Polyneuropathies

Abstract

Background: Polyneuropathies (peripheral neuropathies) are the most common type of disorder of the peripheral nervous system in adults, and specifically in the elderly, with an estimated prevalence of 5-8%, depending on age. The options for treatment depend on the cause, which should therefore be identified as precisely as possible by an appropriate diagnostic evaluation.

Methods: This review is based on the current guidelines and on large-scale cohort studies and randomized, controlled trials published from 2000 to 2017, with an emphasis on non-hereditary types of polyneuropathy, that were retrieved by a selective search in PubMed.

Results: Diabetes is the most common cause of polyneuropathy in Europe and North America. Alcohol-associated polyneuropathy has a prevalence of 22-66% among persons with chronic alcoholism. Because of the increasing prevalence of malignant disease and the use of new chemotherapeutic drugs, chemotherapy-induced neuropathies (CIN) have gained in clinical importance; their prevalence is often stated to be 30-40%, with high variation depending on the drug(s) and treatment regimen used. Polyneuropathy can also arise from genetic causes or as a consequence of vitamin deficiency or overdose, exposure to toxic substances and drugs, and a variety of immunological processes. About half of all cases of polyneu - ropathy are associated with pain. Neuropathic pain can be treated symptomatically with medication. Exercise, physiotherapy, and ergotherapy can also be beneficial, depending on the patient's symptoms and functional deficits.

Conclusion: A timely diagnosis of the cause of polyneuropathy is a prerequisite for the initiation of appropriate specific treatment. Patients with severe neuropathy of unidentified cause should be referred to a specialized center for a thorough diagnostic evaluation.

Figure

Simplified diagnostic algorithm for polyneuropathy. This takes only disease courses and clinical presentations into account, without electrophysiology, laboratory tests, and advanced diagnostic methods. Predominantly those forms discussed in the article are shown, with no claim to completeness. CIDP, chronic inflammatory polyradiculoneuropathy; CIN, chemotherapy-induced neuropathies; GBS, Guillain-Barré syndrome; MMN, multifocal motor neuropathy; SFN, small fiber neuropathy

eFigure

The pathophysiology of polyneuropathy summarized (modified from Callaghan et al. [40])

eFigure:

Feet and lower legs of a patient with vasculitic polyneuropathy (A) Thinning of the small foot muscles as a sign of a subacute to chronic process (B) Acute-onset right-foot extensor paresis