Amyotrophic Lateral Sclerosis (ALS) Basics

Amyotrophic lateral sclerosis (ALS), also called motor neurone disease or Lou Gehrig disease, is a relentlessly progressive disorder in which motor neurones degenerate in the motor cortex, brainstem and spinal cord. As those pathways fail, voluntary movement becomes weaker, muscles waste, and respiratory muscle function eventually declines. Death most often results from respiratory failure, commonly within about 3 to 5 years of symptom onset, although the course varies. The clinical pattern comes from seeing upper and lower motor neurone injury together: - Upper motor neurone dysfunction: spasticity, increased tone, brisk reflexes and an extensor plantar response. - Lower motor neurone dysfunction: weakness, muscle wasting, fasciculations, cramps and reduced or absent reflexes in affected muscles. The weakness is often asymmetric at first. A person may repeatedly trip because one foot is weak, or struggle to turn a key because one hand has lost dexterity. Bulbar-onset disease instead begins with dysarthria, a weak voice, coughing with meals or difficulty managing saliva. Motor neurone loss does not usually damage sensory pathways. Sensation is therefore generally preserved, and eye movements and bowel and bladder...