About ALS

WHAT IS AMYOTROPHIC LATERAL SCLEROSIS?

Amyotrophic lateral sclerosis, more commonly known as Lou Gehrig’s disease, and outside the United State as Charcot’s disease, and motor neuron disease (MND), is a fatal progressive neurodegenerative disease characterized by the death of the motor neurons in the brain and spinal cord. Currently, there is no cure or even a treatment that significantly slow the progression of the disease. Motor neurons innervates muscles responsible not only for mobility, walking and performing activity of daily living, but also for other critical survival functions such as breathing and swallowing. Muscle waste (atrophy) occurs when motor neuron cannot activate muscles, leading to weakness and paralysis affecting the hands and feet and ultimately the diaphragm, muscle responsible for breathing, and other muscles responsible for swallowing. Amyotrophic lateral sclerosis is sporadic in 90% of cases and could be hereditary in 5% to 15%. It incidence is 0.4 to 3/100,000 per year. Its prevalence is 3to 8/100.000. It is estimated that as many as 30,000 Americans may have the disease at any given time. The mean age of onset of the disease in USA is 56 to 63 years. The overall survival is between 3 to 4 years. The survival after diagnosis is approximately 2 years. The time from initial symptoms to diagnosis is approximately one year. In 4% to 10%, survival may exceed 10 years.

WHAT CAUSES AMYOTROPHIC LATERAL SCLEROSIS?

The causes of ALS are only partially understood. The selective vulnerability of motor neurons, causing muscle weakness and paralysis is unknown. However scientists are beginning to better understand the disease mechanism. Several studies demonstrated that the disease is a multisystem disorder, involving not only the motor neurons, but also other supporting cells such as oligodendrocytes, astrocytes, and microglia. These cells are normally responsible for keeping the motor neuron healthy, started produces toxic chemicals that damage the motor neurons and activate inflammatory cells that storm the motor neurons with harmful cytokines and chemicals. Genetic factors have been involved in familial ALS. A mutation in SOD gene is responsible for the production of defective protein toxic for the motor neurons. In addition to the accumulation of misfolded proteins, sodium channels dysfunction causing hyper excitability, mitochondria dysfunction causing energy production drop, neuroinflammation, and increased oxidative stress with the production of free radicals.

WHAT ARE THE SYMPTOMS OF AMYOTROPHIC LATERAL SCLEROSIS?

The symptoms of ALS reflect the loss and dysfunction of upper motor neuron (Motor neuron of the brain) and lower motor neuron (Motor neuron of the spinal cord). The lower motor neuron become disconnected from the muscle causing muscle weakness, cramps and wasting affecting hands, arms, legs and feet. Other symptoms may include increasing clumsiness, difficulty with speaking and swallowing. Ultimately, the muscles responsible from breathing and swallowing became affected causing severe impairment of breathing and swallowing that may require the placement of tracheal and stomach tubes to help the patient to breath and take food. The progression may occur over a period of months and years. The patient senses including smell, touch, hearing, taste and sight remain intact.