|Year : 2013 | Volume
| Issue : 2 | Page : 173-177
Descending necrotizing mediastinitis: Report of three cases and review of literature
Nissar Shaikh1, Muna Maslamani2, Rashid Mazhar3, Abdel Hafiz Ahmed1
1 Department of Anesthesia/Surgical Intensive Care Unit: Hamad Medical Corporation and Weill Cornell Medical College, Doha, Qatar
2 Vice Chair, Department of Medicine, Hamad Medical Corporation and Weill Cornell Medical College, Doha, Qatar
3 Cardiology and Cardiothoracic Surgery, Hamad Medical Corporation, Doha, Qatar
|Date of Web Publication||13-Dec-2013|
Department of Anesthesia/Surgical Intensive Care Unit, Hamad Medical Corporation, P. O. Box 3050; Doha
Source of Support: None, Conflict of Interest: None
Descending necrotizing mediastinitis (DNM) is a rare, severe, life-threatening suppurative infection of the fascial covering of mediastinal cavity. Oropharyngeal cavity is connected to the mediastinum with various fascial planes. The retropharyngeal space is called the "dangerous space" as through this fascial space infection from the mouth and neck rapidly spread to the mediastinum. Gravity and the negative intrathoracic pressure facilitate the spread of infection into the thoracic cavity. Common clinical presentations are fever, odynophagia, dysphonia, dry cough, neck swelling and chest pain. Computerized tomography of neck and chest will diagnose DNM early and it helps in the grading of the disease. Broad spectrum antibiotic therapy and fluid resuscitation with surgical drainage is essential therapeutic aspect. Combination of transcervical and transthoracic drainage is reported to have significantly more survival benefit than the trans-cervical drainage alone. Percutaneous and video-assisted mediastinoscopic drainage has obvious advantages compared with open surgical drainage. We report three cases of DNM, with recurrent laryngeal nerve involvement successfully treated by video-assisted thoracoscopy and percutaneous drainage.
Keywords: Descending necrotizing mediastinitis, retropharyngeal space, transcervical, transthoracic abscess drainage
|How to cite this article:|
Shaikh N, Maslamani M, Mazhar R, Ahmed AH. Descending necrotizing mediastinitis: Report of three cases and review of literature. Arch Int Surg 2013;3:173-7
|How to cite this URL:|
Shaikh N, Maslamani M, Mazhar R, Ahmed AH. Descending necrotizing mediastinitis: Report of three cases and review of literature. Arch Int Surg [serial online] 2013 [cited 2020 Feb 29];3:173-7. Available from: http://www.archintsurg.org/text.asp?2013/3/2/173/122980
| Introduction|| |
Acute suppurative mediastinitis is commonly caused by esophageal perforation and sternotomy infection. Rarely intraoral or cervicofacial necrotizing infection rapidly descends through the fascial planes into the mediastinum. This clinical condition is called descending necrotizing mediastinitis (DNM). DNM is a rapidly progressive and potentially life-threatening infection. Delayed diagnosis can lead to increased morbidity and mortality. 
Fortunately DNM is a rare disease and following are the criteria to diagnose it: (a) Clinical manifestations of severe infection. (b) Demonstration of specific radiological features. (c) Documentation of the necrotizing mediastinal infection intraoperatively or at post-mortem. (d) Relation of oropharyngeal or cervical infection with the development of mediastinitis.  Acute suppurative mediastinitis is a severe life-threatening infection of the connective tissue in the thoracic cavity with involvement of the pleural cavity and median thoracic organs. We report three cases of DNM, review the literature and discuss the management of this surgical emergency.
| Case Reports|| |
A 35-year-old male patient presented to the emergency department with odynophagia, dysphonia fever with chills and rigors, sore throat and dry cough of 1 week duration. He was a controlled hypertensive, but not diabetic. The nasoendoscopy showed swollen and inflamed epiglottis diagnosed as supra glottitis and admitted to intensive care unit (ICU) for close observation and started on Tazocin® (Piperacilin + Tazobactum). The following day he complained of increasing pain and swelling in the anterior aspect of the neck. Computerized tomography (CT) of the neck showed a collection in the anterior part of the neck. Patient went into respiratory distress that necessitated ventilatory support. CT of the neck and chest showed typical features of DNM and collection of fluid in the neck and right pleural space. Transcervical pus (10 ml) was drained and right intercostal drain was inserted, it drained 300 ml of pus in 24 h. The pus grew streptococcus pyogen sensitive to vancomycin, which was added to the therapy. Subsequently, the patient developed clinical and radiological features of left pleural effusion for which a thoracostomy drain was inserted. He was weaned from the ventilator and extubated on day 8. He remained stable with hoarseness. Again, he became febrile, tachypnic and tachycardic on day 10, repeat CT was carried out, which revealed bilateral empyema. Video-assisted thoracoscopy (VAT) and drainage of empyema was performed. He made satisfactory recovery and on day 15, nasoendoscopy showed left vocal cord palsy, started speech therapy. He improved gradually, started on a normal diet and all drains were removed on day 24. He was discharged on day 26 on speech therapy.
