Clinical Differentiation of Diabetic Peripheral Neuropathy and AIDP

Temporal Pattern and Symptom Distribution

The American Diabetes Association recommends assessing diabetic peripheral neuropathy (DPN) after 5 years of type 1 diabetes duration and at diagnosis for type 2 diabetes, as DPN develops gradually over months to years with distal symmetric sensory symptoms 1
Up to 50% of patients with DPN may be asymptomatic at presentation, with a length-dependent pattern of peripheral nerve function loss 1
AIDP presents acutely over days to weeks with ascending motor weakness and areflexia, and patients typically recall the exact day symptoms began 2

DPN predominantly affects sensory and autonomic function, with small-fiber involvement causing burning, tingling, and pain in the toes and feet, and large-fiber involvement producing numbness and loss of protective sensation 2
AIDP predominantly affects motor function, with ascending motor weakness as the hallmark feature, and proximal and distal muscles affected relatively equally 3
Areflexia develops early and is nearly universal in AIDP, with global loss of reflexes, including upper extremities 2

DPN shows axonal features, including reduced amplitude of sensory and motor responses, and mildly slowed conduction velocities 1
AIDP shows demyelinating features, including markedly prolonged distal latencies, severely slowed conduction velocities, and conduction block and temporal dispersion 2
The American Diabetes Association recommends optimizing glycemic control for patients with DPN, as poor glycemic control and longer diabetes duration are associated with DPN 1

Diabetic neuropathy is a diagnosis of exclusion, and CIDP occurs with a two-fold increased risk in diabetes, requiring immunotherapy 1
Consider inflammatory neuropathies when presentation is atypical, and obtain electrophysiology if clinical features are atypical for DPN or if there is rapid progression or acute onset 3, 1
The American Academy of Neurology recommends urgent electrophysiology, lumbar puncture, and neurology consultation for patients with suspected AIDP, characterized by acute onset, motor predominance, and areflexia 2