Ascites and Pleural Effusion

When an underlying derangement in fluid balance occurs, fluid will accumulate in potential spaces including the thoracic cavity and abdominal cavity. These fluid collections are referred to as a pleural effusion in the pleural space or ascites in the peritoneal cavity. Mechanisms underlying pleural effusion and ascites include abnormalities in hydrostatic pressure, oncotic pressure, vascular permeability, or lymphatics. Treatment is aimed at the underlying etiology. Depending on the clinical scenario, a diagnostic fluid sample may be necessary to determine the cause of an abnormal fluid collection. Percutaneous image-guided procedures, such as thoracentesis for drainage of pleural fluid or paracentesis for drainage of ascites, are safe and effective techniques to obtain fluid for diagnostic purposes and have become standard of care. In cases where fluid reaccumulates, these procedures can be performed for symptomatic relief. Image-guided thoracentesis and paracentesis are more cost-effective and result in lower morbidity and mortality compared to non-image-guided invasive alternate diagnostic techniques.