What is Thoracic Empyema?
Thoracic empyema is referred to as a disease where pus, a thick fluid resulting from infection, accumulates in the space between the lungs and the chest wall – an area known as the pleural space. This disease has been known since the time of Hippocrates, an ancient Greek physician, and is known to have a high death rate. Empyema is quite complex and can be caused and progressed by various factors. Hence, healthcare professionals need to be aware of the different stages of the disease for proper handling.
Identifying empyema swiftly is important for successful treatment and increasing the chances of the patient’s survival. The goal of treatment is to remove the source of infection and make sure the lung can expand properly through a combination of medical treatments and surgical interventions.
What Causes Thoracic Empyema?
Many infections in the space around the lungs happen as complications from pneumonia caught either in the community or in the hospital. Other causes can be wounds to the chest, chest surgery, esophagus rupture, lung tuberculosis, lung abscess, abnormal widening of air passages, abscess beneath the diaphragm, or infection of the ribs.
There are certain factors that can make a person more likely to develop an infected lung lining. These include being under 60 years of age, having poor mouth hygiene, having conditions that might cause choking (like seizures, alcohol abuse, or nerves system disorders), using injection drugs, having diabetes, heart disease, liver cirrhosis, or having a weakened immune system (such as having an HIV infection or cancer).
A study found six risk factors in patients with pneumonia caught in the community that later developed an infected lung lining. These included having low levels of a protein called albumin, low sodium levels, high platelet count, high levels of a protein involved in inflammation, and a history of alcohol use or injection drug abuse disorders.
Various types of bacteria were found to be the major cause of infected lung lining caught in the community. These included aerobic Staphylococcus and Streptococcus species and Gram-negative bacteria, such as Escherichia coli, Haemophilus influenzae, and Klebsiella pneumoniae. But, recent studies show that other bacteria and certain staphylococcal species are now common causes in surgically treated infected lung linings. Also, anaerobes (bacteria that grow without oxygen) were found more often in community-acquired pneumonia than we used to think.
In hospital-acquired infected lung lining, bacteria that are resistant to the antibiotic, including Pseudomonas and Enterobacteriaceae, are common. The cultures for anaerobic bacteria often don’t grow well which makes it hard to detect them. Therefore, it’s suggested to use a wide range of antibiotics, including those that can kill anaerobic bacteria.
Fungal lung lining infections are rare but can be very serious. One study found Candida and Aspergillus species in 65 patients who were very ill with a variety of health conditions, including cancer. Most of these were hospital-acquired infections or came along with a bloodstream fungal infection.
Risk Factors and Frequency for Thoracic Empyema
In the United States, about 6 out of every 100,000 people are estimated to have parapneumonic empyema. For adults aged over 65, about 16.1% of them die in the hospital due to this condition.
Signs and Symptoms of Thoracic Empyema
Empyema is a medical condition that presents differently in different people, depending on factors such as their overall health, when they seek medical help, and the type of germs causing the condition. Commonly, empyema shows up in the later stages of untreated pneumonia or mismanaged lung fluid build-up. The symptoms of empyema are similar to those of bacterial pneumonia and may include coughing, difficulty breathing, fever, and/or chest pain.
During a physical examination, the doctor might note a dull sound when tapping on the chest and diminished breathing sounds. However, these signs don’t conclusively indicate empyema, so imaging tests may be necessary for anyone suspected of having fluid build-up related to pneumonia.
- Coughing
- Difficulty breathing
- Fever
- Chest pain
Testing for Thoracic Empyema
If a doctor suspects a patient has empyema, which is a collection of pus in the pleural space (the space between the lungs and the chest wall), certain tests may be used. One of the most common tests is a chest imaging exam. Even with the development of new technologies, normal chest x-rays continue to be an excellent way to look for abnormalities, like pleural effusions, which is when there is an unusual amount of fluid around the lungs.
An asymmetrical, one-sided pleural effusion—where one lung has more fluid around it than the other—can often be seen in patients with pneumonia. Smaller amounts of fluid can be seen with a side view x-ray. If a doctor needs to evaluate the fluid for pooling and measure it, “decubitus” views (x-rays taken while the patient is lying down) can be used.
However, ultrasound and computed tomography (CT) scans can locate fluid even more reliably, and also give more detailed information about the infection. An ultrasound is a helpful approach that avoids radiation and lets the doctor see whether the fluid is free-flowing or “loculated” (segmented into pockets). A study published in 2017 showed that ultrasound was more reliable in diagnosing pleural effusion than traditional x-rays.
A CT scan with a contrast agent (a substance that makes certain areas show up more clearly on the scan) is considered the best method and gives a high success rate for empyema diagnosis. One particular pattern doctors look for in the scan is the “split pleura” sign. If the two layers of pleura (the lining of the lung) show up as being separated by more than 30 mm of fluid, then it strongly suggests a complex pneumonic effusion (a complication of pneumonia) that may need to be drained.
In addition to imaging, doctors often recommend a procedure called thoracentesis. This is where a small amount of fluid is removed from the pleural space with a needle for testing. This process is suggested for all patients who have fluid depth more than 2 cm as shown on a side view x-ray or CT scan and those with lung infection, recent chest injury or surgery, or ongoing infection symptoms.
If the fluid removed is actually pus, it usually means surgical draining is required. However, if the fluid is murky and it’s not clear if there’s an infection, a pH below 7.2 (measured by a blood gas checker) means an invasive procedure for drainage may be required. In addition, a higher than normal number of white blood cells, lower than normal glucose, and higher than normal LDH enzyme level in the fluid further confirm an empyema diagnosis.
