Conditions: Mediastinitis
Mediastinitis is inflammation, often due to infection, in the space between the lungs.
Where is the mediastinum?
The mediastinum is the central compartment of the thoracic cavity, located between the lungs. It extends from the sternum in the front to the vertebral column in the back and spans from the first rib down to the diaphragm. The mediastinum contains various vital structures, including the heart, great vessels, trachea, esophagus, thymus gland, and lymph nodes.
What is mediastinitis?
Mediastinitis is an inflammation of the mediastinum. This condition can result from infections or non-infectious inflammatory processes.
Why is mediastinitis a problem?
Mediastinitis is a serious condition characterized by inflammation of the mediastinum, the central compartment of the thoracic cavity. It can lead to significant health risks, particularly due to its proximity to vital organs, including the heart and major blood vessels.
Infection in the mediastinum can spread rapidly, causing injury to nearby structures and sepsis, which can severely impair cardiovascular function. This is critical because the heart's ability to pump blood efficiently depends on the integrity of surrounding structures.
What causes mediastinitis?
Infection: The most common cause of mediastinitis is infection, which can arise from bacterial, viral, fungal, or parasitic agents. Chest trauma and postoperative infections, including after surgery of the heart, trachea (wind pipe), esophagus (swallow tube), or the low neck are leading contributors.
Esophageal Perforation: Injury to the esophagus, whether from trauma, surgical procedures, or ingestion of caustic substances, can lead to the leakage of gastrointestinal contents into the mediastinum, resulting in infection and inflammation.
Lymphatic Spread: Infections such as pneumonia or abscesses from nearby organs can spread to the mediastinum through lymphatic vessels, causing mediastinitis.
Chest Trauma: Blunt or penetrating injuries to the chest can cause direct inoculation of bacteria into the mediastinal space, leading to infection.
Tuberculosis: In some cases, tuberculosis can infect mediastinal lymph nodes, leading to mediastinitis.
Non-Infectious Causes: Though less common, non-infectious causes can include autoimmune diseases, radiation therapy, and chemical irritants.
How is mediastinitis identified?
Mediastinitis is identified through a combination of clinical evaluation, imaging studies, and laboratory tests.
Clinical Evaluation: Patients typically present with symptoms such as chest pain, fever, tachycardia, and possibly respiratory distress. The patient’s history, such as having had recent surgery, is considered.
Imaging Studies:
Chest X-ray: This is often the first imaging modality used. It may reveal mediastinal widening, pleural effusion, or other abnormalities.
CT Scan: A computed tomography (CT) scan of the chest is more definitive. It can show abnormal fluid collections, inflammation, or abscesses in the mediastinal area. A CT can may be used with I.V. contrast or, in some cases, with swallowed contrast.
Esophogram: A swallow study x-ray study, may show evidence of a hole in the esophagus, causing leakage of non sterile esophageal contents into the mediastinum. The substance swallowed for this study contains a contrast agent that shows up on x-ray. The choice of contrast agent depends on the specific situation and the associated risks and benefits
Laboratory Tests: Blood tests may show elevated white blood cell counts and markers of inflammation, such as C-reactive protein (CRP), all of which will be interpreted in the context of the overall clinical situation. Cultures from potential sources of infection (such as blood or fluids) can help identify specific pathogens.
Other Procedures: In some cases, a thoracentesis or mediastinoscopy may be necessary to drain fluid and/or obtain samples for microbiological analysis or to directly assess the mediastinum.
How is mediastinitis treated?
Mediastinitis is a serious infection that may be life threatening. Treatment is tailored to the specific situation and cause, typically involving a combination of surgical intervention, antibiotic therapy, and supportive care.
Surgical Intervention: The primary treatment for mediastinitis often involves drainage of any abscesses or infected fluid collections with placement of drain(s). This can require sternotomy (opening the chest) or thoracotomy, depending on the location and extent of the infection. Placement of a stent within the esophagus to hold the normal esophagus passageway open may be necessary.
Antibiotic Therapy: Broad-spectrum intravenous antibiotics are initiated at diagnosis. The choice of antibiotics may be adjusted based on culture results and sensitivity testing. Duration of therapy can vary but typically lasts for several weeks.
Supportive Care: Patients may need supportive measures such as intravenous fluids, electrolyte management, and nutritional support. Monitoring in a hospital setting is often essential to watch for complications and ensure timely intervention.
Follow-Up Care: After initial treatment, ongoing follow-up is necessary to monitor for potential complications and ensure recovery. This may involve additional imaging studies and regular clinical evaluations.