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Neuromuscular disorders -

Neuromuscular disorders include a wide range of diseases affecting the peripheral nervous system, which consists of all the motor and sensory nerves that connect the brain and spinal cord to the rest of the body. Muscular dystrophy is a rare type of neuromuscular disease.

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Muscular dystrophy -

Muscular dystrophy (MD) is a group of inherited diseases that cause weakness and loss of muscle mass. In muscular dystrophy, abnormal genes (mutations) interfere with the production of proteins needed to form healthy muscle. It's a progressive condition characterized by eventual loss of strength, increasing disability, and possible deformity. There are nine types of MD.

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Congenital muscular dystrophy -

Congenital muscular dystrophy (CMD) refers to a group of muscular dystrophies that become apparent at or near birth. Symptoms include general muscle weakness and possible joint deformities. CMD progresses slowly and shortens lifespan.

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Duchenne muscular dystrophy -

Duchenne muscular dystrophy (DMD) is one of the most severe forms of inherited muscular dystrophies. Seen almost exclusively in males (it rarely affects females, who have much milder symptoms and a better prognosis), onset of DMD is age two to six years. It's characterized by general muscle weakness and wasting, and eventually involves all voluntary muscles. Survival beyond one's twenties is rare.

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Becker muscular dystrophy -

Symptoms of Becker muscular dystrophy (BMD) are almost identical to CMD. Progressive muscle weakness, most notably of the proximal lower limbs, is the primary manifestation of this condition. The onset of BMD symptoms varies widely, between five and 60 years of age, and, like DMD, it's almost always limited to males.

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Distal muscular dystrophy -

Onset of distal muscular dystrophy (DMD) is anywhere between 40 to 60 years of age. Symptoms of DMD include weakness and wasting of muscles of the hands, forearms, and lower legs. However, total incapacity is rare.

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Emery-Dreifuss muscular dystrophy -

Named for Alan Emery and Fritz Dreifuss, physicians who first described the disorder among a Virginia family in the 1960s, Emery-Dreifuss muscular dystrophy (EDMD) targets the shoulder, upper arm, and shin muscles. Joint deformities are common. Onset is usually apparent in childhood and, while progression of EDMD is slow, sudden death may occur from cardiac problems.

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Facioscapulohumeral muscular dystrophy -

Facioscapulohumeral muscular dystrophy (FSHD) affects the muscles of the face, shoulders, upper arms, and lower legs. Age of onset is childhood to early adulthood. Progression of FSHD can be unpredictable: it can be slow but with rapid periods of deterioration.

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Limb-girdle muscular dystrophy -

Limb-girdle muscular dystrophy (LGMD) causes weakness in the shoulder and pelvic girdle. Onset of LGMD is late childhood to middle age. But life expectancy is generally within a normal range because the heart and breathing muscles are usually not affected.

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Myotonic muscular dystrophy -

A common multi-system disorder that affects all muscle groups and many other organs in the body, myotonic muscular dystrophy (MMD) appears anywhere between 20 to 40 years of age. Progression is slow, sometimes spanning 50 to 60 years.

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Oculopharyngeal muscular dystrophy -

Oculopharyngeal muscular dystrophy (OPMD) symptoms include weakening of throat muscles, which, in time, causes inability to swallow and emaciation from lack of food. Onset is 40 to 70 years, and progression is slow.

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Other neuromuscular diseases -

There are numerous other types of neuromuscular diseases. One of the better known neuromuscular diseases is amyotrophic lateral sclerosis (ALS), or motor neurone disease.

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Motor neurone disease -

Early symptoms of motor neurone disease can include weakness in the ankle or leg, slurred speech, or a weak grip. Weakness gets worse over time, inhibiting walking, speaking, and breathing. Life expectancy after diagnosis is one to five years.

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Spinal muscular atrophies -

Spinal muscular atrophy (SMA) is a disorder affecting the motor neurons—nerve cells that control voluntary muscle movement. The condition ranges through infantile progressive spinal muscular atrophy, intermediate spinal muscular atrophy, juvenile spinal muscular atrophy, and adult spinal muscular atrophy.

