Treatment depends on the underlying cause of the pleural effusion.

Therapeutic aspiration may be sufficient; larger effusions may require insertion of an intercostal drain (either pigtail or surgical). When managing these chest tubes, it is important to make sure the chest tubes do not become occluded or clogged. A clogged chest tube in the setting of continued production of fluid will result in residual fluid left behind when the chest tube is removed. This fluid can lead to complications such as hypoxia due to lung collapse from the fluid, or fibrothorax if scarring occurs. Repeated effusions may require chemical (talc, bleomycin, tetracycline/doxycycline), or surgical pleurodesis, in which the two pleural surfaces are scarred to each other so that no fluid can accumulate between them. This is a surgical procedure that involves inserting a chest tube, then either mechanically abrading the pleura or inserting the chemicals to induce a scar. This requires the chest tube to stay in until the fluid drainage stops. This can take days to weeks and can require prolonged hospitalizations. If the chest tube becomes clogged, fluid will be left behind and the pleurodesis will fail.

Pleurodesis fails in as many as 30% of cases. An alternative is to place a PleurX Pleural Catheter or Aspira Drainage Catheter. This is a 15Fr chest tube with a one-way valve. Each day the patient or care givers connect it to a simple vacuum tube and remove from 600 to 1000 mL of fluid, and can be repeated daily. When not in use, the tube is capped. This allows patients to be outside the hospital. For patients with malignant pleural effusions, it allows them to continue chemotherapy, if indicated. Generally, the tube is in for about 30 days and then it is removed when the space undergoes a spontaneous pleurodesis.

Urinothorax ("pl". urinothoraces) means urine in the fluid-filled cavity that surrounds the lungs. It is a rare cause of pleural effusion secondary to obstructive uropathy whereby urine forms a collection in the pleural cavity. The urine arrives in the pleural space either retroperitoneally under the posterior diaphragm, or via the retroperitoneal lymphatics. It remains a rare, possibly under-diagnosed, differential in the case of transudative pleural effusion.

Handa et al., described 47 cases between 1967 and 2007, noting that it was more prevalent in males, generally ipsilateral to the obstruction, and in most cases relieved by clearance of the obstruction.

A pleural effusion is excess fluid that accumulates in the pleural cavity, the fluid-filled space that surrounds the lungs. This excess can impair breathing by limiting the expansion of the lungs. Various kinds of pleural effusion, depending on the nature of the fluid and what caused its entry into the pleural space, are hydrothorax (serous fluid), hemothorax (blood), urinothorax (urine), chylothorax (chyle), or pyothorax (pus). A pneumothorax is the accumulation of air in the pleural space, and is commonly called a "collapsed lung."