It is estimated that over 20 million Americans have neuropathy. Many people don’t know that prior to the advent of the obesity pandemic and the associated rising rates of diabetes, leprosy was the most common cause of neuropathy worldwide. Although it is now widely recognized that diabetes is the most common cause of neuropathy, for up to 30% of patients the cause of their neuropathy remains unknown. These cases are dubbed “idiopathic,” and – as a neuropathy specialist I assure you – that for many patients this becomes a chronic source of frustration and anxiety.
Some of the questions I hear from idiopathic neuropathy patients include:
- What are the chances my neuropathy will get worse?
- Isn’t there any treatment?
- What else can be done to find the cause of my neuropathy?
It is almost impossible to address these issues without a more specific neuropathy diagnosis.
Diagnosing neuropathy is a two-step process. First, the diagnosis of neuropathy is confirmed. This should include identifying the population of nerves involved, the type of nerve pathology, and the distribution of nerve pathology. Detailed electrodiagnostic testing (electromyography and nerve conduction studies), and possibly a skin biopsy (to detect the involvement of small fiber nerves) or autonomic testing (to detect the involvement of autonomic nerves) may be required. Second, the cause for the neuropathy can be explored, starting with blood tests. In some cases a nerve biopsy or genetic testing may be needed. The more specific the characterization of the neuropathy, the easier it is to know how to look for what might be causing it.
I would argue that for any idiopathic neuropathy patient whose symptoms affect daily activities – whether that is because of pain, weakness, imbalance, or difficulty walking – further steps should be taken to help search for a more specific diagnosis.
Two steps that every health care provider can take include:
Making sure your patient is seen by a neuropathy specialist. A neuropathy (or neuromuscular) specialist is a sub-specialized neurologist. These clinicians can sometimes uncover less common causes of neuropathy such as hereditary, toxic, autoimmune, and paraneoplastic etiologies. They can also more readily discern when a patient might have a more unusual presentation of a common form of neuropathy.
Asking how long it has been since your patient had a neuropathy evaluation. In cases where patients were evaluated for neuropathy a number of years ago, a referral for a repeat evaluation can help determine the underlying cause of neuropathy and guide treatment choices. In some cases the underlying cause of neuropathy may not be evident even after further evaluation, but on-going research helps us to learn more about neuropathy’s various causes, develop new tests, and consider new treatment approaches. Also, for some patients, interval electrodiagnostic testing can help clarify the diagnosis, especially if the neuropathy is progressing.
Hopefully these points can help idiopathic neuropathy patients obtain the clarity they seek and the medical care they need.
Shanna K. Patterson is a neurologist and serves on The Neuropathy Association’s Medical Advisory Committee.