Until recently, it was believed that kids, teens, and people in their 20s and 30s hardly ever develop neuropathy. After all, few young people have the serious diseases, such as diabetes and cancer, that most commonly cause neuropathy. But now, physicians are starting to realize some kids and young people do experience small-fiber neuropathy, and it can lead to many symptoms, including widespread pain.
The most common cause of small-fiber polyneuropathy (SFPN) in kids, teens, and young adults seems to be autoimmunity. In autoimmune conditions, the body’s defense cells (white blood cells) mistake normal cells and tissues as harmful, and attack and destroy them. Well-known autoimmune diseases include rheumatoid arthritis and multiple sclerosis.
Rogue immune cells sometimes attack peripheral nerves, leading to autoimmune nerve conditions such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and multifocal motor neuropathy. The cells under attack are the large myelinated nerve cells, so the major symptom is weakness.
What about the small-fiber nerve cells? They can be attacked in autoimmune diseases that affect many parts of the body. One example is a condition known as Sjögren’s syndrome.
Much of the SFPN diagnosed in kids and young people is different from Sjögren’s because it is caused by autoimmune reactions that specifically target small-fiber nerve cells and nothing else1,2. This causes symptoms of small-fiber polyneuropathy in people without any evidence of other medical causes for neuropathy. Because there are treatments for autoimmune neuropathies3, it’s worth discussing with your doctor whether or not this could be a factor.
Kids and Genes
A rare cause of neuropathy is mistakes (mutations) in the genes that carry instructions for how nerve fibers are made. Some people with genetic neuropathies don’t notice symptoms until they are grown up, but more severe types can cause symptoms in kids and teens. The best-known type is Charcot-Marie-Tooth or CMT. It is actually a family of different neuropathies caused by various gene errors.
Read the NIH fact sheet on Charcot-Marie-Tooth disease.
For appointments at the MGH CMT clinic, click here.
The most common sign of CMT is gradual weakening and shrinking of muscles in the feet and lower legs. Some people with CMT need braces to walk. Later on, CMT can also affect the hands, making it hard for people to get dressed or brush their teeth. These symptoms are caused by damage to the “motor” type of nerve fibers that control the muscles. CMT can also damage the ability to feel things in the hands and feet. Sometimes, but not always, it can cause chronic pain.
Above: Members of a family with neuropathy from sodium channel SCN9a mutation.
The kind of gene mistakes that produce chronic pain as the major problem are those that cause parts of the pain nerve cells to work incorrectly and send pain signals too often or too strongly. This causes specific types of small-fiber polyneuropathy. Some people also have other problems as well.
Mass General has a special clinic for kids and teens with these conditions. Parents and other family members are welcome as well. These Nerve|Gene appointments must be specially arranged in advance by calling 617-643-8277.
If you have, or suspect you have, an inherited form of neuropathy, please consider joining our Neuropathy Gene Registry to connect with genetics experts and other patients with similar conditions.
Oaklander AL, Klein MM.
Oaklander AL, Lunn MP, Hughes RA, van Schaik IN, Frost C, Chalk CH.
Cochrane Database Syst Rev. 2017 Jan 13;1:CD010369.