Leprosy

Definition

Definition of Leprosy
Leprosy or Hansen's disease (HD) is a chronic disease caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Named after physician Gerhard Armauer Hansen, leprosy is primarily a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract; skin lesions are the primary external sign. Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs and eyes. Contrary to folklore, leprosy does not cause body parts to fall off, although they can become numb or diseased as a result of secondary infections; these occur as a result of the body's defenses being compromised by the primary disease. Secondary infections, in turn, can result in tissue loss causing fingers and toes to become shortened and deformed, as cartilage is absorbed into the body.

Symptoms

Symptoms of Leprosy
Skin lesions are the primary external sign. Left untreated, leprosy can be progressive, causing permanent damage to the skin, nerves, limbs, and eyes.

Causes

Causes of Leprosy
Mycobacterium leprae and Mycobacterium lepromatosis are the causative agents of leprosy. M. lepromatosis is a relatively newly identified mycobacterium isolated from a fatal case of diffuse lepromatous leprosy in 2008.

An intracellular, acid-fast bacterium, M. leprae is aerobic and rod-shaped, and is surrounded by the waxy cell membrane coating characteristic of Mycobacterium species.

Due to extensive loss of genes necessary for independent growth, M. leprae and M. lepromatosis are obligate pathogens, and unculturable in the laboratory, a factor that leads to difficulty in definitively identifying the organism under a strict interpretation of Koch's postulates. The use of non-culture-based techniques such as molecular genetics has allowed for alternative establishment of causation.

Diagnosis

Diagnosis of Leprosy
Diagnosis in the U.S. is often delayed because healthcare providers are unaware of leprosy and its symptoms. Early diagnosis and treatment prevents nerve involvement, the hallmark of leprosy, and the disability it causes.

There are many kinds of leprosy but there are common symptoms. These include runny nose, dry scalp, eye problems, skin lesions, and muscle weakness.

Prognosis

Prognosis of Leprosy
Diagnosing the disease early is important. Early treatment limits damage, prevents a person from spreading the disease, and allows the person to have a normal lifestyle.

Treatment

Treatment of Leprosy
Enough synthetic pharmaceuticals that are effective against leprosy have by now been identified, and support a flexible choice of treatments. The WHO Study Group's report on the Chemotherapy of Leprosy in 1993 recommended two types of standard MDT regimen be adopted. The first was a 24-month treatment for multibacillary (MB or lepromatous) cases using rifampicin, clofazimine, and dapsone. The second was a six-month treatment for paucibacillary (PB or tuberculoid) cases, using rifampicin and dapsone. At the First International Conference on the Elimination of Leprosy as a Public Health Problem, held in Hanoi the next year, the global strategy was endorsed and funds provided to WHO for the procurement and supply of MDT to all endemic countries.

Prevention

Prevention of Leprosy
In a recent trial, a single dose of rifampicin reduced the rate at which contacts acquired leprosy in the two years after contact by 57%; 265 treatments with rifampicin prevented one case of leprosy in this period. A non-randomized study found that rifampicin reduced the number of new cases of leprosy by 75% after three years.

BCG offers a variable amount of protection against leprosy as well as against tuberculosis.

Efforts to overcome persistent obstacles to the elimination of the disease include improving detection, educating patients and the population about its cause, and fighting social taboos about a disease that has caused its patients throughout history to be considered "unclean" or "cursed by God" as outcasts. Leprosy is not a hereditary disease. Where taboos are strong, patients may be forced to hide their condition (and avoid seeking treatment) to avoid discrimination. The lack of awareness about Hansen's disease can lead people to believe (falsely) that the disease is highly contagious and incurable.