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Inflammatory myopathies -

The inflammatory myopathies are a group of rare diseases that involve chronic muscle inflammation, muscle weakness, and, in some cases, muscle pain. Myopathy, incidentally, is a general term used to describe a number of conditions affecting the muscles.

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Dermatomyositis -

Dermatomyositis is one of these rare conditions. It causes muscle weakness and skin rash, and inhibits talking or swallowing. There is no cure, but treatment is available to reduce symptoms.

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Polymyositis -

Polymyositis is another disease in the inflammatory myopathy group of diseases. Polymyositis is a condition that causes skeletal muscle to become irritated and inflamed, leading to pain, stiffness, and weakness.

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Inclusion body myositis -

Inclusion body myositis (IBM) is a muscle-wasting condition, which causes muscles to become thin and weak. Symptoms of the disease usually begin after the age of 50, although the disease can occur earlier. IBM occurs more frequently in men than in women. There is no cure for the disorder.

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Disorders of the neuromuscular junction -

The body's neuromuscular system includes all the muscles in the body and the nerves connecting them. Disorders of the neuromuscular junction decrease the nerve's activity, causing weakness. 

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Myasthenia gravis -

Myasthenia gravis (MG) is a common disease of the neuromuscular junction. It's a long-term condition that commonly affects the muscles that control the eyes and eyelids, facial expressions, chewing, swallowing, and speaking. It can affect people of any age.

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Lambert-Eaton syndrome -

The main symptoms of Lambert-Eaton syndrome are weakness in the legs, arms, neck, and face, as well as problems with automatic body functions, such as controlling blood pressure. It's a rare autoimmune disorder, the majority of cases of which are associated with small cell lung cancer.

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Botulism -

Botulism is a rare but serious illness caused by a toxin that attacks the body's nerves. This, in turn, causes breathing difficulties, muscle paralysis, and even death.

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Rhabdomyolysis -

Rhabdomyolysis is a rare muscle injury where muscles break down due to muscle tissue releasing its proteins and electrolytes into the blood. These substances can damage the heart and kidneys and cause permanent disability or even death.

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Cardiomyopathy -

Cardiomyopathy is a disease that affects your myocardium (heart muscle). It's considered a chronic disease and can worsen over time. However, early diagnosis and treatment may improve overall outlook and extend lifespan.

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Sarcopenia -

Sarcopenia is a reduction in skeletal muscle mass due to aging and/or mobility. The condition is a leading cause of frailty.

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Fibromyalgia syndrome -

An often misunderstood disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues, fibromyalgia syndrome is a chronic condition with no cure.

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Tendinosis -

Tendinosis refers to hardening, thickening, and scarring of the tendons often due to repeatedly suffering smaller injuries that don't heal correctly. The tendons are thick, fibrous tissues that attach your muscles to your joints.

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Metabolic diseases of the muscle -

Metabolic diseases of the muscle can affect all the body's voluntary muscles, such as those in the arms, legs, and trunk. There are 10 primary types of this condition. Among these is acid maltase deficiency. Also known as Pompe disease, it's a genetically inherited disease that affects muscle function.

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Debrancher enzyme deficiency -

Debrancher enzyme deficiency is another metabolic disease of the muscle. Also known as Cori or Forbes disease, this condition interferes with the processing of food (in this case, carbohydrates) for energy production.

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Tetanus -

Elsewhere, tetanus is a serious, life-threatening condition caused by bacteria getting into a wound. Symptoms include painful muscle contractions and the locking of the neck and jaw muscles, which is why tetanus is also known as lockjaw.

Sources: (Muscular Dystrophy Association) (Verywell Health) (Cedars-Sinai) (MedlinePlus) (Johns Hopkins Medicine) (National Institute of Neurological Disorders and Stroke) (NHS) (National Institutes of Health)

See also: Piriformis syndrome: why it feels like sciatica

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