Lou Gehrig’s disease, frequently occurring among those aged 50 or more, is often confused with Parkinson’s disease. The accurate name of this rare disease is amyotrophic lateral sclerosis (ALS) but it is commonly called Lou Gehrig’s disease after a famous baseball player, Lou Gehrig, of the New York Yankees suffered from ALS in the 1920s and 1930s. 

Lou Gehrig's disease is a neurodegenerative disease that causes various problems because the body selectively kills motor nerve cells. When both upper and lower motor neurons malfunction, it is called Lou Gehrig's disease.

In a recent video on AMC’s YouTube channel, Professor Kim Hyun-jin at the Department of Neurology of Asan Medical Center said Lou Gehrig's disease is a disease in which the upper motor neurons of the cerebrum and the lower motor neurons of the brain spinal cord progressively die, clinically showing muscle weakness in the early stages and eventually progressing to dyspnea.

The incidence of Lou Gehrig's disease increases mostly among people aged 50 or more. However, it can also develop at a younger age. 

Also, men have a higher incidence of Lou Gehrig’s disease than women.

Cause

Although researchers have found some causative genes for this disease, they have yet to identify the exact pathogenesis. There have been reports that excessive physical activity or head trauma could increase the probability of developing Lou Gehrig’s but a clear causal relationship has not been identified yet. 

“It is known that within 10 percent of all ALS patients have a family history, and several causative genes have been revealed. But in most cases, the disease is sporadic ALS without genetic influence,” Kim said. 

“For sporadic ALS, several hypotheses have been proposed such as oxidative toxicity and protein homeostasis, but the exact cause has remained unknown.”

Confusion with Parkinson’s disease

The symptoms of Lou Gehrig's disease vary depending on which part of the motor nerve cell has a problem. Arms and legs lose strength or the tongue muscles become weak. When eating, food or liquid could end up going down the wrong pipe. Speaking could get difficult. This is why ALS symptoms can be confused with the early symptoms of Parkinson’s disease that commonly occur in the same age group. 

“Parkinson's disease is a disease in which dopamine-secreting neurons in a part of the brain called the substantia nigra are lost, resulting in stiff facial expressions, slow behavior, and gait disturbance,” Kim explained. “It’s different from Lou Gehrig’s but early symptoms could be similar. This is why the patient could get a misdiagnosis.” 

Many neuromuscular diseases and systemic diseases demonstrate symptoms similar to those of ALS, so the patient must see multiple specialists, get multiple tests, and receive an accurate diagnosis, she emphasized. 

Tests, diagnosis

Currently, based on the symptoms of ALS, doctors perform nerve conduction, electromyography, MRI, and blood tests to differentiate it from other diseases. Through this process, evidence of damage to upper motor neurons and lower motor neurons is found, and when other diseases to explain this are excluded, Lou Gehrig's disease is diagnosed.

An early diagnosis of Lou Gehrig’s is crucial because the progress of the disease leads to breathing difficulties. This is directly linked to the quality of life, so it is important to slow the pace of the disease's progression. 

Kim noted that it was difficult to expect a cure in Lou Gehrig’s.

However, there are ways to improve the quality of life by addressing the symptoms that occur during the course of the disease and preventing complications, she said. 

Treatment

Globally, there are two authorized medicines for ALS with proven clinical benefits -- riluzole, which reduces excitotoxicity, and edaravone, which reduces oxidative toxicity. 

Riluzole and edaravone do not improve symptoms. However, they can slow down the disease progression.

Experts say evaluating respiratory function from the beginning and performing respiratory rehabilitation treatment and respiratory support treatment according to the respiratory function help relieve symptoms.

Sometimes, gastrostomy, in which a tube is placed in the stomach to prevent aspiration pneumonia caused by difficulty swallowing and to supply sufficient nutrition, can be also recommended from the early stage of the disease.

Recently, researchers around the world have started developing a cure for Lou Gehrig’s.

“For hereditary ALS, RNA therapy is being tested to eliminate the effect of the causative gene,” Kim said.  “Clinical trials of various drugs based on various mechanisms are being conducted for sporadic ALS patients.”