Leprosy Flashcards
What is the structure and name of the pathogen that causes Leprosy?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar instead?)
How is Leprosy transmitted?
• what is the lost for this infection?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Transmission
Small droplets from nasal secretions with low infectivity – prolonged close contact required.
Humans are armidillos are the only natural hosts of leprosy
How long does it take leprosy to replicate?
• Where does it replicate?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Replication Cycle
2-7 year incubation period where it replicates insides of macrophages, Schwann cells, and PERIPHERAL NEURONS.
Leprosy
• how can it present?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Disease Presentation
2-7 years after an encounter with Leprosy a patient may present with either Tuberculoid or Lepromatous leprosy.
Tuberculoid presents as single skin lesions on the face, limbs, and butt. Nerve involvement may leave some peripheral nerves anesthetic (stocking-glove), but nerves of the face are typically fine.
Lepromatous is much more severe and the patient typically presents with edema and rhinitis followed by extensive lesions on the fact, limbs, and butt. Infiltration near the ear lobes is apparent in these lepromatous leprosy people and AFB can be isolated from these. Further progression of the disease leads to nasal septum collapse, loss of fingers, and atrophy of testicles. The microbe will then continue spreading through the reticuloendothelial system.
How is leprosy able to cause infection?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Pathogenic Mechanism
Lepromatous leprosy avoids TH1 response and thus cannot be walled off by granulomas, response to Lepromatous is preodominantly at TH2 response. Tuberculoid leprosy is not able to avoid TH1 responses and is therefore killed
Leprosy
• where its is most prevalent?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Epidemiology
India and Brazil (virtually absent from U.S. and Europe)
Leprosy
• what bug causes it?
• What is the treatment?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Treatment
Key = early prevention and dx.
Prophylaxis: Sulfones
Tuberculoid: Dapsone + Rifampin for 12 mo. (sulfone that inhbitis PABA metabolism (like sulfonimides do))
Lepromatous: Tuberculoid tx. + Clofazimine for 2 years
Leprosy
• prognosis?
• What is it dependent on?
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Mortality
- *Lepromatous:** Degree of T-cell mediated immunity determines the extent of the disease, no TH1 mediators
- *Tuberculoid**: disease is limited with a good Px.
Leprosy
• How do you diagnose
HANSEN DISEASE (LEPROSY) - Mycobacterium leprae
Structure
ACID FAST BACILLUS (cannot be grown in typical culture media – Lowenstein-Jensen agar?)
Key findings/Diagnosis
Dx: almost always clinical with confirmation of AFB from skin biopsy (from ear lobes in lepromatous)
