12. mycobacterium leprae

MICROORGANISM

1. Ratheesh r.l MYCOBACTERIUM LEPRAE

2. Cultural Characteristics These organisms are unable to cultivate in other medias.

3. pathogenesis Infection occurs by inhalation of bacteria into the respiratory system along with that, the organism also enters into the body from small abrasions present on the skin.

4. Most of the damage done is by entering the nerves, mainly spinal nerves and cause damage to them. It leads to loss of sensation of touch, pain, temperature.

5. It leads to white patches on the skin which arise due to loss of pigmentation from skin. If this disease starts deteriorating , nodes appear on the skin which contains bundles of bacteria, slowly it disseminates into the complete body and causes formation of “ granuloma ” .

6. This granuloma is different from tubercle granuloma due to absence of central necrosis.

7. Clinically 4 types of leprosy are Lepromatous leprosy Tuberculoid type Dimorphic leprosy Inditerminate leprosy

8. 1. Lepromatous leprosy Lepromatous leprosy  is a skin condition consisting of pale macules . The macules will appear on face, hand, feet, ear lobes, and less commonly on the trunk. In the macules a large number of bacilli will be present

9. 2. Tuberculoid type In the  tuberculoid  form of the disease the skin lesions appear as light red or purplish spots.  Tuberculoid leprosy is the more benign  type , even though it is accompanied by nerve involvement, which leads to numbness (usually of the extremities), contractures, and ulceration.

10. 3. Dimorphic leprosy/border line Borderline leprosy  is a cutaneous skin condition with numerous  skin lesions  that are red irregularly shaped plaques . In this type lesions produced possess characteristics of both lepromatous and tuberculoid lesions. This lesions clinically resembles lesions of tuberculoid leprosy but bacteriologically resembles lesion of lepromatous type.

11. 4. Inditerminate leprosy In this type, the lesions produced often resemble maculo -anesthetic patches which are neither characteristic of lepromatous or tuberculoid type . In some cases these lesions heal spontaneously while in others it may progress to lepromatous or tuberculoid type.

12. How to diagnose leprosy Examine skin Check for patches Test for sensation Count the number of patches Look for damage to nerves Dr.T.V.Rao MD 14

13. Diagnosis of Leprosy Diagnosis must therefore be made by doing a biopsy, in which a small piece of skin is taken to analyse for the leprosy bacterium. Early diagnosis is very important because it can prevent permanent deformities and disability . Dr.T.V.Rao MD 15

14. LAB DIAGNOSIS OVERVIEW : 1. Specimens 2. Acid fast staining 3. Skin and nerve biopsy 4. Animal inoculation 5. Lepromin test

15. 1. SPECIMENS Nasal mucosa, skin lesions , ear lobules . Skin and nerve biopsy .

16. Edges of the lesion . Slit and scrape method : Pinch the site tight Incise Scrape & collect material Smear on a slide SKIN :

17. SKIN BIOPSY : Active edges of the patches NERVE BIOPSY : From thickened nerves

18. 2. ACID FAST STAINING Ziehl-Neelson method Decolourising agent = 5% sulphuric acid Lepra cells confirm the diagnosis of lepromatous leprosy The living bacilli will stain uniformly and appear as solid while dead bacilli appear as granular and fragmented .

19. Bacteriological index (B.I) : Number of total bacilli in a tissue. Higher the B.I , severe the infection

20. Percentage of uniformly stained bacilli out of the total number of bacilli counted. For assessing the progress of patients with leprossy . MORPHOLOGICAL INDEX(M.I ) :

21. For histological confirmation of tuberculoid bacilli ( as they cannot be demonstrated in direct smear ) Skin biopsy is also useful in diagnosis and accurate classification of leprosy lesion . 3. SKIN AND NERVE BIOPSY

22. 4. ANIMAL INOCULATION Nine banded armadillo Injection of ground tissue from lepromatous nodules or nasal scrapings from leprosy patient into the foot pad of armadillo. Typical granuloma at the site of inoculation within 6 months.

23. 5. LEPROMIN TEST Delayed type of hypersensitive reaction. First described by Mitsuda in 1919. Lepromins used as antigen

24. Procedure : Carried out by the intradermal injection of 0.1 ml of lepromin .

25. Early reaction or Fernandez reaction Late reaction or Mitsuda reaction Biphasic response :

26. Serological test It include latex agglutination test and ELISA

27. TREATMENT Multi drug therapy is based on dapsone , rifampicin and clofazimine recommended by WHO.