Proven empyema (as defined by the "golden" criteria mentioned earlier) is an indication for prompt chest tube drainage. This has been shown to improve resolution of the infection and shorten hospital admission. Data from a meta-analysis has shown that a pleural fluid pH of <7.2 is the most powerful indicator to predict the need for chest tube drainage in patients with non-purulent, culture negative fluid. Other indications for drainage include poor clinical progress during treatment with antibiotics alone and patients with a loculated pleural collection.

Because of the viscous, lumpy nature of infected pleural fluid, in combination with possible septation and loculation, it has been proposed that intrapleural fibrinolytic or mucolytic therapy might improve drainage and therefore might have a positive effect on the clinical outcome. Intrapleural fibrinolysis with urokinase decreased the need for surgery but there is a trend to increased serious side effects.

Approximately 15 to 40 percent of people require surgical drainage of the infected pleural space because of inadequate drainage due to clogging of the chest tube or loculated empyema. Patients should thus be considered for surgery if they have ongoing signs of sepsis in association with a persistent pleural collection despite drainage and antibiotics. Video-assisted thoracoscopic surgery (VATS) is used as a first-line therapy in many hospitals, although open thoracic drainage remains a frequently used alternative technique.

There is no readily available evidence on the route of administration and duration of antibiotics in patients with pleural empyema. Experts agree that all patients should be hospitalized and treated with antibiotics intravenously. The specific antimicrobial agent should be chosen based on Gram stain and culture, or on local epidemiologic data when these are not available. Anaerobic coverage must be included in all adults, and in children if aspiration is likely. Good pleural fluid and empyema penetration has been reported in adults for penicillins, ceftriaxone, metronidazole, clindamycin, vancomycin, gentamycin and ciprofloxacin. Aminoglycosides should typically be avoided as they have poor penetration into the pleural space. There is no clear consensus on duration of intravenous and oral therapy. Switching to oral antibiotics can be considered upon clinical and objective improvement (adequate drainage and removal of chest tube, declining CRP, temperature normalization). Oral antibiotic treatment should then be continued for another 1–4 weeks, again based on clinical, biochemical and radiological response.

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.

Since the mechanism behind chylothorax is not well understood, treatment options are limited. Drainage of the fluid out of the pleural space is essential to obviate damage to organs, especially the inhibition of lung function by the counter pressure of the chyle. Another treatment option is pleuroperitoneal shunting (creating a communication channel between pleural space and peritoneal cavity). By this surgical technique loss of essential triglycerides that escape the thoracic duct can be prevented. Omitting fat (in particular FFA) from the diet is essential. Either surgical or chemical pleurodesis are options: the leaking of lymphatic fluids is stopped by irritating the lungs and chest wall, resulting in a sterile inflammation. This causes the lung and the chest wall to be fused together which prevents the leaking of lymphatic fluids into the pleural space. The medication octreotide has been shown to be beneficial and in some cases will stop the chylothorax after a few weeks.

In animals, the most effective form of treatment until recently has been surgical ligation of the thoracic duct combined with partial pericardectomy. There is at least one case report (in a cat) of clinical response to treatment with rutin.

If left untreated, the condition can progress to a point where the blood accumulation begins to put pressure on the mediastinum and the trachea, effectively limiting the amount that the heart's ventricles are able to fill. The condition can cause the trachea to deviate, or move, toward the unaffected side.

Treatment of hydrothorax is difficult for several reasons. The underlying condition needs to be corrected; however, often the source of the hydrothorax is end stage liver disease and correctable only by transplant. Chest tube placement should not occur. Other measures such as a TIPS procedure are more effective as they treat the cause of the hydrothorax, but have complications such as worsened hepatic encephalopathy.

A parapneumonic effusion is a type of pleural effusion that arises as a result of a pneumonia, lung abscess, or bronchiectasis. There are three types of parapneumonic effusions: uncomplicated effusions, complicated effusions, and empyema. Uncomplicated effusions generally respond well to appropriate antibiotic treatment.

- Diagnosis

The criteria for a complicated parapneumonic effusion include the presence of pus, Gram stain–positive or culture-positive pleural fluid, pleural fluid pH <7.20, and pleural fluid LDH that is greater than three times the upper limit of normal of serum LDH. Diagnostic techniques available include plain film chest x-ray, computed tomography (CT), and ultrasound. Ultrasound can be useful in differentiating between empyema and other transudative and exudative effusions due in part to relative echogenicity of different organs such as the liver (often isoechogenic with empyema).

