CHAPTER 16: MYCOBACTERIAL DISEASES Flashcards
Tuberculin testing becomes positive how many weeks after infection?
2-10 weeks
Tuberculin test is read _____ after ID injection
48-72 h
MDR-TB is resistant to what particular anti TB drugs?
isoniazid and rifampin
XDR-TB is resistant to what particular anti-TB drugs?
any fluroquinolones and at least one of the ff:
capreomycin, kanamycin, or amikacin
is designed to detect a memory cell–mediated immune response to M. tuberculosis.
tuberculin skin test (TST)
Appears 2-4 weeks after inoculation
Painless brown red papule—indurated nodules or plaque and may ulcerate
Regional lymphadenopathy after 3-8 weeks
Spontaneous healing after 1 year
Tuberculous chancre
Primary inoculation TB
Exogenous inoculation of bacilli into skin of a previously sensitized person with strong immunity against M. tuberculosis
Papule—hyperkeratotic like a wart, enlarged through peripheral expansion
Dorsa of fingers and hands in adults
ankles and buttocks in children
Tuberculosis verrucosa cutis
May appear at sites of inoculation, scrofuloderma scars or distant sites through hematogenous dissemination
Single plaque composed of grouped red brown papules, “apple jelly” color when blanched
classic tubercles are the hallmark histologically
Head and neck lesions are assoc. with lymphangitis and lymphadenitis
Lupus vulgaris
Tuberculous involvement of the skin by direct extension from an underlying focus of infection
Most often in cervical lymph nodes
Suppuration occurs centrally
Heals with characteristic cordlike scars
Scrofuloderma
Erythematous, tender, subcutaneous nodules that favor the posterior lower calf
Lesions resolve spontaneously
Middle aged women-80%
Erythema induratum
gold standard for the diagnosis
culture
Biopsy with acid-fast staining should be done when the history and physi
