Neuromuscular disease
Encyclopedia
Neuromuscular disease is a very broad term that encompasses many disease
s and ailments that either directly, via intrinsic muscle
pathology, or indirectly, via nerve
pathology, impair the functioning of the muscles.
Neuromuscular diseases are those that affect the muscles and/or their nervous control. In general, problems with nervous control can cause either spasticity
or some degree of paralysis
, depending on the location and the nature of the problem. A large proportion of neurological disorder
s leads to problems with movement. Some examples of these disorders include Amyotrophic Lateral Sclerosis
(ALS or Lou Gehrig's Disease), cerebrovascular accident (stroke), Parkinson's disease
, multiple sclerosis
, muscular dystrophy
, myasthenia gravis
, Huntington's disease
(Huntington's chorea), and the Creutzfeldt-Jakob disease
.
, spasticity
/rigidity, loss of muscular control, myoclonus
(twitching, spasming), and myalgia
(muscle pain). Diagnostic procedures that may reveal muscular disorders include direct clinical observations (above all), the testing of various chemical and antigen levels in the blood, and electromyography
(measuring electrical activity in muscles). Diagnostic imaging
may be helpful in certain cases, such as those caused by strokes or tumors.
, genetic/hereditary disorders, such as Huntington's disease
, certain rare tumors, the failure of the connections between the nerves and the muscle fibers, exposure to pernicious environmental chemicals, poisoning - including heavy-metal poisoning, and importantly, unknown causes. The failure of the electrical insulation surrounding nerves, the myelin
, is seen in certain deficiency diseases, such as the failure of the body's system for absorbing vitamin B-12, and also the failure of the myelin is seen in multiple sclerosis
and some other neurological diseases, especially in autoimmune diseases that are thought to attack the myelin.
Some neuromuscular diseases are hypothesized to be caused either by viral infections or by attack by little-known pernicious proteins called prions.
Diseases of the motor end plate include myasthenia gravis
, a form of muscle weakness due to antibodies
to the acetylcholine
receptor, and its related condition Lambert-Eaton myasthenic syndrome
(LEMS). Tetanus
and botulism
are bacterial infections in which bacterial toxins cause increased or decreased muscle tone, respectively.
The myopathies
are all diseases primarily resulting in muscular degeneration, rather than affecting the nerves themselves.
The Muscular dystrophies
, including Duchenne's
and Becker's, are a large group of diseases, many of them hereditary or resulting from genetic errors, where the bnmuscle integrity is disrupted. They lead to progressive loss of strength and decreased life span.
Inflammatory
s of muscle are of the soft tissue sarcoma group and include:
Smooth muscle has been implicated to play a role in a large number of diseases affecting blood vessel
s, the respiratory tract
(e.g., asthma
), the digestive system (e.g. irritable bowel syndrome
) and the urinary tract (e.g., urinary incontinence
). These disease processes are not usually confined to the muscular tissue. In general, muscle tumors are rare, since muscle cells are not constantly dividing cells.
Tumors of the thymus gland are implicated in some cases of myasthenia gravis
and other neuromuscular diseases.
Tumors of the peripheral nervous system are known, but rare, because nerve cells are not ones that divide very much under normal circumstances.
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
s and ailments that either directly, via intrinsic muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
pathology, or indirectly, via nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
pathology, impair the functioning of the muscles.
Neuromuscular diseases are those that affect the muscles and/or their nervous control. In general, problems with nervous control can cause either spasticity
Spasticity
Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...
or some degree of paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
, depending on the location and the nature of the problem. A large proportion of neurological disorder
Neurological disorder
A neurological disorder is a disorder of the body's nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or in the nerves leading to or from them, can result in symptoms such as paralysis, muscle weakness, poor coordination, loss of sensation, seizures,...
s leads to problems with movement. Some examples of these disorders include Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...
(ALS or Lou Gehrig's Disease), cerebrovascular accident (stroke), Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
, multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
, muscular dystrophy
Muscular dystrophy
Muscular dystrophy is a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.In the 1860s, descriptions of boys who...
, myasthenia gravis
Myasthenia gravis
Myasthenia gravis is an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatiguability...