- Treatment

Appropriate management includes chest tube drainage (tube thoracostomy). Treatment of empyemas includes antibiotics, complete pleural fluid drainage, and reexpansion of the lung.

Other treatments include the use of decortication.

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."

Treatment depends on the underlying cause and the severity of the heart impairment. Pericardial effusion due to a viral infection usually goes away within a few weeks without the treatment. Some pericardial effusions remain small and never need treatment. If the pericardial effusion is due to a condition such as lupus, treatment with anti-inflammatory medications may help. If the effusion is compromising heart function and causing cardiac tamponade, it will need to be drained, most commonly by a needle inserted through the chest wall and into the pericardial space called pericardiocentesis. A drainage tube is often left in place for several days. In some cases, surgical drainage may be required by cutting through the pericardium creating a pericardial window.

A hemothorax is managed by removing the source of bleeding and by draining the blood already in the thoracic cavity. Blood in the cavity can be removed by inserting a drain (chest tube) in a procedure called a tube thoracostomy. Generally, the thoracostomy tube is placed between the ribs in the sixth or seventh intercostal space at the mid-axillary line. Usually the lung will expand and the bleeding will stop after a chest tube is inserted.

The blood in the chest can thicken as the clotting cascade is activated when the blood leaves the blood vessels and comes into contact with the pleural surface, injured lung or chest wall, or with the chest tube. As the blood thickens, it can clot in the pleural space (leading to a retained hemothorax) or within the chest tube, leading to chest tube clogging or occlusion. Chest tube clogging or occlusion can lead to worse outcomes as it prevents adequate drainage of the pleural space, contributing to the problem of retained hemothorax. In this case, patients can be hypoxic, short of breath, or in some cases, the retained hemothorax can become infected (empyema).

Retained hemothorax occurs when blood remains in the pleural space, and is a risk factor for the development of complications, including the accumulation of pus in the pleural space and fibrothorax. It is treated by inserting a second chest tube or by drainage by video-assisted thoracoscopy. Fibrolytic therapy has also been studied as a treatment.

When hemothorax is treated with a chest tube, it is important that it maintain its function so that the blood cannot clot in the chest or the tube. If clogging occurs, internal chest tube clearing can be performed using an open or closed technique. Manual manipulation, which may also be called milking, stripping, or tapping, of chest tubes is commonly performed to maintain an open tube, but no conclusive evidence has demonstrated that any of these techniques are more effective than the others, or that they improve chest tube drainage.

In some cases bleeding continues and surgery is necessary to stop the source of bleeding. For example, if the hemothorax was caused by aortic rupture in high energy trauma, surgical intervention is mandatory.

Before the development of modern cardiovascular surgery, cases of acute mediastinitis usually arose from either perforation of the esophagus or from contiguous spread of odontogenic or retropharyngeal infections. However, in modern practice, most cases of acute mediastinitis result from complications of cardiovascular or endoscopic surgical procedures.

Treatment usually involves aggressive intravenous antibiotic therapy and hydration. If discrete fluid collections or grossly infected tissue have formed (such as abscesses), they may have to be surgically drained or debrided.

Chronic mediastinitis is usually a radiologic diagnosis manifested by diffuse fibrosis of the soft tissues of the mediastinum. This is sometimes the consequence of prior granulomatous disease, most commonly histoplasmosis. Other identifiable causes include tuberculosis, IgG4-related disease and radiation therapy. Fibrosing mediastinitis most frequently causes problems by constricting blood vessels or airways in the mediastinum. This may result in such complications as superior vena cava syndrome or pulmonary edema from compression of pulmonary veins.

Treatment for chronic fibrosing mediastinitis is somewhat controversial, and may include steroids or surgical decompression of affected vessels.

Treatment has several goals:

- Relief of symptoms

- Removal of the fluid, air, or blood from the pleural space

- Treatment of the underlying condition

A couple of medications are used to relieve pleurisy symptoms:

- Paracetamol (acetaminophen) or anti-inflammatory agents to control pain and decrease inflammation. Only indomethacin (brand name Indocin) has been studied with respect to relief of pleurisy.

- Codeine-based cough syrups to control the cough

There may be a role for the use of corticosteroids (for tuberculous pleurisy), tacrolimus (Prograf) and methotrexate (Trexall, Rheumatrex) in the treatment of pleurisy. Further studies are needed.