In addition, a culture (a method of growing bacteria in the lab) of the fluid should guide the appropriate antibiotic treatment. Studies show that injecting the fluid directly into blood culture bottles after removal can significantly increase the chances of growing bacteria.
Blood tests are necessary for any patient with empyema. Even though they aren’t usually diagnostic on their own, blood cultures can help identify the bacteria causing the infection and check for bacteremia, which is bacteria in the blood.
Treatment Options for Thoracic Empyema
In 2000, the American College of Chest Physicians published guidelines on how to best treat and manage effusions and empyema, which are both conditions where fluid builds up in the space between your lungs and the chest wall. Astoundingly, they found that the risk of a patient having a poor outcome was connected to three things: the anatomy of the pleural space (the breathing space around your lungs), the types of bacteria found in the pleural fluid, and the chemistry of the fluid.
Based on their findings, if you experience these conditions in their early stages, they can still flow freely and carry low risk. But as they advance into more complex stages like what they call the “fibrinopurulent” stage, there’s a moderate risk of poor outcomes. The most severe case, known as empyema, undoubtedly carries the highest risk.
The main goals when treating empyema involve getting rid of the infection with antibiotics and draining the fluid from your lung space. This can be done using a variety of methods, like inserting a tube into your chest, utilizing certain medications, making use of minimally-invasive surgery (video-assisted thoracoscopic surgery or VATS), or performing an open thoracostomy and decortication which is an open chest surgical procedure.
In most cases, if you’re suspected or confirmed to have empyema, you’ll generally need a wide variety of antibiotics to ensure all types of bacteria are targeted. The specific antibiotics given are decided based on factors like where you contracted the infection and whether you became ill in the community or a healthcare facility.
One common treatment method for empyema is tube thoracostomy. This involves inserting a tube into your chest so that the fluid can be drained under the guidance of radiology. Interestingly, recent studies have found that the size of the chest tube doesn’t influence the results, but its position does.
While there’s some controversy regarding the use of additional drugs to assist with the drainage, it’s been suggested that combination therapy can speed up fluid drainage, reducing the duration of hospital stays and need for surgery. In contrast, sole use of fibrinolytic drugs – compounds that break down blood clots – hasn’t shown to significantly improve symptoms or reduce the need for surgery.
Recently, a new treatment method called a saline lavage (or washing) has been discovered. Initial studies have shown that it may help patients with empyema. This approach involves using a saline solution to irrigate or clean the inside of the chest.
Referral to a surgeon should be considered if tube thoracostomy fails or if the empyema is mainly divided into several separate parts. They may suggest using VATS, which is a less invasive surgical technique that allows the surgeon to visualize and evacuate the infected lung space. Moreover, this method often results in better outcomes in terms of shorter hospital stays and fewer postoperative complications compared to tube thoracostomy.
In case the empyema is resilient to the standard therapies, open thoracostomy, and decortication (an open surgical procedure targeting the lung membrane) may be considered. Acute empyema can lead to long-term consequences like lung scarring and adhesions. If these persist six months after the empyema is resolved, decortication might be considered as a potential solution.
What else can Thoracic Empyema be?
When diagnosing a lung-related condition, these are some possible diagnoses a doctor might consider:
- Pneumonia (this could be caught from the community, healthcare facilities, or due to aspiration)
- Hemothorax (a condition where blood collects in the space between your chest wall and lungs)
- Chylothorax (a rare condition where lymphatic fluid accumulates in the pleural cavity)
- Pulmonary infarct (a blockage in the blood vessels of the lungs)
What to expect with Thoracic Empyema
Empyema, a condition where pus collects in the space surrounding the lungs, can have severe consequences if not addressed immediately and properly after it’s diagnosed. While most individuals do recover, the overall outcomes are less favorable. About 20% of patients will need surgery while another 20% unfortunately pass away within their first year of having been diagnosed.
The risks are even higher for specific groups. Frail elderly individuals and those with weaker immune systems are 1.5 times more likely to experience worse outcomes. This shows the importance of early detection and aggressive treatment for empyema.
Possible Complications When Diagnosed with Thoracic Empyema
Empyema complications can arise from the disease itself, potentially causing severe conditions such as worsening blood infection, septic shock, or even death. Sometimes, complications are a result of the drainage tube not placed correctly or not working, which can lead to problems such as a collapsed lung, abnormal connections between the bronchial tubes and the pleural cavity, and fibrosis of the pleura, which can lead to trapped lungs. A rare complication called ’empyema necessitans’ occurs when the infection extends and dissects into the tissue under the skin of the chest wall.
Common Complications:
- Worsening blood infection
- Septic shock
- Potential death
- Collapsed lung
- Abnormal connections between the bronchial tubes and the pleural cavity
- Fibrosis of the pleura leading to trapped lung
- A rare complication called ’empyema necessitans’
Preventing Thoracic Empyema
If not treated at the right time and in the right way, parapneumonic effusions – a buildup of fluid between the layers of tissue that line the lungs and chest cavity – can worsen and turn into an empyema, which is a collection of pus in the pleural space. The diagnosis of these fluid accumulations, known as pleural effusion, is often delayed.
Healthcare providers should be particularly alert for signs of empyema in patients who have pneumonia, keep experiencing a fever, and show increased signs of inflammation despite having been treated with antibiotics. This is especially the case when these patients haven’t shown improvement with the standard therapy.
It’s also important for patients to know when to seek medical help. If they notice a decline in their breathing condition, chest pain that gets worse when they breathe in or persistent fever despite being treated for a known lung-related illness or after taking antibiotics, they should get medical attention immediately.
