Empyema (Infections of the Pleural Space)
I. What every physician needs to know.
An empyema is a focal infectious collection in the pleural cavity. This infection can be parasitic, fungal, but more likely than not is bacterial. Usually this disease arises when the patient has a pneumonia that spreads. However, it can develop post thoracic surgery or as a result of chest trauma as well as a secondary infection (i.e. UTI) in a patient with heart failure which can cause a transudative effusion.
The bacteria seed the pleural space from the lung and develop a focal infection in the parapneumonic fluid and/or the pleura creating an abscess. Typically gram positive organisms are the main source of infection, although gram negatives, anaerobes, mycobacteria, fungi and parasites can be causes. The start of the fluid draining into the cavity is usually due to an inflammatory process in which the cavity fills with fluid and then gets superinfected with pathogens. A second phase called the fibrinopurulent phase then develops where the fluids gets fibrin deposition and hardens against the pleura. Lastly, the fluid hardens significantly against the pleura and restricts lung expansion, which is called the organization phase. It is the most severe of the exudative pleural effusions and needs prompt drainage as well as antimicrobial treatment.
II. Diagnostic Confirmation: Are you sure your patient has Empyema?
The most common signs associated with an empyema are shortness of breath and pleuritic chest pain. Patients can also have fevers, chills and a productive cough. The history and physical exam are important as one needs to have a high index of suspicion to assume that someone has a complex pleural effusion and/or an empyema.Subsequent imaging with x-rays or a computed tomography (CT) scan can show an effusion that is nonlayering and or “trapped” against the pleural space. Increasingly, the use of bedside ultrasound is being shown in residency programs to help guide diagnostic choices as well.
A. History Part I: Pattern Recognition:
Shortness of breath, pleuritic chest pain, fever, sputum production, less likely coma and death.
B. History Part 2: Prevalence:
Empyemas have been reported as frequently as 5.5 to 7.2 percent of community acquired pneumonias.Many different populations can get empyemas but ones that show signs of a localized infection such as pneumonia have a higher likelihood. Patients that have decreased resistance to capsular organisms due to spleen removal such as trauma patients, sickle cell patients and those with genetic predispositions to infections such as severe combined immunodeficiency syndrome (SCID) can be more susceptible to developing loculated infections from bacteria. Streptococcus pneumoniae is the most prevalent organism in empyema. However a culture result from drainage is only positive in 16 to 19 percent of cases.One also must consider empyema in patients post thoracic surgery, people with risk factors for tuberculosis and in alcoholics and people who aspirate.
C. History Part 3: Competing diagnoses that can mimic Empyema.
Other exudative effusions including uncomplicated and complicated parapneumonic effusions, malignant, haemorrhage into pleural space, tuberculosis, systemic lupus erythematosus (SLE) and collagen vascular diseases, post pericardectomy syndrome, Meig’s syndrome, uremia, pancreatic pseudocyst/severe pancreatitis, pulmonary embolism, ascites, asbestosis and mesothelioma.
D. Physical Examination Findings.
Patients can have fever, tachycardia, hypotension, tachypnea and hypoxia on vital signs. On physical exam will hear decreased breath sounds over the fluid and decreased percussion, fremitus and egophony.
E. What diagnostic tests should be performed?
Usually the first diagnostic test run is a chest x-ray. When an effusion is seen, one can then get a decubitus film and or a chest CT without contrast to further delineate the effusion. In physicians that have proper training, bedside ultrasound can be used to delineate the amount and whether an effusion is loculated. Effusions are usually able to be drained if on decubitus films they layer out to greater than one centimeter. However, with empyemas they do have a higher incidence of loculating so one might see a nonlayering effusion. If this is the case it would be prudent to obtain a CT scan to look for multiple effusions that could be loculating.
1. What laboratory studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?
Once an effusion is seen a thoracentesis should be performed and the fluid sent for multiple laboratories. Studies have shown that drainage under ultrasound guidance have shown less incidence of pneumothorax. The fluid is then sent for lactate dehydrogenase (LDH) and Protein and then the result is compared to levels in blood. This is to differentiate between transudative and exudative fluid. This is known as Light’s criteria and only one of the following is needed for it to be exudative: LDH of fluid to blood ratio of > 0.6, > 2/3 upper limit of normal of the lab, or protein fluid to blood >0.5 confirm exudative effusion.
The fluid is also sent for cell count, cytology, gram stain, culture, pH, and glucose. Ultimately if the fluid reveals pus during the procedure or has a positive gram stain it is considered an empyema. Other diagnostic findings consistent with an empyema are a glucose <30 milligram/deciliter (mg/dL) , pH <7.2 and a high protein level and a significant amount of polymorphonuclear cells on differential.
2. What imaging studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?
See diagnostic tests.
F. Over-utilized or “wasted” diagnostic tests associated with this diagnosis.
Repeat CT scans can be repeated in follow up and may predispose the patient to unwanted radiation, whereas ultrasound and chest X-rays could be used instead.
