Ocular leprosy undergraduate lecture powerpoint

Ocular leprosy undergraduate lecture powerpoint

1. OCULAR LEPROSY OPHTHALMOLOGY DR FRANSISCO (SHO) MARCH / 2021

2. LEPROSY Leprosy, also known as Hansen's disease Is a chronic disease of the skin and peripheral nerves that produces skin lesions, peripheral and facial neuropathy, absorption of digits, limb loss, and facial deformities Humans are the only known natural host of M. leprae . M. leprae was identified by Hansen in 1874

3. MICROBIOLOGY Caused by Mycobacterium leprae is a gram-positive and strongly acid-fast bacillus Mycobacteria are obligate, aerobic, intracellular bacilli, 3 to 5 µm long and 0.2 to 0.4 µm in diameter. They are readily killed by heat but are generally resistant to drying and chemical agents such as chlorine.

4. MICROBIOLOGY The organism grows slowly, requiring about 12.5 days' generation time (doubling time) compared to 14 to 15 hours for Mycobacterium tuberculosis and 20 minutes for Escherichia coli. One result of this extremely slow growth is the long incubation period for leprosy of 1 to 10 years. It may be 20 or more years after exposure before the diagnosis is made.

5. MODE OF TRANSMISSION OF LEPROSY Risk factors include: Overcrowding, Poverty, Poor hygiene Route of spread Person-to-person spread(commonest), Soil contamination Insect vectors Contact with infected armadillos

6. EPIDEMIOLOGY Leprosy continues to remain a public health problem in some 14 countries in Africa, Asia, and Latin America, both in the tropical and subtropical regions. For some 20 years, WHO has focused on a global strategy to eliminate leprosy as a public health problem as defined by a prevalence rate, on the global level, of less than 1 case per 10,000 persons The prevalence approaches 1 case per 1000 population in developing countries

7. PATHOGENESIS OF LEPROSY Leprosy is a chronic, granulomatous infection of the skin, mucous membranes, nerves, eyes, and adnexal tissues of the eyes. The major organs involved are the skin and peripheral nerves, although any organ can be affected, especially later in the disease. Although the bacillus prefers tissues that are cooler than 37°C, bacilli have been found in almost every organ.

8. PATHOGENESIS OF LEPROSY The immunologic defect in leprosy is caused by the selective anergy of T cells to M. leprae and its antigens. This immunodeficiency is either hereditary or acquired through an infection that leads to tolerance from gradual exposure of the patient to the organism. Consequently, cell-mediated immunity is inadequate, and the host is unable to mount an effective response.

9. CLASSIFICATION OF LEPROSY Madrid classification scheme Ridley and Jopling classification WHO classification

10. WHO CLASSIFICATION

11. WHO CLASSIFICATION

12. REACTIONAL STATES Occasionally, one sees reactional states during the course of the disease. These episodes may cause deformities from nerve and soft tissue inflammation and destruction. The reactional states are Reversal (type I lepra reactions) Erythema nodosum leprosum (ENL) (type II lepra reactions).

13. TYPE I REACTION In a type I reaction, the reversal reaction represents a delayed hypersensitivity reaction and is directed toward bacillary antigens. The surrounding tissue is damaged as a result of the reaction. This reaction usually occurs in the borderline and unstable states of leprosy and usually after initiation of treatment; it rarely occurs without treatment.

14. TYPE I REACTION It is clinically characterized as fever, edema , hyperemia , infiltration of skin lesions, and severe peripheral neuritis. In borderline disease, it is responsible for loss of nerve function and deformity. A downgrading reaction indicates development of decreased immunity. In this form of reversal reaction, borderline leprosy drifts toward the lepromatous pole. It generally occurs in the absence of treatment

15. TYPE II REACTION ENL, a type II reaction, is an immune-complex reaction. It occurs in lepromatous or borderline lepromatous patients as a result of immune complex deposition in skin. ENL is characterized by painful erythematous nodules or plaques on the face, arms, and thighs. Fever, malaise, arthritis, orchitis , iridocyclitis , lymphadenopathy, and proteinuria may all occur. The reaction is triggered by a transient imbalance in the patient's immunoregulatory mechanisms.

