Amplified musculoskeletal pain syndrome (AMPS) is a condition that occurs when severe, chronic musculoskeletal pain is present without a clear physical cause such as injury or inflammation. Children and adults with AMPS may have pain all the time or may find harmless stimuli (such as touch or light pressure) painful. AMPS can be diffuse (affecting the entire body) or localized (affecting a single part of the body.)
AMPS that is associated with widespread or total body pain may sometimes referred to by any of these terms:
AMPS affecting specific parts of the body may be referred to as:
While diffuse AMPS and fibromyalgia are similar, AMPS is more commonly used to describe total body pain in children, while fibromyalgia is more commonly used in adults. The terms juvenile fibromyalgia and childhood fibromyalgia are also used in children. Patients with diffuse AMPS may or may not have other symptoms in addition to pain, while fibromyalgia implies the presence of other symptoms including anxiety, fatigue, headaches, and gastrointestinal complaints.
Complex regional pain syndrome (CRPS) and reflex sympathetic dystrophy (RSD) are terms used to describe a localized form of amplified musculoskeletal pain syndrome. Children and adults with localized amplified pain typically have pain and increased sensitivity to touch in one or more limbs, although any part of the body may be involved, and the pain may move from one area to another. Some people with CRPS/RSD also have coolness or color change of the affected area.
People with AMPS do not have an underlying autoimmune, inflammatory or mechanical condition that causes their pain. Though an injury may trigger AMPS, by definition, in a child with AMPS, this pain persists after the injury heals, or is out of proportion to the expected degree of discomfort. Though AMPS itself is not an autoimmune disease, children with autoimmune diseases such as juvenile idiopathic arthritis or lupus may develop AMPS, where they have pain that is more severe than may be expected with their disease.
Pain amplification is more common in teenagers than in younger children. Girls are more affected than boys, and kids and teens who experience anxiety or depression are more likely to develop amplified pain.
Adults can develop both diffuse and localized amplified pain. Diffuse amplified pain in adults is typically called fibromyalgia and is often associated with other symptoms including anxiety, fatigue, headaches, and gastrointestinal complaints. Localized amplified pain in adults is typically referred to as complex regional pain syndrome (CRPS).
Children with AMPS do not have obvious physical symptoms such joint swelling, fevers or rashes.
Children may complain of pain in one specific region, such as a limb (localized AMPS), or they may have generalized pain in the muscles, joints and bones throughout the body (diffuse AMPS).
If the pain is localized to an arm or leg, the child may experience color and temperature changes in the affected areas. These are known as “autonomic changes.” Many children also experience “allodynia,” an abnormal sensation of pain caused by light touch.
There can be additional symptoms, however, these can also be caused by many other, unrelated conditions. These include:
Though there is no clear indication that AMPS symptoms are affected by any particular dietary modification, some patients may find that they feel better when not eating certain foods. As long as a healthy, well-balanced diet is maintained, it is reasonable to avoid foods that worsen symptoms.
The diagnosis is largely based on a thorough review of the patient's medical history, including both physical symptoms and psychological or emotional concerns. A physical exam may identify specific locations of pain, allodynia and autonomic changes, but there will be no signs of joint inflammation. A doctor may order labs or imaging to rule out other causes of pain; however, it is important to note that over-medicalization in the form of unnecessary testing may actually worsen AMPS symptoms. Therefore, if the history and physical exam are very consistent with AMPS, no further testing is required for diagnosis.
The goal of treatment is to break the pain cycle so that the child can resume a normal life. A multidisciplinary approach is taken, including:
Eliminating some medications and teaching the child techniques to improve sleep can also help.
Amplified pain should never be treated with opioids or other strong painkillers, as these medications may be addictive, and do not treat the underlying cause of the pain. In rare cases, the taking of opioids could actually heighten a patient's pain issues by causing hyperalgesia.