Roach: Peripheral neuropathy is difficult to explain
Dear Dr. Roach: I have a question regarding peripheral neuropathy. My brother has been treated for this for the past 10 years. He will be 60 in October. After an MRI found a left parietal tumor, he was seen by a prominent neurosurgeon who felt that the tumor had been there since birth and is not connected to pain and decreased sensation in his feet and hands. He is not diabetic, has no cardiovascular problems and does not use alcohol. Basically, all tests come back normal. For now, they just monitor the tumor.
My brother resisted taking any narcotics until three years ago, and is now on a long-acting narcotic twice a day. The physicians seem to think this is a genetic/autoimmune problem, and my brother is less inclined to keep searching for help.
My question is: Would a trial of IVIG infusion therapy be reasonable? I don't know if his blood work supports checking his immune status, but I am not sure that the results necessarily would reflect the problem. I have read of IVIG use for some neuropathies, but before I try to get my brother to see a neurologist again, I would like to know if this is a possible therapy to try.
Dear M.S.: Peripheral neuropathy is one of the most frequent topics I get questions about, but it is very difficult to answer the questions, because there are many different kinds of peripheral neuropathies ("peripheral" means the part of the nervous system outside the brain and spinal cord, while "neuropathy" means that something is wrong with the nerve).
In general, peripheral neuropathies can be broken down into several categories. Diabetes is the most prevalent one I see, but those caused by prolonged alcohol use and HIV are other common types. Some are indeed autoimmune, such as Guillain-Barre. Other toxins besides alcohol, especially chemotherapy, may cause symptoms in the peripheral nerves. There are genetic or hereditary causes that are relatively rare. Other important causes include infection, especially Lyme disease; hypothyroidism; vitamin deficiencies; and amyloidosis. One cause I see rarely is called paraneoplastic, associated with an existing tumor. That is one way the tumor in the parietal area of the brain could possibly cause the neuropathy.
If the underlying condition can be treated, it should be, but it sounds in your brother's case that despite looking, his doctors haven't been able to find a cause. About a fourth of cases of peripheral neuropathy fall into the idiopathic, or unexplained, category. Intravenous immune globulin is used primarily for the autoimmune types of neuropathy. Only his neurologist can say if it's right for him.
When the underlying condition can't be treated, then we rely on a variety of medications to ease symptoms.
Email questions to ToYourGoodHealth@med.cornell.edu.