Pain

Trigeminal neuralgia, also called tic douloureux, is a condition that affects the trigeminal nerve (the 5th cranial nerve), one of the largest nerves in the head. The trigeminal nerve is responsible for sending impulses of touch, pain, pressure, and temperature to the brain from the face, jaw, gums, forehead, and around the eyes. Trigeminal neuralgia is characterized by a sudden, severe, electric shock-like or stabbing pain typically felt on one side of the jaw or cheek. The disorder is more common in women than in men and rarely affects anyone younger than 50. The attacks of pain, which generally last several seconds and may be repeated one after the other, may be triggered by talking, brushing teeth, touching the face, chewing, or swallowing. The attacks may come and go throughout the day and last for days, weeks, or months at a time, and then disappear for months or years.

Treatment for trigeminal neuralgia typically includes anticonvulsant medications such as carbamazepine or phenytoin. Baclofen, clonazepam, gabapentin, and valproic acid may also be effective and may be used in combination to achieve pain relief. If medication fails to relieve pain, surgical treatment may be recommended.

SOURCE: National Institute of Neurological Disorders and Stroke

Causalgia, also known as Chronic Regional Pain Syndrome, is another term for Reflex Sympathetic Dystrophy Syndrome, a chronic condition characterized by severe burning pain, pathological changes in bone and skin, excessive sweating, tissue swelling, and extreme sensitivity to touch. The syndrome is a nerve disorder that occurs at the site of an injury (most often to the arms or legs). RSDS is diagnosed primarily through observation of the symptoms. Some physicians use thermography to detect changes in body temperature that are common in RSDS. X-rays may also show changes in the bone.

Injection of a local anesthetic usually the first step in treatment. TENS (transcutaneous electrical stimulation), a procedure in which brief pulses of electricity are applied to nerve endings under the skin, has helped some patients in relieving chronic pain. In some cases, surgical or chemical sympathectomy -- interruption of the affected portion of the sympathetic nervous system -- is necessary to relieve pain. Surgical sympathectomy involves cutting the nerve or nerves, destroying the pain almost instantly, but surgery may also destroy other sensations as well. Good progress can be made if treatment is begun early, ideally within three months of the first symptoms. Early treatment often results in remission.

SOURCE: National Institute of Neurological Disorders and Stroke

While acute pain is a normal sensation triggered in the nervous system to alert you to possible injury and the need to take care of yourself, chronic pain is different. Chronic pain persists. Pain signals keep firing in the nervous system for weeks, months, even years. There may have been an initial mishap -- sprained back, serious infection, or there may be an ongoing cause of pain -- arthritis, cancer, ear infection, but some people suffer chronic pain in the absence of any past injury or evidence of body damage. Many chronic pain conditions affect older adults. Common chronic pain complaints include headache, low back pain, cancer pain, arthritis pain, neurogenic pain (pain resulting from damage to the peripheral nerves or to the central nervous system itself), psychogenic pain (pain not due to past disease or injury or any visible sign of damage inside or outside the nervous system).

Is there any treatment?

Medications, acupuncture, local electrical stimulation, and brain stimulation, as well as surgery, are some treatments for chronic pain. Some physicians use placebos, which in some cases has resulted in a lessening or elimination of pain. Psychotherapy, relaxation and medication therapies, biofeedback, and behavior modification may also be employed to treat chronic pain.

SOURCE: National Institute of Neurological Disorders and Stroke

Failed back syndrome describes patients who have undergone prior spine treatment or surgery, yet continue to experience pain. There can be many causes for failed back syndrome, including surgical nerve damage, scar tissue, inflammation or infection, muscle strain, poor body mechanics, structural problems with the spine, or incorrect initial diagnosis. Patients who suffer from failed back syndrome need a comprehensive evaluation in order to determine the cause of the problem and choose a treatment that effectively alleviates the pain.

Glossopharyngeal Neuralgia is characterized by pain in the throat, the tonsillar region, base of the tongue on one side, and ear, and is usually caused by an abnormal artery pressing against the Glossopharyngeal nerve where it enters into the brain stem. The pain can be triggered by swallowing, coughing, or speaking.

Neuropathic pain

Neuropathic pain is defined as pain resulting from injury to the peripheral or central nervous system. Causes of neuropathic pain may include:

• Trauma
• Ischemia
• Toxicity from alcohol, medications, or other substances
• Diabetes or renal failure
• Hereditary conditions
• Infections
• Immune-related conditions and chronic immune-related neuropathies

Neuropathic pain syndrome is experienced differently from person to person.

Phantom limb pain

Sometimes, when a limb is removed during an amputation, an individual will continue to have an internal sense of the lost limb. This phenomenon is known as phantom limb pain. Similarly, many amputees are frequently aware of severe pain in the absent limb. Their pain is real and is often accompanied by other health problems, such as depression.

What causes this phenomenon? Scientists believe that following amputation, nerve cells "rewire" themselves and continue to receive messages, resulting in a remapping of the brain's circuitry. The brain's ability to restructure itself, to change and adapt following injury, is called plasticity.

Our understanding of phantom pain has improved tremendously in recent years. Investigators previously believed that brain cells affected by amputation simply died off. They attributed sensations of pain at the site of the amputation to irritation of nerves located near the limb stump. Now, using imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI), scientists can actually visualize increased activity in the brain's cortex when an individual feels phantom pain. When study participants move the stump of an amputated limb, neurons in the brain remain dynamic and excitable. Surprisingly, the brain's cells can be stimulated by other body parts, often those located closest to the missing limb.

