LEPROSY By Mwila B. C. DEFINITION - PowerPoint Presentation

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LEPROSY

By Mwila B. C.

DEFINITION

Leprosy is a

chronic disease

of the nervous system which affects the skin and nerves caused by a bacteria known as

Mycobacterium Leprae

.

The organism was discovered by

Gerhard Armauer Hansen

in Norway

in

1873

making it the first bacterium to be identified as causing disease in man.

Characteristics of the organism.

It is a strongly acid-fast, rod-shaped organism with parallel sides and rounded ends.

In size and shape it closely resembles the Tubercle Bacillus.

Under the electron microscope the bacillus appears to have a great variety of forms.

Portal of entry of M.Leprae.

Not definitely known.

However the two portals of entry seriously considered are the

skin

and the

upper respiratory tract.

Age at onset

:

Mainly affects young adults in their most productive period of life.

However, it can occur in old age.

INCUBATION PERIOD

The minimum incubation period is as short as few weeks and maximum as long as up to 30 years.

However the average period of incubation is 3-5 years.

Mortality

: The disease is rarely an immediate cause of death.

Cure of disease:

With

multi drug therapy (MDT),

cure is possible upon completion of treatment.

TYPES OF LEPROSY.

LEPROMATOUS LEPROSY

.

This is a type of leprosy which is common in persons with

low

resistance.

Leprosy Bacilli are widely disseminated through out the skin, nerves and

reticulo

-endothelial system.

There may be bacillary invasion of the eyes, testes, bones and mucous membrane of the mouth, nose, pharynx, larynx and trachea.

Lepromatous leprosy cont..

Skin lesions

.

The lesions are multiple, small and symmetrically distributed.

They take the form of macules, infiltrations (plaques), papules and nodules, all of which may be present in the same patient at the same time once the disease has become established

.

Nerve involvement

.

Nerves do not show signs of damage as early as in the other types of leprosy. Nerve thickening may be there and tends to be bilateral and symmetrical.

Other tissues involved are nails of fingers and toes, mucous membranes, eyes, bones, reticulo-endothelial system, testes and kidneys.

Tuberculoid leprosy.

This is a type of Leprosy seen in persons with a good resistance and may be purely neural or combined neural and dermal.

The infection is never widespread but is localised to one area or to a few areas asymmetrically

.

Tuberculoid leprosy cont..

Affected nerves may be thickened, and may be associated with sensory and motor disturbances such as face (trigeminal nerve), neck (great auricular nerve), forearm (

antebrachial

cutaneous

nerve),

little

and ring finger (ulna nerve), hand (median nerve at the wrist) thigh (femoral

cutaneous

nerve), lower leg (common

peroneal

nerve), dorsum of foot (superficial

peroneal

nerve) and sole of foot (posterior

tibial

nerve).

Skin lesions take the form of macules or infiltrations.

Lesions are usually few, large and asymmetrical.

Borderline leprosy

This is a type of Leprosy seen in persons with a limited or variable resistance and usually presents with skin and nerve involvement.

Skin lesions are macular, infiltrated or both, the earliest lesions being macules which are erythromatous or hypo pigmented

.

Nerves are involved asymmetrically and show palpable thickening and impaired function.

Other tissues are not affected directly but indirectly.

Both sensory and motor nerves may be affected.

Indeterminate leprosy

This is an early phase in natural history of Leprosy.

At this stage the disease has not yet

been

determined.

It usually presents as a single

macule

with uncharacteristic histology and absence f bacilli.

Clinical manifestations

Mode of onset is variable.

An erythrematous or hypo pigmented patch with loss of sensation.

Sometimes there may be loss of sensation without skin patches.

There may be tenderness, tingling or thickening of a nerve, an area of anaesthesia with some change in appearance of skin insensitiveness to burning, tingling or numbness of extremities.

Definition of a case of Leprosy.

A case of Leprosy is a person having one or more of the following features, and who has yet to complete a full course of treatment:

Hypo pigmented or reddish skin lesion with definite loss of sensation.

Involvement of the peripheral nerves, as demonstrated by loss of sensation and weakness of the muscles of hands, feet or face.

Skin smear positive for acid-fast bacilli.

Diagnosis of leprosy

Mostly based on signs and

symptoms such as, skin

lesions, single or

multiple and may be

hypopigmented

.

Lesions

may be seen as macules, papules or nodules.

History may reveal sensory

loss

e.

Nerve damage, nerve thickening, weakness of muscles supplied by the affected nerve

.

Skin smear may be positive

TREATMENT.

Multi-drug Therapy (MDT) is used.

None of these drugs should be used as

monotherapy

.

1.

Rifampicin

.

This is the most effective drug against

M.leprae

.

Dose

: 600mg

monthly

2.Clofazimine

Dose:

200-300mg

monthly

3

.

Dapsone

Dose:

100mg daily

Multibacillary – duration 12 months.

Paucibacillary – duration 6 months.

Clinical classification.

Multibacillary

More than 5 lesions.

Distribution more asymmetrical.

Loss of sensation.

Many nerve trunks affected.

Paucibacillary

Up to 5 lesions.

Hypo pigmented or

erythromatous

Asymmetrically distributed.

Definite loss of sensation.

Only one nerve trunk affected.

End of the lecture

Thank your for your attention

And may our good lord bless and protect you all

(Mwila b. c. 2009)