The goal of treatment of malignant pleural effusions is relief of breathlessness. Occasionally, treatment of the underlying cancer can cause resolution of the effusion. This may be the case with types of cancer that respond well to chemotherapy, such as small cell carcinoma or lymphoma. Simple aspiration of pleural fluid can relieve breathlessness rapidly but fluid and symptoms will usually recur within a couple of weeks. For this reason, more permanent treatments are usually used to prevent fluid recurrence. Standard treatment involves chest tube insertion and pleurodesis. However, this treatment requires an inpatient stay of approximately 2–7 days, can be painful and has a significant failure rate. This has led to the development of tunneled pleural catheters (e.g., Pleurx Catheters), which allow outpatient treatment of effusions.

Fibrothorax is diffuse fibrosis of the pleural space surrounding the lungs. It can have several causes including hemothorax, pleural effusion and tuberculosis. It may also be induced by exposure to certain substances, as with asbestos-induced diffuse pleural fibrosis. Idiopathic fibrothorax may also occur.

In fibrothorax, scar tissue is formed around the visceral pleura following inflammation due to pleural effusion or other pathology. The scar tissue lies in a sheet between the pleura, then fuses with the parietal pleura and the chest wall. Over time, generally the course of years, the fibrotic scar tissue slowly tightens, which results in the contraction of the entire hemithorax, and leaves the ribs immobilized. Within the chest, the lung is compressed and unable to expand, making it vulnerable to collapse. At the microscopic level, the scar tissue is composed of collagen fibers deposited in a basket weave pattern. The treatment for fibrothorax is decortication, the surgical removal of the fibrous layer of scar tissue. However, since many of the diseases and conditions resulting in fibrothorax are treatable, prevention remains the preferred method of managing fibrothorax.

A bronchopleural fistula (BPF) is a fistula between the pleural space and the lung. It can develop following Pneumonectomy, post traumatically, or with certain types of infection. It may also develop when large airways are in communication with the pleural space following a large pneumothorax or other loss of pleural negative pressure, especially during positive pressure mechanical ventilation. On imaging, the diagnosis is suspected indirectly on radiograph. Increased gas in the pneumonectomy operative bed, or new gas within a loculated effusion are highly suggestive of the diagnosis. Infectious causes include tuberculosis, "Actinomyces israelii", "Nocardia", and "Blastomyces dermatitidis". Malignancy and trauma can also result in the abnormal communication.

A chylothorax (or chyle leak) is a type of pleural effusion. It results from lymph formed in the digestive system called chyle accumulating in the pleural cavity due to either disruption or obstruction of the thoracic duct.

In people on a normal diet, this effusion can be identified by its turbid, milky white appearance, since chyle contains high levels of triglycerides. It is important to distinguish chylothorax from pseudochylothorax (pleural effusions high in cholesterol), which has a similar appearance, but is caused by more chronic inflammatory processes, and has a different treatment.

Hydrothorax is a type of pleural effusion in which transudate accumulates in the pleural cavity. This condition is most likely to develop secondary to congestive heart failure, following an increase in hydrostatic pressure within the lungs. More rarely, hydrothorax can develop in patients with cirrhosis or ascites. Hepatic hydrothorax is often difficult to manage in end-stage liver failure and often fails to respond to therapy.

Pleural effusions may also develop following the accumulation of other fluids within the pleural cavity; if the fluid is blood it is known as hemothorax (as in major chest injuries), if the fluid is pus it is known as pyothorax (resulting from chest infections), and if the fluid is lymph it is known as chylothorax (resulting from rupture of the thoracic duct).

Oral antibiotics, rest, simple analgesics, and fluids usually suffice for complete resolution. However, those with other medical conditions, the elderly, or those with significant trouble breathing may require more advanced care. If the symptoms worsen, the pneumonia does not improve with home treatment, or complications occur, hospitalization may be required. Worldwide, approximately 7–13% of cases in children result in hospitalization, whereas in the developed world between 22 and 42% of adults with community-acquired pneumonia are admitted. The CURB-65 score is useful for determining the need for admission in adults. If the score is 0 or 1, people can typically be managed at home; if it is 2, a short hospital stay or close follow-up is needed; if it is 3–5, hospitalization is recommended. In children those with respiratory distress or oxygen saturations of less than 90% should be hospitalized. The utility of chest physiotherapy in pneumonia has not yet been determined. Non-invasive ventilation may be beneficial in those admitted to the intensive care unit. Over-the-counter cough medicine has not been found to be effective nor has the use of zinc in children. There is insufficient evidence for mucolytics.