III. Default Management.
When one diagnoses an empyema prompt drainage and antibiotics should be started.
A. Immediate management.
Even before attempting the thoracentesis, the patient should be stabilized and given supplemental oxygen and fluids to resuscitate them. Prompt drainage should occur once one diagnoses an empyema. The key for the hospitalist is quick referral to specialists.
A chest tube should be placed by a qualified physician, a pulmonologist, cardiothoracic surgeon or interventional radiologist. These physicians can use ultrasound or CT guidance to help them with their approach. The chest tube should be large bore to help facilitate drainage and to prevent clotting from the fibrin depositions. In addition to placement of the chest tube, the fibrin deposits from the empyema might need to be removed via different modalities. Sometimes an injection of streptokinase or similar fibrinolytic agents can be used, but more often than not a more aggressive approach is used depending on the severity of the empyema. There is conflicting evidence in the literature as to whether there is a benefit of fibrinolytic therapy. Two studies, MIST 1 and MIST 2, showed conflicting results with the first study showing no benefit from lytic therapy. MIST 2 showed some improvement in length of hospital stay and surgical referral rates with lytic therapy.
If the empyema is caught early and there is minimal fibrin on the pleura then a VATS (video-assisted thorascopic surgery) can be done. It uses a few small incisions of the chest wall for chest tube placement and the fibrin is removed via endoscopy. If there is severe pleural peel a thoracotomy is done by a thoracic surgeon. It comprises of a larger 6 inch incision for surgical drainage. Chest tubes remain in place for 4-7 days and are followed in terms of leaks and overall drainage amount. Differing surgeons have differing strategies for removing a chest tube but they are usually more conservative compared to pneumothoraxes, in regards to how quickly the tube is removed. The chest tube can be slowly pulled out to allow drainage and healing behind the tube.There have been no randomized control trials to compare large bore chest tubes with smaller bore ultrasound guided catheters.
Additionally antibiotics should be started with coverage of respiratory pathogens and anaerobes which are more likely to cause this infection. As the gram stain and culture hopefully reveal the trouble pathogen, antibiotics can be consolidated. The patient will need at least 2 weeks of antibiotics.
B. Physical Examination Tips to Guide Management.
Vital signs are important as we like to see stabilization of the vitals including the fever curve, tachypnea and hypoxia with the chest tube placement. As with any patient with chest tubes in place the hospitalist should follow the output daily and look for signs of chest tube leakage. One can briefly clamp the chest tube and have the patient cough – if there are any bubbles in the chest tube then there is a leak in the system. Leaks signify that there might be an incomplete seal where the tube enters the chest, chest tube container, or in the tubing so all of these areas should be inspected.
Additionally, the chest wall site should be inspected to look for any signs of cellulitis as well. One should also pay attention to the general habitus of the patient as subcutaneous emphysema can occur leading to an air plane in the chest wall, rising to the neck level in severe cases. One would palpate fine crackles on exam. This is a finding that should be relayed immediately to your consulting cardiothoracic surgeon.
C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.
One can follow a complete blood count (CBC) to look for a downtrending white count and typically daily x-rays are done to make sure that a secondary pneumothorax and subcutaneous emphysema are not occurring.
D. Long-term management.
In empyemas the patients tend to do clinically well once the drains are removed and should have follow up appointments with their pulmonologist or cardiothoracic surgeon. Typically, depending on the degree and size of the effusion, follow up pulmonary function tests are done to make sure that the patient does not have some trapped lung from the process that would lead to an obstructive or restrictive flow volume loop.
E. Common Pitfalls and Side-Effects of Management.
A common pitfall is repeat thoracentesis, either due to another loculation or reaccumulation, and pulling chest tubes too early. Additionally there are the side effects of any thoracentesis and chest tube procedure including infection, hemothorax and pneumothorax.
IV. Management with Co-Morbidities.
A. Renal Insufficiency.
When starting empiric antibiotics one must adjust them for the appropriate creatinine clearance.
B. Liver Insufficiency.
Note that in patients with severe liver failure they can have difficulty with wound healing as well as repeat effusions from their ascites crossing the diaphragm. Optimizing nutrition is essential.
C. Systolic and Diastolic Heart Failure.
No change in standard management.
D. Coronary Artery Disease or Peripheral Vascular Disease.
The patient should ideally be off aspirin, clopidogrel or other anticoagulants for a chest tube to be inserted to minimize bleeding. There might be a delay in reinitiating these once chest tubes are removed.
E. Diabetes or other Endocrine issues.
No change in standard management.
If there is an empyema in addition to a patient with a known malignant effusion a long term catheter drainage device such as a Pleur-X® catheter can be placed.
G. Immunosuppression (HIV, chronic steroids, etc).
Once would have a higher suspicion of atypical pathogens such as fungus and parasites causing the effusion as well as some delay in wound healing.
H. Primary Lung Disease (COPD, Asthma, ILD).
This population – depending on the severity of their underlying lung disease – may present in more distress and also might have a slower time to heal given their low pulmonary reserves.
