Neuropathic Pain

Topic Highlights

●    Pain originating from a damaged nerve or nervous system is called neuropathic pain.

●    It is a disease of the peripheral nervous system.

●    Neuropathy may be diffuse, affecting many parts of the body, or focal, affecting a single, specific nerve and part of the body.

●    This visual presentation on neuropathic pain focuses on types of neuropathy, its causes, symptoms, diagnosis, and  treatment.

Transcript

Pain originating from a damaged nerve or nervous system is called neuropathic pain. The pain is often severe and is described as burning. It is a disease of the peripheral nervous system. People with diseases such as diabetes may eventually suffer from nerve damage.

Our body contains a network of peripheral nerves and nerve endings known as nociceptors. Nociceptors are situated directly beneath the skin. They sense unpleasant stimuli such as cuts, burns and pressure on the body. These stimuli are transmitted as electrical impulses via peripheral nerves to the spinal cord, from where they travel up to the brain. The brain interprets these messages as pain and recognizes the location, intensity and danger. Axon is the long fiber-like arm of a neuron or brain cell that carries a message to the next nerve cell. Most axons are covered by a substance called myelin, which aids signal transmission. Damage to the myelin covering results in the transmission of incorrect signals.

Neuropathy may be diffused, affecting many parts of the body; or focal, affecting a single, specific nerve and part of the body.

Diffuse neuropathy may be peripheral affecting the feet and hands or autonomic affecting the internal organs. Peripheral neuropathy affects the peripheral nervous system including nerves in the face, arms, legs, torso, and some nerves in the skull. This often affects people with diabetes and autoimmune diseases such as rheumatoid arthritis and lupus. Certain vitamin deficiencies, some medications and alcoholism may also damage peripheral nerves.

Autonomic neuropathy affects the nerves that serve the internal organs affecting many processes and systems. Most often it affects the organs that control urination and sexual function. Nerve damage impedes bladder control resulting in urinary incontinence. Autonomic neuropathy may affect digestion. Nerve damage can cause gastric stasis, where the stomach empties too slowly. When neuropathy affects the cardiovascular system, people may not experience angina, the pain caused by heart attack. Thus they suffer painless heart attacks and may not receive treatment in time. Autonomic neuropathy can affect the nerves that control sweating. Due to this, regulation of temperature becomes difficult. The patient may experience profuse sweating during the night or while eating.

Focal neuropathy, sometimes known as mononeuropathy, affects a single nerve most often in the wrist, thigh or foot. It may also cause eye problems such as pain behind an eye, inability to focus the eye, and double vision. Focal neuropathy may also cause paralysis on one side of the face known as Bell's palsy and problems with hearing. Sometimes swollen or inflamed tissues can press on the nerve. Carpal tunnel syndrome is an example. Focal neuropathy is unpredictable and occurs most often in older people who have diabetes. Though this kind of neuropathy can be painful, it usually improves after a period of weeks or months without causing long-term damage.

Neuropathic pain may be caused by alcoholism, amputation, back, leg, and hip problems, chemotherapy, diabetes, facial nerve problems, HIV infection or AIDS, multiple sclerosis, shingles and spine surgery.

The symptoms of neuropathy depend on which nerves and what part of the body is affected. The symptoms include burning, tingling, numbness, pressure, squeezing and itching. Symptoms may be constantly present or may be irregular. Patients may experience a burning sensation that makes wearing clothes and walking unbearable. Many patients may not respond to traditional pain treatments.

A doctor will conduct an interview and physical exam. He may ask questions about the pain, its occurrence, and specific triggers that may cause the pain. Tests to diagnose neuropathic pain include Electromyography, nerve conduction tests, nerve biopsy and blood tests.

Anticonvulsant and antidepressant drugs seem to work in some cases. Non-steroidal anti-inflammatory drugs, such as Naproxen or Ibruprofen, may ease pain. If the patient is diabetic proper management of the disease may alleviate the pain. In some cases a stronger painkiller, such as those containing morphine is prescribed.

Some cases may require invasive or implantable device therapies to effectively manage the pain. Electrical stimulation of the nerves involved may significantly control the pain.