A 51-year-old male patient presented to the emergency department complaining of fever with chills and rigors, sore throat, hoarseness and dry cough since 5 days. He was tachycardic and febrile (39C) with a normal blood pressure. Throat examination showed tonsillitis with congested throat. Blood examination revealed leukocytosis (32,000) and renal impairment (blood urea nitrogen 14.2 and serum creatinine 296). Patient was admitted to surgical ICU, started on Tazocin (Piperacillin + Tazobactam) and fluid resuscitation. Chest X-ray showed hilar infiltrates. CT of the neck and chest showed severe inflammatory signs in the neck and left mediastinal collection. CT guided drainage of mediastinal pus was performed. By day 5, the renal function became normal, but he remained febrile with hoarseness of voice. Pus from mediastinal drain grew enterobacter cloacae; antibiotic was changed to ciprofloxacin and clindamycin based on sensitivity. Direct laryngoscopy revealed left vocal cord paralysis and he started speech therapy. On day 9, he became febrile (40C) and short of breath, requiring intubation and ventilation. Neck and chest CT showed paratracheal collection in the neck as well as bilateral pleural and pericardial effusion. Para tracheal collection was drained by suprasternal incision (30 ml pus) and pleural and pericardial effusions were drained with mediastinoscopy.
The patient's condition improved and was weaned from the ventilator and extubated on day 14. He was discharged home on day 22, to be followed in the out-patient department.
A 25-year-old patient presented to the emergency department of our hospital with fever, toothache, dysphagia, trismus, hoarseness and diffuse neck swelling since 10 days. He was febrile (38.8C) and had leukocytosis (28,000). He had a diffuse neck swelling, with swollen floor of the mouth with severe trismus. CT scan of neck and chest showed submandibular, parapharangeal and right mediastinal collections. Para pharyngeal collection was drained through suprasternal incision (200 ml pus). Submandibular collections were drained with multiple incision and caries teeth was removed. Mediastinal collection was drained by VAT (500 ml pus) and thorough lavage was carried out and right intercostal drain was inserted. Patient was extubated on the first post-operative day. Pus culture grew Escherichia coli and the patient continued IV Tazocin® . Fiber-optic laryngoscopy showed left vocal cord palsy. He was followed by the speech therapist and discharged home on day 11, to be followed in the out-patient department.
| Discussion|| |
Cervical necrotizing fasciitis is a rapidly progressing life-threatening infection of the neck and its worst complication is DNM. DNM is a severe necrotizing infection, descending down from the neck through fascial planes, into the mediastinum and affecting the covering fascia of mediastinal structures and the cavities leading to suppurative collection. 
Etiology and risk factors
The common etiologies of DNM are odontogenic infections (40-60%), the retropharyngeal abscess (14%), peritonsillar abscess (11%), clavicular osteomyelitis, cervical lymphadenitis (7%) and traumatic endotracheal intubation (7%). Other infections such as parotitis, thyroiditis accounts for 5% of DNM.  Recently, Pereira et al. reported a fatal case of DNM, secondary to suppurative thyroiditis in apparently healthy female patient.  Various comorbid conditions such as diabetes mellitus, malnutrition and poor oral hygiene are the risk factors for flare-up and spread into the mediastinum. Inadequate treatment and infection with more virulent etiological micro-organism are another risk for the development of DNM.  Recently, Petitpas et al. found that glucocorticoid intake before admission, a pharyngeal focus or gas seen on initial CT scan were the risk factors for the spread of the cervical necrotizing infection into the mediastinum leading to DNM. 
Applied anatomy and pathophysiology
Applied anatomy of the fascial planes of the neck is essential to understand the progress of the oral and neck pathology into the mediastinum. The cervical fascia covers the muscles, vessels and visceral structure of the neck like envelop. The cervical fascia is divided into superficial and deep cervical fascia. The deep cervical fascia forms three main cylindrical compartments, extending from the base of the skull to the mediastinum, namely submandibular, parapharyngeal and retropharyngeal space. The retropharyngeal space is also called danger space as mainly through this space the infection travels from the neck into the mediastinum. These deep cervical fascial spaces are normally bound together with loose connective tissues and communicate with each other, thus making a way for the spread of infection from one space to the other.  Cervical infection can spread through pretracheal space and carotid sheath to the thoracic cavity.
