What is Leprosy?
Leprosy (Hansen’s disease) is a chronic granulomatous disease, affecting peripheral nerves and superficial tissues, especially the nasal mucosa.
What causes Leprosy?
Mycobacterium leprae, which shares the same structural properties of M. tuberculosis but it cannot be grown on agar media or in cell culture
Resevoirs of Mycobacterium leprae?
What are the major forms of leprosy?
tuberculoid and lepromatous, with additional clinical classifications lying between the two extremes.
How is M. leprae transmitted?
It is believed that M. leprae is transmitted via small droplets from nasal secretions of lepromatous leprosy patients.
Infectivity is low and the incubation period is estimated to be 2-7 years. Contraction of the disease requires prolonged close contact with an infected person. Leprosy is virtually absent from North America and Europe, but many new cases still arise in other parts of the world, especially India and Brazil.
Where does M. leprae reside in the body?
M. leprae is an obligate intracellular parasite primarily of macrophages and Schwann cells, although it can also invade peripheral neurons.
The degree of ________ determines the extent of disease.
T cell-mediated immunity. Lepromatous cases lack TH1 mediators.
How does Tuberculoid leprosy present?
Causes single skin lesions on the face, limbs, and buttocks. Peripheral nerve involvement can leave the lesions anesthetic, but facial lesions typically are not. Low numbers of organisms are present in the lesions and the patient is usually not contagious.
Tuberculoid lesions can heal spontaneously and the prognosis is good.
How does Lepromatous leprosy present initially?
It is a progressive disease with the first signs being edema and rhinitis. Lesions are extensive on the face, buttocks, and limbs. Infiltration is notable in the ear lobes, where acid-fast staining bacilli can be readily observed from scrapings. Damage can be severe, with perforation of the nasal septum and collapse of the nose due to cartilage loss, loss of fingers to neurotrophic atrophy, and atrophy of testicles. The microbe spreads to the reticuloendothelial system.
How is leprosy diagnosed?
Because the organism cannot be grown in culture, leprosy is mostly a clinical diagnosis with confirmation from skin biopsies and the detection of acid-fast staining bacilli.
How is leprosy treated?
Antibiotic resistance is a problem, so multidrug therapy is essential.
Drugs for tuberculoid leprosy?
A sulfone (inhibits para-aminobenzoic acid metabolism) when used in combination with rifampin can cure tuberculoid leprosy with 12 months treatment.
Treatment for lepromatous leprosy?
For the lepromatous form, clofazimine is added and treatment lasts at least 2 years. Prophylaxis with sulfones on children in close contact with lepromatous cases may be effective. The key to prevention is early diagnosis and treatment