, Huntington's disease
Huntington's disease
Huntington's disease, chorea, or disorder , is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable in middle age. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea...
(Huntington's chorea), and the Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease
Creutzfeldt–Jakob disease or CJD is a degenerative neurological disorder that is incurable and invariably fatal. CJD is at times called a human form of mad cow disease, given that bovine spongiform encephalopathy is believed to be the cause of variant Creutzfeldt–Jakob disease in humans.CJD...
.
Symptoms and testing
Symptoms of muscle disease may include muscular weaknessMuscle weakness
Muscle weakness or myasthenia is a lack of muscle strength. The causes are many and can be divided into conditions that have true or perceived muscle weakness...
, spasticity
Spasticity
Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...
/rigidity, loss of muscular control, myoclonus
Myoclonus
Myoclonus is brief, involuntary twitching of a muscle or a group of muscles. It describes a medical sign and, generally, is not a diagnosis of a disease. Brief twitches are perfectly normal. The myoclonic twitches are usually caused by sudden muscle contractions; they also can result from brief...
(twitching, spasming), and myalgia
Myalgia
Myalgia means "muscle pain" and is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections...
(muscle pain). Diagnostic procedures that may reveal muscular disorders include direct clinical observations (above all), the testing of various chemical and antigen levels in the blood, and electromyography
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
(measuring electrical activity in muscles). Diagnostic imaging
Medical imaging
Medical imaging is the technique and process used to create images of the human body for clinical purposes or medical science...
may be helpful in certain cases, such as those caused by strokes or tumors.
Causes, including autoimmune diseases and poisoning
Neuromuscular disease can be caused by circulatory problems (strokes, etc.), immunological and autoimmune disorders, the failure of the electrical insulation surrounding nerves myelinMyelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
, genetic/hereditary disorders, such as Huntington's disease
Huntington's disease
Huntington's disease, chorea, or disorder , is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable in middle age. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea...
, certain rare tumors, the failure of the connections between the nerves and the muscle fibers, exposure to pernicious environmental chemicals, poisoning - including heavy-metal poisoning, and importantly, unknown causes. The failure of the electrical insulation surrounding nerves, the myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
, is seen in certain deficiency diseases, such as the failure of the body's system for absorbing vitamin B-12, and also the failure of the myelin is seen in multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
and some other neurological diseases, especially in autoimmune diseases that are thought to attack the myelin.
Some neuromuscular diseases are hypothesized to be caused either by viral infections or by attack by little-known pernicious proteins called prions.
Diseases of the motor end plate include myasthenia gravis
Myasthenia gravis
Myasthenia gravis is an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatiguability...
, a form of muscle weakness due to antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
to the acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...
receptor, and its related condition Lambert-Eaton myasthenic syndrome
Lambert-Eaton myasthenic syndrome
Lambert–Eaton myasthenic syndrome is a rare autoimmune disorder that is characterised by muscle weakness of the limbs...
(LEMS). Tetanus
Tetanus
Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...
and botulism
Botulism
Botulism also known as botulinus intoxication is a rare but serious paralytic illness caused by botulinum toxin which is metabolic waste produced under anaerobic conditions by the bacterium Clostridium botulinum, and affecting a wide range of mammals, birds and fish...
are bacterial infections in which bacterial toxins cause increased or decreased muscle tone, respectively.
The myopathies
Myopathy
In medicine, a myopathy is a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease...
are all diseases primarily resulting in muscular degeneration, rather than affecting the nerves themselves.
The Muscular dystrophies
Muscular dystrophy
Muscular dystrophy is a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.In the 1860s, descriptions of boys who...
, including Duchenne's
Duchenne muscular dystrophy
Duchenne muscular dystrophy is a recessive X-linked form of muscular dystrophy, which results in muscle degeneration, difficulty walking, breathing, and death. The incidence is 1 in 3,000 boys. Females and males are affected, though females are rarely affected and are more often carriers...
and Becker's, are a large group of diseases, many of them hereditary or resulting from genetic errors, where the bnmuscle integrity is disrupted. They lead to progressive loss of strength and decreased life span.
InflammatoryInflammationInflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
muscle disorders
- Polymyalgia rheumaticaPolymyalgia rheumaticaPolymyalgia rheumatica , abbreviated as PMR, is a syndrome with pain or stiffness, usually in the neck, shoulders, and hips. The pain can be very sudden, or can occur gradually over a period of time...
(or "muscle rheumatism") is an inflammatory condition that mainly occurs in the elderly; it is associated with giant-cell arteritis. It often responds dramatically to glucocorticoidGlucocorticoidGlucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
s (e.g. prednisolonePrednisolonePrednisolone is the active metabolite of prednisone, which is also used as a drug.-Uses:Prednisolone is a corticosteroid drug with predominant glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions such as...
). - PolymyositisPolymyositisPolymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
, dermatomyositisDermatomyositisDermatomyositis is a connective-tissue disease related to polymyositis and Bramaticosis that is characterized by inflammation of the muscles and the skin.- Causes :...
and inclusion body myositisInclusion body myositisInclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
are autoimmune conditions in which the muscle is affected. - RhabdomyolysisRhabdomyolysisRhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
is the breakdown of muscular tissue due to any cause. While it may not lead to any muscular symptoms at all, the myoglobinMyoglobinMyoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. The only time myoglobin is found in the...
thus released may cause acute renal failureAcute renal failureAcute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...
.
Tumors
TumorTumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s of muscle are of the soft tissue sarcoma group and include:
- Smooth muscle: leiomyomaLeiomyomaA leiomyoma is a benign smooth muscle neoplasm that is not premalignant. They can occur in any organ, but the most common forms occur in the uterus, small bowel and the esophagus.- Etymology:* Greek:** λεῖος leios "smooth"...
(benign, very common in the uterusUterusThe uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
), leiomyosarcomaLeiomyosarcomaLeiomyosarcoma , aka LMS, is a malignant cancer of smooth muscle....
(malignant, very rare) - Striated muscle: rhabdomyomaRhabdomyomaA rhabdomyoma is a benign tumor of striated muscle. Rhabdomyomas may be either "cardiac" or "extracardiac" . Extracardiac forms of rhabdomyoma are subclassified into three distinct types: Adult type, Fetal type, and Genital type.Cardiac rhabdomyomas are the most common primary tumor of the heart...
(benign) and rhabdomyosarcomaRhabdomyosarcomaA rhabdomyosarcoma is a type of cancer, specifically a sarcoma , in which the cancer cells are thought to arise from skeletal muscle progenitors. It can also be found attached to muscle tissue, wrapped around intestines, or in any anatomic location...
(malignant) - both very rare - MetastasisMetastasisMetastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
from elsewhere (e.g. lung cancerLung cancerLung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
)
Smooth muscle has been implicated to play a role in a large number of diseases affecting blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s, the respiratory tract
Respiratory tract
In humans the respiratory tract is the part of the anatomy involved with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
(e.g., asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
), the digestive system (e.g. irritable bowel syndrome
Irritable bowel syndrome
Irritable bowel syndrome is a diagnosis of exclusion. It is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause. In some cases, the symptoms are relieved by bowel movements...
) and the urinary tract (e.g., urinary incontinence
Urinary incontinence
Urinary incontinence is any involuntary leakage of urine. It is a common and distressing problem, which may have a profound impact on quality of life. Urinary incontinence almost always results from an underlying treatable medical condition but is under-reported to medical practitioners...
). These disease processes are not usually confined to the muscular tissue. In general, muscle tumors are rare, since muscle cells are not constantly dividing cells.
Tumors of the thymus gland are implicated in some cases of myasthenia gravis
Myasthenia gravis
Myasthenia gravis is an autoimmune neuromuscular disease leading to fluctuating muscle weakness and fatiguability...
and other neuromuscular diseases.
Tumors of the peripheral nervous system are known, but rare, because nerve cells are not ones that divide very much under normal circumstances.
See also
- MuscleMuscleMuscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
- ICD-10 Chapter XIII: Diseases of the musculoskeletal system and connective tissueICD-10 Chapter XIII: Diseases of the musculoskeletal system and connective tissue- Infectious arthropathies:* Pyogenic arthritis* Direct infections of joint in infectious and parasitic diseases classified elsewhere* Reactive arthropathies** Reiter's disease...