Sunday, November 23, 2014

Leprosy

Leprosy



DEFINITION
Leprosy is a chronic granulomatous infection of humans that primarily affects the skin and peripheral nerves.


PHYSICAL FINDINGS AND CLINICAL PRESENTATION
● Skin lesion: most common initial presentation
● Sensory loss
● Anhidrosis
● Neuritic pain
● Palpable peripheral nerves
● Nerve damage (most commonly affected nerves are ulnar, median, common peroneal, posterior tibial, radial cutaneous nerve of the wrist, facial, and posterior auricular)
● Muscle atrophy and weakness
● Foot drop
● Claw hand and claw toes
● Lagophthalmos, nasal septal perforation, collapse of bridge of nose, loss of eyebrows resulting in “leonine” facies (Fig.)


Leprosy can present along a spectrum from simple cutaneous skin lesions with minimal sensory loss to severe extensive skin involvement, painful neuritis, muscle wasting and contractures, and multiple peripheral nerve damage.


CAUSE
● Leprosy is caused by Mycobacterium leprae, an obligate intracellular acid-fast rod.
● The mode of transmission remains elusive. Spread in humans is thought to occur via the respiratory route or entry through broken skin.
● Zoonotic transmission from armadillos has not been proved.
● The majority of people exposed to patients with leprosy do not develop the disease because of their natural immunity.
● Incubation period is 3 to 5 years.

DIAGNOSIS
● The diagnosis of leprosy relies on a detailed history and physical examination and is established by the demonstration of acid-fast bacilli in skin smears or skin biopsies of the affected sites.
● Leprosy has been classifi ed according to the World Health


Organization (WHO) system into:
1. Paucibacillary leprosy defi ned as fewer than fi ve skin lesions with no bacilli on skin smear
2. Multibacillary leprosy defi ned as six or more skin lesions and may be skin-smear positive

● Leprosy has also been classifi ed more specifi cally according to the type of skin lesions, sensory and motor defi cits, and biopsy into:

1. Indeterminate leprosy
2. Tuberculoid leprosy (paucibacillary [few organisms], intense infl ammatory reaction; few, welldemarcated skin lesions)
3. Borderline tuberculoid leprosy
4. Borderline lepromatous leprosy
5. Lepromatous leprosy  (multibacillary [numerous organisms], inadequate host response; diffuse,
poorly organized skin lesions)

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