People with diabetes mellitus (DM) sometimes present with acute or subacute, progressive, asymmetrical pain and weakness of the proximal lower limb muscles. The various names for the condition include diabetic amyotrophy or diabetic lumbosacral radiculoplexus neuropathies. Some studies suggest that it may be due to immune-mediated inflammatory microvasculitis causing ischaemic damage of the nerves. Immunotherapies would therefore be expected to be beneficial. This is an update of a review first published in 2009.