What is polyneuropathy?

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What is polyneuropathy?

Polyneuropathy refers to any illness that attacks numerous nerves in the

body, sometimes causing weakness and/or pain. Although the nerve can be inflamed

as in neuritis or painful as in neuralgia, polyneuropathy tends to be a systemic

problem that affects more than one nerve group at a time.

Polyneuropathies are relatively symmetric, often affecting sensory, motor,

and vasomotor fibers simultaneously. They may affect the axon cylinder or the

myelin sheath and, in either form, may be acute (e.g., Guillain-Barré syndrome)

or chronic (e.g., renal failure). Polyneuropathy due to metabolic disorders

(e.g., diabetes mellitus) or renal failure develops slowly, often over months or

years. Often, the same nerves are affected symmetrically, on both sides of the

body, usually in the legs or the arms. Polyneuropathy also tends to be a slowly

progressing, chronic type of disease. It often begins in the legs with tingling,

numbness and an increased sensitivity to touch. Burning pains are typically

worse at night. In more advanced cases, the skin tissue becomes unhealthy and

shiny, and ulcers form.

Nutritional polyneuropathy is common among alcoholics and the

malnourished. A primary axonopathy may lead to secondary demyelination and

axonal destruction in the longest and largest nerves. Nutritional deficiencies

in a number of the B vitamins, especially B1, B12 and folic acid, will cause

polyneuropathy. These deficiencies are usually due to poor diet or digestive

problems that hinder the absorption of nutrients. In other cases, long-term use

of medications will lead to nutrient imbalances. Alcoholism will also deplete

the B vitamins.

Acute polyneuropathy (for example, Guillain-Barré syndrome) begins

suddenly in both legs and progresses upward to the arms. Symptoms include

weakness and a pins-and-needles sensation or loss of sensation. In the most

common form of chronic polyneuropathy, only sensation is affected.

Polyneuropathy often affects the nerves of the autonomic nervous system, which

controls involuntary functions in the body (such as blood pressure, heart rate,

digestion, salivation, and urination).