Leprosy Flashcards
What is leprosy?
Chronic curable Infectious disease Caused by Mycobacterium leprae Affecting skin, peripheral nerves Mucosa of URT and eye Affecting all age groups, males>females
2nd most common cause of neuropathic ulcers in Sri Lanka after diabetes mellitus
How is leprosy transmitted?
Nasal droplet inhalation
Prolonged contact with skin abrasions
By multibacillary form
How is leprosy diagnosed?
Clinical features and suspicion
Positive slit skin smears
Skin biopsy
Nerve biopsy
Lepromin test + (tuberculoid)
What are the important features of Mycobacterium leprae?
Acid fast alcohol fast
Human pathogen
Can’t be cultured in vitro
Very slow growth rate (14 day doubling time)
What is the pathophysiology of leprosy?
Infection by nasal droplets
Genetic and immune susceptibility to infection determines host immune response
Hematogenous dissemination
Immune response is T cell mediated delayed type hypersensitivity
Years long incubation period
Infects Schwann cells, skin, testes, bone
How is leprosy clinically classified?
According to host cell mediated immune response causing different clinical presentations
Ridley and Jopling system
Paucibacillary tuberculoid leprosy if good immunity
Multibacillary lepromatous leprosy if poor immunity
TT BT BB BL LL
What are the clinical features of tuberculoid leprosy?
Not contagious
Lepromin +
Single lesion (up to 3) commonly on face
Asymmetrical
Well demarcated hypopigmented hairless anhydrotic hypoanesthetic macules
Thickened nerves near lesion
What are the clinical features of lepromatous leprosy?
Contagious
Lepromin negative
Multiple lesions in Face, limbs, buttocks
Symmetrical
Pupules/ nodules/ plaques/ macules not hypoanesthetic
Thickened peripheral nerves with glove and stocking anesthesia, trophic ulcers, paralysis
Nasal crusting, epistaxis, keratitis, infertility
What are the DDx for leprosy?
Tuberculoid - Vitiligo Pityriasis alba Pityriasis versicolor Sarcoidosis Granuloma annulare Cutaneous lymphoma
Lepromatous - Leishmaniasis Guttate psoriasis Discoid lupus Neurofibromatosis
What is the treatment for leprosy?
Multi drug therapy (MDT)
Dapsone WHITE
clofazimine BROWN
rifampicin RED
Tuberculoid 6 months
Rifampicin + dapsone
Rifampicin 600mg/month
Dapsone 100mg/day
Lepromatous 12 months
Rifampicin + clofazimine + dapsone
Rifampicin 600mg/month
Dapsone 100mg/day
Clofazimine 300mg/month and 50mg/day
Regimens are given for 4 weeks as blister packs
What are lepra reactions?
Acute episodes of inflammation during the chronic course of leprosy
Due to immune reactions on Mycobacterium antigens
Occur at any time(before during after treatment)
Two types
Type 1 LR from type IV hypersensitivity
Type 2 LR from type III hypersensitivity
Do not stop MDT
Treat with steroids and NSAIDs
What are the clinical features of lepra reactions?
Type 1 - Occur in tuberculoid leprosy Existing lesions flare up Nerve dysfunction
Type 2 - Occur in lepromatous leprosy New ulcerating lesions Less nerve dysfunction Erythema nodosum on trunk and limbs Systemic illness
