Complex regional pain syndrome Health Article

Definition

Complex regional pain syndrome (CRPS) is a chronic pain condition that mainly affects the arms and legs.

Alternative Names

CRPS; RSDS; Causalgia - RSD; Shoulder-hand syndrome; Reflex sympathetic dystrophy syndrome; Sudeck's atrophy

Causes, incidence, and risk factors

Complex regional pain syndrome (CRPS) has two forms:

• CRPS 1 is a chronic nerve disorder that occurs most often in the arms or legs after a minor injury.
• CRPS 2 is caused by an injury to the nerve.

The cause of CRPS is not completely understood. It is thought to result from damage to the nervous system, including the nerves that control the blood vessels and sweat glands.

The damaged nerves are no longer able to properly control blood flow, feeling (sensation), and temperature to the affected area. This leads to medical problems in the:

• Blood vessels
• Bones
• Muscles
• Nerves
• Skin

Possible causes of CRPS:

• Injury or infection in an arm or leg
• Heart attack
• Stroke

The condition can sometimes appear without obvious injury to the affected limb.

This condition is more common in people ages 40-60, but it has been seen in younger people too.

Symptoms

In most cases CRPS has three stages. Often, however, CRPS does not follow this pattern. Some people go into the later stages almost right away. Others stay in the first stage.

Stage 1 (lasts 1-3 months):

• Increased nail and hair growth
• Pain that may move farther up or down the affected limb
• Severe burning, aching pain that increases with the slightest touch or breeze
• Skin that becomes dry and thin, changes color
• Swelling with warmth or coolness

Stage 2 (lasts 3-6 months):

• Decreased hair growth
• Noticeable changes in skin texture and color
• Spread of swelling
• Stiff muscles and joints

Stage 3 (irreversible changes can be seen)

• Contractions involving muscles and tendons
• Limited movement in limb
• Pain in the entire limb
• Muscle wasting

Depression or mood changes may occur with these symptoms, especially in stage 3.

Signs and tests

Diagnosing CRPS can be difficult, but early diagnosis is very important. Often, the symptoms are severe compared to the original injury.

The doctor will take a medical history and do a physical examination. Other tests may include:

• A test to show temperature changes and lack of blood supply in the affected limb (thermography)
• Bone scans
• Nerve conduction studies
• X-rays