0521779407-15 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 18:43
1070 Nontuberculous Mycobacterial Infectionstuberculosis most common etiology; presents as painless enlarge-
ment of cervical nodes that may form sinus tract with chronic
drainage
■Skin and Soft Tissue – M. fortuitum, M. chelonae, M. abscessus and
M. marinum (fish tank granuloma) cause localized skin nodules fol-
lowing traumatic inoculation; lesions may ulcerate and M. marinum
may cause sporotrichoid lesions (nodular lymphangitis)
■Disseminated disease – seen in advanced HIV disease; caused by
MAC; present with persistent fevers and weight loss
tests
■Atypical mycobacteria can colonize respiratory tract; diagnosis
requires two positive sputum cultures if one is smear positive, or
three positive sputum cultures if none are smear positive, or patho-
logic confirmation of invasive disease on biopsy in symptomatic
patients with CXR or chest CT showing cavitary upper lobe disease,
diffuse nodular infiltrates or bronchiectasis
■Other forms of disease require positive cultures
■In disseminated disease in HIV, blood cultures positive in≥95%
differential diagnosis
■Other causes of chronic cough and pulmonary infiltrate, especially
M. tuberculosis, fungal infection, neoplasia, sarcoidosis
■Other causes of cervical adenopathy (see lymphadenopathy and
lymphangitis)
management
■Consider diagnosis in patients with chronic cough and infiltrates
■Obtain specimens for culture
■If AFB smear positive, empirical therapy for M. tuberculosis started
while awaiting results of culture and speciationspecific therapy
■Pulmonary – MAC treated with clarithromycin 500 mg bid (or
azithromycin), plus ethambutol 15 mg/kg daily, plus rifampin 600
mg daily (or rifabutin) until cultures negative for 1 year; M. kansasii
treated with INH 300 mg daily, plus ethambutol, plus rifampin for
18 months (M. kansasii resistant to pyrazinamide); M. abscessus
treated with IV amikacin 15 mg/kg daily plus IV cefoxitin 12 g daily in
divided doses for several weeks followed by 6 months of clarithromy-
cin
■Lymphadenitis – treated by surgical excision; antituberculous ther-
apy not required