What is amplified musculoskeletal pain syndrome?

Amplified musculoskeletal pain syndrome (AMPS) is a condition in which a person has pain that seems to be more intense (amplified) than “normal” pain. Other terms for this condition include complex regional pain syndrome (CRPS), juvenile fibromyalgia, diffuse idiopathic pain and localized idiopathic pain.

Although AMPS can afflict anyone, it can be especially difficult for children, for whom the pain may be stronger. The pain can affect the child’s quality of life and may keep him or her from fully functioning in school or sports, or enjoying activities with friends.

What causes amplified musculoskeletal pain syndrome in children?

The initial cause of AMPS is often an injury or illness that causes pain, such as breaking a bone, straining/pulling a muscle, or a soft tissue injury such as a burn or cut.

In AMPS, there can be an interruption or short circuit in the usual path that pain takes after an injury. Pain normally travels from the site of the injury, through the spinal cord, and up to the brain. In a child who has AMPS, this route is interrupted and the pain signal goes to the autonomic nerves, which control involuntary movements such as breathing.

When the pain reaches the autonomic nerves, they react by constricting (tightening) the blood vessels, which cuts off the flow of blood to these parts of the body. At the same time, there is a buildup of the waste product lactic acid, which is produced when there is a lack of oxygen. These factors combine to cause pain that is more intense (amplified).

What are the symptoms of amplified musculoskeletal pain syndrome?

The main symptom of AMPS is pain, which is either constant or comes and goes. The symptoms may occur right after an illness or injury, or weeks later. The pain can also occur without significant injury.

The pain may be spread throughout the body, or may be concentrated in a particular area (for example, the arm or the leg). The pain can feel like burning or may feel sharp (“needles and pins”).

Other symptoms of AMPS include:

• Allodynia (the skin in the affected area is very sensitive to touch)
• Changes to the skin, including color, temperature and texture
• Edema (swelling)
• Changes to hair in the area
• Problems with movement, including stiffness, tremors and coordination

How is amplified musculoskeletal pain syndrome in children diagnosed?

Because pain is a symptom of many diseases and conditions, diagnosing AMPS can be difficult. The doctor must evaluate the cause(s) of the pain, and eliminate other possible diseases and conditions.

There is no blood test for AMPS. To arrive a diagnosis, the doctor will take the child’s complete medical and family history, including any earlier illnesses or injuries. The doctor will also want to get a sense of the child’s emotional state, especially any instances of mental illness, family dysfunction, or incidents at the child’s school that might cause psychological stress and contribute to the child’s pain.

How is amplified musculoskeletal pain syndrome in children treated?

Depending on the child’s level of pain and ability to function, the treatment is usually a team approach. The team has several specialists, including:

• Doctors
• Nurses
• Physical and occupational therapists
• Child psychologists
• Music therapists
• Recreational therapists

Treatment can last several weeks and involve the following interventions:

• Exercise (strengthening and aerobic) to keep the body moving and improve the child’s flexibility and functioning
• Physical therapy and occupational therapy
• Selected medications
• Psychological counseling to address any stresses or emotional problems the child may be having, such as anxiety, depression or an eating disorder, in addition to learning to function with pain
• Music therapy to help the child relax
• Wellness treatments, including biofeedback, meditation, mind-body skills
• Desensitization (applying pressure to sensitive areas on the body to allow the patient to “break through” the pain and get used to stronger and stronger pressure)

What is the prognosis (outlook) for children who have amplified musculoskeletal pain syndrome?

AMPS is a chronic (long-term) condition, so the outlook depends on the child and the treatments. In the vast majority of cases (up to 85%), children who undergo intensive treatment make a complete recovery.