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.