Evidence-based, cost-effective management of empyema and chylothorax: An algorithm of the Journal of Trauma and Acute Care Surgery Emergency General Surgery Algorithms work group

This algorithm was developed by the Journal of Trauma and Acute Care Surgery Emergency General Surgery Algorithms working group to provide an evidence-based, practical approach to the initial evaluation and management of empyema and chylothorax in adults presenting in the emergency setting.¹ The algorithm is intended to serve as a bedside reference for clinicians. It is presented in three separate diagrams, the first (Fig. 1) depicts the common diagnostic pathway for a new pleural effusion. The pathways for management of empyema (Fig. 2) and chylothorax (Fig. 3) share common themes but are separated for clarity. All three figures are annotated with letters that link to the corresponding text, providing the rationale and references supporting these recommendations. The algorithm is not a substitute for the clinical judgment and experience of bedside clinicians and should not be considered the “standard of care.” We encourage institutions to use these recommendations to formulate local clinical guidelines, recognizing that patient-specific and institutional-specific factors may necessitate modifications to this algorithm.

Figure 1.

Initial diagnostic pathway for undiagnosed pleural effusion; refer to section A: Pleural Fluid Analysis in the manuscript for rationale and references.

Figure 2.

Treatment algorithm for empyema; refer to sections B: Initial Drainage and Antibiotic Therapy, C: Decision Between Initial Surgical or Medical Approach, D: Trial of Intrapleural Enzyme Therapy (IET), E: Thoracoscopic (VATS) Drainage and Decortication, and F: Open Techniques in the manuscript for rationale and references.

Figure 3.

Treatment algorithm for chylothorax; refer to sections G: Diagnostic Evaluation, H: Initial Management, and I: Thoracic Duct Interruption in the manuscript for rationale and references.

Empyema, shortened from empyema thoracis, is a suppurative infection in the pleural cavity, and was known and described as early as the time of Hippocrates.² Chylothorax is the presence of chyle in the pleural cavity, the first description of which has been attributed to Bartolet in 1633.³ In contrast to empyema, one of the early diagnostic hallmarks of chylothorax was that the fluid was “sterile and resists putrefaction”.⁴ They are two essentially unrelated pathologic entities linked only by the fact that they both occur within the pleural space and both initially manifest as pleural effusion. Nevertheless, the management pathways share similar diagnostic branch points and similar therapeutic choices. The process begins with the identification of a new pleural effusion without an obvious etiology. In both empyema and chylothorax, the process is usually unilateral.

DIAGNOSIS

A: Pleural Fluid Analysis

New radiographic findings of a pleural effusion should first be evaluated in the context of the patient’s clinical condition, recent history, and the characteristics of the effusion on chest computed tomography (CT). If the effusion is not readily explained by other known pathology (eg, hemothorax or fluid overload), or if there are signs and symptoms of pneumonia or sepsis, a sample of pleural fluid should be obtained for analysis.^5,6 Depending on the clinical presentation and the size of the effusion, a pleural fluid sample can be obtained by simple thoracentesis or by placement of a small-bore (<14 Fr) chest drain. In either case, the sampling procedure should be done using image guidance, typically ultrasound, to minimize the risk of pneumothorax. If the composition of the fluid is obvious by inspection (eg, purulent, chylous, or serosanguinous) a diagnosis can be made immediately, but the fluid should still be submitted for chemical analysis, including pH, glucose, lactate dehydrogenase (LDH), and triglycerides. The diagnostic interpretation of these results^5–7 is summarized in Table 1. If the effusion is an exudate, especially if pH is between 7.20 and 7.40 and glucose is >40, the differential diagnosis must also include a malignant etiology. In this case, the pleural fluid should be sent for cytology. If initial cytology is negative and suspicion is high, a second sample increases the sensitivity.⁶

TABLE 1.

Diagnostic Criteria for Pleural Effusion

Test	Exudate*	Empyema	Chylothorax
pH	7.2-7.4	<7.2	—
Glucose (mg/dL)	40-60	<40	—
LDH (U/L)	>150	>1,000	—
Triglycerides (mg/dL)	—	—	>110 diagnostic 50-S110 → lipoprotein electrophoresis
Chylomicrons	—	—	Presence confirms diagnosis

^*Exudate may also represent early empyema.

