Amyotrophic lateral sclerosis (ALS), commonly known as “Lou Gehrig’s disease,” is a rare and progressively debilitating neurodegenerative condition. The name comes from Henry Louis Gehrig, a renowned New York Yankees baseball player whose career was cut short when he received the diagnosis in 1939.
In ALS, neurons in specific brain regions and those of the central nervous system begin to degenerate. The effect of ALS is primarily seen on muscles due to the degeneration of motor neurons. The loss of motor neurons — the neurons that send signals to muscles — leads to physical symptoms. The motor neurons wither gradually and rapidly, thereby weakening and atrophy of muscles as they no longer receive signals. In addition, neurons loss in some brain regions that leads to speech deficiencies and cognitive and behavioural symptoms.
This June, the National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, held the second International Conference on Amyotrophic Lateral Sclerosis and Motor Neuron Diseases. During the event, Dr A Nalini, professor and head of the neurology department, NIMHANS, highlighted the various aspects of the disease and its progression.
She explained that as motor neurons degenerate, it causes glitches in the signal transmission between the brain and muscles. Over time, the brain loses its capacity to initiate and control voluntary movements like walking, swallowing, and talking. When the muscles do not receive stimulation from motor neurons, it causes severe muscle weakness and paralysis.
Dr Nalini stated that some sporadic factors that can trigger ALS are abnormal RNA processing, mitochondrial dysfunction, and viral infection.
“ALS gets misdiagnosed with other conditions due to its overlapping symptoms,” she added. Owing to this, individuals with the conditions are often treated for the subsidiary symptoms. As the primary condition is unaddressed, ALS progresses rapidly.
According to Dr Nalini, the main symptoms differentiating ALS from other neurological conditions are fasciculation or tongue muscle twitching, cramping, muscle wasting, bulbar palsy and respiratory difficulties.
“The progression of the condition is asymmetrical, “says Dr Nalini. If ALS begins with damage of bulbar muscles present in head and neck, it can cause trouble in swallowing, speaking and chewing. As the condition progresses, limbs get effected, she explains.
“Wasted limb with brisk reflexes is the feature of ALS which is hardly ever seen in any other disease,” says Dr Nalini.
The below infographic captures some of the symptoms that help neurologists diagnose ALS accurately.
