Complex regional pain syndrome (CRPS)
CRPS—also called reflex sympathetic dystrophy (RSD)—is the term used for a condition that involves persistent pain in one or more limbs with some specific features.
The pain is generally persistent and may be described in various ways including burning, tingling, shooting, "pins-and-needles" or "strange". In the majority of children and adolescents, the pain begins after some triggering events such as a fracture, a sprain, some other type of injury or surgery, but this is not always the case. Some pain is normal after injuries and surgery, but in most people, the pain gradually improves over a period of days to weeks.
In patients who develop CRPS/RSD, the pain may become more severe and may last for a longer time than expected for most people having a similar injury or a similar type of surgery. The distribution of the pain is variable, but often involves the foot and ankle, the knee, the hand, the forearm, the elbow or the shoulder. Often, the pain involves an area similar to that normally covered by a stocking or a glove.
A common feature is that even light touch of the skin can be painful - the term for this is allodynia. Other patients can tolerate light touch, but find it unusually painful to apply mild pressure or tapping over the tissues under the skin, and many who have involvement in their legs find it painful to bear weight or walk. Some patients become very hypersensitive to cold or heat exposure.
Abnormal Appearance and Function of the Limb
Along with this unusual and persistent pattern of pain, CRPS/RSD also involves a number of related problems related to circulation, temperature, changes in tissues and muscle movements.
Circulation The skin may be discolored, often either blue, red, pale or have a blotchy appearance known as "mottling". The skin may be either unusually cold or warm to touch, and different in temperature compared to similar sites on the opposite limb. The skin may also appear thin or shiny.
Swelling There may be mild or severe swelling in the limb. The pattern of this swelling is different from that seen when a specific joint is inflamed.
Tissue changes Some patients show increased or decreased hair growth or abnormal growth of their toenails or fingernails. Some patients show signs of loss of calcium from the bones in the affected limb. If patients don't use their limb for a period of time, they may lose muscle mass or develop stiff joints and tendons.
Some Features of CRPS/RSD in Children and Adolescents
CRPS/RSD is uncommon before age 6 or 7; it becomes more common around age 9 or 10.
CRPS/RSD affects girls much more often than boys.
In children, the legs are affected much more often than the arms.
Overall, the prognosis is very good. The great majority of children and adolescents will recover very well from CRPS/RSD and they are able to resume a full range of normal activities.
CRPS/RSD is a unique condition because the main treatment for it is to move the painful leg or arm. A large number of studies have confirmed that vigorous exercise and use of the leg or arm can improve function and reduce pain in most children and adolescents.