Idiopathic Neuropathy...And Then?

Today's post from neuropathy.org (see link below) is another post talking about the diagnosis of Idiopathic Neuropathy, which leaves many people feeling bewildered and convinced the doctor thinks they're faking it. Simply, it means that the doctor or specialist may have some ideas but just doesn't know for sure what the cause of your neuropathy is. This does not mean that you don't have 'real' neuropathy, (your symptoms will tell you that) or that your neuropathy is in any way diminished by the diagnosis. The treatment should be the same as should the prognosis but you're entitled to ask more questions. Remember, it's not the cause of your neuropathy that counts, it's what's going to be done about it.

So You’ve Been Given An “Idiopathic” Neuropathy Diagnosis. What’s Next?
By Shanna K. Patterson, MD 

The term idiopathic neuropathy means that the cause of neuropathy is not known.

Unfortunately, this label currently applies to approximately 20% of patients with neuropathy, and up to 50% of patients with small fiber neuropathy. This can be a source of great frustration for both patients and neurologists.

Naturally, many patients with idiopathic neuropathy ask, “Is there anything else that can be done to search for the cause of my neuropathy?” The answer depends on the details of each person’s case. For some patients who have been given an idiopathic neuropathy diagnosis, the answer may be “yes.”

Here are a couple questions to think about when deciding whether to discuss this question further with your physician:

1. How long has it been since you underwent testing for potential causes of neuropathy?

• Repeat testing can be informative if a slowly developing or mild condition was previously below the threshold for detection.

• New genetic testing may be available, and could be appropriate in some cases.

• While there is no official recommended time interval when testing should be repeated, raise the possibility of repeating tests if neuropathy symptoms are significant, progressing, or several years have passed since the initial work-up was done.

2. Have you been evaluated by a neuropathy specialist? 
 
Most commonly, physicians think about diabetes, thyroid dysfunction, and certain nutritional deficiencies as causes for neuropathy. However, a neuropathy specialist—neurologists with a focus on neuromuscular diseases such as neuropathy—may be able to determine the underlying cause for some patients who have been given an idiopathic neuropathy diagnosis. In some cases additional detailed history, additional testing, or other analysis of the existing information for an individual patient could be helpful:

• A neuropathy specialist may be able to recognize how certain known medical conditions could be causing neuropathy. For example, kidney or liver diseases, past gastric bypass surgery (which can lead to nutritional deficiencies), or certain rheumatologic disorders can be associated with neuropathy.

• A neuropathy specialist may be able to reveal the underlying cause of neuropathy by taking a more detailed history. For example, asking about past and current medication use can reveal the cause of neuropathy. Medications such as statins (a class of medications used to treat high cholesterol), certain types of chemotherapy, immunosuppressants, and certain HIV medications can cause neuropathy. Also, discussing possible toxic exposures, such as heavy metals or environmental toxins, can be useful in some cases.

• Diabetes is a well recognized and common cause of neuropathy. However, neuropathy can be caused by a milder form of elevated blood sugar levels, known as glucose intolerance. Essentially, this is when blood sugar levels are higher than normal but below the cutoff to diagnose diabetes. Early recognition and treatment of this condition can lead to improvement in neuropathy in some cases.

• A neuropathy specialist may consider testing for less common causes of neuropathy, such as autoimmune or hereditary conditions, when appropriate.

In conclusion, idiopathic neuropathy can seem like a hopeless situation—an incomplete diagnosis—and for these patients symptom management is key. It is important to remember that for some patients, further evaluation by a neuropathy specialist can help determine the underlying cause of neuropathy. This can guide treatment choices, and lead to eventual symptom improvement. For some patients 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 for neuropathy. If your neuropathy symptoms are persistent, a cause of significant distress, or steadily worsening, then partnering with a neurologist with experience in evaluating neuropathy can be worthwhile.

Shanna K. Patterson, M.D. is assistant director of Electromyography and a board-certified attending neurologist at St. Luke’s – Roosevelt Hospital Center. Dr. Patterson also holds an appointment at Columbia University Medical Center as assistant clinical professor of Neurology. She completed both her residency training in Neurology and a fellowship in Clinical Neurophysiology (with an emphasis on electromyography and neuromuscular disorders) at Columbia University.

http://www.neuropathy.org/site/News2?page=NewsArticle&id=8269