Oro-maxillary infections are common, but rarely lead to severe complications like DNM. The cervicomedullary spaces are comparatively less vascular and they are deficient in cell defense mechanism. When the virulent bacterial infection of the oral cavity or neck gets access to these spaces, the spread of infection is rapid. The bacterial fibrinolysin and coagulase, will cause local ischemia, connective tissue necrosis and destruction, thrombosis in the smaller vessels, which produces an atmosphere of lower oxygen, local hypoxia and necrotic tissue, all these will facilitate the bacterial growth.  With the help of the gravity, respiration and negative intrathoracic pressure, pus from cervical spaces rapidly spreads into the mediastinum. The mediastinal structures will be affected by physiological compromise or compression, bleeding or severe sepsis and septic shock. 
Epidemiology and grading
DNM is common in males and affects younger people.  It is classified into two types focal and diffuse. This is according to the CT chest findings with the spread of the DNM. Type 1 DNM, where infection is limited to the superior mediastinal space above the level of the carina. Type 2 DNM is again divided into two types, type 2A, when the infection is still limited to the anterior mediastinum and below the carina. Type 2B when the infection spreads below the level of carina and to the posterior mediastinum. 
Prompt diagnosis is the key to successful management as delay will lead to more spread of the infection and severity. The main clinical manifestations of DNM are fever, odynophagia, dysphonia, trismus, dry cough, neck edema and chest pain.  Laboratory work-up may show leukocytosis or leucopenia, thrombocytopenia and raised acute phase proteins. All our three patients had fever, sore throat, dry cough, dysphonia, dysphagia and leukocytosis [Table 1].
Radiographic imaging plays a vital role in the diagnosis of DNM. Chest X-ray may show wide mediastinum, pleural effusion, pneumomediastinum, with or without air-fluid levels or flask shaped heart due to pericardial effusion. Neck and chest CT are more sensitive and will show the extent of infection. It will also reveal complications such as empyema, pericardial effusion or pseudo aneurysm. In our 1 st and 3 rd patients cervico-thoracic CT showed parapharyngeal [Figure 1] as well as pleural collections [Figure 2], whereas in the 2 nd patient, it showed paratracheal collection with pleural and pericardial effusions. Besides diagnosis, CT scan is also required for the grading of DNM.  All our patients had type 2B DNM. Magnetic resonance imaging is also helpful for details of organ and vascular effect of the DNM. Bacteriology of the mediastinal pus will be useful in guiding the antibiotic therapy. DNM can mimic acute myocardial infarction, but the absence of evolving changes and presence of sepsis will differentiate these two conditions. 
Combined medical and surgical therapy in critical care setup is essential for the management of DNM. Initial treatment will include aggressive fluid resuscitation, broad spectrum antibiotics coverage and fever control. Antibiotics should be changed according to culture and sensitivity results.
Early surgical intervention is essential and treating physicians should be aware of the applied anatomy of the neck, mediastinum and fascial compartment of this regions.  Surgical management is planned according to the CT findings. If the infection is in the superior mediastinum, extension of infection is above 4 th dorsal spine posteriorly or above the level of carina anteriorly, transcervical drainage may be ideal. If the infection spreads below the mentioned levels, then mediastinum should be drained by subxiphoid or trans-thoracic approach.  However as DNM is an aggressive and rapidly progressing infection, many authors , recommend transthoracic drainage in addition to the cervical drainage, irrespective of the level and extent of spread into the mediastinum. Corsten et al. in their meta-analysis documented significantly improved survival in patients with both transcervical and transthoracic drainage.  As all our patients had DNM with involvement of posterior thoracic cavity; which required exploration with possible lavage and debridement; hence, we used VAT in combination with transcervical drainage of paratracheal and parapharyngeal collections.
Various extensive open surgical procedures (Clamshell surgical drainage to the median sternotomy) are described for the surgical therapy of DNM, but these procedures can have severe complication such as sternal osteomyelitis, dehiscence and injury to the phrenic nerve.  Sumi et al. in their study recommended that percutaneous drainage in DNM is as effective as open surgical drain, with advantage of decrease duration of antibiotic therapy, mechanical ventilation and duration of hospital stay.  However, these drains can be easily blocked and need meticulous care, repeated check and milking to keep them patent. Recently, VAT is increasingly used for drainage, irrigation and debridement of the necrotic tissue from the mediastinum as it is minimally invasive, short duration surgery, shorter intensive therapy and hospital stay. 
