Clinical Features of Diabetic Polyneuropathy

Abstract

Neuropathy affects approximately 30-50% of all diabetic patients and is the commonest form of neuropathy in the developed world. It encompasses several neuropathic syndromes including focal and symmetrical neuropathies, by far the commonest of which is distal symmetrical neuropathy. The two main clinical consequences, foot ulceration sometimes leading to amputation and painful neuropathy, are associated with much patient morbidity and mortality. There is now little doubt that glycaemic control and duration of diabetes are major determinants of distal symmetrical neuropathy. In addition potentially modifiable, traditional markers of macrovascular disease such as hypertension, hyperlipidaemia and smoking are also independent risk factors. There is now increasing evidence that the cause of distal symmetrical neuropathy may be nerve ischaemia, though metabolic factors may be important early. Pain is the most distressing symptom of neuropathy and the main factor that prompts the patient to seek medical advice. Pain may also occur within the context of all neuropathic syndromes associated with diabetes, including focal neuropathies. In acute painful neuropathies the pain indeed the neuropathy is self-limiting and usually subsides within a year. Abnormalities of autonomic function are very common in subjects with longstanding diabetes; however, clinically significant autonomic dysfunction is uncommon. Several systems including the cardiovascular, gastrointestinal and genitor-urinary systems may be affected. Focal (asymmetrical) neuropathies including diabetic amyotrophy are well-recognised complications of diabetes. They have a relatively rapid onset and cause major disability, but there may be complete recovery.