Mediastinal infections refer to a group of diseases caused by bacterial, fungal, parasitic, and other infections involving mediastinal structures. These infections can be either primary or secondary in origin. Although the incidence of mediastinal infections is relatively low, they can lead to severe outcomes. Reports indicate that the mortality rate for mediastinal infections ranges from 10% to 30%.
Primary mediastinal infections primarily affect immunocompromised individuals, such as elderly patients or those with chronic illnesses like diabetes. Pathogens may access the mediastinum through various pathways, including the oral cavity, nasal cavity, neck, and bloodstream. Secondary mediastinal infections often result from the spread of infections or inflammation from other sites. Common causes of secondary mediastinal infections include:
- Penetrating chest trauma: Thoracic injuries caused by car accidents, falls, or other traumatic events may lead to bacterial infections, resulting in mediastinal infections.
- Esophageal perforation: This may occur due to ingested foreign bodies, iatrogenic perforation during esophagoscopy, or ulcerative perforation caused by esophageal cancer.
- Postoperative esophageal anastomotic leaks: Leakage at the surgical anastomotic site following esophageal surgery increases the risk of mediastinal infection.
Symptoms and Signs
Acute Mediastinitis
Acute mediastinitis has a rapid onset and manifests with high fever, chills, and other pronounced signs of toxemia. Other symptoms may include difficulty swallowing and retrosternal pain that radiates to the neck or causes earache. If an abscess forms, it may compress the trachea, leading to high-pitched coughing, dyspnea, tachycardia, and cyanosis. Without timely treatment, complications such as shock may occur, posing a life-threatening risk.
Chronic Mediastinitis
Chronic mediastinitis is typically asymptomatic in its early stages. As the condition progresses, symptoms related to adhesion or compression of mediastinal organs may develop. The most common manifestation is superior vena cava obstruction syndrome, characterized by increased venous pressure, swelling of the face, neck, and upper extremities, engorged neck veins, and dilation of collateral veins on the chest wall. Patients may also experience headache, dizziness, respiratory difficulty, and cyanosis. Over time, as collateral circulation develops, the obstruction generally diminishes, and symptoms may improve or resolve.
Diagnosis
Diagnosing mediastinal infections involves blood tests and chest imaging examinations. Blood tests may reveal signs of infection, such as elevated leukocyte counts and increased C-reactive protein levels. Imaging studies, such as chest radiography and ultrasound, can identify mediastinal enlargement or the presence of air in the mediastinum, which are indicative of infection.
Treatment
The treatment of mediastinal infections primarily involves medical therapy and surgical intervention. Medical therapy typically consists of antibiotics or other medications to eliminate the pathogens, alleviate symptoms, and shorten the disease course. For severe cases, surgical intervention may be necessary, including the removal of infected tissues or drainage of abscesses. In cases of secondary mediastinal infections, it is essential to effectively address the underlying primary disease.