Itching pain, cold pain, burning pain, spontaneous pain, or pain induced by a gentle breeze or touch. Dizziness, poor balance –especially in the dark. Weak limbs. Even paralysis.
These are all hallmarks of peripheral neuropathy, of which more than 100 types have been identified.
Half of all neuropathies (nerve damage) are classified as "peripheral neuropathies," according to Mazen Dimachkie, M.D., associate professor of neurology.
"With peripheral neuropathies the patient usually experiences symptoms in the foot because the longest nerves are affected first, and then the pain, numbness, or weakness can transfer to the legs and hands," explains Dr. Dimachkie, director of the UT Neuromuscular Disease Program and the Memorial Hermann Electromyography Laboratory.
"There are more than 100 causes of peripheral neuropathies, and we have to determine the cause in order to properly treat each patient," Dr. Dimachkie explains.
When patients first come to the UT Physicians Neurology Clinic with nerve pain or damage, the neuromuscular specialist clinical evaluation eliminates the majority of these causes and refocuses the laboratory testing on the 10 or so more likely causes that are specific to each individual patient.
Specialized testing comes in the form of a nerve conducting test and electromyogram (EMG), during which nerves are electrically stimulated to measure their response, and muscle signals are analyzed with a needle electrode. Some patients may need a biopsy of the nerve, which is most commonly taken to look for inflammation.
An EMG was the first course of action for patient Farid Bishara, who had such pain in his legs that he couldn't sit still.
"When he first came to see me in January 2004, his pain was excruciating," Dr. Dimachkie recalls. "He was writhing in a pain that he described as shooting and burning, in addition to diffuse arm and leg weakness."
Testing determined that Bishara had chronic inflammatory demyelinating polyneuropathy, or CIDP. CIDP, an autoimmune disease, is caused by damage to the covering sheath, or myelin, of the peripheral nerves. There are two types of CIDP – chronic progressive (the more common variety) and relapsing remitting, Bishara's type.
"He was in a wheelchair for three months and was admitted to TIRR for rehabilitation," explains his wife, Julia. "He has willpower and started walking again."
In addition to physical therapy, Bishara was treated with intravenous immunoglobulin, antibodies from pooled blood donors.
"He did remarkably well with his treatment," Dr. Dimachkie says. "But because it is the relapsing form, it may return."
Bishara did notice an increase in pain over the last month and returned to Dr. Dimachkie for treatment.
"He is still pretty functional but he and his wife are suspicious of a relapse of his disease, and so am I," Dr. Dimachkie says.
Some peripheral neuropathies are associated with cancer, such as lung cancer and multiple myloma, and the nerve damage is the presenting sign. Others can be from a toxic exposure from heavy alcohol consumption, chemotherapy for cancer, or high dose vitamin B6, or an inherited genetic form of the disease. The most common cause that can be pinpointed is diabetes.
"With the growing increase of diabetes and obesity, the incidence of peripheral neuropathy is increasing," Dr. Dimachkie says.
The treatment for peripheral neuropathy depends on the type – for the CIDP type, steroids, intravenous gammaglobulins, and plasmapheresis, which washes the blood, can help.
Antidepressants, antiepileptics, and pain modulating drugs also can help manage the pain of peripheral neuropathy. Physical and occupational therapy with balance training are also quite beneficial.
The neuromuscular group of the UT Neurology Clinic, which is headed up by Dr. Dimachkie, includes Parveen Athar, M.D., and pediatric neurologists Pedro Mancias, M.D., and Ian Butler, M.D. The clinicians also work in tandem with neuropathologists Sozo Papasozomenos, M.D., and Min Wang, M.D.
For more information, or to refer a patient, call 1.877.4UT.DOCS (1.877.488.3627).
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