Neuromuscular Diseases

Neuromuscular diseases is a term that refers to a number of conditions. The best known are the muscular dystrophies (MD). Each year millions of dollars are raised over Labor Day weekend by the Muscular Dystrophy Association's (MDA) telethon. Also falling under the neuromuscular disease category is Lou Gehrig's disease or amyotrophic lateral sclerosis (ALS). All of these diseases are characterized by muscle weakness in one form or another. The reasons can vary from genetic factors to thyroid problems. (Read about "Genetics" "Thyroid")

Neuromuscular diseases can be grouped into the following categories:

• Muscular Dystrophies - Becker Muscular Dystrophy (BMD), Congenital Muscular Dystrophy (CMD), Distal Muscular Dystrophy (DD) which is also known as Miyoshi, Duchenne Muscular Dystrophy (DMD) which is also known as Pseudohypertrophic, Emery-Dreifuss Muscular Dystrophy (EDMD), Facioscapulohumeral Muscular Dystrophy (FSH), Limb-Girdle Muscular Dystrophy (LGMD), Myotonic Muscular Dystrophy (MMD) which is also called Steinert's, Oculopharyngeal Muscular Dystrophy (OPMD)
• Motor Neuron Diseases - Adult Spinal Muscular Atrophy (SMA), Amyotrophic Lateral Sclerosis (ALS) which is also known as Lou Gehrig's Disease, Infantile Progressive Spinal Muscular Atrophy (SMA1) which is also known as SMA Type 1 or Werdnig-Hoffman, Intermediate Spinal Muscular Atrophy (SMA2) which is also known as SMA Type 2, Juvenile Spinal Muscular Atrophy (SMA3) which is also known as SMA Type 3 or Kugelberg-Welander, Spinal Bulbar Muscular Atrophy (SBMA) which is also known as Kennedy's Disease or X-linked SBMA
• Inflammatory Myopathies - Dermatomyositis (DM), Polymyositis (PM), Inclusion Body Myositis (IBM)
• Neuromuscular Junction Diseases - Myasthenia Gravis (MG), Lambert-Eaton Syndrome (LES), Congenital Myasthenic Syndrome (CMS)
• Peripheral Nerve Diseases - Charcot-Marie-Tooth Disease (CMT) which is also known as Peroneal Muscular Atrophy, Dejerine-Sottas Disease (DS), Friedreich's Ataxia (FA)
• Mitochondrial Myopathies - Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers (MERRF), and mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS)
• Other Myopathies - Myotonia Congenita (MC)which is also known as Thomsen's and Becker's Disease, Paramyotonia Congenita (PC), Central Core Disease (CCD), Periodic Paralysis (PP) (Hypokalemic and Hyperkalemic), Endocrine Myopathies (EM)

Below you will find a listing of many of these conditions along with a short explanation on the causes, symptoms and possible treatments.

Muscular Dystrophies

The National Institute of Neurological Diseases and Stroke (NINDS) says muscular dystrophy is a group of genetic diseases. (Read about "Genetics") Some are present in infancy or childhood. Others may not appear until middle age or later. The muscles of the body slowly get weaker and weaker. The voluntary muscles (the ones we control) are the ones usually affected. Some of the MD's also affect the heart muscle and other involuntary muscles as well, according to NINDS. Duchenne Muscular Dystrophy is considered the most common MD in children, myotonic muscular dystrophy is the most common in adults. Follow the alphabetical list below for more information.

