Background: Pulmonary arteriovenous malformations (PAVMs) are direct communications etween the smaller pulmonary arteries and veins. These are lesions in the vasculature that allow blood to bypass the capillary system, flowing from arteries directly into veins. Patients may be asymptomatic in the milder forms, or have respiratory distress and haemoptysis in the severe types. These can be congenital in origin or acquired. This case describes a patient who presented clinically with a non-resolving pneumonia.
Case: Patient is a 51 years old male, non-hypertensive, nondiabetic, asthmatic who came in due to recurrent episode of hemoptysis. Initially treated as a case of pneumonia and or PTB. A CT-scan with contrast and CT-angiogram were done and revealed AV malformation. On admission patient was stable and not in respiratory distress. He was referred to surgical service for possible thoracotomy. On the third hospital day patient underwent elective thoracotomy and right middle lobe lobectomy. The operation was unremarkable and on the tenth hospital day patient was discharged improved.
Histopathologic Findings: The specimen showed lung tissue exhibiting areas of varisized thin and partially thick vascular channels lined by endothelial cells and fined with red blood cells surrounded by extensive intraalveolar hemorrhage and focal areas of atelectasis. The area is in close proximity to a bronchus and accompanying medium-sized arteries, predominantly extended to the pleural lining. Elastic stain (von Gieson) highlights the elastic lamina of the thin-walled and thick walled vessels. Moderate plasmolymphocytic and few neutrophillic infiltrates are noted within the peribronchial and some alveolar spaces indicative of bronchopneumonia.
Discussion: PAVMs is an unusual and rare case. The diagnosis of PAVM should be suspected in patients with any of the following presentations: (1) one or more pulmonary nodules associated with typical roentgenographic findings, (2) mucocutaneous telangiectases, and (3) unexplained findings such as dyspnea, hemoptysis, hypoxemia, polycythemia, clubbing, cyanosis, cerebral embolism, or brain abscess. A practical approach would be to screen patients initially with chest radiograph, followed by shunt measurement by 100% oxygen. The definitive diagnosis is established by means of direct imaging study such as a computed tomography with contrast, pulmonary angiogram and currently by CT-angiogram. Our case presented with pneumonia, later developed hemoptysis and was confirmed with PAVM by CT-scan and CT-angiogram, and underwent right middle lobectomy. Other treatment options are embolization and lung transplantation.
Conclusion: PAVMs are rare and unusual cases. The rarity of cases and the variability of presentation poised a great challenge. The advent of sophisticated radioimaging like CT-angiogram provided our opportunity to deliver timely treatment. This A V malformation case in particular which presented as a non- resolving pneumonia with an unusual location in the right middle lobe is a significant contribution to our registry. Its rarity should alert clinicians to include PAVM's in the differential diagnosis of patients with pneumonia and hemoptysis.
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