ALS
| Amyotrophic lateral sclerosis | |
|---|---|
| Other names |
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| Parts of the nervous system affected by ALS, causing progressive symptoms in skeletal muscles throughout the body | |
| Specialty | Neurology |
| Symptoms | Early: Stiff muscles, muscle twitches, gradual increasing weakness Late: Difficulty in speaking, swallowing, and breathing; respiratory failure; Rare: frontotemporal dementia |
| Complications | Falling; Respiratory failure; Pneumonia; Malnutrition |
| Usual onset | 45–75 years |
| Causes | Unknown (90% to 95%) or genetic (5% to 10%) |
| Risk factors | Genetic risk factors, age, male sex, heavy metals, organic chemicals, smoking, electric shock, head injury |
| Diagnostic method | Clinical diagnosis of exclusion based on progressive symptoms of upper and lower motor neuron degeneration for which no other explanation can be found. Supportive evidence from electromyography, genetic testing, and neuroimaging |
| Differential diagnosis | Multifocal motor neuropathy, Kennedy's disease, hereditary spastic paraplegia, nerve compression syndrome, diabetic neuropathy, post-polio syndrome, myasthenia gravis, multiple sclerosis |
| Treatment | Walker, wheelchair, non-invasive ventilation, feeding tube, augmentative and alternative communication, symptomatic management |
| Medication | Riluzole, edaravone, tofersen, dextromethorphan/quinidine |
| Prognosis | Life expectancy highly variable but typically 2–4 years after diagnosis |
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Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a rare, terminal neurodegenerative disease defined by the progressive loss of both upper and lower motor neurons that normally control voluntary muscle contraction. ALS is the most common of the motor neuron diseases. ALS often presents in its early stages with gradual muscle stiffness, twitches, weakness, and wasting. Motor neuron loss typically continues until the abilities to eat, speak, move, and breathe without mechanical support are lost. It is estimated that at least 50% of people with ALS experience significant changes in thinking and behavior, with 15% of individuals going on to develop frontotemporal dementia. An ALS diagnosis is made based on a person's signs and symptoms, with additional testing conducted to rule out other potential causes. Depending on which areas of the body are affected first, ALS may be classified as limb-onset (beginning with weakness in the arms or legs) or bulbar-onset (beginning with difficulty in speaking or swallowing). Respiratory onset occurs in approximately 1%–3% of cases.
Most cases of ALS (about 90–95%) have no known cause and are known as sporadic ALS. Both genetic and environmental factors are believed to be involved in the onset of ALS. Approximately 5–10% of ALS cases have a known genetic cause and often linked to a family history of ALS; such cases are known as familial ALS or hereditary ALS. Four disease-linked genes are responsible for approximately half of all genetic cases.
There is no known cure for ALS. The goal of treatment is to slow the disease progression and improve symptoms. FDA-approved treatments that slow the progression of ALS include riluzole and edaravone. Non-invasive ventilation may result in both improved quality and length of life. Mechanical ventilation can prolong survival but does not stop disease progression. A feeding tube may help maintain weight and nutrition. Death is usually caused by respiratory failure. The disease can affect people of any age but usually starts around the age of 60. The average survival from onset to death is two to four years, though this can vary; about 10% of those affected survive longer than ten years.
Descriptions of the disease date back to at least 1824 by Charles Bell. In 1869, the connection between the symptoms and the underlying neurological problems were first described by French neurologist Jean-Martin Charcot, who in 1874 began using the term amyotrophic lateral sclerosis.