Peripheral neuropathy in leprosy and its consequences.

Leprosy causes a 'mononeuritis multiplex' of immunological origin that results in autonomic, sensory and motor neuropathy. When detected and treated early, primary impairments may be reversible. However, 11-51% of patients do not recover. In addition, 33-56% of newly registered patients already have clinically detectable impairments, often no longer amenable to drug treatment. Among new patients, 6-27% present with secondary impairments, such as wounds, contractures and shortening of digits. All patients with impairments should be taught methods to prevent further impairment and subsequent disability (POID). As the result of impairments, many people experience limitation of activities of daily living, which can be partially overcome with the help of assistive devices, training, and surgery. As a result of these limitations, because of visible impairments, or simply because of the diagnosis 'leprosy', many people are restricted in their participation in society. Many overcome activity limitations and participation restrictions without assistance, despite residual impairments. However, some require intervention, such as physical or occupational therapy, reconstructive surgery or temporary socioeconomic assistance. Information on these issues is not collected routinely, and the few tools that exist to measure the severity or extent of impairment have not been widely used, nor have they been used to generate cohort-based statistics. There are no agreed indicators for monitoring POID activities or rehabilitation interventions. Work in the general field of rehabilitation has resulted in the ICIDH-2, which provides a conceptual framework for rehabilitation and the entire area of 'consequences of health conditions'. Although experience to date is very limited, the conceptual framework appears appropriate to leprosy. Data on the prevalence and incidence of primary and secondary impairments have been reported from several countries, the link between impairments and activity limitations has been investigated, and a few studies of the magnitude of the need for rehabilitation have been reported. Research priorities include studies of methods to improve detection of autonomic, sensory and motor neuropathy; trials of alternative drugs or regimens for treating neuropathy; studies of the use of various POID-monitoring systems that may be derived from these; studies of the design and use of instruments to assess limitations of activities and restrictions on participation; assessments of needs for rehabilitation and the development of methods to do these; studies of the efficacy of various types of rehabilitation interventions for particular conditions; and studies of the cost-effectiveness of such interventions.