Can people affected by leprosy at risk of developing plantar ulcers be identified? A field study from central Ethiopia.

In the ALERT leprosy control programme, 75 people affected by leprosy, in three different geographical areas, were investigated. Each person was documented as having anaesthesia to the 10 g monofilament. The study sought to determine why some people developed ulcers whilst others did not. According to the records, 43 had an ulcer during the last 5 years but 32 had never had an ulcer. In order to examine protective sensation on the sole of the foot, various sensory modalities were tested and the functional anatomy of the foot was examined. The results showed, as may be expected, that it is not possible to define a specific threshold for protective sensation that could be applied to all cases. Some people with only slightly diminished sensation developed ulcers, while many others with almost complete anaesthesia remained ulcer-free. In these rural communities, being a farmer reduced the risk of developing an ulcer, but no other demographic features were significant. Graded monofilaments were found to be the most appropriate test, with loss of sensation at any of five points tested being a 'positive' result. The 10 g filament was the most sensitive, but only 43% of feet identified by this test actually developed an ulcer. As people with partial loss of sensation were excluded from this study, this figure may be lower under programme conditions. The 50 g and 100 g filaments decrease the number of feet identified as at risk, but increase the percentage which actually develop an ulcer, to 46% and 49%, respectively. An appropriate test for selecting those for special programmes which may have a limited capacity, for example the provision of subsidized footwear or involvement in self-care groups, would be a 100 g filament, which would detect 86% of those feet likely to develop an ulcer, while reducing the number of those selected who are not at great risk. Vibrometry was found to be no better than graded filaments and an examination of functional anatomy did not help in identifying those at risk.

The pattern of decline in bacillary index after 2 years of WHO recommended multiple drug therapy: the AMFES cohort.

With effective antibiotic treatment, the bacillary index (BI) in multibacillary leprosy patients declines over a number of years. This can be quantified as a rate of decline in log-units per year or as the time until smear negativity is reached. In the AMFES cohort 220 cases had data on the changes in their BI over time, while 170 cases are documented until smear negativity. The average BI at the start was 3.3 (SD 1.5; range 0.3-5.5) and the mean rate of decline was 0.85 units per year (median 0.7 units per year); in the first 2 years after diagnosis, the mean rate of decline was 1.15 units per year. The rate of decline was not related to any clinical features of the disease except delay in diagnosis: patients presenting for treatment early had a significantly faster rate of clearing the bacilli (adjusted relative risk 2.3; 95% CI 1.0-5.1). Fifty-eight percent of cases took longer than 3 years to reach smear negativity, but this time interval is largely determined by the initial BI and classification, making it a less useful indicator of bacterial clearance. More severe impairment at the start of treatment was associated with a faster return to smear negativity, for which no obvious explanation can be given. Reversal reactions, which occurred in 25% of the cases reviewed, are not associated with a more rapid clearance of bacilli.