EMPYEMA MANAGEMENT

B: Initial Drainage and Antibiotic Therapy

If a contrast-enhanced chest CT has not been obtained earlier in the clinical evaluation, it should be obtained as soon as possible. The radiographic density of the pleural fluid on CT, measured in Hounsfield units (HU), may help differentiate serous fluid from exudative fluid or pus. Empyema fluid generally measures 15 to 45 HU, compared with 0 to 10 HU for simple fluid (by definition, distilled water has a density of 0 HU). If not already done, a small-bore chest drain should be placed under image guidance. Even with more complex fluid collections, there is no evidence that larger chest tubes improve drainage, and they are associated with significantly higher morbidity, including an independent risk of empyema.⁸ Chest tubes placed for empyema should be routinely flushed to help maintain patency. Empiric antibiotics should be started based on the clinical situation and local antibiotic resistance patterns. For community-acquired empyema, the most common causative organisms are streptococci, methicillin-sensitive Staphylococcus aureus, and Enterobacteriaceae. Coverage with a second-generation or third-generation cephalosporin or an extended-spectrum penicillin is generally sufficient. For hospital-acquired cases, initial empiric coverage for methicillin-resistant Staphylococcus aureus and Pseudomonas species is important. If culture results are available, antibiotic coverage should be tailored appropriately. Repeat CT imaging should be obtained at 48 to 72 hours to assess for adequacy of drainage. If the CT demonstrates complete drainage of the effusion, a full course of antibiotics should be completed. There is no strong evidence to guide the duration of antibiotic therapy, but the American Association of Thoracic Surgery recommends a 2-week course after complete drainage, with adjustments based on the clinical course.⁵ For simple empyema, chest tube drainage and antibiotics may be all that is required for resolution.

If standard treatment of empyema with antibiotics and chest drain fails (in up to 34% of cases in prior studies),⁹ then intrapleural enzyme therapy (IET) and/or video-assisted thoracoscopic surgery (VATS) are considered as the next management steps. Some studies report that a hospital source of infection was associated with a 71% risk of IET treatment failure, significantly higher than that with a community source of infection.¹⁰

C: Decision Between Initial Surgical or Medical Approach

There is evidence to support both an initial surgical approach or an initial trial of medical management followed by timely surgery if medical management fails. The arguments in favor of initial VATS focus on higher success rates, shorter chest drain duration, and shorter hospital stay,^11,12 whereas the evidence supporting initial medical therapy shows that surgical intervention, with its attendant risks, can be avoided in most patients. In addition, patient-centric metrics such as quality of life assessment and freedom from pain favor nonoperative management.^13,14 The fourth Multicenter Intrapleural Sepsis Trial (MIST) is an RCT (n=604) comparing VATS and IET in adult patients with pleural infection, initiated in April 2025 and projected end date of September 2029 (https://fundingawards.nihr.ac.uk/award/NIHR161731) may add weight to one decision pathway or the other. Recent consensus guidelines have favored a stepwise approach beginning with IET,^5–7 but the decision-making for an individual patient should balance local resources, surgical capabilities, and patient preferences.

D: Trial of Intrapleural Enzyme Therapy (IET)

If the follow-up CT shows incomplete drainage and fluid loculations, a trial of intrapleural fibrinolytic (tissue plasminogen activator, TPA) and deoxyribonuclease (DNase) as intrapleural enzyme therapy (IET), delivered through the chest drain, should be considered. The two agents work synergistically; tPA breaks down the fibrin structure of the blood clot, whereas DNase breaks down free DNA from dead white blood cells, reducing the thickness and viscosity of pleural fluid. The use of IET has been extensively studied, including in several large clinical trials. Although there is insufficient evidence to support routine use of IET in all cases of empyema, the British Thoracic Society has suggested its use, based on expert consensus.⁶ The current consensus recommendation is concurrent administration of 10 mg TPA and 5 mg DNase each twice daily for 3 days, with the chest tube clamped for at least 1 hour after administration, based on the MIST trials.^13–16 On the basis of a retrospective case series, a reduced dose of 5 mg TPA and 5 mg DNase, each administered twice daily for 3 days, may be as effective and can be considered in patients with a potentially higher bleeding risk.^17–19 The bleeding complication risk associated with IET use in pleural infection was estimated at 4.1%, and use of a half-dose regimen did not decrease this risk significantly (3.5%).¹⁹

E: Thoracoscopic (VATS) Drainage and Decortication

Thoracoscopic drainage and decortication can be undertaken as a primary modality, or if complete drainage and clinical improvement have not been achieved by 5 to 7 days after IET. Earlier literature was divided on the benefits of thoracoscopy over thoracotomy, but much of this work dates to the early days of minimally invasive surgery. With increased experience in minimally invasive techniques and improved equipment, thoracoscopy has emerged as the primary approach for lung decortication and should be utilized as the initial therapy in nearly all cases of empyema that do not respond to simple drainage.^5,6,20 In addition to standard VATS, there is emerging experience with robotic-assisted thoracoscopy, which has been shown to be safe and effective. Potential advantages of a robotic approach include superior visualization, improved instrument control and fine dissection, and a lower risk of conversion to thoracotomy, although data from large clinical trials or series are needed to confirm this.

F: Open Techniques

In cases where thoracoscopic decortication fails to achieve complete resolution of the intrathoracic collections or allow full expansion of the trapped lung, consideration should be given to thoracotomy and open decortication. If the patient is felt to be too frail to tolerate thoracotomy, some form of long-term open or semi-open drainage of the thorax should be done. This can involve the use of a long-term large-bore tube, either for open or closed drainage. An alternative is to create an open thoracic flap and marsupialize the chronic empyema space, usually with resection of a segment of one rib and suturing the corresponding parietal pleura to the skin, allowing intrapleural contents to drain freely through the opening in the chest wall. Although once common, especially in the treatment of tuberculosis, with the improvements in antibiotic therapy, anesthetic techniques, and surgical critical care over the years, such therapies are rarely necessary in the current era.

