Pulmonary thin-section CT findings in acute Moraxella catarrhalis pulmonary infection

Abstract

Objective: Moraxella catarrhalis is an important pathogen in the exacerbation of chronic obstructive pulmonary disease. The aim of this study was to assess the clinical and pulmonary thin-section CT findings in patients with acute M. catarrhalis pulmonary infection.

Methods: Thin-section CT scans obtained between January 2004 and March 2009 from 292 patients with acute M. catarrhalis pulmonary infection were retrospectively evaluated. Clinical and pulmonary CT findings in the patients were assessed. Patients with concurrent infection including Streptococcus pneumoniae (n = 72), Haemophilus influenzae (n = 61) or multiple pathogens were excluded from this study.

Results: The study group comprised 109 patients (66 male, 43 female; age range 28-102 years; mean age 74.9 years). Among the 109 patients, 34 had community-acquired and 75 had nosocomial infections. Underlying diseases included pulmonary emphysema (n = 74), cardiovascular disease (n = 44) or malignant disease (n = 41). Abnormal findings were seen on CT scans in all patients and included ground-glass opacity (n = 99), bronchial wall thickening (n = 85) and centrilobular nodules (n = 79). These abnormalities were predominantly seen in the peripheral lung parenchyma (n = 99). Pleural effusion was found in eight patients. No patients had mediastinal and/or hilar lymph node enlargement.

Conclusions: M. catarrhalis pulmonary infection was observed in elderly patients, often in combination with pulmonary emphysema. CT manifestations of infection were mainly ground-glass opacity, bronchial wall thickening and centilobular nodules.

Figure 1

Acute Moraxella catarrhalis infection in a 42-year-old alcoholic male with diabetes mellitus, 2 days after onset of fever and cough with sputum. A transverse thin-section CT of the right upper lobe shows consolidation, ground-glass opacity, bronchial wall thickening (arrowhead) and centrilobular nodules (arrow).

Figure 2

Acute Moraxella catarrhalis infection in a 75-year-old alcoholic male with pulmonary emphysema, 4 days after onset of fever, cough and dyspnea. A transverse thin-section CT of the right upper lobe shows consolidation, ground-glass opacity and bronchial wall thickening (arrow). Pleural effusion is also present.

Figure 3

Acute Moraxella catarrhalis infection in a 72-year-old alcoholic female with cardiovascular disease and renal failure, 3 days after the onset of fever and cough with sputum. A transverse thin-section CT of the right lower lobe shows centrilobular nodules (arrowheads), bronchial wall thickening (arrow) and mild bronchiectasis.

Figure 4

Acute Moraxella catarrhalis infection in a 76-year-old alcoholic male with pulmonary emphysema, 3 days after onset of fever and cough. A transverse thin-section CT at the tracheal carina level shows ground-glass opacity and bronchial wall thickening (arrowhead).