Leprosy ( Hansen’s disease ) Turki M. Alanazi

objectives• Definition.• Overview.• Modes of transmission• Risk factors.• Clinical features.• Types/classifications.• Diagnosis• Pathogenesis• Treatment.• Complications.•Epidemiology & preventions.

What is leprosy? • Leprosy (also known Hansen’s Disease) is an infectious

disease caused by Mycobacterium leprae which involves the skin and peripheral nerves.

History of leprosy• Leprosy was recognized in the ancient civilizations

of China, Egypt and India.

• The earliest documented account of leprosy is around 1550 B.C on Egyptian papyrus.

• Through out history, the badly affected have often been hated by their communities and families.

CONT ..•Discovered by Gerhard Armauer Hansen in

1873.

Global Project on the History of Leprosyhttp://www.leprosyhistory.org/graphics/gallery/hansen.jpg

Overview• Key facts about

leprosy :

▫ Leprosy is a chronic infectious disease caused by an acid-fast, rod-shaped bacillus, Mycobacterium leprae.

▫ Unlike other mycobacteria, it does not grow in artificial media or even in tissue culture. Scollard, DM et al. 2006. “The continuing challenges of leprosy ”.

Clinical microbiology reviews 19, no. 2: 338-81 .

Facts… • M. leprae multiplies very slowly and the incubation

period of the disease is about five years. (average 3 yrs)

• Symptoms can take as long as 20 years to appear.

• Leprosy is not highly infectious.

• Leprosy is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated cases.

• Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs and eyes.

Transmission • The exact mechanism of transmission of leprosy

is not known.

• the most widely held belief is that the disease is transmitted by contact between cases of leprosy and healthy persons.

• & Transmission nasal discharges (droplets).

• Leprosy is known to occur at all ages ranging from early infancy to very old age.

Risk Factors for Leprosy• Close contact — Contacts of patients with leprosy have a higher risk of

developing leprosy than the general population

• People who live in the areas where leprosy is endemic (parts of India, China, Japan, Nepal, Egypt, and other areas) and

especially those people in constant physical contact with infected people.

• Immunity – immunocompromised individuals are more susceptible to infection.

• Genetic influences - There is some evidence that genetic defects in the immune system may cause certain people to be more likely to become infected (region q25 on chromosome 6).

• Armadillo exposure — Leprosy is enzootic in the nine-banded armadillo

Classification of Leprosy•Two types of classification :

▫Skin smear result classification. ( WHO )▫Clinical classification. (Ridley Jopling)

Classification of Leprosy▫Skin smear result (WHO) classification :

• 1- Paucibacillary leprosy (PB) – few Bacilli;• Two to five skin lesions with negative skin smear

results at all sites.

• 2. Multibacillary leprosy (MB);• Any form of leprosy in which the patient shows

positive smears at any site

Classification of LeprosyClinical (Ridley Jopling) classification :

1. Indeterminate leprosy (IL)2. Tuberculoid leprosy (TT)3. Lepromatous leprosy (LL)4. Borderline leprosy (BL)

Borderline tuberculoid leprosy (BT) Borderline borderline leprosy (BB) Borderline lepromatous leprosy (BL)

Clinical features 1. Skin lesions, usually anaesthetic

Hypopigmented or erythematus patch / plaque .2. Complete / partial loss of sensation.

Painless wounds or burns on the hands or feet Paresthesias: tingling or numbness in the hands or feet Diminished sensation or loss of sensation within skin

patch(es)3. Thickening of peripheral nerves.4. Lumps or swelling on the earlobes or face.5. Tender, enlarged peripheral nerves.

Indeterminate leprosy :Hypopigmented patch, sensation normal, no palpable peripheral nerve and slit skin smear negative

Tuberculoid Leprosy: Annular, erythematous, anasthetic patch with well defined and raised borders and SSS Negative.

Tuberculoid leprosy: Two hypopigmented patches, hypoasthetic well defined borders, palpable peripheral nerve and SSS negative.

Borderline lepromatous leprosy (BL/MB)

Borderline lepromatous case showing borderline tuberculoid and "punched- out" mid borderline lesions

together with papular and nodular lesions more typical of lepromatous disease.

A -Claw hand due to median and ulnar nerve damage.

B- hands showing neurotrophic atrophy .

Objectives • Definition.• Overview.• Modes of transmission• Risk factors.• Clinical features.• Types/classifications.•Diagnosis•Pathogenesis•Treatment.•Complications.• Epidemiology & preventions.

Pathogenesis •The areas most commonly affected by

leprosy are the superficial peripheral nerves , skin ,mucous membranes of the upper respiratory tract, eyes , and tests

•Tissue damage is caused by the degree to which cell-mediated immunity is expressed , the extent of bacillary spread and multiplication , immunologic complication and nerve damage

Cont…•M leprae is an obligate intracellular acid-

fast bacillus with unique ability to enter nerves

Diagnosis •Diagnosis of leprosy is most commonly based

on the clinical sign and symptoms.

• In an endemic country or area, an individual should be regarded as having leprosy if he or she shows ONE of the following cardinal signs :

•skin lesion consistent with leprosy and with definite sensory loss, with or without thickened nerves

•positive skin smears

Cont…• If you have a suspicious skin sore, your

doctor will remove a small sample of the abnormal skin and send it to a laboratory to be examined. This is called a skin biopsy . A skin smear test may also be done. With paucibacillary leprosy, no bacteria will be detected. In contrast, bacteria are expected to be found on a skin smear test from a person with multibacillary leprosy.

Treatment •Common drugs i. Dapson ii. Refampicine iii. Clofazimine

The combination of these three drugsIs known as multi drug therapy (MDT)

Cont…•6 month regimen for Paucibacillary

(PB) LeprosyoDapson 100 mg (daily)oRefampicin 600 mg (monthly)

Cont…•12 month regimen for Multibacillary

(MB) LeprosyoDapsone 100 mg (daily)oRefampicin 600 mg (monthly)oClofazimine 300 mg (monthly) oro50 mg (daily)

complication• disfigurement• hair loss, particularly on the eyebrows and eyelashes• muscle weakness• permanent nerve damage in the arms and legs• inability to use the hands and feet• Nosebleeds • iritis (inflammation of the iris of the eye), glaucoma

(an eye disease that causes damage to the optic nerve), and blindness

• Infertility • kidney failure

References•WHO.•UPTODATE. •Kumar & Clarks clinical medicine.