Differential response to intravenous immunoglobulin (IVIg) therapy among multifocal and polyneuropathy types of painful diabetic neuropathy

Peripheral neuropathy associated with diabetes mellitus often causes severe neuropathic pain that is difficult to alleviate. We evaluated the effect of intravenous immunoglobulin (IVIg) therapy on six patients with two phenotypes of painful diabetic neuropathy: three patients with multifocal neuropathy and three with symmetric polyneuropathy. All patients were treated with IVIg therapy and pain levels were evaluated on the Visual Analog Scale. Three patients were also assessed by quantitative sensory testing. All three patients with multifocal neuropathy showed a marked improvement in severe pain, while the patients with symmetric polyneuropathy did not respond to IVIg therapy. Pain associated with diabetic neuropathy is multifactorial and causative factors are heterogeneous. Our results show that IVIg therapy can alleviate pain in patients with multifocal diabetic neuropathy.