary/breathing problems:
  • Shortness of breath
  • Weak cough
  • Difficulty clearing the throat and lungs
  • Extra saliva
  • Inability to lie flat in bed
  • Repeated chest infections and pneumonia
  • Respiratory failure

Symptoms with the progression of the disease:

• Not be able to stand or walk, get in or out of bed on their own
• Dysphagia
• Dysarthria
• Dyspnea 
• Weight loss
• Malnourishment
• Muscle cramps and neuropathy 
• Anxiety and depression
• Dementia

Risk factors

• Age: increases with age and is most commonly between 40 and 70
• Gender: males are more likely to develop ALS before the age of 65
• Race and ethnicity: Caucasians and non-Hispanics are most likely to develop the disease
• Heredity: in 5-10% of the cases
• Smoking
• Environmental toxin exposure: lead, pesticides such as Aldrin, Dieldrin, and DDT
• Military service

Complications

• Breathing problems requiring BiPAP or tracheostomy
• Difficulty with speaking
• Malnutrition and dehydration
• Dementia

Diagnosis

• EMG
• A nerve conduction study
• MRI
• Blood and urine tests
• Muscle biopsy

Treatment

The goal of treatment is to improve symptoms:

• Supportive health care: 
  • Physical therapy
  • Nutritional counseling
  • Speech therapy
  • Assistive devices: splints, braces, grab bars,…
• Non-invasive ventilation
• Medications to manage symptoms including muscle cramps, stiffness, excess saliva, phlegm, unwanted episodes of crying and/or laughing, or other emotional displays
• FDA-approved medications:
  • Riluzole (Rilutek)
  • Edaravone (Radicava)

Anesthetic management

Preoperative and perioperative management

Postoperative management

• Transfer patient to ICU
• Administer paracetamol or NSAIDs postoperatively for pain management
  • Avoid opioids because of respiratory depression
• Respiratory distress may require prolonged mechanical ventilation as well as re-intubation
  • Be aware that weaning is often prolonged and difficult
• Consider that bulbar symptoms like dysphagia or dysarthria as well as cognitive impairment may lead to malnutrition and require intravenous or tube feeding 

Suggested reading

• Gaik C, Wiesmann T. 2021Anaesthesia recommendations for Amyotrophic lateral sclerosis. Orphananesthesia.https://www.orphananesthesia.eu/en/rare-diseases/published-guidelines/amyotrophic-lateral-sclerosis/1684-amyotrophic-lateral-sclerosis-2/file.html
• Sarna R, Gupta A, Arora G. Amyotrophic lateral sclerosis and anaesthetic challenges: Perioperative lignocaine infusion-an aid. Indian J Anaesth. 2020;64(5):448-449. 
• Thampi SM, David D, Chandy TT, Nandhakumar A. Anesthetic management of a patient with amyotrophic lateral sclerosis for transurethral resection of bladder tumor. Indian J Anaesth. 2013;57(2):197-199.
• Marsh, S., Pittard, A., 2011. Neuromuscular disorders and anaesthesia. Part 2: specific neuromuscular disorders. Continuing Education in Anaesthesia Critical Care & Pain 11, 119–123.

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