Q If the cause of my neuropathy can't be found, how does that affect treatment and prognosis?
A In one-quarter to one-third of patients with neuropathy, no cause can be found. In this case, the neuropathy is called “idiopathic.” The translation from the Greek roots means “of its own kind,” but one frustrated patient pointed out that the term makes her think of a combination of “idiotic and pathetic.”
When a cause for the neuropathy is not known, your physician will direct treatment at alleviating the symptoms. Neuropathic pain, if present, can be treated by any one or a combination of available medications. And physical therapy can help improve or limit any functional impairment. In most instances, idiopathic neuropathy is self-limiting and isn't commonly debilitating.
If significant deterioration does occur, your neurologist may recommend a nerve and muscle biopsy, if one has not already been done. The biopsy could reveal uncommon conditions that might be missed by other tests such as non-systemic vasculitis, amyloidosis, or atypical chronic inflammatory demyelinating polyneuritis (CIDP).
If your doctor suspects that the neuropathy is autoimmune rather than idiopathic, an approach might be to try an immune therapy, such as prednisone (a steroid), plasmapheresis (blood removal and reinfusion after antibodies have been filtered out), or intravenous gammaglobulins (a treatment to quiet the autoimmune response). In the absence of a firm diagnosis, however, treatment with these therapies is controversial and would require the patient's informed consent, with full consideration of the potential risks and benefits, as well as approval by the patient's insurance company.