• Becker Muscular Dystrophy (BMD) - BMD is a variant of form of Duchenne muscular dystrophy or DMD (see below), according to the Muscular Dystrophy Association (MDA). It is one of the genetically related diseases. (Read about "Genetics") It is much less severe than DMD with the onset more likely in adolescence or early adulthood. BMD is believed to occur once in 18,000 births. MDA says that it almost always affects males, seldom females. The first signs are usually the inability to keep up during gym classes or military training. A waddling type gait or walking on the toes is often an attempt to compensate for the muscle weakening. MDA says there can also be heart problems as the disease progresses. Survival is usually into middle to late adulthood.
• Congenital Muscular Dystrophy (CMD) - CMD is a set of MD's that tend to show themselves almost from birth and certainly by the age of two, according to MDA. The first signs tend to be a lack of muscle tone in the child, a sort of floppiness. Later they will not develop physically as expected. (Read about "Child Development") The disease can affect joints and, in some forms, mental functioning.
• Distal Muscular Dystrophy (DD) also called Miyoshi - DD is a set of MD's that affects the hands, forearms, lower legs and feet. The onset of symptoms is usually between 40 and 60 years of age, according to MDA. Muscle weakness progresses slowly and isn't life threatening.
• Duchenne Muscular Dystrophy (DMD) also called Pseudohypertrophic - NINDS calls DMD the most common MD. It tends to manifest itself in early childhood, between 2 and 6 years of age and is more often seen in boys. General weakness is one of the first signs. The calves of children with DMD will often be enlarged. MDA says that as DMD progresses a child will slowly lose the ability to walk. DMD progresses slowly but surely and will eventually affect all voluntary muscles. According to NINDS, most boys are unable to walk by age 12, and later may need a respirator to breathe. Girls in these families have a 50 percent chance of inheriting and passing the defective gene to their children.
• Emery-Dreifuss Muscular Dystrophy (EDMD) - EDMD affects the upper arms, shoulders and the calves. The muscle weakening tends to become apparent by the age of ten, according to MDA. Stiff joints in the elbows, neck and heels are early signs. A serious result of EDMD is a disruption of the heart's electrical system. This requires constant monitoring. In some cases, a pacemaker may be required. EDMD progresses slowly
• Facioscapulohumeral Muscular Dystrophy (FSH) - FSH mainly affects the face, shoulder and upper arm muscles according to MDA. The Facioscapulohumeral Muscular Dystrophy Society (FMDS) says some of the early symptoms include trouble opening and closing the eyes and moving the mouth and lips such as when puckering for a kiss or whistling. In most cases, FSH will first show up in the teen years. It is very slow progressing and a normal life span is the usual case.
• Limb-Girdle Muscular Dystrophy (LGMD) - LGMD gets its name from the fact that the muscles around the shoulder girdle and the pelvic girdle are the ones affected. LGMD can show up anywhere from childhood on into middle age. It progresses slowly, but as muscle strength drops, a person begins to need assistance walking and may eventually have to use a wheel chair. The earlier LGMD manifests itself, the faster it progresses, according to MDA. Waddling type gait is usually one of the first signs. Heart and breathing problems often surface as LGMD progresses. The heart and respiratory systems need to be monitored carefully for LGMD patients. (Read about "The Heart & Cardiovascular System" "Respiratory System")
• Myotonic Muscular Dystrophy (MMD) also known as Steinert's - NINDS calls MMD the most common MD affecting adults. It usually affects people in their late teens into adulthood but can begin earlier. The earlier it begins the more severe it is, according to MDA. MMD tends to affect the feet, hands, face and neck first. MMD is different from other MD's because often the muscles are unable to relax after contracting. The progression of MMD is very slow and can last 50 to 60 years. In males, early balding in the front and wasting muscles in the face, creating a thin hollow look is common, according to MDA. MMD will eventually go on to affect most other parts of the body. The heart requires monitoring in MMD patients. The electrical circuit can be affected. Cataracts (Read about "Cataracts") are also a common problem for MMD patients.
• Oculopharyngeal Muscular Dystrophy (OPMD) - OPMD usually doesn't manifest itself until mid-life, the 40's and 50's, according to MDA. Impacted are the muscles of the face, particularly the eyelids, leading to droopy eyelids, and the muscles of the throat used for swallowing. OPMD progresses slowly with swallowing problems being the main issue. The droopy eyelids result in the person having to tilt their heads farther back to see.

There is no specific treatment for any of the forms of MD. Physical therapy (Read about "Rehabilitation") to prevent contractures (a condition in which shortened muscles around joints cause abnormal and sometimes painful positioning of the joints), orthoses (orthopedic appliances used for support) and corrective orthopedic surgery may be needed to improve the quality of life in some cases. The cardiac problems that occur with Emery-Dreifuss MD and myotonic MD may require a pacemaker. The myotonia (delayed relaxation of a muscle after a strong contraction) occurring in myotonic MD may be treated with medications such as phenytoin or quinine.

