Discussion
Mycobacterium abscessus is a ubiquitous, rapidly growing mycobacterium. It frequently infects the lung tissue, notably in susceptible hosts with structural lung disease, such as cystic fibrosis2. In fact Nontuberculous mycobacteria (NTM), especially the subspecies Mycobacterium abscessus subsp. abscessus has emerged as the leading and worrisome pathogen in cystic fibrosis patients. Over the past twenty years the NTM incidence among cystic fibrosis patients has increased from 3.3% to 22.6%. The isolation of NTM was associated with increased morbidity and mortality3.
Untreated it causes slow but progressive deterioration resulting in long-term symptoms, declining pulmonary function and impaired quality of life. Occasionally it can also cause fulminant acute respiratory failure2.
Patients with Mycobacterium abscessus complex are not considered as candidates for lung transplant in many centers, but it is not considered as a definite contraindication for lung transplantation. However, one may anticipate a higher incidence of post-operative complications in these patients4.
The organism’s resistance to antimicrobials and multiple adverse effects of these treatment options, makes the treatment of Mycobacterium abscessus particularly challenging2.
In the case described above, the child was not responding to conventional treatment options; including a combination of antibiotic regimes, mucoactive agents and extensive physiotherapy5.
Therapeutic bronchoscopic lavage with normal saline and instilment of Dornase alfa cleared the left upper lobe bronchus with re-inflation of the affected lung. This was accompanied with improvement in the child’s symptoms, clinical findings, lung function parameters (FEV1 and FVC) and radiological resolution of the airway collapse.
The use of sequential therapeutic bronchoscopies with installation of recombinant human DNase was reported previously in one case series in cystic fibrosis patients with allergic bronchopulmonary aspergillosis1. There were no studies or reports in the literature pertaining to Mycobacterium abscessus which could have guided us on the extent to which therapeutic bronchoscopies should be repeated. We were encouraged by the fact that small improvements were made with each procedure. Overall, we feel that the removal of some of the plug at bronchoscopy with installation of Dornase alfa paved the way for a better therapeutic result with sequential procedures. This is the first reported successful therapeutic resolution of a lung collapse in a Cystic fibrosis patient with Mycobacterium abscessus , using bronchoscopic lavage with installation of recombinant human DNase.