ACUTE MEDIASTINITIS dinakaran m.b.b.s.pptx

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1. ACUTE MEDIASTINITIS DINAKARAN SOUNDARAPAULRAJ GROUP 18 15122017

2. DEFINITION Mediastinitis is inflammation of the mediastinum . Anatomy T he area in thorax that lies between lungs. t he great vessels lie in superior mediastium , the thymus and fat in the anterior part of inferior , the heart in the middle esophgus and aorta in the posterior part of inferior mediastinium

3. OF MEDIASTINITIS I t is a fulminant infectious process that spreads rapidly along the continuous fascial planes connecting the cervical and mediastinal compartments. Sclerosing or fibrosing mediastinitis results from chronic mediastinal inflammation that originates in the lymph nodes, most frequently from granulomatous infections such as histoplasmosis or tuberculosis. Acute Mediastinitis Chronic Mediastinitis

4. Etiologic factors in acute mediastinitis E sophageal perforation Deep sternotomy wound infection Oropharynx and neck infections Ludwig’s angina Quinsy Retropharyngeal abscess Cellulitis and suppurative lymphadenitis of the neck Infections of the lung and pleura Subphrenic abscess Rib or vertebral osteomyelitis Hematogenous or metastatic abscess

5. Clinical Classification of Acute Mediastinitis 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 posterior mediastinal abscesses are characteristic for tuberculous or pyogenic spinal infections

6. Acute Mediastinitis: Etiologies and Clinical Settings Perforation of a thoracic viscus Esophagus Iatrogenic Balloon dilatation (for achalasia) Bougienage (for peptic stricture) Esophagoscopy Sclerotherapy (for variceal bleeding) Spontaneous Postemetic (Boerhaave’s syndrome) Straining during: Elimination Weight lifting Seizure Pregnancy Childbirth Ingestion of foreign bodies Trauma Blunt Penetrating Postsurgical Infection Anastomotic leak Erosion by cancer

7. Perforation of a thoracic viscus 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

9. Esophageal perforation The most common site of rupture is the distal esophagus on the left side. Acid and other stomach contents cause a fulminant mediastinitis and shock.   Pneumomediastinum  is common.

10. Symptoms and Signs chest and abdominal pain fever, vomiting hematemesis, Subcutaneous emphysema Mediastinal crunch (Hamman sign), a crackling sound synchronous with the heartbeat, may be present

11. Diagnosis Chest and abdominal x-rays shows mediastinal air, pleural effusion, or mediastinal widening. Diagnosis of esophageal rupture is confirmed by esophagography with a water-soluble contrast agent , which avoids potential mediastinal irritation from barium.

12. Treatment   Parenteral antibiotics selected to be effective against oral and GI flora (eg,  clindamycin  450 mg IV q 6 h plus  ceftriaxone  2 g once/day, for at least 2 wk). Patients who have severe mediastinitis with  pleural effusio n  or pneumothorax require emergency surgical exploration of the mediastinum with primary repair of the esophageal tear and drainage of the pleural space and mediastinum.

13. SURGICAL MANAGEMENT • Cervical esophageal perforation can be treated by drainage alone . • Drainage alone is less successful with thoracic or abdominal perforation because containment of contamination is difficult. • Intrathoracic esophageal disruption requires aggressive mediastinal and pleural drainage. • parietal pleura opened along the entire length of the esophagus, & both the mediastinum and pleural space are de brided , irrigated, and drained by thoracostomy

14.   Descending N ecrotizing M ediastinitis (DNM) It occurs as a complication of infections that may arise from odontogenic or cervicofascial infections or cervical trauma. As infection spreads along deep cervical fascial planes into the mediastinum, widespread cellulites , necrosis, abscess formation and sepsis may occur.

15. Symptoms   pyrexia neck and mandibular rigidity Odynophagia neck swelling dysphagia tachypnea tachycardia shortness of breath hypotension trismus

16. Diagnosis   C ervico-thoracic computed tomography (CT) scan -  neck infection with soft-tissue infiltration and oedema of the muscular tissue and signs of mediastinal infection (uncapsulated fluid collections or abscess with gas bubbles).

17. Management of DNM IV antibiotics airway management surgical drainage of the cervical and mediastinal collections . Posterolateral thoracotomy incision remains the standard approach. It allows comprehensive access to the entire hemithorax, including the ipsilateral mediastinum and pericardium.

18. Posterolateral thoracotomy incision

19. Mediastinits after cardiothoracic surgery Mediastinitis is a severe and frequently infectious complication that involves the mediastinal space and the sternum. Some anatomical and physiological characteristics favor the severe nature of infections in the mediastinum. The large quantity of loose cell tissue and vascular network favors the dissemination of infection.. Pressure variations within the mediastinal cavity contribute to mobilize septic liquids. T he incidence of dehiscence and deep sternal infection has not decreased in recent years. The incidence of mediastinitis varies from 1 to 2% .