Motor Neuron Diseases

The National Institute of Neurological Diseases and Stroke (NINDS) calls motor neuron diseases (MNDs) progressive, degenerative disorders that affect nerves in the upper or lower parts of the body. (Read about "Nervous System") Some are inherited, according to NINDS. Common MNDs include amyotrophic lateral sclerosis (ALS), which is better known as Lou Gehrig's disease, progressive muscular atrophy and post-polio syndrome. (Read about "Post-Polio Syndrome") Generally, MNDs strike in middle age. Symptoms may include difficulty swallowing, limb weakness, slurred speech, impaired gait, facial weakness and muscle cramps. (Read about cramps in "Feet, Ankles and Legs") Respiration may be affected in the later stages of these diseases. The cause(s) of most MNDs are not known, but environmental, toxic, viral or genetic factors are all suspects. (Read about "Genetics") Follow the alphabetical list below for more information on some common MNDs.

• Adult Spinal Muscular Atrophy (SMA) - The spinal muscular atrophies (SMAs) are a group of genetics diseases (Read about "Genetics") that affect the voluntary muscles of the body. The Muscular Dystrophy Association (MDA) says they do not affect the involuntary muscles, like the ones that control our bladders and bowels. (Read about "The Urinary System") Almost always, the muscles that help us breathe are affected. Because of that, treatments often involve dealing with respiratory problems. (Read about "Respiratory System") SMAs differ mainly in the time of onset and how fast they progress, according to MDA. At this point, there are no cures for any of the SMAs. Adult SMA tends to show up in middle age, according to NINDS, and progresses rapidly. Symptoms include progressive limb weakness and atrophy of the muscles, difficulty speaking and swallowing, and respiratory problems. Many times, NINDS says, SMA is a form of amyotrophic lateral sclerosis. Genetic counseling is considered important for someone diagnosed with SMA, according to NINDS.
• Amyotrophic Lateral Sclerosis (ALS) also known as Lou Gehrig's Disease - ALS is a progressive muscle wasting disease that strikes about 5,000 people each year in the United States, according to NINDS. It is commonly known as Lou Gehrig's disease. The New York Yankee first baseman died from ALS in 1941. NINDS says that some 20,000 people are living with the disease. ALS occurs when the nerve cells that control voluntary muscles are lost. As the nerve cells die off, the muscles weaken and waste away. Symptoms vary depending on which muscles weaken first. Eventually paralysis occurs. ALS usually shows itself in middle age, according to NINDS. Men are more likely to get ALS than women. About 10 percent of the time ALS appears to be inherited, according to MDA. The rest of the time the cause cannot be pinpointed. The disease tends to progress rapidly but many people survive for years with ALS. Recently new drugs have been approved that appear to help ALS patients.
• Infantile Progressive Spinal Muscular Atrophy (SMA1) also known as SMA Type 1 or Werdnig-Hoffman - SMA Type 1 is also called Werdnig-Hoffmann disease. It shows up in the first few months of life and is considered the most severe, according to MDA. Symptoms, according to NINDS, may include a floppiness of the child, lack of movement in the arms and legs, swallowing, feeding and breathing problems. Affected children are not able to sit or stand. The disease progresses rapidly.
• Intermediate Spinal Muscular Atrophy (SMA2) also known as SMA Type 2 - SMA Type 2 begins later than Type 1, anywhere from 3 months to 18 months. The symptoms are much the same as Type 1. The child may be able to sit up but will not be able to stand, according to MDA. The progression of the disease varies. The severity is dependent on the amount of respiratory problems. (Read about "Respiratory System")
• Juvenile Spinal Muscular Atrophy (SMA3) also known as SMA Type 3 or Kugelberg-Welander - SMA Type 3 is also called Kugelberg-Welander after the doctors who first described it. It usually first appears between 5 and 15 years of age, according to MDA, but can appear as early as two. MDA calls it the milder form of the childhood SMAs. Symptoms mostly involve difficulties with leg motions and may include tremors in the fingers, according to NINDS. MDA says the greatest danger, if it occurs, is from respiratory problems. (Read about "Respiratory System")
• Spinal Bulbar Muscular Atrophy (SBMA) also known as Kennedy's Disease or X-linked SBMA - SBMA is also called Kennedy's disease. SBMA is usually adult onset in nature but NINDS says it can occur as early as 15 years of age. Symptoms include weakness in the limbs and the face resulting in difficulty in lifting heavy objects, climbing stairs or just standing up. NINDS adds there may also be weakness of the facial and tongue muscles, resulting in difficulty swallowing and speech impairment. The disease also impacts the production of male hormones and can result in such things as enlarged breasts, infertility (Read about "Infertility") and possible shrinkage of the testes, according to MDA. The disease progresses slowly. SBMA usually only affects men, according to MDA. The gene that is responsible for the disease is passed on by the mother.

