Abstract
Peripheral neuropathies are a group of disorders that affect the peripheral nervous
system, for which hundreds of etiologies have been identified. This article presents
a stepwise approach to the evaluation and workup of peripheral neuropathy, which starts
with a detailed history of symptoms, family and occupational history, and a neurological
as well as general physical exam. Pattern recognition of various neuropathies can
help to build a differential diagnosis based on the presentation. Such patterns include
acute versus chronic, primary demyelinating versus axonal, hereditary versus acquired,
asymmetric versus symmetric, presence of facial palsies, sensory or motor predominant,
and presence of prominent autonomic symptoms. Early categorization of the type of
neuropathy can help focus the workup for peripheral neuropathy. Nerve conduction studies
and electromyography (NCS/EMG) is the primary diagnostic tool in the evaluation of
patients with large-fiber polyneuropathy. One of the most important roles of NCS/EMG
is to help categorize polyneuropathy as primary axonal versus primary demyelinating.
The finding of a primary demyelinating polyneuropathy narrows the differential diagnosis
of polyneuropathy dramatically and increases the chances of finding a treatable etiology.
Laboratory workup includes serum studies and potentially cerebrospinal fluid, genetic
studies, immunological markers, and fat pad biopsy for select patients. Skin biopsy
may be used to assess intraepidermal nerve fiber density if small-fiber neuropathy
is suspected, and nerve biopsy may be useful in select cases. In recent years, magnetic
resonance imaging and neuromuscular ultrasound have also shown promise in the evaluation
of peripheral neuropathy. Identification of the etiology of neuropathy is crucial
and often time-sensitive, as an increasing number of causes are now reversible or
treatable.
Keywords peripheral neuropathy - polyneuropathy - diagnosis - clinical - neurophysiologic
