British Journal of Radiology (2007) 80, e19-e20
© 2007 British Institute of Radiology
doi: 10.1259/bjr/20155253
Stenotrophomonas maltophilia pneumonia after bone marrow transplantation: case report with emphasis on the high-resolution CT findings
E L Gasparetto, MD, PhD
1
D B Bertholdo, MD
1
T Davaus, MD
1
E Marchiori, MD, PhD
2 and
D L Escuissato, MD, PhD
1
1 Departments of Radiology of the University of Paraná, Curitiba, 2 University of Rio de Janeiro, Rio de Janeiro, Brazil
Correspondence: Emerson L Gasparetto, Rua Capote Valente 500, ap.2215, CEP: 05409-000 São Paulo – SP, Brazil. E-mail: gasparetto{at}hotmail.com
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Abstract
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A 6-year-old female patient who underwent bone marrow transplantation because of Fanconi anaemia presented with fever, dyspnoea and cough 17 days after the procedure. The physical examination revealed diffuse crackles. Chest radiographs demonstrated diffuse alveolar opacities in both lungs. High-resolution CT showed a diffuse and bilateral lung lesion characterized by multifocal areas of air-space consolidation associated with ground-glass attenuation and small centrilobular nodules. The culture of the material obtained with bronchoalveolar lavage only demonstrated growth of Stenotrophomonas maltophilia. The patient rapidly presented respiratory insufficiency and death in the same day.
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Introduction
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Pulmonary infections are a common complication after bone marrow transplantation (BMT). The infectious agents affecting those patients include viruses, bacteria and fungi. Considering the bacterial infections, gram-negative organisms from gastrointestinal tract or oral mucosa are the most frequent causes of infectious pneumonia after BMT [1, 2].
Stenotrophomonas maltophilia is a nosocomial gram negative bacillus, which has been presenting with increased incidence in the last decades [3]. According to Lai et al [3], patients receiving immunosuppressive therapy present a higher risk of S. maltophilia infection. Other risk factors are the presence of central venous catheter, previous antibiotic therapy, intubation or tracheostomy, prolonged hospitalization and severe mucosits. Labarca et al [4] described five cases of S. maltophilia bacteraemia after allogeneic BMT. In this study, recent allogeneic BMT was considered a significant risk factor for this infection.
The high-resolution CT scan is a useful imaging tool for the investigation of patients with pulmonary complications after BMT [5]. According to Escuissato et al [2], the most frequent high-resolution CT features in patients with bacterial pneumonia after BMT include nodules, ground-glass attenuation, air-space consolidation, bronchial wall thickening and nodules with halo sign. To our knowledge, the high-resolution CT findings of S. maltophilia pneumonia after BMT were not previously described.
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Case report
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A 6-year-old female patient who underwent BMT because of Fanconi anaemia presented with fever, dyspnoea and cough 17 days after the procedure. The physical examination revealed severe mucositis and the lung auscultation demonstrated diffuse crackles.
The chest radiographs demonstrated diffuse alveolar opacities in both lungs. The high-resolution CT showed a diffuse and bilateral lung lesion, characterized by multifocal areas of air-space consolidation with air-bronchograms, associated with ground-glass attenuation and some small centrilobular nodules (Figure 1
).
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Figure 1. (a) High-resolution CT demonstrates multifocal areas of air-space consolidation, some of then with air bronchogram (arrow), associated to areas of ground-glass attenuation and some small centrilobular nodules. (b) Air-space consolidations, ground-glass attenuation and small centrilobular nodules are also seen, as well as bronchial wall thickening.
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The culture of the material obtained with bronchoalveolar lavage demonstrated growth solely of S. maltophilia. The patient rapidly presented with respiratory insufficiency and died the same day.
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Discussion
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BMT has been widely used for the treatment of malignant and non-malignant diseases. Pulmonary complications occur in 40–60% of patients after BMT, being responsible for a significant morbidity and mortality rate. Lung parenchyma complications can be infectious and non-infectious. Pulmonary infections in a patient who received BMT are more commonly caused by fungi, bacteria or viruses. Bacterial pneumonia usually occurs in the first 100 days post-transplantation [1, 2]. Lossos et al [4], studying 255 patients who underwent BMT, found 37 (15%) cases of bacterial pneumonia. According to the authors, the most predominant bacteria during the first 100 days following transplant were gram-negative pathogens, mainly Enterobacteriaceae and Pseudomonas aerguginosa. After the first 100 days, the most common pathogens were Streptococcus pneumoniae and Haemophilus influenza.
