Mycobacterium leprae: Difference between revisions

Revision as of 13:31, 27 November 2019

About 1 million cases worldwide each year, but is rare in North America
- Number may be underestimated due to difficulties with reliable diagnosis
Most commonly occurs in Southeast Asia (especially India) and Brazil
Decreasing incidence over the past several decades, likely due to short-course multidrug therapy starting in 1982
Humans are thought to be the main reservoir, but it has been found in animals as well (particularly armadillos)
Transmitted most likely by respiratory droplets, though can also be transmitted by direct contact, transplacentally, through breast milk, and after animal exposure

Age, with peaks in adolescence and ≥30 years
Adult men (compared to adult women)
Duration of contact with an infected patient, and the burden of bacilli in the patient

Incubation period of 3-5 years (with wide range)
Classic presentation is anaesthetic hypopigmented skin lesion with thickened nerves
Clinical spectrum from tuberculoid, paucibacillary disease to lepromatous, multibacillary disease
- Paucibacillary (PB) disease has 1 to 5 skin lesions, without bacilli on skin slit smear
- Multibacillary (MB) disease has more than 5 skin lesions, with or without nerve involvement or bacilli on slit-skin smear (regardless of number of lesions)

Disease	Treatment
Paucibacillary	6 months of rifampin, dapsone, and clofazimine
Multibacillary	12 months of rifampin, dapsone, and clofazimine
Rifampin resistance	6 months of at least two second-line drugs with clofazimine, followed by 18 months of one second-line drug with clofazimine
Quinolone resistance	As for rifampin resistance, but without a fluoroquinolone

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+== Background ==
+=== Microbiology ===
+* Slow-growing [[Has Gram stain::acid-fast]] [[Has shape::bacillus]]
+=== Epidemiology ===
+* About 1 million cases worldwide each year, but is rare in North America
+** Number may be underestimated due to difficulties with reliable diagnosis
+* Most commonly occurs in Southeast Asia (especially India) and Brazil
+* Decreasing incidence over the past several decades, likely due to short-course multidrug therapy starting in 1982
+* Humans are thought to be the main reservoir, but it has been found in animals as well (particularly armadillos)
+* Transmitted most likely by respiratory droplets, though can also be transmitted by direct contact, transplacentally, through breast milk, and after animal exposure
+=== Risk Factors ===
+* Age, with peaks in adolescence and ≥30 years
+* Adult men (compared to adult women)
+* Duration of contact with an infected patient, and the burden of bacilli in the patient
+=== Pathophysiology ===
 == Clinical Presentation ==