2. ACUTE MEDIASTINITIS: Typical Clinical Features of Acute Mediastinitis Clinical Classification of Acute Mediastinitis Etiologies and Clinical Settings diagnosis management Complications of acute mediastinitis
3. ACUTE MEDIASTINITIS Acute mediastinitis is rare and dramatic condition of a fulminating and usually fatal course Typical Clinical Features of Acute Mediastinitis . sudden and dramatic onset , with chills, high fever, and prostration. Patients are restless and irritable, Tachycardia, tachypnea, . severe substernal chest pain, worsened by breathing or coughing, and unrelieved by opiates. The pain may be referred into the neck and ear if the process involves the superior mediastinum , whereas posterior or inferior mediastinal involvement may cause radicular pain radiating around the chest and pain between the scapulae.
4. Signs: supraclavicular fullness and tenderness over the sternum or sternoclavicular joints, crepitus and other signs of mediastinal and subcutaneous emphysema may be prominent. Hamman's sign (a crunching sound synchronous with cardiac systole, heard over the anterior thorax) is characteristic but not always present. Later, tracheal deviation, jugular venous distention, and other signs of compression of mediastinal structures may appear .
5. Clinical Classification of Acute Mediastinitis Involvement of different mediastinal regions tends to have typical causes: infection in the superior mediastinum is most often the result of direct extension from neck infection; anterior mediastinal infection is typical after surgery or penetrating wounds to the anterior thorax; and posterior mediastinal abscesses are characteristic for tuberculous or pyogenic spinal infections.
6. Acute Mediastinitis: Etiologies and Clinical Settings Perforation of a thoracic viscus Esophagus "Spontaneous": forceful vomiting (Boerhaave's syndrome); pneumatic trauma Direct penetrating trauma Impacted foreign body Instrumentation: esophagoscopy; sclerotherapy; esophageal obturator airway Erosion: carcinoma; necrotizing infection
7. Trachea or main bronchi Direct penetrating trauma Instrumentation: bronchoscopy; intubation Foreign body Erosion of carcinoma
8. Direct extension of infection from elsewhere Intrathoracic: lung; pleura; pericardium; lymph node; paraspinous abscess Extrathoracic: From above: retropharyngeal space; odontogenic From below: pancreatitis Mediastinitis following sternotomy for cardiothoracic surgery "Primary" mediastinal infection: inhalational anthrax
9. 1 : Mediastinitis Resulting from Visceral Perforation : Boerhaave's syndrome refers to esophageal rupture associated with forceful vomiting, classically after overeating or excessive drinking. It is the most familiar example of acute mediastinitis , In addition to the clinical manifestations described previously, hematemesis may be present before the actual rupture, and tends to diminish or stop after rupture occurs. clinical manifestations: Unilateral or bilateral hydropneumothorax is common and quickly progresses to empyema
10. The diagnosis of esophageal perforation ☻ depends on an appropriate degree of clinical suspicion. ☻ On the chest roentgenogram , ● the hallmarks are diffuse mediastinal widening ● presence of air in the mediastinum and elsewhere in soft tissues. ● Mediastinal air-fluid levels may be seen, ● pneumothorax or hydropneumothorax may be present. ☻ CT can delineate these abnormalities more clearly.
11. The diagnosis is usually established by contrast studies, endoscopic examination, although percutaneous mediastinal aspiration, using a subxiphoid approach, is advocated by some as a means of earlier diagnosis ☻ Successful management of frank, uncontained esophageal perforation : ● early surgical repair, drainage of the mediastinum and often the pleural space, ● administration of appropriate antibiotics, ● Percutaneous catheter aspiration of mediastinal abscesses, under CT guidance, IF infection is localized and the clinical setting is less urgent
12. ☻ Complications of acute mediastinitis after : esophageal rupture ● localized abscess formation, ● extensive pleural empyema, ● and persistent esophagocutaneous fistulas. ● Mortality reported due to acute mediastinitis after esophageal rupture has ranged from 10% to 20%to as high as 40% to 50% □ Timing of surgical drainage has been of prime importance in determining the clinical outcome
13. ☻ Other potential iatrogenic causes of mediastinitis include: ● bronchoscopic perforation and migration of indwelling central venous catheters. ● use of laser and mechanical endobronchial procedures, in the setting of malignancy with chronic airway colonization or postobstructive pneumonia, add to the likelihood of potential mediastinal complications. ● Intravascular catheters may be another source of acute mediastinitis when the catheter tip erodes through the vessel wall into the mediastinum. Instillation of hyperosmotic, vesicant, or vasoactive substances via these catheters may induce a chemical, rather than an infectious, inflammation
14. Direct Extension of Infection from Other Sites: secondary to : oropharyngeal infection Infection originating in periodontal tissues in the tonsillar region, or after pharyngeal perforation extend via the prevertebral, visceral, or pretracheal spaces or in the carotid sheaths although the usual route is via the retropharyngeal space to the posterior mediastinum, • also named descending necrotizing mediastinitis , is perhaps the most clinically devastating form of the disorder . • Odontogenic infection is consistently the most common source of descending necrotizing mediastinitis
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16. Routine serial postoperative cervicothoracic CT imaging and aggressive reexploration and drainage guided by these imaging findings appear to reduce the mortality of this condition Although thoracoscopic and other percutaneous drainage procedures have been described and may be appropriate in selected patients, thorough open drainage and irrigation remain the standard approach. Treatment of descending necrotizing mediastinitis requires aggressive surgical drainage, usually via a cervical approach. thoracic exploration be reserved for cases in which the infection extends below the level of the fourth vertebral body or the tracheal bifurcation .