S. maltophilia is a gram-negative bacterium with a high pathogenesis in humans, including pneumonia. It is usually a nosocomial bacillus and its frequency has been increasing, especially in immunocompromised and clinically debilitated patients [3, 4]. Labarca et al [4] reported five cases of S. maltophilia bacteraemia after bone marrow transplant. In this study, the authors concluded that recent allogeneic BMT is a significant risk factor for S. maltophilia bacteraemia. Other factors that predisposed to develop this infection were severe mucositis and prolonged neutropenia. Lai et al [3], studying cases of S. maltophilia bacteraemia, reported the risk factors for this infection as patients receiving immunosuppressive therapy, presence of central venous catheter, previous antibiotic therapy, intubation or tracheotomy, prolonged hospitalization and severe mucous lesions. Concerning the risk factors, our patient was severely immunocompromised because of BMT for Fanconi anaemia and presented severe mucositis. In addition, although highly resistant to antibiotics, the treatment of S. maltophilia infections with ticarcillin-clavulanate and moxalactam has shown good results. The infection usually results in increased morbidity in patients who have undergone BMT, but not significant mortality [6].
The high-resolution CT is an important tool for the investigation of pulmonary infections after bone marrow transplantation [3, 5]. Escussiato et al [2] studied the high-resolution CT features in 111 patients with infectious pneumonia after BMT. This study included 26 cases of bacterial pneumonia. Concerning the high-resolution CT findings of those patients, 21 (81%) had nodular opacities, 18 (69%) presented air-space consolidation and nine (35%) cases had areas of ground-glass attenuation. Reittner et al [7] described high-resolution CT findings of 114 patients with infectious pneumonia. There were 35 cases of bacterial pneumonia, including five immunocompromised patients. The most common high-resolution CT findings were air-space consolidation, ground-glass opacities, reticular opacities and small centrilobular nodules. In the present case, the high-resolution CT showed multifocal areas of air-space consolidation, ground-glass attenuation areas and small centrilobular nodules in both lungs.
In conclusion, although rare, S. maltophilia pneumonia should be considered in the differential diagnosis of infectious pulmonary complications after BMT. Areas of air-space consolidation, ground-glass attenuation and small centrilobular nodules may be seen at the high-resolution CT scans. However, those findings are non-specific and did not permit the differential diagnosis with the other causes of infectious pneumonia after BMT.
Received for publication October 3, 2005.
Revision received February 4, 2006.
Accepted for publication February 9, 2006.
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References
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- Lossos IS, Breuer R, Or R, et al. Bacterial pneumonia in recipients of bone marrow transplantation. Transplantation 1995;60:672–8.[Medline]
- Escuissato DL, Gasparetto EL, Marchiori E, et al. Pulmonary infections after bone marrow transplantation: high-resolution CT findings in 111 patients. AJR Am J Roentgenol 2005;185:608–15.[Abstract/Free Full Text]
- Lai CH, Chi CY, Chen HP, et al. Clinical characteristics and prognostic factors of patients with Stenotrophomonas maltophilia bacteremia. J Microbiol Immunol Infect 2004;37:350–8.[Medline]
- Labarca JA, Leber AL, Kern VL, et al. Outbreak of Stenotrophomonas maltophilia bacteremia in allogenic bone marrow transplant patients: role of severe neutropenia and mucositis. Clin Infect Dis 2000;30:195–7.[CrossRef][Medline]
- Heussel CP, Kauczor HU, Heussel G, Fischer B, Mildenberger P, Thelen M. Early detection of pneumonia in febrile neutropenic patients: use of thin section CT. AJR Am J Roentgenol 1997;169:1347–53.[Abstract/Free Full Text]
- Looney WJ. Role of Stenotrophomonas maltophilia in hospital-acquired infection. Br J Biomed Sci 2005;62:145–54.[Medline]
- Reittner Pia, Ward S, Heyneman L, et al. Pneumonia: high-resolution CT findings in 114 patients. Eur Radiol 2003;13:515–21.[Medline]
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Abstract
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