Special Considerations

The approach outlined above is primarily intended for the management of empyema that results from pneumonia or as a complication of the management of chest trauma. Empyema arising as a complication of lung resection or esophagectomy is often the result of broncho-pleural fistula or anastomotic leak. The therapeutic approach, although similar, must often be individualized and is driven by the need to control the primary surgical problem and any aerodigestive fistula.

CHYLOTHORAX MANAGEMENT

G: Diagnostic Evaluation

Once the diagnosis of chylothorax is made, a workup to determine the etiology should be undertaken. Chylothorax, as a result of direct injury to the thoracic duct, is an uncommon complication (incidence of <2%) of intrathoracic or mediastinal surgery or following blunt or penetrating trauma. Thoracic or mediastinal malignancy, especially lymphoma, is the most common medical cause of chylothorax, although numerous other uncommon causes exist. CT of the chest should be obtained to evaluate for potential malignancy or other anatomic causes for the chyle leak. Lymphangiography is the most direct method for localizing the site of a chyle leak. All forms of lymphangiography involve administering a contrast agent into the lymphatic system, followed by imaging to detect tracer leakage. Access to the lymphatic system can be challenging, as can high-resolution imaging of the enhanced lymphatic system. The traditional approach involves injecting a lipid-based dye into the web spaces between the toes, although image-guided injection of the inguinal lymph nodes is an alternative method. Both approaches have a reported success rate of about 60% to 70%. Dynamic contrast magnetic resonance imaging lymphangiography (DCMRL) is a technique that is emerging as a potential reference standard, although it requires both sophisticated imaging equipment and significant technical skill, which currently limit its widespread availability.^21–23 Use of CT imaging with intranodal contrast injection has also been reported to be successful in limited settings.^24,25 The best modality for a particular clinical situation will largely be dictated by institutional capabilities.

H: Initial Management

Initial treatment for chylothorax is nonoperative management aimed at maintaining drainage of the thoracic cavity and reducing the volume of lymphatic flow. This is most directly achieved by stopping oral intake entirely and supporting the patient with parenteral nutrition. Dietary restrictions that limit fat intake, especially long-chain triglycerides, combined with high protein intake, can reduce chyle flow. The addition of medium-chain triglycerides (MCTs) to supplement fat intake may be feasible, as MCTs are directly absorbed by intestinal cells rather than transported in chyle. For patients requiring enteral tube feeding, several specialized formulas can be used. In adults, standard low-fat/MCT options include Nutrison Peptisorb or elemental formulas such as Vivonex TEN. In infants, specialized formulas like Enfaport are formulated specifically to manage chylothorax by reducing long-chain fats. Dietary measures can be supplemented by pharmacologic interventions that decrease chyle flow, most notably the somatostatin analog octreotide, which diminishes splanchnic perfusion and secondarily gastrointestinal secretions. It has a high success rate, near 80% to 90%, when combined with parental nutrition. The time to resolution of the thoracic duct leak is 5 to 10 days.^26,27 Octreotide dosing should start at 100 to 200 mcg every 8 hours. For patients who respond to octreotide and require longer-term treatment, a long-acting somatostatin analog with once-monthly dosing (Sandostatin) can be used.

After nonoperative management is established, the output of the thoracic drain should be followed to determine efficacy. If the output drops below 500 mL/day within about 5 to 7 days, there is a good chance that the leak will seal with ongoing nonoperative management. If the output remains above 500 mL/day after 5 to 7 days, or if a significant volume of drainage persists after 2 weeks, spontaneous healing is unlikely, and intervention to seal the thoracic duct leak should be undertaken. If the primary etiology is malignant and the overall prognosis is poor, steps to limit and manage the chylothorax include pleurodesis or chronic chest drainage. In all other cases, intervention to seal the chyle leak should be undertaken.

I: Thoracic Duct Interruption

Noninvasive approaches to thoracic duct embolization (TDE) have low complication and good success rates in some centers. If the equipment and expertise exist, a trial of TDE by interventional radiology using standard lymphangiography or more advanced techniques, including CT or MR lymphangiography, is reasonable to attempt. If TDE is unsuccessful, surgical ligation of the thoracic duct should be done, using a thoracoscopic or robotic approach if feasible. In cases of surgical injury or thoracic trauma, the success rate of surgical ligation is very high, but it depends on the ability to identify the thoracic duct itself and determine the level of injury. In practice, it can be challenging to identify the site of leakage in the operative field. The traditional approach to enhance the visibility of the thoracic duct is to administer heavy cream or another fat load orally shortly before the operation to ensure a high flow of chyle, which is rich in chylomicrons and hence milky rather than clear. This technique is often highly effective, but the extent of fat absorption varies. Near-infrared fluoroscopy is also highly effective after intranodal indocyanine green injection. This technique is well-suited to thoracoscopic or robotic approaches and is likely more reliable than fat ingestion. If the leak cannot be visualized, mass ligation of the tissue around the esophageal hiatus can be performed to attempt to control the duct blindly.