Clinical Presentation and Diagnosis of Distal Symmetric Polyneuropathy (DSP)

Sensory Manifestations

Symptoms of DSP typically begin symmetrically in the toes and feet, later progressing to fingertips as the condition advances in a length-dependent pattern 1
Patients experience distal paresthesia, hyperesthesia, numbness, and sensory loss that affects the feet more than the hands 2
Sensory symptoms commonly include pain and positive sensory symptoms in a stocking-and-glove distribution, changes in proprioception and vibratory sensitivity, and elevated touch detection threshold and impaired sharpness detection 2

Motor impairment is relatively rare compared to sensory deficits in DSP, with motor symptoms typically consisting of mild to severe distal weakness in the lower limbs, occurring in approximately 10% of patients 2
Motor nerve involvement is often a later manifestation after sensory symptoms have become established 3

Small fiber polyneuropathy, a common subtype of DSP, presents with prominent pain and autonomic symptoms with minimal or absent motor findings 1
Skin biopsy with intraepidermal nerve fiber (IENF) density assessment is a validated marker of small fiber sensory pathology, highlighting the predominance of sensory involvement 4
IENF are the nerve terminals of somatic unmyelinated C fibers, which are predominantly affected in small fiber sensory neuropathy (SFSN) 5

Physical examination in DSP typically reveals distal sensory loss, reduced or absent reflexes, and sometimes distal muscle weakness 1
Autonomic symptoms may also be present in DSP, including orthostatic hypotension, alternating diarrhea and constipation, urinary retention, and sexual dysfunction 1
Orthostatic hypotension has been reported in about 10% of patients with certain types of medication-induced DSP 2
Autonomic testing can document autonomic system dysfunction in polyneuropathy, which is particularly relevant to small fiber polyneuropathy 4