nontuberculous%20mycobacterial%20disease
NONTUBERCULOUS MYCOBACTERIAL DISEASE
Nontuberculous mycobacteria are ubiquitous and are usually found in soil, natural and treated water sources. They are relatively uncommon cause of pulmonary disease and likely to cause disseminated disease.
May cause both asymptomatic infection and symptomatic disease in humans.
There is no evidence of animal-to-human or human-to-human transmission in immunocompetent hosts.
Nontuberculous mycobacterial pulmonary disease is a generally slowly progressive infection.
Signs and symptoms are generally nonspecific.

Introduction

  • Nontuberculous mycobacterial (NTM) pulmonary diseases are ubiquitous & are usually found in soil, natural & treated water sources
    • Relatively uncommon cause of pulmonary disease
    • Likely to cause disseminated disease except Mycobacterium kansasii which causes lung infection w/o dissemination among HIV-coinfected patients w/ low CD4 counts
  • May cause both asymptomatic infection & symptomatic disease in humans
  • There is no evidence of animal-to-human or human-to-human transmission in immunocompetent hosts
  • NTM pulmonary disease is a generally slowly progressive infection

Etiology

  • M avium complex (MAC) is the most common NTM species causing pulmonary disease in the US
    • Includes at least 2 mycobacterial species: M avium & M intracellulare
    • M intracellulare is the more common respiratory pathogen
    • Commonly found in indoor water systems, pools & hot tubs
  • M kansasii & M abscessus are the 2nd & 3rd most common pulmonary pathogen, respectively

Signs and Symptoms

  • Generally nonspecific
  • Chronic or recurring cough w/ sputum production
  • Dyspnea, chest pain
  • Fatigue, malaise, weightt loss, fever, hemoptysis
  • May be complicated by symptoms caused by coexisting lung diseases

Risk Factors

  • Hot tub exposure
  • Older men who are smokers, older women w/ no smoking history
  • Excessive alcohol use
  • Co-existing illnesses: chronic obstructive pulmonary disease (COPD), cystic fibrosis, pneumoconiosis, prior tuberculosis (TB), esophageal motility disorders, pulmonary alveolar proteinosis, malignancy
  • There is an association between bronchiectasis, nodular NTM pulmonary disease & specific body type especially postmenopausal women (eg pectus excavatum, scoliosis, mitral valve prolapse, joint hypermobility)
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