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Radiographic findings of pulmonary blastomycosis
PA G E 4
A D VA N C E S
RADIOGRAPHIC FINDINGS OF PULMONARY BLASTOMYCOSIS Background Classical radiographic findings of pulmonary blastomycosis in dogs are usually described as diffuse nodular or military interstitial lesions. Bacterial or aspiration pneumonia radiographic findings are typically described as asymmetrical, lobar
A D VA N C E S
alveolar infiltrates. It has been assumed that there is minimal overlap between radiographic patterns seen with bacterial or aspiration pneumonia and patterns seen with most pulmonary mycotic diseases. However, pulmonary radiographic patterns resembling lobar masses and patterns typically associated with bacterial pneumonia have been observed occasionally in dogs with pulmonary blastomycosis.
Objectives To identify radiographic patterns in dogs with pulmonary blastomycosis and radiographic factors associated with outcome.
Procedure The medical records of 125 dogs with pulmonary blastomycosis were reviewed. The primary radiographic pattern and percentage of lobar involvement at the time of initial examination were recorded for each lung lobe.
Results Seventy-nine dogs survived, 38 died, and 8 were euthanized without treatment. The initial radiographic pattern was variable and not significantly associated with outcome. Pulmonary infiltrates had a mean half-time for radiographic resolution of 41.4 days. Pulmonary masses had a mean half-time to resolution of 90.8 days. Transient radiographic worsening occurred in 20 of 87 (23%) dogs but was not predictive of a poor outcome. Pulmonary bullae, usually associated with an alveolar pattern, were seen in 20 (16%) dogs. Accuracy of using 20% or less percentage of right caudal lung lobe involvement to predict a favorable outcome was 74.4%. The accuracy of using less than 4 affected lobes to predict a favorable outcome was 65.8%.
Author Conclusion A non-uniform distribution of pulmonary infiltrates is equally as common as a diffuse nodular interstitial pattern in dogs with pulmonary blastomycosis. Followup radiography should be performed no more often than every 4 to 6 weeks in clinically stable patients. Transient radiographic worsening occurring during the initial weeks of treatment is not associated with a poorer prognosis.
Inclusions Three figures, 1 table, 12 references.
Editor Annotation Blastomycosis, although a regional disease, has well known thoracic radiographic changes. A military or nodular interstitial lung pattern is considered the classic appearance of pulmonary blastomycosis. In this retrospective study of 125 dogs with blastomycosis, thoracic radiographs were carefully evaluated for lung pattern, time for resolution of lung changes, and any radiographic change that might predict the outcome of the patient. It was determined that over 59% of affected dogs had an alveolar or pulmonary mass lesion rather than the “classic” appearance of military or small nodules. This could have serious ramifications, as either pneumonia or pulmonary neoplasia might be initially diagnosed, delaying appropriate treatment. The median time to resolution of the main radiographic pattern in this study was 185.5 days but ranged as long as 355 days. Since treatment duration is based on resolution of pulmonary infiltrates, this long persistence of radiographic changes is important. There was transient worsening of the radiographic changes in 23% of dogs, but this did not correlate with patient outcome. This study emphasizes some important considerations for veterinarians practicing in areas where blastomycosis is endemic. (MML) Crews LJ, Feeney DA, Jessen CR, et al. Radiographic findings in dogs with pulmonary blastomycosis: 125 cases (1989-2006). J Am Vet Med Assoc 2008;232:215-221.
PAG E 5
A D VA N C E S
RADIOGRAPHIC FINDINGS OF PULMONARY BLASTOMYCOSIS Background Classical radiographic findings of pulmonary blastomycosis in dogs are usually described as diffuse nodular or military interstitial lesions. Bacterial or aspiration pneumonia radiographic findings are typically described as asymmetrical, lobar
A D VA N C E S
alveolar infiltrates. It has been assumed that there is minimal overlap between radiographic patterns seen with bacterial or aspiration pneumonia and patterns seen with most pulmonary mycotic diseases. However, pulmonary radiographic patterns resembling lobar masses and patterns typically associated with bacterial pneumonia have been observed occasionally in dogs with pulmonary blastomycosis.
Objectives To identify radiographic patterns in dogs with pulmonary blastomycosis and radiographic factors associated with outcome.
Procedure The medical records of 125 dogs with pulmonary blastomycosis were reviewed. The primary radiographic pattern and percentage of lobar involvement at the time of initial examination were recorded for each lung lobe.
Results Seventy-nine dogs survived, 38 died, and 8 were euthanized without treatment. The initial radiographic pattern was variable and not significantly associated with outcome. Pulmonary infiltrates had a mean half-time for radiographic resolution of 41.4 days. Pulmonary masses had a mean half-time to resolution of 90.8 days. Transient radiographic worsening occurred in 20 of 87 (23%) dogs but was not predictive of a poor outcome. Pulmonary bullae, usually associated with an alveolar pattern, were seen in 20 (16%) dogs. Accuracy of using 20% or less percentage of right caudal lung lobe involvement to predict a favorable outcome was 74.4%. The accuracy of using less than 4 affected lobes to predict a favorable outcome was 65.8%.
Author Conclusion A non-uniform distribution of pulmonary infiltrates is equally as common as a diffuse nodular interstitial pattern in dogs with pulmonary blastomycosis. Followup radiography should be performed no more often than every 4 to 6 weeks in clinically stable patients. Transient radiographic worsening occurring during the initial weeks of treatment is not associated with a poorer prognosis.
Inclusions Three figures, 1 table, 12 references.
Editor Annotation Blastomycosis, although a regional disease, has well known thoracic radiographic changes. A military or nodular interstitial lung pattern is considered the classic appearance of pulmonary blastomycosis. In this retrospective study of 125 dogs with blastomycosis, thoracic radiographs were carefully evaluated for lung pattern, time for resolution of lung changes, and any radiographic change that might predict the outcome of the patient. It was determined that over 59% of affected dogs had an alveolar or pulmonary mass lesion rather than the “classic” appearance of military or small nodules. This could have serious ramifications, as either pneumonia or pulmonary neoplasia might be initially diagnosed, delaying appropriate treatment. The median time to resolution of the main radiographic pattern in this study was 185.5 days but ranged as long as 355 days. Since treatment duration is based on resolution of pulmonary infiltrates, this long persistence of radiographic changes is important. There was transient worsening of the radiographic changes in 23% of dogs, but this did not correlate with patient outcome. This study emphasizes some important considerations for veterinarians practicing in areas where blastomycosis is endemic. (MML) Crews LJ, Feeney DA, Jessen CR, et al. Radiographic findings in dogs with pulmonary blastomycosis: 125 cases (1989-2006). J Am Vet Med Assoc 2008;232:215-221.
PAG E 5