What is Complex Regional Pain Syndrome?
Complex regional pain syndrome (CRPS) is a chronic pain condition that most often affects one limb (the arm, leg, hand, or foot) usually after an injury. CRPS is believed to be caused by damage to, or malfunction of, the peripheral and central nervous systems. The central nervous system is composed of the brain and spinal cord; the peripheral nervous system involves nerve signaling from the brain and spinal cord to the rest of the body. CRPS is characterized by prolonged or excessive pain and changes in skin color, temperature, and/or swelling in the affected area.
The Two Types of CRPS: CRPS-I and CRPS-II
Individuals without a confirmed nerve injury are classified as having CRPS-I, also known as reflex sympathetic dystrophy syndrome. CRPS-II, also known as causalgia, is when there is an associated, confirmed nerve injury.
Symptoms of Complex Regional Pain Syndrome
CRPS symptoms vary in severity and duration, although some cases are mild and eventually go away. In more severe cases, individuals may not recover and may have long-term disability.
- Continuous burning or throbbing pain, usually in your arm, leg, hand or foot
- Sensitivity to touch or cold
- Swelling of the painful area
- Changes in skin temperature — alternating between sweaty and cold
- Changes in skin color, ranging from white and mottled to red or blue
- Changes in skin texture, which may become tender, thin or shiny in the affected area
- Changes in hair and nail growth
- Joint stiffness, swelling and damage
- Muscle spasms, tremors, weakness and loss (atrophy)
- Decreased ability to move the affected body part
- Medial complex or neuro origin pain from radiculopathy caused by either foraminal narrowing or neural encroachment from the herniated disc with radiculitis or a chemical radiculitis caused by a leakage of the nucleus pulposous
Causes of Complex Regional Pain Syndrome
The cause of complex regional pain syndrome isn’t completely understood. It’s thought to be caused by an injury to or an abnormality of the peripheral and central nervous systems, as CRPS typically occurs as a result of a trauma or an injury. Complex regional pain syndrome occurs in two types, with similar signs and symptoms, but different causes:
Also known as reflex sympathetic dystrophy syndrome (RSD), this type occurs after an illness or injury that didn’t directly damage the nerves in your affected limb. About 90 percent of people with complex regional pain syndrome have type 1.
Once referred to as causalgia, this type has similar symptoms to type 1. But type 2 complex regional pain syndrome follows a distinct nerve injury.