20. Mediastinitis is a severe and frequently infectious complication that involves the mediastinal space and the sternum. Some anatomical and physiological characteristics favor the severe nature of infections in the mediastinum . The large quantity of loose cell tissue and vascular network favors the dissemination of infection. Pressure variations within the mediastinal cavity contribute to mobilize septic liquids. The incidence of mediastinitis varies from 1 to 2% ,  incidence of dehiscence and deep sternal infection has not decreased in recent years. Mediastinits after cardiothoracic surgery

21. Diagnosis persistent fever after the 4 th  day postoperatively  sternal instability, chest pain, fever (>38° C) associated with the culture of sternal secretion and/or positive hemoculture Tomographic findings following sternectomy may include retrosternal hematoma and fluid collection.  signs of dehiscence and bone erosion, in addition to subcutaneous collections and bilateral pleural effusion may indicate an infectious process In 2003, Benlolo  assessed prospectively the sternal puncture method to diagnose early infection. The needle was coupled to a 10 ml syringe and the aspiration occurred after the needle was introduced 1CM deep. 

22. Treatment The immediate goal of treatment is complete eradication of infection followed by stabilization of the sternum and chest wall. O pen mediastinal packing to debridement with closure over drains, to placement of vascularized tissue flaps. In addition, negative pressure therapy (NPT) has been used to aide in the treatment of mediastinal infection Aggressive sternal debridement followed by VAC therapy and secondary closure with the transposition of omental and bilateral pectoralis major flaps, controls wound infection and reduces hospitalization.

23. Surgical debridement was described after Shumacker and Mandelbaum's study, followed by a greater omentum graft.

24. Schroeyers  expanded the concept of using omental graft and recommended that muscle graft be used to fill in the space left after debridement. The rectus abdominis muscles and pectoralis major muscles, which are detached and brought to the sternal midline to be sutured, allowing the complete closure of the wound .

25. POSTOPERATIVE CARE It is recommended that antibiotic therapy be kept for at least 6 weeks and, if there is osteomyelitis, the therapy should continue for 3 months. Due to the high degree of catabolism that these patients present, special attention should be given to their nutritional state. Enteral diet is stimulated and optimized. Hyperbaric oxygen therapy is breathing pure oxygen (100%) at pressures above atmospheric ones ,t he amount of oxygen dissolved in tissues increases from 10 to 20 times , thus creating an environment which is not appropriate for bacteria in general, especially anaerobic ones.   I t also acts as a coadjuvant in the control of infections to accelerate the healing process.

26. PREVENTION Strict preoperative assessment of the patient to look for associated infectious processes . Adequate pulmonary preparation avoiding smoking . A voiding the use of the two internal thoracic arteries in diabetic patients . U se of iodine-coated plastic fields that adhere to the skin . Frequent wash of the mediastinum and the subcutaneous tissue with saline solution at the time of closure.

27. Differential diagnosis Pulmonary embolism . Myocardial infarction . Spontaneous pneumomediastinum . Mediastinal tumour and/or  superior vena cava syndrome . Cellulitis  of the neck. Necrotising fasciitis  affecting the neck. Pneumonia ± empyema or lung abscess . Mediastinal tuberculosis.

28. Presentation Recent cardiothoracic surgery or instrumentation. Upper GI endoscopy. Bronchoscopy. Recent dental or oropharyngeal infection. Upper respiratory tract infection . Ingestion of a foreign body (particularly button batteries by young children, which may cause oesophageal rupture).

29. Management of acute mediastinitis Where the patient has significant and worsening   hypoxia , intubation and artificial ventilation may be required. Intubation is likely to be difficult to achieve so experienced anaesthetic input may be needed; emergency  cricothyroidotom y / tracheostomy   m ay be necessary. The patient's respiratory status must be stabilised before sending for investigations such as CT/MRI scan.

30. Antibiotics piperacillin vancomycin ceftazidime     quinolone Clindamycin and   aminoglycoside

31. Complications Pneumomediastinum, pneumoperitoneum and  pneumothorax . Overwhelming sepsis leading to multi-organ failure and death Adult respiratory distress syndrome . Respiratory failure  leading to death. Pericarditis Secondary pneumonia Pleural effusions and empyema

32. Prognosis In the presence of comorbid conditions, the mortality rate may be as high as 67%. Studies of descending necrotising mediastinitis in the last decade indicate mortality rates ranging between 11.1-34.9%. High clinical suspicion in susceptible individuals, early diagnosis and prompt aggressive management are the best way to reduce morbidity and mortality.

33. REFERENCE Schwartz’s Principles of Surgery Tenth Edition Pg no679 http://www.scielo.br/scielo.php?pid=S0066-782X2007001300013&script=sci_arttext&tlng=en Sabiston Textbook of Surgery, 17th ed., pg no1738

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