According to NINDS, there is currently no cure or standard treatment for the MNDs. Symptomatic and supportive treatment can help patients be more comfortable while maintaining their quality of life.

Inflammatory Myopathies

Inflammatory myopathies are also referred to as myositis. They are a group of diseases that involve the inflammation of the voluntary muscles and the eventual weakening of those muscles. The Myositis Association of America (MAA) calls them autoimmune diseases, meaning the body's own immune system (Read about "The Immune System") attacks the muscles. All of them cause a weakness in the muscles that can make it difficult to stand and walk. People with these diseases also tend to have other autoimmune diseases such as rheumatoid arthritis. (Read about "Rheumatoid Arthritis") There are various drugs that have shown some success treating each of the diseases.

• Inclusion Body Myositis (IBM) - IBM usually sets in after the age of 50. MDA calls it the most common muscle disease of those over 50. The onset and progression of symptoms is slow, taking months and even years, according to MAA. All of the voluntary muscles are affected equally. Many people experience weakness in the hands causing difficulty with gripping, pinching and buttoning as some of the first symptoms. As the disease progresses there may be weakness of the wrist and finger muscles and atrophy or shrinking of the quadricep muscles in the legs. Atrophy of the forearms is also characteristic. About half of the people affected by the disease have problems swallowing. More men than women are affected, according to MDA. A muscle biopsy (Read about "Biopsy") is required for a definitive diagnosis.
• Dermatomyositis (DM) - In addition to the usual muscle weakness, DM is characterized by a rash. (Read about "Skin Rash") The rash is described as patchy, bluish-purple discolorations on the face, neck, shoulders, upper chest, elbows, knees, knuckles and back. Some patients may also develop hardened bumps of calcium deposits under the skin. NINDS says the rash often is the first sign of the disease. MDA says the rash can come weeks, months or even years before other symptoms. The disease tends to have a rapid onset once symptoms first appear. Onset can occur from childhood on.
• Polymyositis (PM) - PM does not have the rash associated with DM. It also tends to progress slower. MDA says that many patients can't pinpoint when they first had symptoms because of the slow progression. The muscles closest to the central portion of the body are the ones that are affected first. The muscles at the extremities are affected less. MAA says PM almost always affects people over 20 years of age.

According to NINDS, currently there is no cure for inflammatory myopathies. However, there are several approaches to treating them and helping patients maintain as normal a lifestyle as possible, including medications, as well as speech and physical therapy. (Read about "Rehabilitation")

Neuromuscular Junction Diseases

Diseases of the neuromuscular junction are caused when the place where the nerve cells (Read about "Nervous System") and muscle cells meet doesn't work correctly, hence the name neuromuscular junction. Two of the diseases, Myasthenia Gravis (MG) and Lambert-Eaton Syndrome (LES) are considered autoimmune diseases. That means they are the result of the body's immune system (Read about "The Immune System") attacking itself. Congenital Myasthenic Syndrome is inherited, according to MDA. Each of the diseases is described in greater detail below.

