Diagnostic Evaluation of Immune-Mediated Neuropathies

Abstract

AbstractThe peripheral nerves consist of bundles of long neuronal axons as they exit the central nervous system (CNS). Some peripheral nerves are wrapped in a myelin sheath generated by Schwann cells, whereas others are unmyelinated. Peripheral nerves serve different motor, sensory, and autonomic functions. The term peripheral neuropathy is usually used to describe symmetric and universal damage to adjacent nerves. The damage and clinical manifestations are usually located distally with a proximal progression. Several disorders can damage peripheral nerves and cause peripheral neuropathy; it is important to differentiate actual neuropathy from other disorders that can have a similar clinical presentation [1]. The diagnosis of peripheral neuropathy necessitates a thorough workup of possible etiologies to identify immune-mediated causes that are amenable to immunosuppressive or immunomodulatory therapies. Importantly, patients may occasionally suffer from more than one disease-causing their peripheral neuropathy. Clinically relevant co-comorbidities such as diabetes mellitus, HIV infection, chronic alcohol abuse, etc. need to be considered. Evidence-based guidelines and diagnostic algorithms for the diagnosis of peripheral neuropathy have been published for specific neuropathic phenotypes such as distal symmetric peripheral neuropathy, small fiber neuropathy, or inflammatory neuropathies. However, they are only applicable for specific neuropathic conditions or when a specific diagnosis is already suspected on clinical grounds. By focusing on the initial steps of the diagnostic workup, this standard operating procedure provides a practical guideline including clinical and additional diagnostic parameters that help to identify the underlying cause of peripheral neuropathy [2].