Pulmonary Arteriovenous Malformation Masquerading as Massive Pulmonary Thromboembolus

Abstract

We present a case of a 78-year-old male with hereditary haemorrhagic telangiectasia and severe hypoxia incorrectly diagnosed as pulmonary embolism following a false positive ventilation/perfusion scan. Anti-coagulation and thrombolysis was complicated by an upper gastro-intestinal haemorrhage. Pulmonary arteriovenous malformations resulted in a clinically significant right-left shunt and created an apparent perfusion defect evident upon radionuclide imaging, leading to diagnostic uncertainty and a potentially dangerous treatment modality.

The role of nuclear medicine in a case of Rendu–Osler–Weber disease with pulmonary involvement

“…HHT with pulmonary AVM should be considered in patients with severe hypoxia due to right-to-left shunting and the presence of multiple telangiectases. [7] This case illustrates the risk of misinterpreting a V/Q scan with unmatched perfusion defects in a patient with hemorrhagic telangiectasia.…”

“…V/Q scan needs to be interpreted in the context of the clinical likelihood for PTE. [ 6 7 ] The occurrence of a false positive scan is an unusual event, but it is vital that the nuclear physician has the knowledge of a number of sources of errors when reporting the study. [ 6 7 ] Congenital lung vascular anomalies is described as one of the causes of segmental mismatches, consequently a potential pitfall in the interpretation of V/Q scan.…”

“…[ 6 7 ] The occurrence of a false positive scan is an unusual event, but it is vital that the nuclear physician has the knowledge of a number of sources of errors when reporting the study. [ 6 7 ] Congenital lung vascular anomalies is described as one of the causes of segmental mismatches, consequently a potential pitfall in the interpretation of V/Q scan. [ 6 ] Single photon-emission computed tomography is the mainly used nuclear imaging modality to rule out PTE.…”

“…HHT with pulmonary AVM should be considered in patients with severe hypoxia due to right-to-left shunting and the presence of multiple telangiectases. [ 7 ]…”