• Myasthenia Gravis (MG) - MG results in muscle weakness of the voluntary muscles. MDA says that women tend to develop this autoimmune disease in their 20's, while men usually develop it after the age of 60. It is estimated that about 20,000 people in the United States are dealing with MG. MG can cause weakness of the muscles of the eyes, arms and legs, as well as creating problems with speaking and swallowing. NINDS says that myasthenia gravis is distinctive in that the muscle weakness increases during periods of activity and improves after periods of rest. The greatest danger is if the muscles that control breathing are affected. There are treatments for MG. Certain medications help improve the signals from the nerve cells to the muscle cells. In addition, NINDS says that the surgical removal of the thymus gland, improves symptoms in certain patients and may cure some people.
• Lambert-Eaton Syndrome (LES) - LES is also an autoimmune disease. MDA says the symptoms are similar to MG but differ in that symptoms get better after brief exertion instead of worse. LES usually appears in middle age. The hips and thighs are generally where it first manifests itself. Concern with the disease surrounds the fact that about 40 percent of LES sufferers will develop cancer (Read about "Cancer: What It Is") at some point. MDA says most of those cancers will be small cell lung cancers. (Read about "Lung Cancer") There are treatments available for LES.
• Congenital Myasthenic Syndrome (CMS) - CMS is not an autoimmune disease but instead is the result of inherited gene defects. MDA says that in most types of CMS, someone must get a bad gene from each parent. Symptoms of muscle weakness are much the same as with MG and often show up early in life. Treatment depends on the exact gene defect. MDA says some treatments that help with one defect will actually make things worse if another defect is the reason.

According to NINDS, currently there is no cure for neuromuscular junction diseases. Medication and treatment options focus on symptomatic relief.

Peripheral Nerve Diseases

Diseases of the peripheral nerve impact the nerves that control our extremities, our arms and legs. (Read about "Nervous System") The three listed below are all genetically caused. (Read about "Genetics")

• Charcot-Marie-Tooth Disease (CMT) - CMT is one of the most common inherited disorders, according to MDA. It is estimated to affect between 100,000 and 125,000 people in the United States. NINDS says CMT causes a slow degeneration of the muscles in the foot, lower leg, hand and forearm, and a mild loss of sensation in the limbs, fingers and toes. The first sign of CMT, according to MDA are usually foot problems such as a high arched foot or flexed toes resulting in unusual walking. NINDS says other symptoms of the disorder may include foot bone abnormalities such as high arches and hammer toes, problems with hand function and balance, occasional lower leg and forearm muscle cramping, loss of some normal reflexes, occasional partial sight and/or hearing loss (Read about "Hearing Loss"), and, in some patients, scoliosis. (Read about "Curvature of the Spine") There are two types of the disease. MDA says type 1 usually appears in childhood or the teen years, type 2 later. NINDS says the earlier the symptoms appear, the more severe they are. There is no cure for CMT. Treatment may involve physical therapy (Read about "Rehabilitation"), braces and/or shoe inserts.
• Dejerine-Sottas Disease (DS) - DS is sometimes referred to as Type 3 CMT, according to MDA. It is also caused by problems with specific genes. MDA says some of the symptoms include the late development of certain motor skills, including walking, until the child is 3 or 4 years of age. (Read about "Child Development") Other symptoms can include the loss of the ability to walk in later years, hearing and other sensory problems.
• Friedreich's Ataxia (FA) - FA is a relatively rare genetic disease (Read about "Genetics") that affects about 5,000 people in the United States. MDA says that people of French-Canadian background have a higher rate of the disease. NINDS says FA causes progressive damage to the nervous system affecting balance and coordination. The symptoms include muscle weakness, speech problems and even heart disease. Symptoms usually begin between the ages of 5 and 15 but can appear as early as 18 months or as late as 30 years of age. The first symptom is usually difficulty in walking. The balance and movement problems gradually worsen and slowly spread to the arms and then the trunk. Foot deformities such as clubfoot (Read about "Clubfoot"), flexion (involuntary bending) of the toes, hammer toes, or foot inversion (turning in) may be early signs. Rapid, rhythmic, involuntary movements of the eyeball are common. (Read about "The Eye") Most people with Friedreich's ataxia develop scoliosis (Read about scoliosis in "Curvature of the Spine") which, if severe, may impair breathing. Other symptoms include chest pain, shortness of breath, and heart palpitations. MDA says most FA patients develop heart disease. (Read about "Coronary Heart Disease") There are no known cures.

