Leprosy overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae.[1] Leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions are the primary external symptom. Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs, and eyes.
Historical Perspective
Contrary to popular conception, leprosy does not cause body parts to simply fall off, and it differs from tzaraath, the malady described in the Hebrew scriptures and previously translated into English as leprosy.[2]
Historically, has affected humanity since at least 300 BC, and was well-recognized in the civilizations of ancient China, Egypt and India.[3]
Classification
The clinical manifestations of leprosy vary but primarily affect the skin, nerves, and mucous membranes.[4] Patients with this chronic infectious disease are classified as having paucibacillary (tuberculoid leprosy), multibacillary Hansen's disease (lepromatous leprosy), or borderline leprosy.
Pathophysiology
Worldwide, 1-2 million persons are permanently disabled as a result of Hansen's disease. However, persons receiving antibiotic treatment or having completed treatment are considered free of active infection. Although the mode of transmission of Hansen's disease remains uncertain, most investigators think that M. leprae is usually spread from person to person in respiratory droplets.
Causes
A bacillus, Mycobacterium leprae, that multiplies very slowly and mainly affects the skin, nerves, and mucous membranes. The organism has never been grown in bacteriologic media or cell culture, but has been grown in mouse foot pads.
Epidemiology and Demographics
In 1995, the World Health Organization (WHO) estimated that between two and three million individuals were permanently disabled because of leprosy.[5] Although the forced quarantine or segregation of patients is unnecessary—and can be considered unethical—a few leper colonies still remain around the world, in countries such as India, and Vietnam.
Risk Factors
Close contacts of patients with untreated, active multibacillary disease are at highest risk of acquiring leprosy. Children are more susceptible than adults to contracting the disease.
Diagnosis
History and Symptoms
This chronic infectious disease usually affects the skin and peripheral nerves but has a wide range of possible clinical manifestations. Patients are classified as having paucibacillary or multibacillary Hansen's disease. Paucibacillary Hansen's disease is milder and characterized by one or more hypopigmented skin macules. Multibacillary Hansen's disease is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis.
Physical Examination
Paucibacillary Hansen's disease is milder and characterized by one or more hypopigmented skin macules. Multibacillary Hansen's disease is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis.
Laboratory Findings
Lepromin skin test can be used to distinguish lepromatous from tuberculoid leprosy, but is not used for diagnosis. Other tests include skin lesion biopsy and skin scraping examination for acid fast bacteria.
Treatment
Medical Therapy
The age-old social stigma associated with the advanced form of leprosy lingers in many areas, and remains a major obstacle to self-reporting and early treatment. Effective treatment for leprosy appeared in the late 1940s with the introduction of dapsone and its derivatives. However, leprosy bacilli resistant to dapsone gradually evolved and became widespread, and it was not until the introduction of multidrug therapy (MDT) in the early 1980s that the disease could be diagnosed and treated successfully within the community.
Secondary Prevention
Prevention consists of avoiding close physical contact with untreated people. People on long-term medication become noninfectious (they do not transmit the organism that causes the disease).
References
- ↑ Sasaki S, Takeshita F, Okuda K, Ishii N (2001). "Mycobacterium leprae and leprosy: a compendium". Microbiol Immunol. 45 (11): 729–36. PMID 11791665.
- ↑ Leviticus 13:59, Artscroll Tanakh and Metsudah Chumash translations, 1996 and 1994, respectively.
- ↑ "Leprosy". WHO. Retrieved 2007-08-22.
- ↑ Naafs B, Silva E, Vilani-Moreno F, Marcos E, Nogueira M, Opromolla D (2001). "Factors influencing the development of leprosy: an overview". Int J Lepr Other Mycobact Dis. 69 (1): 26–33. PMID 11480313.
- ↑ WHO (1995). "Leprosy disabilities: magnitude of the problem". Weekly Epidemiological Record. 70 (38): 269–75. PMID 7577430.