Leprosy and tuberculosis concomitant infection: a poorly understood, age-old relationship.

Historically, archaeological evidence, post-mortem findings and retrospective analysis of leprosy institutions' data demonstrates a high observed incidence of concomitant infection with leprosy and tuberculosis (TB). However, reports of concomitant infection in the modern literature remain scarce, with estimates of annual new case detection rates of concomitant infection at approximately 0.02 cases per 100,000 population. Whilst the mechanism for this apparent decline in concomitant infections remains unclear, further research on this topic has remained relatively neglected. Modelling of the interaction of the two organisms has suggested that the apparent decline in observations of concomitant infection may be due to the protective effects of cross immunity, whilst more recently others have questioned whether it is a more harmful relationship, predisposing towards increased host mortality. We review recent evidence, comparing it to previously held understanding on the epidemiological relationship and our own experience of concomitant infection. From this discussion, we highlight several under-investigated areas, which may lead to improvements in the future delivery of leprosy management and services, as well as enhance understanding in other fields of infection management. These include, a) highlighting the need for greater understanding of host immunogenetics involved in concomitant infection, b) whether prolonged courses of high dose steroids pre-dispose to TB infection? and, c) whether there is a risk of rifampicin resistance developing in leprosy patients treated in the face of undiagnosed TB and other infections? Longitudinal work is still required to characterise these temporal relationships further and add to the current paucity of literature on this subject matter.

Peroneal strength as an indicator in selecting route of tibialis posterior transfer for foot drop correction in leprosy.

OBJECTIVES: Tibialis posterior tendon transfer (TPT) technique, using either the Circum-tibial (CT) or Inter-osseus (IO) route is the standard surgical technique to correct foot drop. The selection of the route of transfer is usually dependent on the surgeon's preference. This study aims to identify criteria to help make that selection. SUBJECTS AND METHODS: A study was carried out on 381 feet during the period 1999 to 2010. All the patients operated during this period were included in the study. The CT route was used for those with peronei power 4 or 5, while the IO route was used when peronei power was 3 or less. RESULTS: In this case series the mean effective range of motion (above 90 degrees) was 11 and 12 degrees in CT and IO routes, respectively. The results were comparable in terms of rest position, active dorsiflexion and effective range of motion. All patients had a post-operative heel to toe gait, except for one of the 381 operated feet. Only three of the 381 feet had a reduction in navicular height of more than 2 cm, the medial arch being maintained in the others. CONCLUSIONS: TPT is a standard procedure to correct foot drop deformity in leprosy. Pre-selection for route of transfer, CT or IO, based on peronei strength avoids the complication of iatrogenic inversion. The technique of insertion and routine tendo-achilles lengthening provides a good range of movement. The deep tunnelling has not compromised the results, while giving excellent cosmetic appearance.

Incidence of ocular complications in patients with multibacillary leprosy after completion of a 2 year course of multidrug therapy.

AIM: To evaluate the incidence of and risk factors for ocular complications in multibacillary (MB) leprosy patients following completion of 2 year, fixed duration, multidrug therapy (MDT). METHODS: Biannual eye examinations were conducted prospectively on a cohort of MB patients who had completed MDT and followed up for 5 years. The incidence of ocular pathology was calculated as the number of events per person year of event free follow up of patients who did not have the specific finding before completion of MDT. RESULTS: 278 patients had one or more follow up visits after completion of MDT. The incidence of lagophthalmos was 0.24%/patient year (95% CI 0.10% to 0.37%); corneal opacity, 5.35%/patient year (95% CI 4.27% to 6.70%); uveal involvement, 3.78%/patient year (95% CI 2.96% to 4.83%); and cataract that reduced vision to 6/18 or less, 2.4%/patient year (95% CI 1.77% to 3.26%). Overall, 5.65%/patient year (95% CI 4.51% to 7.09%) developed leprosy related ocular disease and 3.86%/patient year (95% CI 3.00% to 4.95%) developed leprosy related, potentially blinding ocular pathology during the period following MDT. Age and other disability also predicted incident eye disease. CONCLUSIONS: Every year, approximately 5.6% of patients with MB who have completed MDT can be expected to develop new ocular complications of leprosy, which often (3.9%) are potentially vision threatening. Because many of these complications cannot be detected without slit lamp examination, periodic monitoring, particularly of older patients and those with other disability, is recommended, in order to detect and treat ocular complications satisfactorily.

Multi-centre, double blind, randomized trial of three steroid regimens in the treatment of type-1 reactions in leprosy.

OBJECTIVE: The objective of this randomized trial was to compare three different steroid regimens in treating type 1 reactions in leprosy in routine clinical practice. DESIGN: The study design was a multicentre, double-blind, randomized, controlled, parallel group trial in patients with acute reversal reactions. The trial was conducted in six leprosy treatment centres in India. A total of 334 participants with acute type 1 reaction were recruited to the trial and randomized to one of three prednisolone regimens: high dose (60 mg per day) or low dose (30 mg per day) both tapered over 20 weeks, and short duration (60 mg per day tapered over 12 weeks). The main outcome measure was the proportion of patients failing to respond to treatment and requiring additional steroids. RESULTS: At the end of 12 months, 46% on the short course required additional steroids compared with 31% on the low dose and 24% on the high dose regimen. CONCLUSIONS: The two 20-week regimens were significantly better than the 12-week regimen. The high dose 20-week regimen was marginally and non-significantly better than the low dose regimen, but the high dose regimen contained 50% more steroid. Reactions in leprosy persist over many months and require long courses of steroids.

Nasal mucosa and skin of smear-positive leprosy patients after 24 months of fixed duration MDT: histopathological and microbiological study

The skin and nasal mucosa of 10 lepromatous leprosy patients who had completed 24 doses of fixed duration multidrug therapy (MDT) but who continued to be skin-smear positive for acid-fast bacilli (AFB) were examined histopathologically. The nasal mucosa showed granuloma fractions that exceeded those seen in the skin specimens, signifying that activity in this region subsides much more gradually than the activity in the skin. Mouse foot pad studies done using T900r mice with an inoculum from the nasal mucosa biopsy specimens of these patients did not demonstrate any growth of Mycobacterium leprae, indicating that these bacilli were not viable. A skin specimen from one patient grew significant amounts of bacteria in the T900r mouse foot pad. These results show that 2 years of treatment with MDT would prevent dissemination of M. leprae from the nasal mucosa and, therefore, should preclude further transmission of the disease. It also indicates that viable bacteria might persist in the skin of patients, especially those with an initial bacterial index of > or = 4+ who have completed 24 doses of regular MDT. Therefore, a more cautious approach to administering only 12 doses of MDT to highly positive multibacillary patients is suggested.