Table 1.
Comparison of diabetic polyneuropathy and atypical diabetic neuropathy subtypes
| Features/symptoms/signs | DSP | DRPN | CIDP | PSFN-WL | PSFN-TI | DMN |
|---|---|---|---|---|---|---|
| Symptoms | ||||||
| Acute/subacute onset | No | Yes | Yes | Yes | Yes | At times |
| Progression rate | Years | Weeks/months | Weeks/months | Days | Days | Variable |
| Pain/allodynia | <20 % (feet) | Yes | No | Yes | Yes (with or without diffuse pain) | Yes (focal) |
| Numbness/tingling | Yes | At times | Yes | No | At times | Yes (focal) |
| Weakness | Late | Yes | Yes | No | No | Motor nerve |
| Dysautonomia | Yes | Yes (~50 %) | No | Yes | Yes (>85 %) | No |
| Signs | ||||||
| Decreased vibration, joint position | Yes | Variable | Yes | Uncommon | Uncommon | No |
| Decreased pin-pain, temperature | Yes | Variable | At times | Mild or absent | Yes | Yes (focal) |
| Weakness/atrophy, proximal | No | Yes | Yes | No | No | At times |
| Weakness/atrophy, distal | Late | At times | Yes | No | No | At times |
| Absent knee reflexes | Late | Yes | Yes | No | No | No |
| Absent ankle reflexes | Yes | Variable | Yes | No | No | No |
| Orthostatic hypotension | Mild | Yes | No | No | Yes (~33 %) | No |
| Anatomical pattern | ||||||
| Symmetric | Yes | No | Yes | Yes | Yes | No |
| Proximal predominant | No | Yes | When severe | No | No | Variable |
| Stocking-glove | Yes | No | Yes | Yes | Yes | No |
| Associated features | ||||||
| Weight loss | No | Yes | No | Yes | At times | No |
| Onset after DM treatment | No | No | No | No | Yes | No |
| Immunotherapy response | No | Anecdotal | Yes | No | No | No |
| Diagnostic results | ||||||
| Abnormal NCS findings | Yes | Common | Yes | No | No | Common |
| Abnormal needle EMG | Yes | Yes | Yes | No | No | At times |
| Abnormal autonomic tests | Late | Common | No | Yes | Yes | No |
| Elevated ESR | No | Yes | No | No | No | No |
| Elevated CSF protein level | At times | Yes | Yes | No | No | No |
| Prognosis | ||||||
| Chronic/progressive | Yes | No | ~33 % | No | No | Yes |
| Monophasic/resolution | No | Yes (partial) | Often | Yes (months) | Yes (months) | No |
| Pathophysiology | ||||||
| Metabolic/microvascular | Yes | No | No | No | No | No |
| Immune-mediated | No | Yes | Yes | Yes | No | No |
| Compressive/ischemic | No | No | No | No | No | Yes |
CIDP chronic inflammatory demyelinating polyneuropathy, CSF cerebrospinal fluid, DM diabetes mellitus, DMN diabetic mononeuropathy, DRPN diabetic radiculoplexus neuropathy, DSP distal symmetric polyneuropathy, EMG electromyography, ESR erythrocyte sedimentation rate, NCS nerve conduction study, PSFN-TI treatment-induced painful small-fiber neuropathy, PSFN-WL painful small-fiber neuropathy with weight loss