Cath Lab Digest

Peripheral neuropathy can be triggered by disparate causes such as diabetes, alcoholism, certain chemotherapy medications and HIV. Given the importance of identifying the correct etiology in order to facilitate appropriate treatment, these authors discuss pertinent clues in the patient history and physical exam, and share perspectives on helpful diagnostic testing.

   In podiatric practice, we commonly see peripheral neuropathy, the primary factor leading to ulceration, which can subsequently lead to infection and ultimately amputation. Neuropathy may also lead to Charcot osteoarthropathy, which occurs most commonly in those with diabetic neuropathy but can occur in those without diabetes.^1-3

   Diabetes is the leading cause of peripheral neuropathy.⁴ However, peripheral neuropathy can be a complication of HIV, alcoholism, malnutrition and cancer. It can also be triggered by medication toxicities or hereditary causes.

   The prognosis of neuropathy can differ depending on the etiology. For some patients, neuropathy is reversible and in many cases, one can slow down or even stop the progression by implementing proper etiology-based treatment.^5-13 Accordingly, it is crucial to determine the specific cause or causes of each patient’s neuropathy. By being aware of the type and degree of neuropathy, the physician is better able to assist the patient in preventing serious complications and improve the patient’s quality of life.

   Determining the cause of peripheral neuropathy is difficult for several reasons. There is no algorithm that has proven reliable and one leading neurologist has even opined that diagnosing neuropathy is a “mind game” wherein the physician must constantly be including and excluding diagnoses with each part of the examination.¹⁴ This is not only due to the fact that the same neuropathy can be caused by different diseases but also because the same disease can cause several different neuropathies.¹⁵

   While there is no definitive algorithm, there are guidelines on how to approach the history, physical exam and any additional testing.^14,16,17

Key Considerations With The Patient History

   The most important diagnostic tool in determining the etiology of peripheral neuropathy is a thorough history. This requires knowledge of the different causes of neuropathy and their possible presentations. For a differential diagnosis of the more common etiologies, see “A Guide To The Differential Diagnosis Of Peripheral Neuropathy” on page 58.

   Having a disease that causes neuropathy clearly does not mean that a patient has or will have neuropathy. Therefore, the onset of the neuropathy and the onset of diabetes or other diseases are important historical components in determining correlation. While we have all certainly encountered patients in whom peripheral neuropathy was the presenting symptom of diabetes, this is rare.

   When peripheral neuropathy presents early in the disease progression of those who have their diabetes under good control, there is more than likely an alternate cause for the peripheral neuropathy.¹⁸ Since diabetic neuropathy is a microangiopathy, one would expect another microvascular disease, such as nephropathy and retinopathy, to be present during the same timeframe.^4,14