Leprosy Flashcards
What type of mycobacteria fit the following description?
environmentally-acquired infections that cause neither TB nor leprosy
How does atypical mycobacteria present in healthy adults? kids? immunocompromised?
adult is usually cutaneous; scrofula in children; immunosuppressed hosts may have systemic symptoms, particularly from M. kansasii or MAI/C
How do you treat atypical mycobacteria infections?
may be difficult to treat once established; require multiple antibiotics
How do you culture M. leprae?
TRICK QUESTION: M. leprae has no in vitro culture system, slowest growing human pathogen, prefers 30C to 37C
Why is leprosy an uncommon disease?
M. leprae has an extremely long incubation period, doesn’t transmit easily, only 5-10% of humans believed susceptible to disease
leprosy aka _______ disease
Hanson’s disease
Describe the tuberculoid presentation of leprosy
paucibacillary, hypopigmented macular/plaque-like skin lesions, vigorous CMI both contains infection and damages nerves, PPD+
Describe the lepromatous presentation of leprosy
multibacillary, weak CMI, extensive cutaneous symptoms, PPD-
how do you test for leprosy?
Lepromatous: skin smear, biopsy, molecular probe, serology
tuberculoid: biopsy or serology but sensitivity is low – physical exam, history, &PPD
Why do you use a PPD test in suspected leprosy?
test symptomatic pts to determine what stage of leprosy they are in, the PPD tests anti-leprosy immunocompetence NOT EXPOSURE!
tx for leprosy?
2 yrs, dapsone and rifampin
what other skin presentation may be seen in lepromatous pts?
erythema nodosum
in severe cases of lepromatous leprosy, what drug may be required? what are some concerns with this drug?
thalidomide POTENT TERTOGEN (inhibits limb growth in the fetus)
What are the four groups of atypical mycobacteria?
1-photochromogens: pigmented in light, M. kansasii, environmental source, resembles pulm TB same tx as TB, M. marinum: fresh and salt water source, granulomatous ulcerating lesions (tetracycline tx)
2-scotochromogens: pigmented in dark, M. scrofulaceum, H2O reservoir
3-nonchromogens: no pigment, MAI, MAC, looks like TB, highly drug resistant
4-rapidly growing mycobacteria: no pigment, M. fortuitum, M. chelonei, immunocompromised, hip prosthetics, indwelling caths, puncture wounds
In an AIDS patient with TB-like sx, why bother differentiating M. avium from M. tuberculosis?
tx is different, one is environmentally acquired, the other was from another person
