Leprosy Flashcards
Reservoir of leprosy
Humans
Armadillo
Risk factors for leprosy
Low level of education
Poor hygiene
Food shortages
Most important risk factor
Intimacy and duration of contact with leprosy patients
Morphologic index
A measure of uniformly stained solid bacilli on slit-skin smear examination.
Calculated as percentage of viable bacilli among the total number of bacilli counted under oil-immersion microscopy
Bacteriologic Index
A logarithmic-scaled measure of the density of bacilli of all forms found in the dermis upon slit-skin smear examination
Approach to diagnosis of
leprosy
Clinical diagnosis - 2 out of 3:
- Hypopigmented or erythematous skin lesion/s with definite loss or impairment of sensation
- Involvement of peripheral nerves demonstrated by definite thickening with sensory impairment
- Positive AFB
- positive AFB in slit-skin smears
-presence of AFB in a skin smear or biopsy sample
-Positive result in biopsy PCR
WHO Classification of leprosy
Modes of transmission
- Shed in large members from the mouth and nose of patients with untreated multibacillary leprosy (droplet infection)
- From damaged skin
- Human-to-human transmission
- Zoonotic transmission through wild armadillos
- Enters the body through the respiratory tract or through skin (wounds or tattoos)
Various spectrum of leprosy based on clinical , bacteriologic, pathologic, and immunologic parameters
Tuberculoid leprosy
Lepromatous leprosy
Comprise several common immunologically mediated inflammatory states that cause considerable morbidity
Lepra reactions
occur in almost half of patients with borderline forms of leprosy but not in patients with pure lepromatous disease
Type 1 Lepra reactions
Classic signs of Type 1 Lepra Reactions
Inflammation within previously involved macules, papules and plaques, and on occasion, the appearance of new skin lesions, neuritis, and fever
Nerve trunk most frequently involved in Type 1 lepra reaction
ulnar nerve at the elbow
Most dramatic manifestation of type 1 lepra reaction
foot drop
Type 1 lepra reaction preceding the initiation of appropriate antimicrobial therapy
Downgrading reactions
Type 1 lepra reaction which occur after the initiation of therapy
Reversal reactions
Most characteristic microscopic feature of type 1 lepra lesions
Edema
Occurs exclusively in patients near the lepromatous end of the leprosy spectrum (BL/LL)
Type 2 Lepra Reaction: erythema nodosum leprosum
Most common features of type 2 lepra reaction
crops of painful erythematous papules that resolve spontaneously in a few days to week but may recur; malise and fever
play a central role in the pathobiology of type 2 lepra reaction
TNF
An unusual reaction seen exclusively in patients from the Caribbean and Mexico who have the diffuse lepromatosis form of lepromatous leprosy, most often those who are untreated
Lucio’s phenomenon
Lesions are characterized by ischemic necrosis of the epidermis and superficial dermis, heavy parasitism of endothelial cells with AFB, and endothelial proliferation and thrombus formation in the larger vessels of the deeper dermis
Lucio’s phenomenon
Most common complication of leprous neuropathy
Plantar ulceration (metatarsal heads)
Slit lamp evaluation of LL patients
“corneal bleeding”
Only leprosy treatment that is bactericidal
Rifampin
Causes red0black skin discoloration that accumulates, particularly in lesional areas
Clofazimine
WHO classification for patients with few bacteria in the dermis (BI<2)
Paucibacillary
WHO classification for patients with many bacteria in the dermis (BI >2)
Multibacillary
WHO recommended treatment for paucibacillary leprosy
Dapsone 100 mg daily
Rifampin 600 mg monthly (supervised) for 6 months
WHO recommended treatment for multibacillary leprosy
Dapsone 100 mg daily &
Clofazimine 50 mg daily (unsupervised),
Rifampin 600 mg plus Clofazimine 300 mg monthly (supervised)
- treatment for 2 years or until smears become negative
Antimicrobial regimens recommended for the treatment of leprosy in adults
Mechanisms and adverse effects of various drugs used for leprosy
