small fiber neuropathy

Etiology

• diabetes mellitus (15%)
• idiopathic (70%)

Epidemiology

• median age 54 years
• mean body mass index = 30.4 kg/m2

Pathology

• peripheral neuropathy, sensory neuropathy & autonomic neuropathy

Clinical manifestations

• distal pain without hyporeflexia or muscle weakness
• neuropathic pain, abnormal sensation to pinprick, heat, or cold
• autonomic dysfunction (generally mild)
• no motor weakness
• normal proprioception & vibratory sensation
• nearly all patients have cutaneous neuropathic pain in the lower extremities
• 17% have upper extremity involvement

Diagnostic procedures

• nerve conduction studies & electromyography are normal
• thermoregulatory sweat test
• quantitative sensory testing
• skin biopsy to measure intraepidermal nerve fiber density

Complications

• development of large-fiber sensory & motor neuropathy (1/3)

More general terms

• sensory neuropathy
• autonomic dysfunction (dysautonomia)