NEUROPATHIC PAIN GLOSSARY

1. Disease: Many diseases can cause neuropathic pain, but 30% of cases are due to diabetes. Other diseases include complex regional pain syndrome, central pain syndrome, facial nerve problems (such as trigeminal neuralgia or geniculate neuralgia), Parkinson’s disease, multiple sclerosis, fibromyalgia, Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, vasculitis, connective tissue disorders, an underactive thyroid (hypothyroidism), kidney disease, liver disease, multiple myeloma, alcoholism, forms of cancer, and more.
2. Injury: Even after an injury heals, damage to the nervous system can remain. Spinal injuries such as herniated discs and spinal cord compression can damage nerves around the spine as well. Iatrogenic injuries—which occur when nerves are cut during surgical procedures either intentionally or unintentionally—are one of the leading causes of chronic neuropathic pain. Postoperative neuropathic pain (PONP) is another form of injury that can develop if nerves were damaged during a surgery.
3. Infection: Shingles, Lyme disease, syphilis, Epstein-Barr virus, hepatitis B and C, leprosy, diphtheria, and HIV or AIDS can trigger neuropathic pain.
4. Limb loss: Phantom limb syndrome can take place after a limb or appendage is amputated. The nerves near the amputation send incorrect signals to the brain, making it feel as though the missing limb is in pain.

Neuropathic pain symptoms

—Shooting, burning, or stabbing pain

—Tingling, numbness, “pins and needles”

—Spontaneous pain occurring without a trigger

—Pain caused by typically non-painful events such as brushing against something, being in cold temperatures, or combing your hair

—Unpleasant or abnormal sensations

—Muscle weakness, lack of coordination, and falling

—Difficulty sleeping

Neuropathic pain conditions featured in this issue

Complex regional pain syndrome (CRPS) typically develops after an injury, surgery, stroke, or heart attack. It is characterized by prolonged pain that is out of proportion to the initial injury’s severity. It causes burning or throbbing pain, sensitivity to touch or cold, swelling, decreased ability to move the affected body part, changes in skin temperature, color, or texture, and more. CRPS was previously called reflex sympathetic dystrophy (RSD) or causalgia.

Diabetic neuropathy is nerve damage caused by injury to the nerves from high blood sugar or glucose in individuals with diabetes. It most often affects nerves in the legs and feet, as well as the hands. Diabetic neuropathy can affect as many as half of people living with diabetes. It can cause numbness, pain, and inability to feel temperature changes. Diabetic nerve damage can cause injuries to go unchecked until they are severe enough to require amputation.

Geniculate neuralgia is caused by damage to a small nerve near the ear. It causes pain in the ear, often sharp or stabbing but sometimes dull or burning. It also can cause facial pain.

Idiopathic neuropathy describes neuropathic pain that has no obvious cause. Individuals may experience numbness, pain, weakness, or difficulty walking. The condition may also affect the autonomic nervous system, causing nausea, vomiting, digestive problems, abnormal sweating, or sexual dysfunction.

Phantom limb pain/phantom pain describes pain that feels as though it is coming from a limb or appendage that has been removed either in a surgery or accident. The pain is believed to be caused by the brain continuing to receive pain signals associated with the missing body part.

Postsurgical or postoperative neuropathic pain develops when nerves are damaged during a surgery. The nerve damage changes the signals sent to the brain, causing long-term pain. It may manifest as stabbing or shooting pain, and individuals with this type of neuropathic pain are often either very sensitive to touch in that area, or have reduced sensation in that area.

Pudendal neuralgia is long-term pelvic pain originating from damage to the pudendal nerve, a major nerve in the pelvic area. This condition causes pain that can appear in the buttocks, perineum, anus, vulva, labia, clitoris, scrotum, or penis. Pudendal neuralgia can cause pain during sex and incontinence.

Trigeminal neuralgia causes neuropathic pain in the face, often manifesting as a sharp or electric shock-like pain. Mild stimulation, such as brushing your hair or teeth or putting on makeup, can trigger severe pain. Cold temperatures or wind can cause a painful attack as well.

Experts’ neuropathic pain analogies

Steven Richeimer, MD, Chief, Division of Pain Medicine at University of South California, explains the two types of pain using a car alarm analogy. “When the car alarm is going off because somebody jimmied the lock or there’s a broken window, that’s nociceptive pain [pain caused by direct damage to the body’s tissue, muscles, bones, or skin]: The alarm system’s doing what it should do because there’s damage happening to the car or body. But if you inspect your car and there’s nothing wrong, nothing has jostled it, no cat prints on the hood, no broken windows, but the alarm is going off, there’s something wrong with the alarm system. That’s neuropathic pain.”

Peter Abaci, MD, a pain specialist with IPM Medical Group, a California practice that focuses on the management of chronic pain, likens neuropathic pain to a computer virus. “Regardless of what type of neuropathic pain a patient may have, it typically impacts the physical body and it also impacts the wiring of the brain. So it’s kind of like your computer gets rewired, and then the way the body functions gets thrown out of whack. So to get things working better and feeling better and functioning better, it often takes a more comprehensive and integrated approach to address all the things that are impacted by the issue.”