Department of Neurology

Patient Information

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Neuromuscular Diseases Treated

Amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), commonly referred to in the US as Lou Gehrig’s disease, is characterized by progressive weakness which is typically fatal by 3 to 5 years after the onset of symptoms. It most commonly affects adults from 20-80 years of age with an average onset age of 56 years. It is a neurodegenerative disease that results in the loss of motor neurons in the brain and spinal cord, which leads to weakness, atrophy, and twitching (fasciculations) of voluntary muscles. The paralysis can begin in the arms, legs, or head, and as the disease progresses eventually involves muscles controlling breathing and swallowing. There is no known cure for ALS, and riluzole, the only FDA-approved medication for treating the disease, only extends survival by a few months. Therefore, supportive measures designed to optimize function, breathing, and nutrition are mainstays of treatment. Unfortunately, the underlying cause of the disease is still not completely understood, but research is being actively pursued to better understand the mechanism of the disease and identify more effective treatments.


Dermatomyositis (DM) is a progressive acquired inflammatory disorder of muscle that also affects the skin. It can afflict both adults and children and typically more females than males. The disease is caused by inflammation of blood vessels in the skin and muscle. The weakness involves muscles closest to the trunk including neck, shoulder, and hip muscles. Uncommonly, swallowing can be affected. Sometimes there is associated pain. The rash of DM is found on the eyelids, cheeks, nose, back, upper chest, elbows, knees and knuckles and can be patchy and reddish or purplish in color. Calcium deposits can also form under the skin. Sometimes the skin rash can occur without weakness, called amyopathic DM. The diagnosis is made by detecting elevations of elevated muscle enzymes in the blood (creatine phosphokinase, i.e. CPK, or aldolase), autoantibodies in the blood such as antinuclear antibodies, abnormalities typical of a muscle disease on EMG/nerve conduction testing, magnetic resonance imaging (MRI) of muscle, and findings on muscle biopsy including inflammation of the muscle. Both skin and muscle biopsies also typically show signs of inflammation of blood vessels (i.e. vasculitis). Treatment consists of medications designed to suppress inflammation including corticosteroids, immunosuppressive therapies like methotrexate and azathioprine, and intravenous immunoglobulin.


Polymyositis (PM) is an acquired progressive inflammatory muscle disease that typically occurs over the age of 20 and affects more women than men. The disorder causes weakness that affects muscles of the torso and near it such as the neck, hip, shoulder muscles. Some patients also develop muscle pain and trouble breathing or swallowing. Patients with PM can sometimes have other autoimmune diseases, especially rheumatologic conditions. The diagnosis is made by detecting elevations of elevated muscle enzymes in the blood (creatine phosphokinase, i.e. CPK, or aldolase), autoantibodies in the blood such as antinuclear antibodies, abnormalities typical of a muscle disease on EMG/nerve conduction testing, magnetic resonance imaging (MRI) of muscle, and findings on muscle biopsy including inflammation and damage to muscle fibers (i.e. necrosis). Treatment consists of medications designed to suppress inflammation including corticosteroids, immunosuppressive therapies like methotrexate and azathioprine, and occasionally intravenous immunoglobulin. Some patients who do not respond to therapy are sometimes later found to have a disease called inclusion body myositis.

Inclusion body myositis

Inclusion body myositis (IBM) is an acquired progressive inflammatory muscle disease that typically occurs over the age of 50 and affects more men than women. IBM causes a very slow progression of weakness most commonly beginning in the quadriceps muscles and finger flexor muscles. This can cause difficulty climbing up stairs or getting up out of chairs and gripping objects. Other muscles of the arms and legs can become involved later in the course. Swallowing problems can also arise. The diagnosis is made by detecting elevations of elevated muscle enzymes in the blood (creatine phosphokinase, i.e. CPK, or aldolase), abnormalities typical of a muscle disease on EMG/nerve conduction testing, magnetic resonance imaging (MRI) of muscle, and findings on muscle biopsy including inflammation and vacuoles (“inclusion bodies”) that distinguish this disease from other inflammatory myopathies such as polymyositis and dermatomyositis. Unfortunately, unlike other inflammatory myopathies, there is currently no definitive treatment for this disease, though patients can benefit from supportive therapies such as bracing and assistive devices as needed.

