BRITT TALLEY DANIEL MD
Medical City Dallas
7777 Forest Lane Suite B-220.
GENERAL: This is a term that refers to disease of peripheral nerves. Peripheral refers to the tips of the body—the feet and hands where the illness usually starts. Polyneuropathy means many (poly), diseased (path), nerves (neuro). It is a general term referring to disease of the motor, sensory, and autonomic nerve fibers of the human body. Polyneuropathy refers to a large class of specific diseases that may all cause nerve damage. The word car is a general term, while a four door 1996 Ford Taurus would be a specific type of car. In America the three most common causes of polyneuropathy are Diabetes Mellitus, Alcoholism, and Idiopathic (a general term meaning the cause is unknown.) There are several hundred different specific types of polyneuropathy.
SYMPTOMS: The most common symptoms are numbness, tingling, or an asleep feeling in the feet or hands. The symptoms usually start in the feet and move up the legs, reaching the hands later. The symptoms usually begin distally (at the tips of the limbs—the soles on the feet, or the fingers and palms in the hands) and move proximally (feet to legs, hands to forearms.) There may be burning or aching pain, weakness, cramps, loss of balance, or atrophy (loss of muscle bulk.) For many patients with pain the symptoms are worse later in the day and may significantly disturb sleep.
PHYSICAL FINDINGS: The neurologic exam may reveal decreased deep tendon reflexes—usually starting distally with lost ankle jerks and moving proximally to the knees or arms. There may be gait ataxia (falling on walking heel to toe.) A sensory loss for pin and temperature in a stocking distribution and decreased vibratory perception, usually in the feet, may be found. There may be visible decreased muscle bulk in the small muscles of the feet or hands.
LAB FINDINGS: Diabetics have elevated blood sugars, alcoholics may have no lab abnormalities or elevated liver function tests. There are a number of complicated, esoteric blood tests that can be run to screen for defined types of polyneuropathy. Commonly urine is tested for heavy metals. The main test that is abnormal is the Electromyogram (EMG), an outpatient, mildly painful test which has two parts: 1.The needle exam—requiring the insertion of a small needle in multiple muscles and recording the electrical activity. 2.Nerve Conduction Studies—a test requiring attaching small electrodes over muscles or nerves and delivering a shock to stimulate the nerve. The EMG gives objective evidence of slowing in nerve conduction or damage to muscle fibers from nerve damage. It is considered to be an extension of the neurologic exam and may show changes when the blood work or physical exam are normal. Another test that may be helpful is the Nerve Biopsy. This is another mildly painful outpatient procedure whereby a surgeon removes a branch of a peripheral sensory nerve—the sural nerve which goes to the back of the leg and foot. The tissue is then studied under a microscope, with special chemicals and stains to search for different diseases. This procedure leaves the patient with permanent numbness in the area where the nerve is removed.
TREATMENT: If the nerve damage relates to a treatable disease, then that disease should be treated. For examples, diabetics should maintain tight blood sugar control and work with their endocrinologist, Family Practioner, or Internist. Alcoholics should become completely abstinent and work with their psychiatrist, drug counselor, and AA. The burning, painful symptoms common to many types of Polyneuropathy can sometimes be treated by medication. This is symptomatic treatment like aspirin for a fever. Common drugs that are used here are the Anticonvulsants—gabapentin, or pregabalin Antidepressants—amitriptyline, venlaflaxine, and duloxetine.
General treatment ideas are protecting the feet from ulcers, cuts, or injuries, careful toenail cutting, and wearing comfortable shoes. Gait aids such as a cane or a walker plus physical therapy instruction in gait training may help with imbalance problems.