Atypical Mycoses Flashcards
what does atypical mycobacteria exclude?
TB and leprosy
how are atypical mycobacteria acquired?
environmentally
how does an atypical mycobacterial infection present in an immunocompetent adult and child?
adult- cutaneous
child- scrofula
how does immunosuppression influence presentation of atypical mycobacterial infection?
have systemic symptoms particularly from M kansasii or MAI/MAC
how are atypical mycobacterial infections treated?
require multiple antibiotics once established (difficult)
how is M leprae cultured?
it cannot be cultured in vitro
is M leprae infection associated with latency? where does the bacterium grow?
long latency- slowest growing pathogen.
prefers 30C areas (nose and skin)
what is notable about transmission of leprosy?
does not transmit easily and only 5-10% of people are susceptible
what are the two types of presentation of Hansen’s disease?
tuburculoid- paucibacillary with vigorous CMI containing infection and damaging nerves
lepromatous- multibacillary, weak CMI response with extensive cutaneous symptoms (disease occurs on a spectrum)
what is the significance of PPD for M lepromatous infection?
for tuberculoid variant demonstrates exposure (positive is indicative of disease) for lepromatous variant is testing immunocompetence because it is validating that there is CMI deficiency with negative result
how is lepromatous infection tested? how does this differ from tuberculoid?
skin smear, biopsy, molecular probe and serology
tuburculoid has low sensitivity with biopsy or serology
how is tuberculoid infection verified?
physical exam, history and positive PPD
how is Hansen’s disease treated?
with two years of dapasone plus rifampin (add another agent for lepromatous until skin smears are negative)
what is a complication of treatment of lepromatous variant?
may develop erythema nodosum that may require immunomodulant treatment if severe (thalidomide- worry about teratogenicity)