Myasthenia gravis

Myasthenia gravis is an acquired disease affecting the connection between the nerve and the muscle, also known as the neuromuscular junction. It is an autoimmune condition wherein there is disruption of the normal function of the acetylcholine receptors on the muscle.

People with this disease experience fatigable and fluctuating weakness of the arms and legs, as well as the eyelids and muscles controlling the eyes. Speaking and swallowing can be affected and if the muscles for breathing are severely affected, an individual may need to be hospitalized.

Testing includes an examination of strength, laboratory tests for antibodies, possibly electrical tests. Treatment may include medication to reduce weakness or to suppress the immune system.

Muscular dystrophies

Muscular dystrophies are a group of heritable muscle diseases that weaken the muscles of the body. They include disorders such as Duchenne muscular dystrophy, facioscapulohumeral muscular dystrophy, and limb girdle muscular dystrophy. The main symptoms involve progressive muscular weakness, muscle wasting, frequent falls, difficulty walking, muscle cramps and stiffness, limited range of motion, difficulty breathing, problems with swallowing, developmental delay or regression, and orthopedic problems, including scoliosis and contractures. Although muscular dystrophies predominantly affect skeletal muscle, they may affect other types of muscle (cardiac and smooth) or other body systems. They are caused by genetic defects in muscle proteins, and the death of muscle cells. The diagnosis is made by detecting elevations of elevated muscle enzymes in the blood (creatine phosphokinase, i.e. CPK, or aldolase), abnormalities typical of a muscle disease on EMG/nerve conduction testing, magnetic resonance imaging (MRI) of muscle, and findings on muscle biopsy that include evidence of damage to muscle fibers and a dystrophic pattern. Sometimes, but not always, a genetic abnormality can be found as well. Patterns of heritability include autosomal dominant, autosomal recessive, and X-linked, but sporadic cases occur and can have onset at any age. Recognition of the specific genetic defect allows doctors to counsel patients in regards to both the rate and pattern of disease progression and the likelihood of passing the disease on to their offspring. There is no cure for muscular dystrophies and treatment is often limited to supportive care.

Peripheral neuropathy

Peripheral neuropathy is the term used to represent a variety of diseases affecting the nerves leaving the spinal cord and entering the limbs. The most common pattern of injury involves degeneration of the most distant portions of the nerves causing a glove and stocking loss of sensation and strength. Painful burning, cold sensation or shock-like pain may occur. Occasionally, nerves involved in organ function may also be involved causing a variety of symptoms including lightheadedness, excessive or too little sweating, dry mouth and constipation. Extreme forms of neuropathy may cause weakness of the muscles about the shoulders and pelvis causing problems with standing or raising arms above the head. There are a variety of causes for neuropathy including episodic increases in blood sugar or early diabetes, endocrine abnormalities such as hypothyroidism, certain vitamin deficiencies or immune system abnormalities. Peripheral neuropathy is diagnosed by a combination of neurological examination and evaluation of nerve health through electrical testing called electromyography or “EMG”. Neuropathy may be treated through identification and management of the underlying cause and there are several different types of medications useful for reducing pain. Neuromuscular disease specialists at the University of Washington Medical Center excel in the diagnosis and management of these conditions.

Guillain-Barre Syndrome

Guillain‐Barré syndrome (GBS) is a type of autoimmune peripheral neuropathy. It is an
autoimmune disease, meaning that the immune system that is used to defending the body
against foreign (bacterial, fungal, parasitical) invaders gets confused and starts to attack the
body (in the case the peripheral nervous system) as though it is a foreign invader.

