Atypical diabetic neuropathies

Diabetic radiculoplexus neuropathy (diabetic amyotrophy) is characterised by unilateral acute or subacute pain emanating from the pelvis, and weakness or atrophy of the pelvic girdle and thigh musculature. The pain from radiculopathy is not relieved by rest and is typically worse at night, causing sleep disturbance. Drugs for painful neuropathy may provide symptomatic relief. Radiculopathy is usually self-limiting, but may take many months to resolve.

Occasionally, diabetes causes a mononeuropathy, especially rapid-onset cranial nerve paresis or foot drop. Mononeuropathies of the third, fourth or sixth cranial nerve are most common. A structural cause (eg an aneurysm pressing on the implicated nerve) should be excluded by brain imaging before the diagnosis of a diabetic mononeuropathy is made. Typically, these diabetic mononeuropathies spontaneously resolve over several months, possibly because they are precipitated by transient, sudden occlusion of the vessels supplying the nerves.