Glossary of Medical and Health Terms

Leprosy (Hansen's Disease)

Leprosy, or Hansen's disease, is a chronic infectious disease caused by the bacterium Mycobacterium leprae. 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. 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.

Historically, leprosy has affected humanity since at least 300 BC, and was well-recognized in the civilizations of ancient China, Egypt and India. In 1995, the World Health Organization (WHO) estimated that between two and three million individuals were permanently disabled because of leprosy. 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.

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.

Characteristics

The clinical symptoms of leprosy vary but primarily affect the skin, nerves, and mucous membranes. Patients with this chronic infectious disease are classified as having paucibacillary (tuberculoid leprosy), multibacillary Hansen's disease (lepromatous leprosy), or borderline leprosy.

Borderline leprosy (also termed multibacillary), of intermediate severity, is the most common form. Skin lesions resemble tuberculoid leprosy but are more numerous and irregular; large patches may affect a whole limb, and peripheral nerve involvement with weakness and loss of sensation is common. This type is unstable and may become more like lepromatous leprosy or may undergo a reversal reaction, becoming more like the tuberculoid form.

Paucibacillary Hansen's disease is characterized by one or more hypopigmented skin macules and anaesthetic patches, i.e., damaged peripheral nerves that have been attacked by the human host's immune cells.

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 (nose bleeds) but typically detectable nerve damage is late.

Contrary to popular belief, Hansen's bacillus does not cause rotting of the flesh; rather, a long investigation by Paul Brand yielded that insensitivity in the limbs extremities was the reason why unfelt wounds or lesions, however minute, lead to undetected deterioration of the tissues, the lack of pain not triggering an immediate response as in a fully functioning body. Recently, leprosy has also emerged as a problem in HIV patients on antiretroviral drugs.

Associated ICD-10 code: A30.

Source: http://en.wikipedia.org/wiki/Leprosy

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