Table 5

When should nerve conduction studies be requested, and a nerve biopsy considered, in a diabetic with a distal polyneuropathy?

CIDP, chronic inflammatory demyelinating polyneuropathy;
CMT, Charcot-Marie-Tooth.
When should nerve conduction studies be requested?

  1. When there is a rapid progression of limb weakness (for example, superimposed CIDP)

  2. When there is a family history of neuropathy with clinical features to suggest underlying CMT disease

When should a nerve biopsy be considered?

  1. If there is prominent early autonomic neuropathy (amyloid)

  2. If there is rapid progression of limb weakness (CIDP)

  3. If there is a rapid multifocal clinical pattern (vasculitis—combining the nerve biopsy with a muscle biopsy will increase the yield of diagnosis of vasculitis)