Leprosy

•       Caused by bacteria Mycobacterium leprae

•       It causes damage to the skin and the peripheral nervous system.

•       Disease develops slowly (from six months to 40 years)

•       Results in skin lesions and deformities, most often affecting the cooler places on the body

•       Skin, mouth, respiratory tract, eyes, peripheral nerves, superficial lymphnodes and testis

Signs of leprosy

•       Pale or slightly reddish patch

•       Definite loss of sensation in the patch

•       Signs of damage to nerves

–      Definite loss of sensation in cooler areas of body hands/feet

–      Weakness of muscles of hands/feet/face

–      Visible deformity of hands/feet/face

Symptoms of Leprosy

•            Symptoms are similar to those that may occur  with syphilis, tetanus

•            Numbness and loss of temperature sensation (cannot  sense very hot or cold temperatures)

•             As the disease progresses, the sensations of touch, then pain, and eventually deep pressure are decreased or lost

Mode of transmission of Leprosy 

•       Slow communicable disease

•       Incubation period between first exposure and appearance of signs of disease varies from 2- 20 years

•       Direct contact with untreated leprosy patient  - shed numerous bacilli from damaged skin, nasal secretions, mucus membrane of mouth and hair follicles

•       Materno – foetal transmission across plancenta

•       From milk of leprosy patient to infant

Types of leprosy

•       Lepromatous leprosy

•       Skin lesions are symmetrical, hypopigmented, erythomateous macules, nodules or diffuse infiltrates

•       Lesions are anaesthetic, sensory disturbance not distinct as TT

•       Tuberculoid leprosy

•       Lesions are either single or as a symmetrical hypopigmented, erythematous macule

•       Distinct sensory impairment

Pathophysiology of Leprosy

•       Sebaceous glands and hair follicles

•       Onset, small cutaneous nerve fibers are involved

•       With bacillary multiplication, contiguous skin areas, including autonomic nerve fibers, dermal appendages, and blood vessels, are invaded

•       As infection spreads along sensory nerves, motor fibers within parent nerve trunks are damaged

•       Leprosy bacilli are unable to penetrate nervous system proximal to the dorsal root ganglions

•       Central nervous system infection does not occur

•       Little systemic reaction, and tissue destruction occurs mainly in cool, superficial locations: the skin (except in folds)

•       Peripheral nerves in subcutaneous loci, oral and nasopharyngeal mucous membranes (not enteric or vaginal); the testes (not the ovaries); anterior third of the eye

Summary

•       Leprosy is a disease caused by the bacteria mycobacterium leprae and the disease develops slowly and results in skin lesions and deformities, most often affecting the cooler places

•       Classified in to five types indeterminate leprosy, tuberculoid leprosy, borderline tuberculoid leprosy, lepromatous leprosy, mid borderline leprosy

•       Leprosy have clinically detectable lesion all over the body with inolvement of sensory at first and motor fibres at the later stages with significant bactermia affecting every organ