Undergrad Rounds: ALS

Amyotrophic Lateral Sclerosis (ALS)

The neurodegenerative disorder that affects the large α-motor neurons in the corticospinal tract and certain connected motor cortex neurons, leading to the inability to effectively communicate with muscles, and leads to atrophy and eventually paralysis. 

Diagnosis of ALS

Electromyography (EMG) and Nerve Conduction Velocity (NCV) are used to detect damage to lower motor neurons and track progression. Blood or urine samples can also help rule out other conditions, such as heavy metal poisoning. Imaging techniques such as MRIs of the cervical spine can help find abnormalities in the spinal cord.

Disruption to te Nervous System

ALS degenerates the large α-motor neurons in the anterior horn of the spinal cord, while also affecting the upper motor corticospinal neurons in the motor cortex. It can also impact sensory pathways. 

Intracellular Disruption of Motor Neurons 

ALS also affects fundamental biological processes such as RNA binding, vesicle trafficking, and cell division. Can also create oxidative stress which leads to neurodegeneration and support cell disruption. 

Cycad nuts in Guam

The finding that dietary excitotoxic amino acids can raise ALS-like risk, but does not explain global ALS incidence. 

Treatments for ALS

Medications such as Riluzole serve to block glutamate release, Edaravone reduces oxidative stress, and Sodium Phenylbutyrate-Taurursodiol serves as a histone deacetylase inhibitor to prevent protein aggregation. Other treatments serve as end-of-life care, such as physical therapy, occupational therapy, speech therapy, etc. Emerging treatments such as CRISPR and other genetic manipulations could be effective in the future.