Chronic pain caused by nerve damage may be far more common in children and young adults than previously thought, according to a new study at Massachusetts General Hospital. Their findings, which are being published in the journal Pediatrics,could lead to more accurate testing and diagnosis of children with widespread chronic pain.
In a small study of young patients with chronic, unexplained pain, researchers say tests found that most had small-fiber polyneuropathy, a condition rarely reported in children. They call this new syndrome juvenile-onset small-fiber polyneuropathy or JOSeFINE.
Small-fiber polyneuropathy (SFPN) in adults is most commonly associated with diabetes, although it can also be triggered by exposure to toxic chemicals. SFPN involves widespread damage to nerves that carry pain signals from the skin and also control bodily functions such as heart rate, blood pressure and sweating. Symptoms of SPFN include chronic pain in several parts of the body, often in the feet or lower legs, along with gastrointestinal problems, dizziness, fainting and a rapid heart rate.
To see how common the disorder is in children, researchers at Massachusetts General Hospital (MGH) reviewed the records of 41 young patients who were treated for persistent widespread pain that began before the age of 21. All of the patients had a battery of diagnostic tests, including several tests recommended for SFPN.
An analysis of the results found that 24 of the 41 patients met their criteria for a diagnosis of SFPN, meaning that at least one test indicated the presence of the disease. Of the remaining 17 patients, 16 were determined to possibly or probably have SFPN, based on abnormal test results. Sweat production – a sensitive diagnostic test for SFPN – was reduced in 82 percent of patients.
"We've found the beginnings of a way to better evaluate young patients with otherwise unexplained widespread body pain," said co-author Anne Louise Oaklander, MD, director of the Nerve Injury Unit in the MGH Department of Neurology. "By identifying the tests that are useful for diagnosing this condition, we hope to reduce the use of unnecessary, expensive, sometimes painful and potentially harmful testing that many of these children have undergone."
Oaklander says some families traveled thousands of miles to MGH with their sick children in a desperate search for answers to their chronic pain.
"Because everyone wanted to help these children, they had undergone myriad tests, two thirds had been hospitalized, and some had tried many medications, usually without benefit," she said.
Based on the study findings, Oaklander says doctors at MGH will now take a two-part approach to evaluating chronic pain in children. They'll first be evaluated by a neurologist for small-fiber neuropathy, and if that is confirmed, specific blood tests will be given to pinpoint the cause.
"It's important to consider this diagnosis, since there are treatments for many symptoms of neuropathy – including medications that increase blood pressure and improve gastrointestinal function – and for some of the underlying causes," Oaklander said.