Leprosy: Type, Symptoms, Transmission, Pathophysiology of 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

Symptoms of Leprosy

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

Types of leprosy

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

Diagnosis of Leprosy

Clinical Examination: The first step in diagnosing leprosy involves a thorough clinical examination by a trained healthcare provider. They look for characteristic skin lesions, loss of sensation, and nerve involvement.

Skin Smear Test: A skin smear test involves taking a small sample from skin lesions to examine under a microscope. It helps identify the presence of acid-fast bacilli, indicating leprosy infection.

Biopsy: A skin biopsy may be performed to confirm the diagnosis and determine the specific type of leprosy.

Nerve Biopsy: Nerve involvement is common in leprosy. A nerve biopsy helps in assessing nerve damage and guiding treatment.

Treatment Options for Leprosy:

Multidrug Therapy (MDT): MDT is the primary and most effective treatment for leprosy. It involves combining three antimicrobial drugs: dapsone, rifampicin, and clofazimine. The duration of treatment varies based on the type and severity of leprosy.

Single Drug Therapy (SDT): For milder cases of leprosy, single drug therapy with rifampicin is sometimes used.

Steroids: In certain cases, corticosteroids may be prescribed to manage inflammatory reactions known as leprosy reactions.

Supportive Care: Patients may receive supportive care to manage any complications arising from leprosy, such as wound care for skin ulcers or physical therapy for nerve damage.


       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

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Pathophysiology Notes