LEPROSY Flashcards
Mycobacterium leprae infects
- macrophages and
- Schwann cells
clumps or globi within macrophages
Lepra cells
Obligate, intracellular bacillus, acid-fast staining,
rod-shaped bacterium, never been grown in artificial media
Mycobacterium leprae
Temperature required for survival of Mycobacterium leprae
between 27ºC and 30ºC
calculated as the percentage of viable bacilli among the total number of bacilli
Morphologic Index
(measure of the density of bacilli of all forms found in
the dermis): varying from 0 to 6+; falls an average of 1 log unit/year with multidrug therapy
Bacteriologic Index
M. Leprae has (cell)
cytoplasm, plasm membrane, cell wall and capsule.
Cell wall of M. Leprae composed of
- Arabinogalactans (which support mycolic acids)
- lipoarabinomannan (LAM)
Capsule contains phthiocerol dimycocerosate and ____ - its detection is helpful in serologic diagnosis
of leprosy
phenolic glycolipid (PGL-1)
Immunologic components of M. leprae:
Polysaccharide:
Protein:
Polysaccharide: induce mainly a humoral immune response
Protein: both humoral and cell-mediated immune response
special type of diffuse lepromatosis known as diffuse leprosy of Lucio and Latapí. Found mainly in Mexico and Central America
Mycobacterium Lepromatosis
WHO Leprosy Disability Grading System
Hands and Feet
Grade 0
Grade 1 -
Grade 2 -
Grade 0 - no anesthesia and no visible impairment
Grade 1 - signifies anesthesia but no visible impairment
Grade 2 - visible impairment
WHO Leprosy Disability Grading System
Eyes
Grade 0
Grade 1
Grade 2
Grade 0 - no eye problems due to leprosy and no evidence of visual loss
Grade 1 - eye problems due to leprosy without severe effects on vision
Grade 2 - severe visual impairment; includes lagopthalmos, iridocyclitis and corneal opacities
Transmission of M. leprae
- Can be shed in large numbers from the mouth and nose of patients with untreated multibacillary leprosy (droplet infection) and sometimes from damaged skin.
- Zoonotic transmission through wild armadillos
- Main route of entry - respiratory tract!!!!
- Wound or tattoos - skin is also possible
Reservoir of M. leprae
Humans - main reservoir of infection for M. Leprae!!!!
Armadillos - also a reservoir for human infection
Certain species of monkeys and red squirrels are infected, but there is not evidence of transmission
Relatively stable: types of leprosy
- LL
- TT
Unstable both clinically and immunologically types of leprosy
- BL,
- BB,
- BT
The host tissue’s reaction and related damage due to
delayed hypersensitivity
WHO Simplified Clinical Classification of Leprosy
- negative slit-skin smear results at all body sites
Paucibacillary leprosy
WHO Simplified Clinical Classification of Leprosy
positive smears at any body site
Multibacillary leprosy
Clinical criteria
- one to five skin lesions, and no or only one involved peripheral nerve
Paucibacillary leprosy
Clinical criteria
- six or more skin lesions, and/or more than one involved peripheral nerve
Multibacillary leprosy
Ridley-Jopling Classification of Leprosy
- Early clinical type manifests are one or few hypopigmented or faintly erythematous, ill-defined to well-defined macular lesions, measuring 1-5 cm in diameter
- Occurs on the external aspects of the limbs, buttocks, and face
- Mild to moderate impairment of touch and/or thermal sensations
Indeterminate Leprosy (IL)
Ridley-Jopling Classification of Leprosy
- No thickening of cutaneous and peripheral nerves
- Often, but not always, the first clinical sign of leprosy
- Heals spontaneously or progresses to a determinate form of the disease (TT, BT, BB, BL or LL)
Indeterminate Leprosy (IL)
Ridley-Jopling Classification of Leprosy
- Presents either as a well-defined, hypopigmented macule or as a raised, erythematous/brown/copper-colored plaque with a well-defined edge
- May be found on any part of the skin; characterized by complete loss of fine touch and temperature sensations
- Single or few (up to three) in number, can be of any size; seldom measure >10 cm in diameter
=Plaque-type lesions: raised clear-cut edge often slopes inward to a flattened and sometimes hypopigmented central area
Tuberculoid (TT) Leprosy
Ridley-Jopling Classification of Leprosy
- Skin surfaces of the lesion is dry, hairless, and anesthetic because of destruction of underlying superficial cutaneous nerves
- Autonomic nerve damage: responsible for surface dryness and loss of sweating
- Slit-skin exam: no acid-fast bacilli
- Lepromin skin test: strongly positive
Tuberculoid (TT) Leprosy
Ridley-Jopling Classification of Leprosy
- Characterized by either macular or plaque-type lesions numbering three to nine or more; asymmetrically located on any part of the body
- Margins of the lesions: poorly defined to well-defined, sometimes both forms are seen
