Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Pulmonary infarction
- Radiologic Findings
- Chest PA radiograph shows ill-defined ground glass opacity and consolidation in the peripheral portion of the left lower lung, causing obliteration of costophrenic angle. Axial CT images depict a pleural-based polygonal shape consolidation with central lucencies. Enhanced CT was not performed because the patient had an increased BUN. Follow-up d-dimer test, perfusion scan, and clinical course confirmed acute pulmonary infarction.
- Brief Review
- The patient was diagnosed as drug induced nephrotic syndrome. Patients with nephrotic syndrome are at an increased risk for thrombotic events, such as pulmonary thromboembolism. Increased platelet activation, enhanced red blood cell aggregation, and an imbalance between procoagulant and anticoagulant factors are thought to underlie the excessive thrombotic risk.
Pulmonary thromboembolism is the most common cause of pulmonary infarction. Less than 15% of emboli cause true pulmonary infarction. On pathologic study, pulmonary infarction is characterized by ischemic necrosis of alveolar walls, bronchioles, and blood vessels within an area of hemorrhage. Most infarcts occur in the lower lobes, and the majority is multiple. Usually they are roughly cone-shaped areas of hemorrhage and edema that point toward the hilum and are based on the pleura and accompanied by a small pleural effusion. Presence of central lucencies had 98% specificity and 46% sensitivity for pulmonary infarction. When the vessel sign and negative air bronchogram were combined with central lucencies, specificity was increased to 99%.
Following infarction, fibrous replacement converts the infarct into a contracted scar, with indrawing of the pleura. Local hemorrhage may be the dominant finding with no evidence of tissue necrosis. These lesions resolve without residual scar formation when the consolidation is the result of pulmonary hemorrhage without true infarction. Radiographic clearing of pulmonary hemorrhage occurs quickly, often within a week, whereas infarction takes several months to resolve and frequently leaves permanent linear scars. By 3 months, infarct shadows either are totally resolved or show no more than linear scarring or pleural thickening. As infarcts resolve, they tend to ‘melt away like an ice cube’ whereas acute pneumonia disappears in a patchy fashion.
- References
- 1.Hansel DM, Imaging of Disease of the Chest 5th Ed.p385-
2. Revel MP, Triki R, Chatellier G, Couchon S, Haddad N, Hernigou A,et al. Is It Possible to Recognize Pulmonary Infarction on Multisection CT Images? Radiology 2007;244:875-882
3. Int J Nephrol. 2014;2014:906760 doi:10.1155/2014/916760.Epub 2014.Apr 16.
- Keywords
- Lung, Vascular, Vascular,