16. OCULAR MANIFESTATIONS OF LEPROSY External adnexal tissues Corneal and conjunctival Scleral and uveal lesions

17. EXTERNAL ADNEXAL TISSUES Madarosis Trichiasis Lagophthalmos Ectropion of the lower eyelid Dry eye syndrome(DES) Leprotic dacryocystitis

18. EXTERNAL ADNEXAL TISSUES Patient with borderline leprosy with classic leonine facies of leprosy from accentuated facial skin folds. Note madarosis , nasal septum involvement, and ectropion secondary to facial nerve paralysis

19. CORNEAL INVOLVEMENT 1.Thickened corneal nerve 2.Corneal pearls 3.Superficial punctate keratitis (SPK) 4.Corneal lepromas 5.Interstitial keratitis 6.Exposure keratitis 7.Decreased corneal sensation 8.Corneal ulcers

20. CORNEAL INVOLVEMENT

21. CORNEAL LEPROMAS Corneal lepromas occur more commonly in South America and Japan but are relatively infrequent. These lesions are large granulomas with epithelioid cells, lymphocytes, and bacteria. They may become large enough to involve the visual axis and compromise vision. Lepromas usually arise at the limbus (most commonly the lateral limbus ) or on the sclera and then encroach onto the cornea.

22. CORNEAL LEPROMAS Ocular lepromas occasionally occur in the palpebral aperture. These may occur at the limbus or in the episcleral tissues where bacilli are localized with a granulomatous response. It may progress to involve the visual axis.

23. INTERSTITIAL KERATITIS Interstitial keratitis may occur by two possible mechanisms. Secondary to a deeper extension of the avascular keratitis with necrosis. Result of an immunologic response without a preceding area of avascular keratitis or necrosis

24. CONJUNCTIVAL INVOLVEMENT Mild conjunctival inflammation Odema and dilated blood vessels

25. SCLERAL AND UVEAL LESIONS Episcleritis Scleritis Scleromalacia and staphylomas Lepromatous iridocyclitis Acute Uveitis Chronic low-grade uveitis Iris pearls Ciliary body dysfuction Glaucoma and Cataract

26. SCLERAL AND UVEAL LESIONS Intercalary staphylomas are a result of long-standing episcleritis and scleritis secondary to leprosy. The frequent attacks may result in scleromalacia , scleral thinning, and staphylomas

27. CHRONIC LOW-GRADE UVEITIS The chronic iritis often associated with lepromatous leprosy may result in marked iris atrophy with stromal loss, iris pigment epithelium loss, and frank iris holes.

28. IRIS PEARLS Iris pearls arise from the surface connective tissue of the iris and can be recognized on the iris surface even early in the disease These creamy white particles consist of bacilli and monocytes and are rarely associated with an inflammatory response. Iris pearls are pathognomonic of ocular leprosy and look like grains of sand on the iris surface, often occurring near the pupillary border.

29. IRIS PEARLS

30. IMVESTIGATION OF LEPROSY Skin biopsies Biopsies of ocular tissues Intradermal skin test

31. TREATMENT OF OCULAR LEPROSY Early diagnosis and prompt treatment with antimicrobials ( dapsone , rifampin , and clofazimine given orally) may prevent late complications such as Ectropion , lagophthalmos Exposure, and other forms of keratitis Forms of uveitis As with tuberculosis, treatment of ocular leprosy requires systemic therapy, based on the disease type and the degree of resistance.

32. TREATMENT OF OCULAR LEPROSY Dapsone and rifampin are the initial drugs of choice; Clofazimine is used in dapsone -resistant disease. Type I lepra reactions should be treated with oral corticosteroids. Thalidomide is the drug of choice for ENL but must not be used in women of childbearing age because of teratogenicity. Local ocular complications of leprosy such as keratopathy , trichiasis , iritis , and glaucoma must also be addressed.

33. TREATMENT OF OCULAR LEPROSY

34. REFERENCES Duane;volume-5,Chapter 63. AAO, 2019/2020 Medscape