Neuromuscular disease is a very broad term which encompasses many different diseases affecting the functioning of muscles. Among the best known diseases are muscular dystrophy (MD) and amyotrophic lateral sclerosis (ALS), more commonly known as Lou Gehrig's disease. Some of the diseases attack the body at a very young age and others will suddenly present themselves at mid-life. The signs and symptoms are as different as the diseases themselves.
Muscular dystrophy is a genetic disease that may present itself at at birth or later in life. The muscles get weaker over time, especially the voluntary muscles -- the ones we have control over. Some of the diseases may take a toll on the heart or involuntary muscles, as well. Symptoms include a waddling gait, lack of muscle tone in children, walking on your toes, weakness and losing ability to walk, depending on the exact form of muscular dystrophy and the severity of the disease.
Motor Neuron Diseases
Motor neuron diseases (MNDs) are degenerative, progressive disorders. They affect the nerves in either the upper or lower parts of your body. This is the category in which Lou Gehrig's disease is classified. Signs of MNDs usually present themselves in mid-life. Symptoms include weakness of arms and legs, difficulty swallowing, challenged gait, slurred speech, weakness in the face and muscle cramping. As the disease progresses, respiration can be affected.
Inflammatory myopathies are another form of neuromuscular disease. They are also called myositis. People with these disease experience the inflammation of their voluntary muscles. Those muscles weaken over time. People with myositis often tend to have other autoimmune diseases like rheumatoid arthritis. Symptoms include pain most likely in the upper arms, shoulders, top part of the back, hips and thighs. People with inflammatory myopathies may also have trouble swallowing, which can lead to poor nutrition and weight loss.
Diseases of the Neuromuscular Junction
This group of diseases occur where the nerve and muscle cells meet. The junction doesn't work properly. Lambert-Eaton Syndrome (LES) and Myasthenia Gravis (MG) are part of this category. Symptoms of MG include problems swallowing and speaking and muscle weakness during periods of activity. The weakness tends to get better after rest. LES is similar to MG, however, muscle weakness actually improves after activity, instead of getting worse.
Peripheral Nerve Diseases
Peripheral nerve diseases wreak havoc on the nerves that control legs and arms. Charcot-Marie-Tooth Disease (CMT) is the most well-known of these conditions. It's an inherited disorder affecting between 100,000 and 125,000 people in the U.S., according to St. Francis Hospital. The muscles in your feet, forearms, legs and hand slowly degenerate. The first sign of CMT is when your toes are flexed or your foot is highly arched due to unusual walking. Other symptoms include problems with hand balance and function, foot bone abnormalities, arm or leg cramping, possible hearing loss or vision problems and the loss of some normal reflexes. Some patients also experience scoliosis.
Mitochondrial myopathies and other myopathies classify the rest of the neuromuscular diseases that don't fall into other groups. Mitochondria provide energy to the muscles so when they were is disorder, you feel weak and lack energy. Typical mitochondrial myopathies include Kearns-Sayre syndrome, mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS) and myoclonus epilepsy with ragged-red fibers (MERRF). Symptoms and signs include movement disorders, blindness, deafness, eyelids that droop, vomiting, heart failure, dementia, seizures and arrhythmia.