Diabetic neuropathic pain in a leg amputated 44 years previously

The mechanism of neuropathic pain in the diabetic limb is far from clear. Phantom limb pain likewise is of obscure aetiology. The development of typical pain in an absent leg in a patient with diabetes many years after the amputation stimulates thought as to the mechanism, not only of neuropathic pain, but also of phantom limb pain. A 58-year-old man was diagnosed with type 2 diabetes 44 years after having undergone left below knee amputation for congenital AV malformation, at the age of 13. Eight months before the diagnosis of diabetes he began to complain of pain in the leg on the amputated side-pain very similar to that described in typical diabetic neuropathy. This was followed by similar pain in the right leg. MR scan of the spine revealed a small syringohydromyelia of the thoracic cord in addition to a prolapse of disc at L(5)/S(1) level on the left side, which was first noted 5 years previously. There were no other features of S(1) compression. The typical neuropathic character of the pain involving both the amputated and the intact limbs that developed with the diagnosis of type 2 diabetes suggest that the neuropathic pain may originate from centres higher than peripheral nerves.