Pulmonary mycobacterium abscessus infection
Pulmonary Mycobacterium abscessus infection is a type of pulmonary non-tuberculous mycobacterial infection where the causative organism is Mycobacterium abscessus.
Clinical presentation
Pulmonary disease is often indolent, but progressive causing persistent symptoms, a decline of pulmonary function, and impaired quality of life. However, in some situations, the disease can also follow a fulminant course with acute respiratory failure.
Pathology
Mycobacterium abscessus are Gram-positive, non-motile, acid-fast rods being around 1.0 - 2.5 µm long by 0.5 µm wide.
M. abscessus complex is differentiated into 3 subspecies:
- M. abscessus subsp. abscessus
- M. abscessus subsp. massiliense
- M. abscessus subsp. bolletii
M. abscessus complex can cause pulmonary disease, especially in those with underlying structural lung diseases, such as cystic fibrosis, bronchiectasis, and prior pulmonary tuberculosis.
Radiographic features
CT
There can be considerable overlap in common CT findings of M. abscessus pulmonary infection and Mycobacterium avium intercellulare (MAC).
According to some reports, lobar volume loss, nodule, airspace consolidation, and thin-walled cavities are thought to be more frequently seen in with MAC than M. abscessus .
On CT, the most commonly described findings include branching nodular opacities (i.e., the tree-in-bud pattern) and bronchiectasis.
Cavities may be seen in around 17% of patients.
Other less common CT findings include:
Treatment and prognosis
M. abscessus is resistant to many antibiotics and thus is very difficult to treat. Combination therapy of intravenous amikacin with cefoxitin or imipenem and an oral macrolide have been recommended by the American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA).
