LEPROSY. A chronic contagious disease primarily affecting the peripheral nerves secondarily involving skin, mucosa of mouth and upper respiratory tract, reticulo-endothelial system, eyes, bones and testes.
Causative agent: Mycobacterium leprae. • Mode of infection: close contact with an open case of leprosy. • Incubation period: average 3-5 years.
CLASSIFICATION: • · Lepromatous leprosy. • · Tuberculoid leprosy. • · Borderline leprosy. • · Indeterminate leprosy.
LEPROMATOUS LEPROSY. Develops in infected persons with low resistance. Clinicaly.The skin, nerves, bones and internal organs are involved in this type.
Skin lesions. Consist of ill-defined multiple erythematos macules, papules, nodules or plaques. The lesions are symmetrically distributed on the face, limbs and trunk. The outer third of eye brows are usually lost
Other organs: liver, testicles, lymph nodes and bones may be involved. Eye affection with keratitis, iridocyclitis and iris atrophy. Lepromin test is negative, indicating low degree of immunity.
TUBERCULOID LEPROSY. • Develops in persons with good immunity. Clinically. • The skin and peripheral nerves are the only tissues showing clinical evidence of involvement
Skin lesions • . Consist of erythematous or hypopigmented plaques with well-defined edges and anaesthetic dry hairless surface. The lesions are few, large and asymmetrically distributed.
Peripheral nerves • are early involved in tuberculoid leprosy resulting in wasting and paralysis of the small muscles of the hands and feet, anaesthesia of limbs and trophic changes. In some cases the condition may be limited to peripheral nerves only (neural type). The ulnar nerve is the most commonly affected, less frequently the posterior tibial and the great auricular.
Lepromin test is strongly positive indicating high degree of cell mediated immunity.
BORDERLINE LEPROSY This type is immunologicaly unstable and usually evolves into one of the previous two polar types. It is intermediate between lepromatous and tuberculoid types and therefore a wide range of pathological and clinical manifestations can be encountered
Skin lesions. Consist of erythematous macules and plaques, intermediate between lepromatous and tuberculoid in number, size and anaesthesia. They are asymmetrically distributed. • Lepromin test is weakly positive or negative.
INDETERMINATE LEPROSY • . • This type occurs in those whose immunological status has not yet been determined. It is a transitory phase in the disease process. The skin lesions consist of hypopigmented macules which are nonspecific in appearance.
DIAGNOSTIC PROCEDURES • . • 1. Skin smear. • 2. Nasal smear. • 3. Skin biopsy. • 4. Nerve biopsy. • 5. Lepromin test.
TREATMENT OF LEPROSY • . • 1. General measures: • · Good nourishing diet. • · Tonics and vitamins. • 2. Chemotherapy: • · SULPHONES: dapsone tablets are given usually in a dose of 100 mg/day. • · Rifampicin is given in a dose of 600 mg/m daily on an empty stomach. • · CLOFAZIMINE (LAMPRENE): dose is 100mg/m daily.
COMBINED THERAPY • : various regmins of combined therapy are now recommended to decrease the possibility of emmergence of resistant strains. Combined therapy is particularly recommended in lepromatous leprosy.
DURATION OF TREATMENT • . It depends on the type of leprosy. Tuberculoid leprosy requires treatment for three years or until all signs of activity have seized. Lepromatous leprosy requires treatment for life. In border line leprosy the period of treatment varies betwen 6-9 year and depends on the evolution of the disease. • Causative agent: Mycobacterium leprae.