Approach to diagnosis and differential diagnosis of chronic polyneuropathies

Chronic polyneuropathy is a common disorder with heterogenic clinical presentation and many different etiologies. Polyneuropathy has an estimated prevalence of about 2% in the general population. Despite being common, polyneuropathy remains a diagnostic challenge for most clinicians for many reasons, including the large number of potential causes and the fact that a specific cause often cannot be identified even after appropriate testing. The result is often a one size fits all strategy from an unnecessarily expensive shotgun approach to a pessimistic attitude that too rapidly deems a neuropathy as idiopathic. Shotgun approach is expensive as many tests have a low yield. It necessitates many false positive results, and may give a false sense of assurance if all tests are negative. Another approach is to select tests based on clinical features and nerve conduction studies. A great many of etiologies for polyneuropathies exist (maybe higher than 50 etiologies). The principle question is how to formulize our approach to cover all possible etiologies and reduce the rate of false negative approach. To approach for polyneuropathies, we must conduct a systematic approach to reach the precise diagnosis by the minimum laboratory tests required. The main goal of this presentation is to show how to make a systematic approach.