Smoking cessation and reducing indoor air pollution, such as that from cooking indoors with wood or dung, are both recommended. Smoking appears to be the single biggest risk factor for pneumococcal pneumonia in otherwise-healthy adults. Hand hygiene and coughing into one's sleeve may also be effective preventative measures. Wearing surgical masks by the sick may also prevent illness.

Appropriately treating underlying illnesses (such as HIV/AIDS, diabetes mellitus, and malnutrition) can decrease the risk of pneumonia. In children less than 6 months of age, exclusive breast feeding reduces both the risk and severity of disease. In those with HIV/AIDS and a CD4 count of less than 200 cells/uL the antibiotic trimethoprim/sulfamethoxazole decreases the risk of "Pneumocystis pneumonia" and is also useful for prevention in those that are immunocomprised but do not have HIV.

Testing pregnant women for Group B Streptococcus and "Chlamydia trachomatis", and administering antibiotic treatment, if needed, reduces rates of pneumonia in infants; preventive measures for HIV transmission from mother to child may also be efficient. Suctioning the mouth and throat of infants with meconium-stained amniotic fluid has not been found to reduce the rate of aspiration pneumonia and may cause potential harm, thus this practice is not recommended in the majority of situations. In the frail elderly good oral health care may lower the risk of aspiration pneumonia. Zinc supplementation in children 2 months to five years old appears to reduce rates of pneumonia.

According to a recent study, the main risk factors for RA-ILD are advancing age, male sex, greater RA disease activity, rheumatoid factor (RF) positivity, and elevated titers of anticitrullinated protein antibodies such as anticyclic citrullinated peptide. Cigarette smoking also appears to increase risk of RA-ILD, especially in patients with human leukocyte antigen DRB1.

A recently published retrospective study by a team from Beijing Chao-Yang Hospital in Beijing, China, supported three of the risk factors listed for RA-ILD and identified an additional risk factor. In that study of 550 RA patients, logistic regression analysis of data collected on the 237 (43%) with ILD revealed that age, smoking, RF positivity, and elevated lactate dehydrogenase closely correlated with ILD.

Recent studies have identified risk factors for disease progression and mortality. A retrospective study of 167 patients with RA-ILD determined that the usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) was a risk factor for progression, as were severe disease upon diagnosis and rate of change in pulmonary function test results in the first 6 months after diagnosis.

A study of 59 RA-ILD patients found no median survival difference between those with the UIP pattern and those without it. But the UIP group had more deaths, hospital admissions, need for supplemental oxygen, and decline in lung function.

Pericardial effusion ("fluid around the heart") is an abnormal accumulation of fluid in the pericardial cavity. Because of the limited amount of space in the pericardial cavity, fluid accumulation leads to an increased intrapericardial pressure which can negatively affect heart function. A pericardial effusion with enough pressure to adversely affect heart function is called cardiac tamponade. Pericardial effusion usually results from a disturbed equilibrium between the production and re-absorption of pericardial fluid, or from a structural abnormality that allows fluid to enter the pericardial cavity.

Normal levels of pericardial fluid are from 15 to 50 mL.

Malignant pleural effusion is a condition in which cancer causes an abnormal amount of fluid to collect between the thin layers of tissue (pleura) lining the outside of the lung and the wall of the chest cavity. Lung cancer and breast cancer account for about 50-65% of malignant pleural effusions. Other common causes include pleural mesothelioma and lymphoma.

Treatment is directed at correcting the underlying cause. Post-surgical atelectasis is treated by physiotherapy, focusing on deep breathing and encouraging coughing. An incentive spirometer is often used as part of the breathing exercises. Walking is also highly encouraged to improve lung inflation. People with chest deformities or neurologic conditions that cause shallow breathing for long periods may benefit from mechanical devices that assist their breathing. One method is continuous positive airway pressure, which delivers pressurized air or oxygen through a nose or face mask to help ensure that the alveoli do not collapse, even at the end of a breath. This is helpful, as partially inflated alveoli can be expanded more easily than collapsed alveoli. Sometimes additional respiratory support is needed with a mechanical ventilator.

The primary treatment for acute massive atelectasis is correction of the underlying cause. A blockage that cannot be removed by coughing or by suctioning the airways often can be removed by bronchoscopy. Antibiotics are given for an infection. Chronic atelectasis is often treated with antibiotics because infection is almost inevitable. In certain cases, the affected part of the lung may be surgically removed when recurring or chronic infections become disabling or bleeding is significant. If a tumor is blocking the airway, relieving the obstruction by surgery, radiation therapy, chemotherapy, or laser therapy may prevent atelectasis from progressing and recurrent obstructive pneumonia from developing.