Recurrent flu-like illness with migrating pulmonary infiltrates of unknown aetiology

Natural history of Mycobacterium fortuitum pulmonary infection presenting with migratory infiltrates: a case report with microbiological analysis

Background

Presence of Mycobacterium fortuitum in respiratory tracts usually indicates mere colonization or transient infection, whereas true pulmonary infection occurs in patients with gastroesophageal disease. However, little is known about the diagnostic indications for true M. fortuitum pulmonary infection and the natural history of the disease.

Case presentation

A 59-year-old man was referred to our hospital for treatment against M. fortuitum pulmonary infection. Fifteen years before the referral, he underwent total gastrectomy, after which he experienced esophageal reflux symptoms. After the referral, the patient was closely monitored without antimicrobial therapy because of mild symptoms and no pathological evidence of M. fortuitum pulmonary infection. During the observation, chest imaging showed migratory infiltrates. Two years after the referral, his lung biopsy specimen revealed foamy macrophages and multinucleated giant cells, indicating lipoid pneumonia. However, he was continually monitored without any treatment because there was no evidence of nontuberculous mycobacterial infection. Four years after the referral, he developed refractory pneumonia despite receiving adequate antibiotic therapy. After confirmation of granulomatous lesions, multiple antimicrobial therapy for M. fortuitum resulted in a remarkable improvement with no exacerbation for over 5 years. Random amplified polymorphic DNA polymerase chain reaction analysis revealed identical M. fortuitum strains in seven isolates from six sputum and one intestinal fluid specimens obtained during the course of the disease.

Conclusions

We have described a patient with M. fortuitum pulmonary infection who presented with migratory infiltrates. The pathological evidence and microbiological analysis suggested that M. fortuitum pulmonary infection was associated with lipoid pneumonia and chronic exposure to gastrointestinal fluid. Therefore, physicians should carefully monitor patients with M. fortuitum detected from lower respiratory tract specimens and consider antimicrobial therapy for M. fortuitum infection when the patient does not respond to adequate antibiotic therapy against common pneumonia pathogens.

[Cryptogenic organising pneumonia]

Organising Pneumonia (formerly called Bronchiolitis Obliterans with Organising Pneumonia) is a particular form of inflammatory and fibroproliferative lung disease. Its idiopathic form called Cryptogenic Organising Pneumonia, was recently defined by an ATS/ERS consensus conference. The disease onset is subacute with cough, dyspnea, fever, asthenia, weight loss, crackles, and elevation of biological inflammatory markers. Bronchoalveolar lavage reveals a mixed alveolitis with elevated lymphocyte, neutrophil, and eosinophil counts. Chest imaging usually shows multifocal alveolar opacities predominating in the subpleural regions, often with a migratory pattern. Lung biopsy reveals budding connective tissue filling the distal airspaces. Diagnosis is established by combining clinical, radiological and histological criteria. Similarities with other disease processes can lead to delayed or erroneous diagnosis. Most patients respond well to corticosteroid therapy. Relapses are frequent but can generally be controlled with moderate doses of prednisone and do not worsen the prognosis. The therapeutic strategy aims at reducing the steroid doses while maintaining an optimal disease control.