I. Gastrointestinal or Nutrition Issues.
Difficulty with nutritional deficiencies could preclude adequate wound healing.
J. Hematologic or Coagulation Issues.
Patients likely will need to have an international normalized ratio (INR) of less than 1.5 depending on your institution’s policy to have a chest tube placed for drainage. The patient might need to be reversed with Vitamin K and or fresh frozen plasma. In a patient anticoagulated with a Novel Anticoagulant (NOAC), supportive care is best, letting the agents clear. In the case of a patient on dabigatran (Pradaxa®), idarucizumab (Praxbind®), an antibody fragment has recently been approved in the United States for reversal.
K. Dementia or Psychiatric Illness/Treatment.
One would need to obtain consent for the procedure by the health care power of attorney and/or guardian.
V. Transitions of Care.
A. Sign-out considerations While Hospitalized.
One should sign out to check a chest x-ray in patients that become more hypoxic or tachypnic with an empyema and chest tube in place and to empirically place then on suction if they are on waterseal.
B. Anticipated Length of Stay.
Patients with an empyema are usually in the hospital from 4 to 14 days.
C. When is the Patient Ready for Discharge.
When patient is free of the chest tube and afebrile and hemodynamically stable.
D. Arranging for Clinic Follow-up.
1. When should clinic follow up be arranged and with whom.
Patient should follow up with their internist as well as the cardiothoracic surgeon/pulmonologist who was involved in their care.
2. What tests should be conducted prior to discharge to enable best clinic first visit.
Chest x-ray without chest tubes.
3. What tests should be ordered as an outpatient prior to, or on the day of, the clinic visit.
Depending on the cardiothoracic surgeon or pulmonologist a repeat chest x-ray might need to be done again to show clearance.
E. Placement Considerations.
Depending on the antibiotic the patient might need a peripherally inserted central catheter (PICC) line and intravenous antibiotics.
F. Prognosis and Patient Counseling.
VI. Patient Safety and Quality Measures.
A. Core Indicator Standards and Documentation.
B. Appropriate Prophylaxis and Other Measures to Prevent Readmission.
VII. What’s the evidence?
Light, R W. “Pleural Effusion”. New England Journal of Medicine. vol. 346. 2002. pp. 1971-1977.
Wait, M A, Sharma, S, Hohn, J, Dal Nogare, A. “A Randomized Trial of Empyema Therapy”. CHEST. vol. 111. 1997. pp. 1548-1551.
Landreneau R, J, Keenan, K, Hazelrigg, S R, Mack, M J, Naunheim, K S. “Thoracoscopy for Empyema and Hemothorax”. CHEST. vol. 109. 1996. pp. 18-24.
Breen, D P, Daneshvar, C. “Role of interventional pulmonology in the management of complicated parapneumonic pleural effusions and empyema”. Respirology. 2014. pp. 1-9.
Pollack, CV. “Idarucizumab for Dabigatran Reversal”. NEJM. vol. 373. 2015. pp. 511-520.
Soni, NJ. “Ultrasound in the Diagnosis and Management of Pleural Effusions”. Journal of Hospital Medicine. vol. 10. 2015. pp. 811-816.
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- I. What every physician needs to know.
- II. Diagnostic Confirmation: Are you sure your patient has Empyema?
- A. History Part I: Pattern Recognition:
- B. History Part 2: Prevalence:
- C. History Part 3: Competing diagnoses that can mimic Empyema.
- D. Physical Examination Findings.
- E. What diagnostic tests should be performed?
- F. Over-utilized or “wasted” diagnostic tests associated with this diagnosis.
- III. Default Management.
- A. Immediate management.
- B. Physical Examination Tips to Guide Management.
- C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.
- D. Long-term management.
- E. Common Pitfalls and Side-Effects of Management.
- IV. Management with Co-Morbidities.
- A. Renal Insufficiency.
- B. Liver Insufficiency.
- C. Systolic and Diastolic Heart Failure.
- D. Coronary Artery Disease or Peripheral Vascular Disease.
- E. Diabetes or other Endocrine issues.
- F. Malignancy.
- G. Immunosuppression (HIV, chronic steroids, etc).
- H. Primary Lung Disease (COPD, Asthma, ILD).
- I. Gastrointestinal or Nutrition Issues.
- J. Hematologic or Coagulation Issues.
- K. Dementia or Psychiatric Illness/Treatment.
- V. Transitions of Care.
- A. Sign-out considerations While Hospitalized.
- B. Anticipated Length of Stay.
- C. When is the Patient Ready for Discharge.
- D. Arranging for Clinic Follow-up.
- 1. When should clinic follow up be arranged and with whom.
- 2. What tests should be conducted prior to discharge to enable best clinic first visit.
- 3. What tests should be ordered as an outpatient prior to, or on the day of, the clinic visit.
- E. Placement Considerations.
- F. Prognosis and Patient Counseling.
- VI. Patient Safety and Quality Measures.
- A. Core Indicator Standards and Documentation.
- B. Appropriate Prophylaxis and Other Measures to Prevent Readmission.