Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
An electromyogram (EMG) is a test that is used to record the electrical activity of muscles.
When muscles are active, they produce an electrical current. This current is usually
proportional to the level of the muscle activity. An EMG is also referred to as a myogram.
EMGs can be used to detect abnormal electrical activity of muscle that can occur in many
diseases and conditions, including muscular dystrophy, inflammation of muscles, pinched nerves,
peripheral nerve damage (damage to nerves in the arms and legs),
amyotrophic lateral sclerosis
(ALS), myasthenia gravis,
disc herniation,
and others.
Why is an EMG test done?
An EMG is often performed when patients have unexplained muscle weakness. The EMG helps to
distinguish between muscle conditions in which the problem begins in the muscle and muscle
weakness due to nerve disorders. The EMG can also be used to detect true weakness, as opposed to
weakness from reduced use because of pain or lack of motivation. EMGs can also
be used to isolate the level of nerve irritation or injury.
How is an intramuscular EMG done?
A needle is inserted through the skin into the muscle. The electrical activity is detected by
this needle (which serves as an electrode). The activity is displayed visually on an
oscilloscope and may also be detected audibly with a speaker.
Since skeletal muscles are often large, several needle electrodes may need to be placed at
various locations to obtain an informative EMG.
After placement of the electrode(s), the patient may be asked to contract the muscle (for
example, to bend the leg).
The presence,
size, and shape of the wave form (the action potential) produced on the
oscilloscope provide information about the ability of the muscle to respond to
nervous stimulation. Each muscle fiber that contracts produces an action potential. The size of
the muscle fiber affects the rate (how frequently an action potential occurs) and the size
(the amplitude) of the action potential.
Sciatica pain, caused by irritation of the sciatic nerve, typically radiates from the low back to behind the thigh to below the knee. Disc herniation is usually the cause of sciatica. Medication to alleviate pain, physical therapy, and bed rest are treatments for sciatica.
There are many causes of back pain. Pain in the low back can relate to the bony lumbar spine, discs between the vertebrae, ligaments around the spine and discs, spinal cord and nerves, muscles of the low back, internal organs of the pelvis and abdomen, and the skin covering the lumbar area.
A pinched nerve can be caused of a variety of conditions, for example, carpal tunnel syndrome, herniated disc, sciatica, arthritis, spinal stenosis, trauma, and more. Common symptoms of a pinched nerve include pain, numbness, tingling, and weakness. Treatment of a pinched nerve depends on the cause of the pinched nerve.
Muscle spasms are involuntary muscle contractions that come on suddenly and are usually quite painful. Dehydration, doing strenuous exercise in a hot environment, prolonged muscle use, and certain diseases of the nervous system may cause muscle spasms. Symptoms and signs of a muscle spasm include an acute onset of pain and a possible bulge seen or felt beneath the skin where the muscle is located. Gently stretching the muscle usually resolves a muscle spasm.
Neck pain (cervical pain) may be caused by any number of disorders and diseases. Tenderness is another symptom of neck pain. Though treatment for neck pain really depends upon the cause, treatment typically may involve heat/ice application, traction, physical therapy, cortisone injection, topical anesthetic creams, and muscle relaxants.
Carpal tunnel syndrome is a condition in which irritation of the wrist's median nerve causes tingling and numbness of the thumb, index, and the middle fingers. This condition is known as tarsal tunnel syndrome in the ankles and feet. Treatment of carpal tunnel syndrome depends on the severity of the symptoms and the nature of any disease that might be causing the symptoms.
A herniated disc may be caused by injury or degeneration from age. Symptoms depend on the location of the herniation and whether nerve tissue is being irritated. An MRI or CT scan is performed to diagnose a herniated disc. Treatment may involve physical therapy, cortisone injection, pain medications, antiinflammatory medications, muscle relaxants, and surgery.
Myasthenia gravis, a chronic autoimmune neuromuscular disease. Varying degrees of weakness of the voluntary muscles of the body are the main characteristics. A defect in the transmission of nerve impulses ot the muscles is the cause of myasthenia gravis. Symptoms include weakness of th eye muscles, facial expression, and difficulty swallowing. Treatment of myasthenia gravis are medical therapies to control the symptoms of the disease.
Degenerative disc disease makes the disc more susceptible to herniation (rupture) which can lead to localized or radiating pain. The pain from degenerative disc or joint disease of the spine is usually treated conservatively with intermittent heat, rest, rehabilitative exercises and medications to relieve pain, muscle spasm and inflammation.
