What is pain amplification syndrome?
Pain amplification syndrome is a condition (not a disease) in which patients develop an abnormal pain sensitivity. The nervous system registers and processes normal sensations from movement and environmental experience as pain signals. Think of the nervous system as an electronic sensor: The sensor has a detection threshold. All signals with an intensity level below the threshold are perceived as “normal” and all signals above the threshold are “pain.” In children with pain amplification syndrome, the threshold is too low. Normal sensations and movements cause the nervous system to experience pain.
What are the causes?
We need to understand much more about what causes pain syndromes, experience over time with many patients with this condition reveals some common triggers. Joint flexibility is the most common cause of musculoskeletal pain in children, and is often responsible for what is known as “growing pains.” Patients with pain amplification syndrome often have flexible joints and have previously experienced joint and muscle discomfort. Some patients have had numerous orthopedic injuries in the past, or a particular traumatic injury that causes pain sensitivity in one part of the body.
In some patients, emotional trauma, psychological difficulties or psychiatric conditions can trigger pain sensitivity. In most patients, sleep is affected and is not restful. Even when psychological factors are not an initial cause, the stress from experiencing pain and the resulting disruption in school and activities can amplify pain sensitivity. We don’t know enough about the genetics of pain perception, but children with pain amplification syndrome commonly have family members with pain difficulties.
What are the symptoms?
Symptoms include body aches, joint and muscle pain, abnormal sensations of burning, tingling, numbness or pressure, headache, and chronic abdominal pain. In some cases, light touch to the skin causes pain sensations. Accompanying features include “dysautonomia,” wherein the autonomic nervous system does not perfectly regulate blood flow throughout the body. This results in symptoms of Raynaud’s phenomenon (cold sensitivity of the hands and feet with color changes, numbness, tingling and burning) and dizziness, particularly when standing up. These symptoms are not dangerous but can be uncomfortable and worrisome to patients.
What are the treatments?
A number of therapies work together to reset the abnormal pain sensitivity. Physical activity, particularly aerobic exercise, is very important in normalizing the pain threshold. Therapeutic massage can desensitize the nervous system and help the patient feel touch and movement as normal and not painful. Developing a regular, restful sleep schedule is important.
Finally, psychological therapy is often a critical aspect of the therapeutic program. This therapy is focused on stress management and coping techniques. In some cases, medications that decrease nerve signal transmission can be used. These medical treatments only assist the other therapies and are generally not effective in children when used alone.
What kind of testing is involved?
No laboratory or imaging tests can confirm the diagnosis of pain amplification syndrome. The diagnosis can be difficult to establish because numerous other medical conditions could potentially cause the symptoms. It’s important to take a step back and look at the “big picture” of a patient’s history and symptoms. Patients commonly have extensive investigations with many specialists before reaching a pain amplification syndrome diagnosis. Physicians with experience in pain amplification syndrome can help recognize the condition. Rheumatologists often help because they are familiar with symptoms and diagnostic challenges posed by autoimmune and inflammatory diseases.
Is there a cure?
Pain amplification syndrome is not a disease, so no cure is needed. This is a condition that patients learn to manage and control.
What can patients and families expect when treating pain amplification syndrome?
Families can expect more good days and fewer bad days as patients work through the abnormal pain sensitivity. The overall trend is gradual recovery, which can be measured by regular school attendance and activity participation. Reassurance that the patient does not have a serious disease often provides a big boost as the therapeutic program moves forward.
How bad does pain have to get before you see a pediatric rheumatologist?
Patients should be evaluated when symptoms become a significant concern and affect school attendance or participation in sports and activities. Pediatricians and subspecialty colleagues should seek rheumatologists’ expertise for help evaluating a pain amplification syndrome diagnosis and/or making treatment recommendations.
For questions or more information, please contact Andrew Shulman, MD, PhD, pediatric rheumatologist at CHOC, at 714-509-8617.