History and exam
Key diagnostic factors
common
underlying lung disease
Pulmonary Mycobacterium avium complex classically develops in individuals with a history of lung disease such as prior tuberculosis, bronchiectasis, cancer, silicosis, and cystic fibrosis.
chronic productive cough
Present in most patients with pulmonary Mycobacterium avium complex or hypersensitivity pneumonitis.
dyspnea
Present in most patients with pulmonary Mycobacterium avium complex or hypersensitivity pneumonitis.
weight loss
Present in most patients, especially in HIV-related disseminated disease.
fatigue
Present in most patients, especially in HIV-related disseminated disease.
fever
Occurs in most patients with Mycobacterium avium complex infection, especially in HIV-related disseminated disease.
lymphadenopathy
Cervical lymphadenopathy is noted primarily among children.[34] Mediastinal lymphadenopathy can be seen with pulmonary Mycobacterium avium complex (MAC) disease. Intra-abdominal lymphadenopathy is often a component of disseminated MAC disease. Lymphadenopathy can also be seen in the setting of immune reconstitution and inflammatory syndrome.
uncommon
immunocompromised
HIV infection or general severe immune suppression, leukemia, lymphoma, organ transplantation, or other immunosuppressive therapy.
hot tub use
History of recent hot tub use should be elicited in patients with history and chest x-ray changes of pneumonitis.
Other diagnostic factors
common
age under 5 years
Cervical lymphadenitis predominantly affects children (mean age 2.8 years).[33]
middle-to-old age
Middle-aged or older individuals are predominantly affected in pulmonary Mycobacterium avium complex.
night sweats
May occur in association with fever in patients with subacute Mycobacterium avium complex.
abdominal pain
May occur in patients with disseminated Mycobacterium avium complex.
diarrhea
May occur in patients with disseminated Mycobacterium avium complex.
rhonchi/crackles
These findings are very nonspecific and may represent underlying lung disease or pulmonary Mycobacterium avium complex.
hepatomegaly
Associated with disseminated Mycobacterium avium complex, especially patients with HIV.
splenomegaly
Associated with disseminated Mycobacterium avium complex, especially patients with HIV.
uncommon
thin body habitus
In postmenopausal women with nodular/bronchiectatic Mycobacterium avium complex.
pectus excavatum
In postmenopausal women with nodular/bronchiectatic Mycobacterium avium complex.
scoliosis
In postmenopausal women with nodular/bronchiectatic Mycobacterium avium complex.
systolic click and murmur
Mitral valve prolapse is associated with nodular/bronchiectatic Mycobacterium avium complex in postmenopausal women.
Risk factors
strong
underlying lung diseases
Such as healed tuberculosis, COPD, cystic fibrosis, bronchiectasis, malignancy, or pneumoconiosis.[3][13][28]
Believed to predispose to Mycobacterium avium complex (MAC) disease by interfering with pulmonary clearance mechanisms. However, such specific defects have not been identified.
Associated with type of MAC that causes cavitary lung disease.
HIV/AIDS
CD4 T-cell count under 50 cells/microliter is the primary risk factor.
Other factors that have been associated with disseminated Mycobacterium avium complex (MAC) disease in HIV-infected patients include high plasma HIV-1 RNA levels (>100,000 copies/mL), previous opportunistic infections (particularly cytomegalovirus disease) and previous colonization of the respiratory or gastrointestinal tract with MAC.[5]
severe immunosuppression
Due to leukemia, lymphoma, organ transplantation or other immunosuppressive therapy.[30]
weak
smoking
Associated with the development of pulmonary Mycobacterium avium complex.
excessive alcohol use
Associated with the development of pulmonary Mycobacterium avium complex.
increasing age
Older male smokers have higher risk of developing cavitating lung disease from Mycobacterium avium complex.
Postmenopausal, nonsmoking women with no underlying lung disease or immunosuppression are more prone to develop mid-lung nodular bronchiectatic disease (middle lung syndrome/Lady Windermere syndrome).[29]
hot tub use
Hypersensitivity pneumonitis secondary to exposure to aerosolized Mycobacterium avium complex in indoor hot tubs (hot tub lung) has been described.[6]
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