Botulism is an illness caused by a neurotoxin produced by the bacterium Clostridium botulinum. There are three types of botulism: food-borne, wound, and infant. Symptoms include muscle paralysis, dry mouth, constipation, slurred speech, and blurred vision. If food-borne and wound botulism are detected early enough, they may be treated with an antitoxin. Infant botulism is treated intravenously with BabyBIG (Botulism Immune Globulin).
Radiculopathy, a condition in which a nerve or nerves along the spine are compressed causing pain, numbness, weakenss, and tingling along the nerve(s). Some causes of radiculopathy include bone spurs, disc hernation, osteoarthritis, tumors, infection, and neuropathy. Treatment depends on the are of nerve compression. Surgery is generally not required.
Polymyositis is a disease of the muscle featuring inflammation of the muscle fibers. It results in weakness of the muscles which can be severe and when associated with skin rash, is referred to as dermatomyositis. Although the cause of this disease is unknown, diagnosis includes physical examination of muscle strength, blood tests for muscle enzymes, electrical tests of muscle and nerves, and conformation by a muscle biopsy. Treatment of Polymyositis and Dermatomyositis includes high doses of cortisone-related medications, immune suppression, and physical therapy.
Thoracic Outlet Syndrome is a condition where symptoms are produced from compression of nerves or blood vessels because the passageway through the neck and armpit is inadequate. Symptoms of thoracic outlet syndrome include neck, shoulder and arm pain, and numbness or impaired circulation to the extremities.
There are many types of urinary incontinence (UI), which is the accidental leakage of urine. These types include stress incontinence, urge incontinence, and overflow incontinence. Urinary incontinence in men may be caused by prostate or nerve problems. Treatment depends upon the type and severity of the UI and the patient's lifestyle.
Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease) is a neurological disease that progresses rapidly. The disease attacks the nerve cells responsible for the control of voluntary muscles. Early symptoms include cramping, twitching, or stiffness of the muscles; slurred nasal speech; difficulty swallowing or chewing, and muscle weakness in an arm or leg. Currently, the cause of ALS is not known. ALS is a fatal disease. No cure has been found for ALS, however, the drug riluzole (Rilutek) is FDA approved, and this drug reduces the damage to motor neurons by decreasing the release of glutamate.
Dystonia disorders cause involuntary movements and prolonged muscle contraction, resulting in twisting body motions, tremor, and abnormal posture. There are many forms of dystonia. Some types of dystonia respond to dopamine, or can be controlled with dedative-type medications, or surgery.
Cauda equina syndrome is a medical emergency condition that is caused by the uncommon compression of the nerves at the end of the spinal cord. Symptoms of cauda equina syndrome include lower back pain, tingling and/or numbness in the buttocks and lower extremities, bowel or bladder incontinence, and weakness in the legs. Causes of cauda equina syndrome include herniated discs, hematomas, or infection. Treatment is generally prompt surgery.
Charcot-Marie-Tooth disease is one of the most common inherited neurological disorders. Charcot-Marie-Tooth disease affects the peripheral nerves. Symptoms include weakness of the lower leg muscles and foot, foot drop, foot deformities, etc. There are several forms of Charcot-Marie-Tooth disease. Inherited gene mutations are the cause of Charcot-Marie-Tooth disease. There is no cure for Charcot-Marie-Tooth disease; however, therapeutical measures and mild exercise may help symptoms.
A nerve problem might affect your bladder control if the nerves that are supposed to carry messages between the brain and the bladder do not work properly. Such problems include urine retention, poor control of sphincter muscles, and overactive bladder. Treatment depends upon the cause of the nerve damage and resulting type of bladder control problem.
A nerve conduction velocity test (NCV) is an electrical
test that is used to determine the adequacy of the conduction of the nerve
impulse as it courses down a nerve. This test is used to detect signs of nerve
injury.
In this test, the nerve is electrically stimulated, and
the electrical impulse 'down stream' from the stimulus is measured. This is
usually done with surface patch electrodes (they are similar to those used for
an electrocardiogram) that are placed on the skin over the nerve at various
locations. One electrode stimulates the nerve with a very mild electrical
impulse. The resulting electrical activity is recorded by the other electrodes.
The distance between electrodes and the time it takes for electrical impulses to
travel between electrodes are used to calculate the speed of impulse
transmission (nerve conduction velocity). A decreased speed of transmission
indicates nerve disease. ...
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