(mentions CMT) The Many Ills of Peripheral Nerve Damage

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The Many Ills of Peripheral Nerve Damage

http://www.nytimes.com/2009/10/20/health/20brod.html?_r=1

If you have ever slept on an arm and awakened with a " dead " hand, or sat too

long with your legs crossed and had your foot fall asleep, you have some inkling

of what many people with peripheral neuropathy experience day in and day out,

often with no relief in sight.

And numbness and tingling are hardly the worst symptoms of this highly variable

condition, which involves damage to one or more of the myriad nerves outside the

brain and spinal cord. Effects may include disabling pain, stinging, swelling,

burning, itching, muscle weakness, twitching, loss of sensation,

hypersensitivity to touch, lack of coordination, difficulty breathing, digestive

disorders, dizziness, impotence, incontinence, and even paralysis and death.

I realize now that I had a mild, reversible bout of peripheral neuropathy

several decades ago when a misplaced shot of morphine damaged a sensory nerve in

my thigh. It took three years for the nerve to recover, and for much of that

time I could not tolerate anything brushing against my leg.

One of my sons, too, was afflicted when a nerve behind his knee was injured

during a basketball game. He had no feeling or mobility in his foot for nine

months, but after several years the nerve healed and he regained full use of his

foot.

And a good friend was nearly paralyzed, also temporarily, following a flu shot,

by a far more serious form of peripheral neuropathy — an autoimmune affliction

called Guillain-Barré syndrome, in which one's own antibodies attack the myelin

sheath that protects nerves throughout the body.

There are hundreds of forms of peripheral neuropathy. A medical guide describing

them, compiled by a team of neurologists at the behest of the Neuropathy

Association, fills a booklet the size of a two-year wall calendar.

The association, which sponsors research and provides education and support for

patients and families dealing with peripheral neuropathy, estimates that the

disorder afflicts more than 20 million Americans at any given time. If the cause

can be corrected, peripheral nerves can regenerate slowly and patients can

recover, although not always completely.

But many people never recover. They must learn to live with the disorder, with

the help of treatments and devices that can ease their discomfort and

disability. With such a wide array of symptoms and causes, getting a correct

diagnosis is often a challenge. Worse, frustrated patients are sometimes told,

" It's all in your head. "

Causes Behind an Ailment

There are three types of peripheral nerves: sensory nerves, which transmit

sensations like pain, touch, heat and cold; motor nerves, which control the

action of muscles throughout the body; and autonomic nerves, which regulate

functions that are not under conscious control, like blood pressure, digestion

and heart rate. Symptoms of neuropathy depend on what nerves are involved.

Someone with damaged sensory nerves might not feel heat, for example, and could

be scalded by an overly hot bath. Neuropathy of the motor nerves can result in

weakness, lack of coordination or paralysis; neuropathy of the autonomic nerves

can lead to high blood pressure, irregular heart rate, diarrhea or constipation,

impotence and incontinence.

The list of possible causes of neuropathy is far too long for this column. They

include inherited conditions like Charcot-Marie-Tooth disease; infections or

inflammatory disorders like hepatitis, Lyme disease, AIDS, rheumatoid arthritis

and lupus; organ diseases like diabetes, hypothyroidism and kidney disease;

exposure to toxic substances like industrial solvents, heavy metals, sniffed

glue and some cancer drugs; trauma to or pressure on a nerve from an injury,

cast, crutches, abnormal body position, repetitive motion (as in carpal tunnel

syndrome), tumor or abnormal bone growth; alcoholism; and deficiency of vitamin

B12.

The most common cause, accounting for nearly a third of neuropathy cases, is

diabetes, especially among those whose blood sugar levels are poorly controlled.

Half of all people with diabetes eventually begin to lose sensation and develop

pain and sometimes weakness in their feet and hands. In people with diabetes,

even minor injuries to the feet, if not quickly and properly treated, can result

in gangrene and amputations.

In nearly a third of cases, no cause is ever found, leaving patients with no

other recourse than treatment of their symptoms.

Suspected cases are best referred to a neurologist, who should begin by taking a

complete personal and family medical history and performing a physical and

neurological examination, checking on reflexes, muscle strength and tone,

sensations, balance and coordination.

A complete workup is likely to include blood tests, urinalysis, a nerve

conduction study and electronic measurements of muscle activity. Imaging

studies, like a CT scan or an M.R.I., may reveal a tumor, vertebral damage or

abnormal bone growth. In some cases, a nerve or muscle biopsy may be done.

Relief and Restoration

If the underlying cause cannot be corrected, the goals of treatment are relief

of symptoms and restoration of lost functions. Pain control is paramount.

Effective relief may come from over-the-counter remedies or a lidocaine patch

but sometimes requires prescribed opiates.

Many with neuropathic pain have benefited from drugs licensed for other uses,

including antiseizure medications like gabapentin, topiramate (Topamax) and

pregabalin (Lyrica) and antidepressants like the tricyclic amitriptyline and the

selective serotonin and norepinephrine reuptake inhibitor duloxetine

(Cymbalta).Vitamin B12 deficiency can be treated with supplements and fortified

cereals or by judicious consumption of meats, poultry, fish, eggs and dairy

products.

And since alcohol and tobacco are particularly risky for people with neuropathy,

or a health problem that predisposes them to it, they have every reason to quit

smoking and to drink only in moderation.

Many patients are helped by physical therapy, occupational therapy and devices

like braces, splints and wheelchairs. Railings on stairways and in the bathroom,

elimination of tripping hazards like scatter rugs, and improved lighting

(including night-lights) can reduce the risk of falls. For those insensitive to

heat, a thermometer should be used to test water in a tub, shower or sink.

Orthopedic shoes are invaluable to patients with lost sensitivity in their feet

or impaired balance.

A variety of mechanical aids can make it easier to live with peripheral

neuropathy, among them kitchen tools made by Oxo. Those with digestive problems

might try eating small frequent meals and sleeping with their heads elevated.

Other helpful sources include the book " Peripheral Neuropathy: When the

Numbness, Weakness and Pain Won't Stop " (Demos Health, 2006), by Dr. Norman

Latov, professor of neurology and neuroscience at Weill Cornell Medical College;

and the Neuropathy Association, 60 East 42nd Street, Suite 942, New York, N.Y.

10165-0930 (800-247-6968, or online at www.neuropathy.org). The association

maintains a list of support groups and of centers that specialize in diagnosing

and treating neuropathy.