ElectricPE: The Diagnosis of Pulmonary Embolism: Case Study 16
Jeffrey R. Galvin, M.D. and James J. Choi, B.S.
Peer Review Status: Internally Reviewed
The chest radiograph revealed a hyperlucent Right lung with
markedly attenuated vasculature.
This was
compared with films sent in from the outside hospital that showed
normal vasculature and density in the right lung. This constellation
of findings was considered very strong evidence of pulmonary embolus.
It is known as a Westermarks sign. (RADIMAGE)
The perfusion scan showed multiple segmental perfusion defects
with multiple areas of abnormal wash out on the ventilation scan.
The V/Q
was read as high probability for pulmonary embolus based on the
multiple large perfusion defect. The abnormalities in ventilation,
although present, are less severe.
An angiogram revealed multiple clots.
This case was found to have a PO2 of 45 on room air. His mental status improved markedly with oxygen.
Case Assessment
This case was a 64 year old male with a strong predisposition to the
formation of deep venous thrombi. These risk factors included the
presence of an adenocarcinoma and bed rest. He presented with
confusion related to hypoxemia and Westermarks sign on chest
radiography
1. The chest x-ray is usually abnormal although often non-specific. (REFERENCE) In this case the chest radiograph combined with the older comparison was essentially diagnostic.
2. Pulmonary emboli are often associated with disturbed ventilation. This is confirmed by the prevalence of hypoxemia in patients with pulmonary embolus. It is not surprising therefore, that the ventilation scan may be abnormal in patients with pulmonary embolus. Matched ventilation perfusion defects are associated with the presence of pulmonary emboli. (REFERENCE)
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