How is pleural effusion diagnosed?
A physician may suspect a pleural effusion based on a patient’s past medical history and description of his or her symptoms. Diagnosis is usually accomplished with a simple chest x-ray, although further radiographic tests may be needed to confirm the presence of pleural fluid. Ultrasound and CT (computed tomography) scan of the chest are often used to confirm pleural effusion. A special chest x-ray technique, a lateral decubitus film, can confirm the presence of fluid and enable the physican to make an estimate of the amount. This x-ray technique is performed with the patient lying on his or her side, allowing the free-flowing fluid to shift in the chest. It can be seen pooling along the side wall of the chest and measuring the depth of the fluid gives an idea of how much fluid is present. Occasionally, bronchoscopy (a direct visual examination of the airways through a viewing tube) helps the doctor find the cause of the fluid. In about 20% of people with pleural effusion, the cause is
