Small fiber neuropathy: Getting bigger!

Abstract

Etiological and clinical heterogeneity of small fiber neuropathy (SFN) precludes a unifying approach and necessitates reliance on recognizable clinical syndromes. Symptoms of SFN arise from dysfunction in nociception, temperature, and autonomic modalities. This review focuses on SFN involving nociception and temperature, examining epidemiology, etiology, clinical presentation, diagnosis, pathophysiology, and management. Prevalence of SFN is 52.95 per 100,000 population, and diabetes and idiopathic are the most common etiologies. Dysesthesia, allodynia, pain, burning, and coldness sensations frequently present in a length-dependent pattern. Additional autonomic features in gastrointestinal, urinary, or cardiovascular systems are frequent but poorly objectified. SFN is diagnosed by intraepidermal nerve fiber density and quantitative sensory and autonomic tests in combination with normal nerve conduction. Pathophysiological understanding centers on sodium channel dysfunction, and genetic forms are beginning to be understood. Treatment is directed at the underlying etiology supported by symptomatic treatment using antidepressants and anticonvulsants. Little is known about long-term outcomes, and systematic cohort studies are needed.

Diagnosis and management of sensory polyneuropathy

“…In small fiber neuropathies (SFNs) the thinly myelinated (Aδ) and unmyelinated (C) fibers responsible for the transmission of thermal and noxious sensory input are affected 12. Clinically, this nerve damage translates to symptoms of sharp, painful, or burning paresthesia; sensory loss or numbness; and the inability to discriminate between hot and cold sensations.…”

“…Peripheral sensory nerves vary in size and function, ranging from the smallest unmyelinated C fibers and thinly myelinated Aδ fibers that conduct noxious and thermal information12 to the larger Aβ fibers that transmit proprioceptive and vibratory information 3. As a result, disorders of sensory nerve function are diverse and depend on the type of nerve fiber that is affected; patients present with a wide range of symptoms, from pain predominant (small fiber) to ataxia predominant (large fiber) problems.…”

Raynaud’s phenomenon in Northern Sweden: a population-based nested case–control study

“…The rheumatic diseases included were systemic sclerosis, CREST syndrome, rheumatoid arthritis, juvenile rheumatoid arthritis, reactive arthritis, unspecified arthritis, systemic lupus erythematosus, psoriatic arthritis, ankylosing spondylitis, Sjögren's syndrome, Ehlers-Danlos the first, population-based, data collection, CHINS2 the second, casebased, data collection, RP Raynaud's phenomenon, CS cold sensitivity syndrome, fibromyalgia, gout, polymyositis, dermatomyositis, Dercum's disease, and mixed connective tissue disease. The use of therapeutic drugs was collected in free text, and coded by one of the study physicians (AS) into two broad categories based on whether the substance has a documented negative effect on either peripheral nerves [21] or circulation [22]. Beta-adrenergic antagonists, as well as oral contraceptives and hormone replacement therapies, were also analyzed separately.…”

Limbic Encephalitis Associated with Voltage-Gated Potassium Channel-Complex Antibodies: Patient Report and Literature Review

“…The symptoms of small fiber neuropathy (SFN), which arise from dysfunction in nociception, temperature and autonomic modalities [34], are most adequately assessed by assessment of ENF density [35] and a combination of cardiovagal, sudomotor and adrenergic functions tests [36]. A peripheral basis for autonomic dysfunction was suspected in the present patient because of the association with SFN.…”