According to NINDS, currently there is no cure for peripheral nerve diseases. Treatment options focus on symptomatic relief and medications to block pain.

Mitochondrial Myopathies

Mitochondria are found in every cell of the body. They are little energy factories. The nerves cells in our brains (Read about "The Brain" "Nervous System") and in our muscles need a lot of energy so when the mitochondria don't work right there can be problems.

The National Institute of Neurological Disorders and Stroke (NINDS) says some of the more common mitochondrial myopathies include Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers (MERRF), and mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS).

Muscle weakness and not having the energy to do many things especially exercise is a symptom of mitochondrial myopathies. NINDS says other symptoms can include:

• heart failure or rhythm disturbances (Read about "Arrhythmia")
• dementia (Read about "Dementia")
• movement disorders
• stroke-like episodes (Read about "Stroke")
• deafness
• blindness
• droopy eyelids
• reduced ability of the eyes to move
• vomiting
• seizures (Read about "Seizures")

Mitochondrial myopathies can hit at any time from birth on but NINDS says most of the time it develops before the age of 20. The progression of the diseases varies with progressive weakness and sometimes death. There is no cure or specific treatment says NINDS. Vitamin therapies have had some success for some patients. (Read about "Vitamins & Minerals") Physical therapy (Read about "Rehabilitation") can also help.

Other Myopathies

Myopathy basically means a disease of the muscles. Below are some others muscle diseases that do not fall into other categories.

• Myotonia Congenita (MC) (Thomsen's and Becker's Disease) - There are two types of MC according to MDA, Thomsen's and Becker's. Becker's is the more common of the two, according to MDA. Thomsen's is rarer and less severe. They differ in the way they are inherited, via dominant gene with Thomsen's and recessive gene with Becker's. Both types cause the same problems. The muscles are stiff and slow to relax after a contraction. Exercise tends to relieve many of the symptoms, according to NINDS.
• Paramyotonia Congenita (PC) - PC is also inherited. It has much the symptoms as MC but they are not relieved by exercise. In fact, they are made worse. People with PC are also sensitive to the cold, according to MDA.
• Central Core Disease (CCD) - CCD is a rare genetic disease (Read about "Genetics"), according to MDA. It causes poor muscle development and weakness. MDA warns that people with CCD should be careful about surgery because they have a greater chance of reacting to certain anesthetic drugs. (Read about "Anesthesia")
• Periodic Paralysis (PP) (Hypokalemic and Hyperkalemic) - PP results in so-called attacks of muscle weakness and in some cases, temporary paralysis. Between the attacks, the muscles work in the normal manner. According to NINDS, the two most common types of periodic paralyses are hypokalemic (caused by mutations in the calcium channel gene on chromosome 1) and hyperkalemic (caused by mutations in the sodium channel on chromosome 17). (Read about "Genetics") Hypokalemic attacks are usually triggered by strenuous exercise, according to MDA. Attacks of hypokalemic periodic paralysis usually last for a few hours or persist for several days. MDA says some people will have only a few attacks in their entire life. Hyperkalemic attacks are frequent, lasting usually 1 to 2 hours. They can be as short as 15 minutes or may last days, according to MDA. The attacks are usually triggered by strenuous exercise, stress (Read about "Stress") or ingestion of certain foods, according to NINDS. Individuals with hyperkalemic periodic paralysis may display a rise in potassium levels in the blood during attacks. Hyperkalemic attacks often begin at an early age.
• Endocrine Myopathies (EM) - Myopathies can also occur when certain glands either over-produce or under-produce certain hormones. For example, hyperthyroid myopathy is the result of too much thyroid hormone. (Read about "Thyroid") MDA says it can result in weakness in the muscles of the upper arm and upper leg and also involve some muscle wasting. Hypothyroid myopathy results from too little thyroid hormone. MDA says weakness can develop in the arm and leg muscles. Stiffness and muscle cramps are common. (Read about cramps in "Feet, Ankles and Legs") The symptoms of both hyper- and hypo-thyroid myopathy usually improve with treatment of the underlying thyroid condition, according to MDA.

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