- Smaller satellite lesions around a larger one: indicates downgrading of the lesion from TT to BT leprosy
Borderline Tuberculoid (BT) Leprosy
Ridley-Jopling Classification of Leprosy
- Susceptibility to a Type 1 leprosy reaction, that exacerbates skin lesions and/or peripheral nerves
- If not diagnosed and treated early - tends to downgrade across the spectrum to BB, BL or LL leprosy
- Slit skin smears: negative to 1+
Borderline Tuberculoid (BT) Leprosy
Ridley-Jopling Classification of Leprosy
- Unstable form of leprosy; downgrade toward BL and LL disease (especially if not treated)
- Multiple plaque lesions, not infrequently, macular lesions; various shapes and sizes, bilateral and usually occur in a more or less symmetrical distribution
= Moderately shiny and the central area looks pale
Mid-Borderline (BB) Leprosy
Ridley-Jopling Classification of Leprosy
- Minimal loss of sensation over the lesions
- Nerve damage: variable; many nerves may be thickened, asymmetrical
- Not commonly observed and rapidly changes its spectrum
- Lepromin test: negative
- Slit-skin smears: moderate number of AFB (2+ to 3+)
Mid-Borderline (BB) Leprosy
Ridley-Jopling Classification of Leprosy
- Numerous bilateral, round or oval, macular, diffusely infiltrated, erythematous or hypopigmented lesions with moderately defined borders
= Usually 2-3 cm in diameter, may have a coppery hue, tend to become symmetrical - Some loss of sensation, particularly over older lesions
- Untreated patients - new ill-defined skin lesions continue to develop
Borderline Lepromatous (BL) Leprosy
Ridley-Jopling Classification of Leprosy
- Widespread but asymmetrical thickening of peripheral nerves, with or without tenderness, leads to sensory and motor deficits
- Lepromin test: negative results
- Slit-skin examination: bacteriologic index varying from 3+ to 4+
Borderline Lepromatous (BL) Leprosy
Ridley-Jopling Classification of Leprosy
- Presents with innumerable bilateral, symmetrically distributed, diffusely indurated, erythematous, copper-colored or skin-colored patches or plaques
- No loss of sensation over these lesions; smooth, shiny surface
- Lesions spread over the face, earlobes, ears, extensor aspects of the upper and lower extremities, back and buttocks
Lepromatous (LL) Leprosy
Ridley-Jopling Classification of Leprosy
- Bilateral earlobe thickening and eyebrow loss occurs
= “Lion face” - coarse induration on the face resulting in gross skin folds, particularly when associated with loss of eyebrows and thickening of earlobes - Polar type (LLp): 10-15% from the time of onset, with sensory loss in a “glove-and-stocking” distribution
- Slit-skin smear exam: 4+ to 6+ with globi
Lepromatous (LL) Leprosy
Clinical Manifestation: Lepromatous Leprosy
Systemic Involvement: AFB Involvement of testes:
first to sterility and then gynecomastia and impotence
Clinical Manifestation: Lepromatous Leprosy
Systemic Involvement: AFB Eye involvement:
- corneal anesthesia,
- episcleritis,
- iridocyclitis,
- iris atrophy,
- cataract and glaucoma,
- lagophthalmos,
- corneal ulceration and perforation
- blindness
Clinical Manifestation: Lepromatous Leprosy
Systemic Involvement: AFB Nose: portal of entry
- earliest site of involvement in LL leprosy;
- chronic rhinitis with loss of smell sensation
- Saddle perforation due to bone destruction “Saddle-nose disfigurement”, common in advanced LL disease
Clinical Manifestation: Lepromatous Leprosy
Histoid Leprosy:
- Rare form of LL leprosy
- Waxy, shiny, firm, symmetrical or asymmetrical nodules and plaques observed over normal-looking skin
- Histologic examination: specific spindle-cell granulomas
- Slit-skin smear examination: high bacteriologic and microbiologic indices without globi in most cases
Clinical Manifestation: Lepromatous Leprosy
- Rare form of non-nodular LL leprosy occurring in Mexico and Central America
- Characterized by diffuse shiny infiltration of the skin and widespread sensory loss
- Complicated by an unusual reaction known as Lucio’s phenomenon
Diffuse leprosy of Lucio and Latapi
skin looks shiny and has a shiny appearance, with obvious diffuse induration of the earlobes and forehead, loss of eyebrows, sometimes eyelashes and not infrequently all
body hair
“Lepra bonita” (beautiful leprosy)
- Some countries (India and Nepal), observed in 2-10% of all leprosy cases
- Only peripheral nerve involvement and no skin lesions
- Nerve thickening and sensory loss occurs in the affected area, with or without a motor deficit
- Can manifest at different points along the disease spectrum
- Classified as paucibacillary or multibacillary on the basis of the absence or presence of AFB in nerve biopsy section or the number of thickened nerves (single or multiple)
Primary Neurotic Leprosy
