Atypical or nontuberculous mycobacteria, such as Mycobacterium avium complex (MAC) and Mycobacterium abscessus, are germs that live in soil and water and do not spread from person to person. They mainly cause slow lung disease in people with damaged lungs, plus skin, lymph node and disseminated infections in immunocompromised patients.
Key symptoms
- Chronic cough, sputum and fatigue lasting months
- Weight loss, low-grade fever and night sweats
- Coughing up blood
- Painless swollen neck node in young children
- Skin nodules or nonhealing wounds after injury, surgery or tattoos
What you find on exam
- Crackles or wheeze; signs of bronchiectasis or COPD
- Thin, often older woman in the classic nodular form
- Firm, non-tender neck node that may drain
- Skin nodules or ulcers along lymph vessels
Tests
- At least 2 sputum cultures positive for acid-fast bacilli for lung disease
- CT chest: nodules with bronchiectasis, or cavities
- Rule out tuberculosis; HIV test
- Biopsy with culture for skin or node disease; blood cultures for disseminated disease
Treatment basics
- Not every positive culture needs treatment; decide with symptoms, imaging and cultures
- MAC lung disease: azithromycin, rifampin and ethambutol until 12 months after cultures turn negative
- Amikacin, including the inhaled liposomal form, for cavities or refractory disease
- Neck node infection in children: surgical removal of the node
- Airway clearance for bronchiectasis; monitor vision, hearing and liver
Red flags
- Heavy coughing of blood
- Fever and weight loss in advanced HIV: disseminated disease
- Vision changes on ethambutol or hearing loss on amikacin
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; CDC, Guideline for Isolation Precautions (2007) and PPE sequence. Written by Making Synapses. Making Synapses is not affiliated with these organizations.