Leprosy - Causes, Symptoms and Treatment
Leprosy, also known as Hansen's disease, is a chronic, systemic infection characterized by progressive cutaneous lesions. Leprosy occurs in three distinct forms:
Causes of Leprosy
Leprosy is caused by Mycobacterium leprae, an acid-fast bacillus that attacks cutaneous tissue and peripheral nerves, producing skin lesions, anesthesia, infection, ,and deformities. Contrary to popular belief, leprosy is not highly contagious but actually has a low rate of infectivity. Continuous, close contact is needed to transmit it. In fact, 9 out of 10 persons have a natural immunity to it. Susceptibility appears highest during childhood and seems to decrease with age. Presumably, transmission Occurs through airborne respiratory droplets containing M. leprae or by inoculation through skin breaks (with a contaminated hypodermic or tattoo needle. for example). The incubation period is unusually long-6 months to 8 years. Leprosy is most prevalent in the underdeveloped areas of Asia (especially India and China), Africa, South America, and the islands of the Caribbean and Pacific. About 11 million people worldwide suffer from this disease; approximately 4,000 are in the United States, mostly in California, Texas, Louisiana, Florida, New York, and Hawaii.
Signs and Symptoms of Leprosy
M. leprae attacks the peripheral nervous system, especially the ulnar, radial, posterior-popliteal, anterior-tibial, and facial nerves. The central nervous system appears highly resistant. When the bacilli damage the skin's line nerves, they cause anesthesia, anhidrosis, and dryness; if they attack a large nerve trunk, motor nerve damage, weakness, and pain Occur, followed by peripheral anesthesia, muscle paralysis, or atrophy.
In later stages, clawhand, footdrop, and ocular complications - such as corneal insensitivity and ulceration, conjunctivitis, photophobia, and blindness - can occur. Injury, ulceration, infection, and disuse of deformed parts cause scarring and contracture. Neurologic complications occur in both lepromatous and tuberculoid leprosy but are less extensive and develop more slowly in the lepromatous form. Lepromatous leprosy can invade tissue in virtually every organ of the body, but the organs generally remain functional.
The lepromatous and tuberculoid forms affect the skin in markedly different ways. In lepromatous disease, early lesions are multiple, symmetrical, and erythematous, sometimes appearing as macules or papules with Smooth surfaces. Later, they enlarge and form plaques or nodules called lepromas on the earlobes. nose, eyebrows, and forehead,giving the patient a characteristics leonine appearance. In advanced stages, M. leprae may infiltrate the entire skin surface. Lepromatous leprosy also causes loss of eyebrows, eyelashes, and sebaceous and sweat gland function; and, in advanced stages, conjunctival and scleral nodules. Upper respiratory lesions cause epistaxis, ulceration of the uvula and tonsils, septal perforation, and nasal collapse. Lepromatous leprosy can lead to hepatosplenomegaly and orchitis. Fingertips and toes deteriorate as bone resorption follows trauma and infection in these insensitive areas.
When tuberculoid leprosy affects the skin (sometimes its effect is strictly neural), it produces raised, large, erythematous plaques or macules with clearly defined borders. As they grow, they become rough, hairless, hypopigmented, and leave anesthetic scars.
In borderline leprosy, skin lesions are numerous, but smaller, less anesthetic, and less sharply defined than tuberculoid lesions. Untreated, borderline leprosy may deteriorate into lepromatous disease.
Occasionally, acute episodes intensify leprosy's slowly progressing course. Whether such exacerbations are part of the disease process or a reaction to therapy remains controversial. Erythema nodosum leprosum (ENL), seen in lepromatous leprosy, produces fever, malaise, lymphadenopathy, and painful red skin nodules, usually during antimicrobial treatment, although it may occur in untreated people. In Mexico and other Central American countries, some patients with lepromatous disease develop Lucio's phenomenon, which produces generalized punched-out ulcers that may extend into muscle and fascia. Leprosy may also lead to tuberculosis, malaria, secondary bacterial infection of skin ulcers, and amyloidosis.
Diagnosis for Leprosy
Early clinical indications of skin lesions and muscular and neurologic deficits are usually sufficiently diagnostic in patients from endemic areas. Biopsies of skin lesions are also diagnostic. Biopsies of peripheral nerves or smears of the skin or of ulcerated mucous membranes help confirm the diagnosis. Blood tests show increased erythrocyte sedimentation rate; decreased albumin, calcium, and cholesterol levels; and, possibly, anemia. Differential diagnoses include many skin and systemic diseases, such as lupus erythematosus, lupus vulgaris, sarcoidosis, yaws, and dermal leishmaniasis.
Treatment for Leprosy
Treatment consists of antimicrobial therapy using sulfones, primarily oral dapsone, which may cause hypersensitivity reactions.
Failure to respond to sulfones or the occurrence of respiratory involvement or other complications requires alternative therapy, such as rifampin in combination with clofazimine or ethionamide. Clawhand, wristdrop, or footdrop may require surgical correction.
When a patient's disease becomes inactive, as determined by the morphologic and bacterial index, treatment is discontinued according to the following schedule: tuberculoid, 3 years; borderline, depends on the severity of the disease but may be as long as 10 years; lepromatous, lifetime therapy.
Because ENL is commonly considered to be a sign that the patient is responding to treatment, antimicrobial therapy should be continued. Thalidomide and clofazimine have been used successfully to treat ENL at the National Hansen's Disease Center (NHDC); however, this treatment requires a signed consent form and strict adherence to established NHDC protocols. Corticosteroids may also be given as part of ENL therapy. With timely and correct treatment, leprosy has a good prognosis and is seldom fatal. Untreated, however, it can cause severe disability. The lepromatous type may lead to blindness and deformities.
Any patient suspected of having leprosy may be referred to the Gillis W. Long Hansen's Disease Center in Carville, Louisiana, or to a regional center. At this international research and educational center, patients undergo diagnostic studies and treatment and are educated about their disease. Patients are encouraged to return home as soon as their medical condition permits. The federal government pays the full cost of their medical and nursing care.
Special Considerations and Prevention Tips for Leprosy
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