3.2.0.0 Di­ag­no­sis

3.2.1.0 Di­a­bet­ic Pe­riph­er­al Neu­ropa­thy

Pa­tients with type 1 di­a­betes for 5 or more years and all pa­tients with type 2 di­a­betes should be as­sessed an­nu­al­ly for DPN using the med­i­cal his­to­ry and sim­ple clin­i­cal tests. Symp­toms vary ac­cord­ing to the class of sen­so­ry fibers in­volved. The most com­mon early symp­toms are in­duced by the in­volvement of small fibers and in­clude pain and dyses­the­sia (un­pleas­ant sen­sa­tions of burn­ing and tin­gling). The in­volvement of large fibers may cause numb­ness and loss of pro­tec­tive sen­sa­tion (LOPS). LOPS in­di­cates the pres­ence of dis­tal sen­so­ri­mo­tor polyneu­ropa­thy and is a risk fac­tor for di­a­bet­ic foot ul­cer­a­tion. The fol­low­ing clin­i­cal tests may be used to as­sess small-‍ and large-‍ fiber func­tion and pro­tec­tive sen­sa­tion:

1. Small-‍fiber func­tion: pin­prick and tem­per­a­ture sen­sa­tion

2. Large-‍fiber func­tion: vi­bra­tion per­cep­tion and 10-g monofilament
3. Pro­tec­tive sen­sa­tion: 10-g monofilament

These tests not only screen for the pres­ence of dysfunc­tion but also pre­dict fu­ture risk of com­pli­ca­tions. Elec­tro­phys­i­o­log­i­cal test­ing or re­fer­ral to aneu­rol­o­gist is rarely need­ed, ex­cept in sit­u­a­tions where the clin­i­cal fea­tures are atyp­i­cal or the di­ag­no­sis is un­clear.

In all pa­tients with di­a­betes and DPN, caus­es of neu­ropa­thy other than di­a­betes should be con­sid­ered, in­clud­ing tox­ins (e.g., al­co­hol), neu­ro­tox­ic med­i­ca­tions (e.g., chemother­a­py), vi­ta­min B12 deficien­cy, hy­pothy­roidism, renal dis­ease, ma­lig­nan­cies (e.g., mul­ti­ple myelo­ma, bron­chogenic car­ci­no­ma), in­fec­tions (e.g., HIV), chron­ic inflam­ma­to­ry de­myeli­nat­ing neu­ropa­thy, in­her­it­ed neu­ropathies, and vas­culi­tis (108). See the Amer­i­can Di­a­betes As­so­ci­a­tion (ADA) po­si­tion state­ment “Di­a­bet­ic Neu­ropa­thy” for more de­tails (107).