subject: MYCOBACTERIUM ULCERANS DIAGNOSIS AND MANAGEMENT [print this page] MYCOBACTERIUM ULCERANS DIAGNOSIS AND MANAGEMENT
M. ulcerans causes chronic ulceration, usually on anexposed area of the body, often the lower limbs. The conditionhas a wide distribution in the tropics and is oftencalled Buruli ulcer. The pathogenesis of M. ulceransdisease is related to its unique ability to produce a tissuedamagingtoxin, mycolactone, recently characterized as amacrolide molecule which causes cell death by apoptosis.Histology shows numerous acid-fast bacilli withinextensive areas of necrotic fatty tissue with little inflammatoryreaction. The organisms can be grown in Lowenstein-Jensen medium at 30-33C. Clinical lesions begin asa subcutaneous nodule which ulcerates through the skin.Subcutaneous extension produces an ulcer withmarkedly undermined edges. Patients (most commonlychildren aged 5-15) are systemically well unless there issecondary bacterial infection. Long-term complicationsare determined by the site of the lesion; facial ulcers candestroy an eye; limb lesions may require amputation; scarsaround a joint lead to contractures. The disease is a majorcause of morbidity in West Africa.Standard treatment is surgical and excision of earlylesions is usually curative. Established ulcers requireextensive debridement to remove all infected tissue, followedby grafting. Antibiotics have not been shown to beeffective despite in vitro sensitivities, but there have beenfew formal trials. Local heat may encourage healing, as thebacteria are killed by temperatures over 33C. Manytopical treatments have been tried but there is little evidenceabout their benefit. Recent evidence suggests thattopical nitric oxide treatment may be beneficial. When thelesion affects a region near to a joint, active and passivemovement of that joint must be encouraged to preventcontractures.
Penicillin aluminium monostearate is very effectivegiven once only in a single dose of 1.5 g (0.75 g for childrenunder 10 years). Tetracycline (2.0g/day in divided doses for14 days) can be used in those allergic to penicillin, apartfrom pregnant women and children under 8 years, whoshould receive erythromycin for 2 weeks.
