Peripheral neuropathy occurs as a component of several common and many rare diseases. It is heterogenous in aetiology, diverse in pathology, and varied in severity. The term peripheral neuropathy includes symmetric polyneuropathy, single and multiple mononeuropathy, and radiculopathy. Further classification depends on a mixture of phenomenological, pathological, and genetic or other aetiological features. All of these things cause problems for epidemiologists who, without agreed definitions of what constitutes a case, find it difficult to describe patterns of occurrence of disease. Perhaps it is not very surprising that information about the descriptive epidemiology of peripheral neuropathy derived from population based studies is scarce.What data do exist suggest that peripheral neuropathy may be rather commoner than is usually thought. A recent study, carried out in two regions of Italy, estimated the frequency of chronic symmetric symptomatic polyneuropathy in people over the age of 55 years attending general practitioners' surgeries. Probable polyneuropathy was diagnosed if they answered positively to a screening questionnaire for neuropathic symptoms and showed signs compatible with peripheral neuropathy when examined by a neurologist.' Around 8% of people met these diagnostic criteria for polyneuropathy. The commonest condition associated with polyneuropathy was diabetes. This study was not population based; only people already attending their general practitioner were included-a group in whom chronic disease is likely to be overrepresented and who will therefore be at increased risk of neuropathy. Despite this caveat, the rate of polyneuropathy detected was surprisingly high. Two studies of prevalence, one in Bombay2 and the other in Sicily,3 also suggest that peripheral neuropathy is common in the community. Cases were identified by a door to door survey. Those who answered positively to questions about sensory or motor symptoms were examined by a neurologist. In Bombay the prevalence of peripheral neuropathy was 2-4% and the commonest diagnoses were carpal tunnel syndrome and diabetic peripheral neuropathy. In Sicily, 7% of the population responded positively to the initial screening questions. After further investigation, diabetic neuropathy was diagnosed in 0 3% but no details about the frequency of other types of neuropathy were published.Peripheral neuropathies are a disparate group of diseases. Attempts to consider them as a whole emphasise their contribution to the burden of disease and disability in the community, but may obscure interesting epidemiological features that could lead to a better understanding of aetiology. In this review we consider the commoner forms of peripheral neuropathy separately.
Diabetic neuropathiesThe neuropathic complications of diabetes mellitus include distal, symmetric, predominantly sensory neuropathy, autonomic neuropathy, asymmetric proximal neuropathy, and cranial and other mononeuropathies. Several of these neuropathic manifestations may coexist in same patient....
