Treatment for Pleural Effusion
Treatment of pleural effusion depends on the underlying cause. For example, treatment directed at congestive heart failure reduces the pleural fluid most of the time. Removal of the offending drug often resolves drug-induced pleural effusion. Two conditions that require special consideration include empyema and malignant effusion.
Bacterial pneumonia can cause pleural effusion that is not infected, called a parapneumonic effusion. When the fluid is infected or quite inflamed it is called a complicated parapneumonic effusion, or an empyema. Infection in the pleural space causes severe inflammation, which causes adhesions to form and "scarring down" of the pleural space. This, in turn, can compress the lung until the infection clears. The infection is very difficult to eradicate without draining the fluid. If a thoracentesis is performed for an empyema, the fluid rapidly reaccumulates. Therefore, therapy is directed at draining the pleural space completely and keeping it empty until the infection has cleared.
The most common method for treating an empyema is drainage with a chest tube. Antibiotics are required regardless of the method of drainage. The chest tube is inserted into the pleural space between the ribs on the patient's side. The patient is usually given light sedation or analgesic intravenously. The patient's skin is then prepped with iodine containing a preparation that decreases the bacteria on the skin and limits the risk for infection. The skin and underlying tissue to the pleural membrane is anesthetized using a small needle, very similar to thoracentesis. An incision is made into the skin, and the underlying tissue is separated (dissection) until the pleural space is entered. Some physicians use a trocar instead of dissection to place a chest tube. A tube, usually about as big around as a small finger is inserted in the pleural space. This tube is sutured into place and the skin around the tube is sutured. This tube is often hooked up to a suction device to facilitate drainage. The chest tube is left in place for several days until the fluid stops forming and drainage is minimal.
Complications are rare and include bleeding, infection, and a puncture in the lung. Chest tube placement is somewhat uncomfortable and the site where the tube is placed remains uncomfortable until the tube is removed. Usually patients with a chest tube require systemic analgesics, either pills or injections, until the tube is removed.
It may not be possible to drain all the fluid because of formation of fibrin septa, or partitions. Fibrin is a molecule that is a key component in the formation of blood clots. In an empyema, there is a lot of fibrin that can create pockets of fluid (loculated effusion) that cannot reach the drainage site. There are two ways to deal with a loculated effusion: chemically and surgically. A chemical that breaks up fibrin, such as urokinase and streptokinase, can be instilled through a chest tube daily for several days. The chemical may succeed in breaking up the fibrin adhesions, allowing the fluid to drain. Decortication is a surgical procedure performed under general anesthesia in which the surgeon manually breaks up the adhesions and drains the pleural space. The surgeon puts a chest tube into place so the pleural space continues to drain (postsurgically) until fluid ceases to be produced and drainage resolves, typically a few days.
Malignant Pleural Effusions
Malignant pleural effusions are generally treated to relieve shortness of breath and/or chest pain caused by the presence of mesothelioma (caused by asbestosis) or neoplasms that have metastasized from elsewhere in the body; the lungs or breast are usually the primary site. Metastatic involvement is far more frequent than primary malignancies of the pleura (mesotheliomas). There are four ways to treat a malignant pleural effusion and the choice depends on the individual case. The first method is chemotherapy. If the tumor(s) responds to this therapy, the pleural effusion may resolve. The second method is intermittent thoracentesis. If the fluid reaccumulates very slowly (over several months) pleural effusion is drained intermittently by thoracentesis, as needed. The third method is pleurodesis, which is done if the pleural effusion reaccumulates rapidly after drainage. The fourth method is the use of a pleural-peritoneal shunt.
Pleurodesis is often performed to control malignant pleural effusion and is occasionally used to control nonmalignant pleural effusion. Pleurodesis employs a sclerosing agent that causes inflammation and scarring on the pleural surfaces so the parietal and visceral pleura adhere. This closes the space, so fluid cannot accumulate.
There are two methods. In one, a chest tube is used to drain fluid. Once the fluid is drained, the sclerosing agent is injected through the chest tube into the pleural space. The sclerosing agent is allowed to distribute itself over a couple of hours and then the chest tube is attached to a suction device. Suction brings the two pleural surfaces together and allows them to "scar" together. It takes a few days for the fluid to drain sufficiently before the sclerosing agent can be injected. The chest tube stays in place, typically for a few days, until drainage decreases to a reasonable level. Unfortunately, this can take several days to accomplish. As mentioned above, the chest tube is usually uncomfortable and the patient usually needs analgesics.
The second method uses thoracoscopy. A small incision or incisions are made in the skin and a small thoracoscope is passed through the incision to visualize the pleura. The sclerosing agent is placed under direct visualization onto the pleural surface. Complications with this procedure include a small risk for bleeding and infection. Pneumothorax is uniformly present and requires a chest tube for a short time after the procedure. Proponents of this procedure believe the sclerosing agent can be more efficiently applied to the pleura. However, there are no studies showing one method to be superior to the other. Several agents can be used for pleurodesis, including talc, bleomycin, and doxycycline.
Unfortunately, not every patient with a symptomatic pleural effusion is a candidate for a pleurodesis and the procedure does not work in every case. Patients with a life expectancy of less than a few months generally are not candidates. Patients with a very low functional status and patients with a trapped lung also are not candidates. A trapped lung does not expand and fill up the chest after drainage of the fluid. This can happen when the visceral pleura has become so encased with tumor or scarring that it prevents the lung from expanding. Lungs may not reexpand when a tumor blocks the bronchial tubes and air cannot pass into that area of the lung. If the lung does not reexpand, pleurodesis simply cannot work. Patients with very low fluid pH also are not candidates for pleurodesis.
Pleural abrasion with or without pleurectomy
Patients who have failed pluerodesis and are surgical candidates may be considered for pleural abrasion with or without pleurectomy. In this procedure, the surgeon mechanically roughens the surfaces of the pleural membranes, causing inflammation and injury that leads to scarring and adhesion of the opposing sides. The pleural membranes can also be removed during this procedure. This procedure is done infrequently.
A pleural-peritoneal shunt may be considered for selected patients. One end of a catheter is placed in the pleural space, the catheter is tunneled under the skin, and the other end is placed in the abdominal cavity (peritoneal cavity). The catheter has a one-way valve and an area that can be compressed to pump fluid from the pleural space into the peritoneal space. The main drawback in this procedure is that the catheter can clog. The fluid, rich in malignant cells, is pumped into the peritoneal cavity, where tumor involvement can occur. This procedure can be effective for relieving symptoms.