Treatments for phantom pain may include analgesics, anticonvulsants, and other types of drugs; nerve blocks; electrical stimulation; psychological counseling, biofeedback, hypnosis, and acupuncture; and, in rare instances, surgery.

SOURCE: National Institute of Neurological Disorders and Stroke

Reflex sympathetic dystrophy syndrome (RSDS) - also known as complex regional pain syndrome - is a chronic condition characterized by severe burning pain, pathological changes in bone and skin, excessive sweating, tissue swelling, and extreme sensitivity to touch. The syndrome, which is a variant of a condition known as causalgia, is a nerve disorder that occurs at the site of an injury (most often to the arms or legs). It occurs especially after injuries from high-velocity impacts such as those from bullets or shrapnel. However, it may occur without apparent injury.

The symptoms of RSDS usually occur near the site of an injury, either major or minor, and include: burning pain, muscle spasms, local swelling, increased sweating, softening of bones, joint tenderness or stiffness, restricted or painful movement, and changes in the nails and skin. One visible sign of RSDS near the site of injury is warm, shiny red skin that later becomes cool and bluish. The pain that patients report is out of proportion to the severity of the injury and gets worse, rather than better, over time. It is frequently characterized as a burning, aching, searing pain, which may initially be localized to the site of injury or the area covered by an injured nerve but spreads over time, often involving an entire limb. It can sometimes even involve the opposite extremity. Pain is continuous and may be heightened by emotional stress. Moving or touching the limb is often intolerable. Eventually the joints become stiff from disuse, and the skin, muscles, and bone atrophy.

The symptoms of RSDS vary in severity and duration. However, there are usually three stages associated with RSDS, and each stage is marked by progressive changes in the skin, nails, muscles, joints, ligaments, and bones.

Stage one lasts from 1 to 3 months and is characterized by severe, burning pain at the site of the injury. Muscle spasm, joint stiffness, restricted mobility, rapid hair and nail growth, and vasospasm (a constriction of the blood vessels) that affects color and temperature of the skin can also occur.

In stage two, which lasts from 3 to 6 months, the pain intensifies. Swelling spreads, hair growth diminishes, nails become cracked, brittle, grooved, and spotty, osteoporosis becomes severe and diffuse, joints thicken, and muscles atrophy.

As the patient reaches stage three, changes in the skin and bones become irreversible, and pain becomes unyielding and may now involve the entire limb. There is marked muscle atrophy, severely limited mobility of the affected area, and flexor tendon contractions (contractions of the muscles and tendons that flex the joints). Occasionally the limb is displaced from its normal position, and marked bone softening is more dispersed.

The cause of RSDS is unknown. The syndrome is thought to be the result of damaged nerves of the sympathetic nervous system - the part of the nervous system responsible for controlling the diameter of blood vessels. These damaged nerves send inappropriate signals to the brain, interfering with normal information about sensations, temperature, and blood flow.

Since RSDS is most often caused by trauma to the extremities, other conditions that can bring about RSDS include sprains, fractures, surgery, damage to blood vessels or nerves, and cerebral lesions. The disorder is unique in that it simultaneously affects the nerves, skin, muscles, blood vessels, and bones.

RSDS can strike at any age, but is more common between the ages of 40 and 60. It affects both men and women, but is most frequently seen in women. Although it can occur at any age, the number of RSDS cases among adolescents and young adults is increasing. Investigators estimate that two to five percent of those with peripheral nerve injury and 12 to 21 percent of those with hemiplegia (paralysis of one side of the body) will suffer from RSDS.

RSDS is often misdiagnosed because it remains poorly understood. Diagnosis is complicated by the fact that some patients improve without treatment. A delay in diagnosis and/or treatment for this syndrome can result in severe physical and psychological problems. Early recognition and prompt treatment provide the greatest opportunity for recovery.

RSDS is diagnosed primarily through observation of the symptoms. However, some physicians use thermography - a diagnostic technique for measuring blood flow by determining the variations in heat emitted from the body - to detect changes in body temperature that are common in RSDS. A color-coded "thermogram" of a person in pain often shows an altered blood supply to the painful area, appearing as a different shade (abnormally pale or violet) than the surrounding areas of the corresponding part on the other side of the body. An abnormal thermogram in a patient who complains of pain may lead to a diagnosis of RSDS. X-rays may also show changes in the bone.

Physicians use a variety of drugs to treat RSDS, including corticosteroids, vasodilators, and alpha- or beta-adrenergic-blocking compounds. Elevation of the extremity and physical therapy are also used to treat RSDS. Injection of a local anesthetic, such as lidocaine, is usually the first step in treatment. Injections are repeated as needed. TENS (transcutaneous electrical stimulation), a procedure in which brief pulses of electricity are applied to nerve endings under the skin, has helped some patients in relieving chronic pain.

In some cases, surgical or chemical sympathectomy - interruption of the affected portion of the sympathetic nervous system - is necessary to relieve pain. Surgical sympathectomy involves cutting the nerve or nerves, destroying the pain almost instantly. But surgery may also destroy other sensations as well.

SOURCE: National Institute of Neurological Disorders and Stroke