Peripheral nerves are all the nerves that come out of the central nervous system (brain and
spinal cord) and control muscles, sensation, and default basic bodily functions (such as
bladder/bowel control, heart rate, blood vessel caliber, etc.). In GBS, the immune system
attacks the myelin sheath of nerves (the insulation around the electrical wires). The disease
entity is also known as acute inflammatory demyelinating polyradiculoneuropathy (AIDP).

What are the symptoms?
Clinical symptoms experienced in GBS are the result of the immune system attack on the
peripheral system, and can involve weakness, numbness, tingling, pain, blood pressure
instability. The disease can present in a variety of ways: from mild to severe, minutes to days,
patchy to widespread. Classically, the disease is presented as an ascending weakness, with
weakness starting in the legs and proceeding up the body. Patients can complain of pain in the
legs and back, as well as numbness, tingling, weird sensations.

The disease becomes a medical emergency when respiratory function is compromised. This can
affect one‐third of patients, and machines to tide over a patient’s breathing and care in an
intensive care unit may be necessary.

What is the cause?
The disease is rare and can affect 4‐40 people per million per year. It can affect all ages,
however there is a predominance in patients over age 55. The reason why the immune system
becomes confused is not always clear on an individual basis. Up to two‐thirds of patients have
prior medical events such as viral infections, bacterial infections, surgery, or vaccinations. Prior
infections can include the flu virus, meningococcal bacterial infection, Campylobacter jejuni
bacterial infection, cytomegalovirus (CMV) infection, Epstein‐Barr virus (EBV) infection,
Mycoplasma pneumoniae bacterial infection.

Different types of vaccinations have been associated with GBS and the data is controversial. It is
most likely that the H1N1 flu vaccine of 1976 caused an increase in the number of patients with
GBS. However since then multiple studies have been conducted to study the connection
between influenza vaccinations and GBS. The answer seems to be if there is a connection, it is a
very small association. A study of Kaiser Permanente Northern California found 550 confirmed
cases of GBS in their 3.2 million patient database over the years of 1995‐2006. Only 18 cases
(3.3%) occurred within 6 weeks of vaccination. The United States Center for Disease Control has
found only a minimal increase in the cases of GBS in the seasonal influenza vaccines or H1N1
influenza vaccines of the 2009‐2010 H1N1 season. It is clear that the influenza virus causes
death and disabilities, and therefore, each individual must weigh their risk of being afflicted with
flu versus their minimal increased chance of developing GBS (increasing the risk from ~1.2 to 1.9
per 100,000 people).

What are the tests to diagnose GBS?
The diagnosis of GBS is a clinical diagnosis aided by several tests. The main tests are to rule out
diseases of the central nervous system affecting the brain and spinal cord. Nerve conduction
studies to study the conduction speeds of nerves can be helpful but may not show any
abnormalities in the early part of the disease when the diagnosis is the most pressing. Repeat
nerve conduction studies sometimes may be needed. Spinal fluid study may be helpful and can
show a specific pattern after a few days of the disease (albumino‐cytological dissociation). The
spinal fluid studies are most helpful in ruling out central nervous system infection/inflammatory
diseases that would make the diagnosis of GBS less likely.

What are the treatments for GBS?
The most important treatment for GBS is to support the patient through their period of
respiratory compromise. As the disease is an autoimmune disease, medications to counter an
overactive immune system are used. Plasma exchange (washing one’s blood of bad
humors/humoral agents) or intravenous immunoglobulin (IVIg, a collection of human antibodies
used to counteract the bad humors/humoral agents) is used in patients early in the disease or
moderately‐to‐severely disabled. Corticosteroids are not indicated.

What to expect?
GBS can be very scary where someone healthy can in minutes‐to‐days be left weak, in pain, or
on a respirator. The disease usually reaches its maximal effect at nine days but by definition
should not progress beyond four weeks. Death can occur in 3‐10% of patients, and is usually
related to lung and heart failure. Most people get better. Patients can recover function over a
few weeks to as long as a few years. Having a good support system, good attitude, and good
physical therapy are all keys to improvement. Recurrence can occur in 2‐5%. Fatigue is a
common complaint.

Electrodiagnostic Testing

EMG and Nerve Conduction Studies

Electromyography, or EMG, involves testing the electrical activity of muscles. This is a very sensitive test and can be used to identify general disorders of nerves and muscles and, when multiple muscles are studied, allows the physician to localize a problem to a specific anatomic point. EMG testing is often performed with another test, a nerve conduction study (NCS) which measures how well signals travel along a nerve.

Why are these tests performed?
EMG and NCS, also called electrodiagnostic testing, might be considered if a patient has any of the following symptoms: numbness or tingling, weakness, muscle pain, muscle twitching, double vision, droopy eyelids, among other concerns.

How to prepare for the test?
No special preparation is usually necessary for the EMG/NCS. To ensure accurate readings, the patient should avoid using any creams or lotions the day of the test and make sure his or her skin is clean. Testing usually takes one to two hours. There are no restrictions on activity before or after the testing. Although the testing can be uncomfortable, there are no lasting effects.

Nerve Conduction Study (NCS)

Nerve conduction studies look at the size and speed of electrical signals as they travel through a nerve and are performed to help find the cause of abnormal nerve function.

How is the test performed?
A hand-held device delivers electric pulses to the nerve at different sites along its path. The resulting electrical activity is recorded by surface electrodes (similar to that used for EEG or EKG) placed on the skin at different places along the nerve path. The distance between the electrodes and the time the pulses take to travel between them are used to calculate the nerve conduction velocity. Each nerve tested will require multiple pulses to provide reliable results. This test is then repeated on other nerves with the final number dependent on the type of problem being evaluated.

How will the test feel?
The small electrical pulses cause a short, mild tingling feeling similar to a static charge. This can sometimes be uncomfortable but lasts less than a second apiece.

What are the risks?
There are essentially no risks for NCS.

Electromyography (EMG)

How is the test performed?
Unlike nerve conduction studies, this test requires that a needle electrode be inserted through the skin into each muscle to be tested as it detects much smaller changes in electrical activity. The electrical activity detected by this electrode is relayed to a recording instrument and displayed on a screen. It may also be heard through a speaker or with headphones.

How will the test feel?
The needle insertion into the muscle is similar in principle to an intramuscular injection or vaccination, but nothing is injected. The needle electrode does not have a hollow core and is therefore smaller, but there is usually some mild discomfort when the electrode is inserted into the relaxed muscle under the skin. Unfortunately, topical or local anesthetics do not reach the muscle and cannot alleviate this discomfort.

After the electrode is placed, the activity of the muscle at rest and when contracted is recorded. This can be uncomfortable and the patient may feel muscle soreness at the site of the needle electrode during the test. After the test, the muscles studied may feel tender for a short time afterwards. Cold compresses during the first 4-6 hours and acetaminophen (ie Tylenol) may be useful in reducing musculoskeletal soreness.

What are the risks?
Risks with an EMG are minimal. There may be some bleeding at the insertion sites. Without proper care, the electrode sites may become infected.

Special precautions
Patients who have a cardiac pacemaker, implantable defibrillator device, transcutaneous nerve stimulator (TENS), a bleeding disorder, a skin infection, or are on blood thinners (anticoagulation) such as warfarin should alert their examiner prior to the study. Patients who are taking mestinon (pyridostigmine) should also inform the examiner before taking the test, as they may need to discontinue this medication temporarily. On the testing day, patients should avoid using skin lotions or creams and ensure that their skin is clean.

When the examination is complete, the examiner will analyze the results and report them to the referring physician. Some findings require extensive analysis and cannot be immediately reported to the patient on the day of the procedure.

Additional Patient Resources