Complications and prognosis
The most worrisome complications of DNM are empyema, severe sepsis and septic shock.  Other complications are pleural and pericardial effusion causing compression of the vital intrathoracic organs, pneumothorax and pneumomediastinum.  The vascular complications of DNM are hemorrhage, thrombosis of internal jugular vein and carotid pseudoaneurysm.  The involvement of carotid sheath in DNM will affect IX, X and XI cranial nerves. ,, Landers et al. reported a case of DNM complicated by tracheobronchial fistula and tracheobronchial necrosis.  All our patients had recurrent laryngeal nerve involvement. The recurrent laryngeal nerve innervate laryngeal muscles in the neck; after branching off from the vagus nerve in the thorax through a circuitous route, looping around the large arteries and rising up along the trachea and esophagus. In our patients, the infection descended down into the thoracic cavity from the neck during which the recurrent laryngeal nerve must have been affected leading to hoarseness.
The morbidity and mortality of the DNM depends on associated comorbid conditions (diabetes mellitus, immunocompromised status); Main risk factors for mortality are diabetes mellitus, comorbidity, surgery, multi-organ failure and septic shock.  The mortality of DNM is from 15% to 40%. ,,,,,, Early diagnosis, surgical intervention and supportive intensive therapy prevented mortality in our patients.
| Conclusion|| |
Early surgical intervention in patients with DNM will decrease the ICU and hospital stay. Combination of transcervical drainage and VAT may have a survival benefit in patients with DNM. DNM patients may have recurrent laryngeal nerve involvement leading to vocal cord paralysis and hoarseness of voice and other complications.
| References|| |
|1.||Estrera AS, Landay MJ, Grisham JM, Sinn DP, Platt MR. Descending necrotizing mediastinitis. Surg Gynecol Obstet 1983;157:545-52. |
|2.||Aknan C, Kantari F, Centinkaya S. Imaging in mediastinum: A systematic review based on etiology. Clin Radiol 2004;59:966-72. |
|3.||Novellas S, Kechabtia K, Chevallier P, Sedat J, Bruneton JN. Descending necrotizing mediastinitis: A rare pathology to keep in mind. Clin Imaging 2005;29:138-40. |
|4.||Pereira O, Prasad DS, Bal AM, McAteer D, Abraham P. Fatal descending necrotizing mediastinitis secondary to acute suppurative thyroiditis developing in an apparently healthy woman. Thyroid 2010;20:571-2. |
|5.||Mihos P, Potaris K, Gakidis I, Papadakis D, Rallis G. Management of descending necrotizing mediastinitis. J Oral Maxillofac Surg 2004;62:966-72. |
|6.||Petitpas F, Blancal JP, Mateo J, Farhat I, Naija W, Porcher R, et al. Factors associated with the mediastinal spread of cervical necrotizing fasciitis. Ann Thorac Surg 2012;93:234-8. |
|7.||Chow AW. Life threatening infection of head, neck and upper respiratory track. In: Hall JB, Schmidt GA, Wood LD, editors. Principles of Critical Care. New York: McGraw-Hill; 1998. p. 887. |
|8.||Makeieff M, Gresillon N, Berthet JP, Garrel R, Crampette L, Marty-Ane C, et al. Management of descending necrotizing mediastinitis. Laryngoscope 2004;114:772-5. |
|9.||Endo S, Murayama F, Hasegawa T, Yamamoto S, Yamaguchi T, Sohara Y, et al. Guideline of surgical management based on diffusion of descending necrotizing mediastinitis. Jpn J Thorac Cardiovasc Surg 1999;47:14-9. |
|10.||Kiernan PD, Hernandez A, Byrne WD, Bloom R, Dicicco B, Hetrick V, et al. Descending cervical mediastinitis. Ann Thorac Surg 1998;65:1483-8. |
|11.||Balkan ME, Oktar GL, Oktar MA. Descending necrotizing mediastinitis: A case report and review of the literature. Int Surg 2001;86:62-6. |
|12.||Chang HY, Yang YN, Yin WH, Youg MS. Descending necrotizing mediastinitis mimicking acute ST segment elevated myocardial infarction. Acta Cardiol Sin 2010;26:123-6. |
|13.||Marty-Ané CH, Berthet JP, Alric P, Pegis JD, Rouvière P, Mary H. Management of descending necrotizing mediastinitis: An aggressive treatment for an aggressive disease. Ann Thorac Surg 1999;68:212-7. |
|14.||Lavini C, Natali P, Morandi U, Dallari S, Bergamini G. Descending necrotizing mediastinitis. Diagnosis and surgical treatment. J Cardiovasc Surg (Torino) 2003;44:655-60. |
|15.||Corsten MJ, Shamji FM, Odell PF, Frederico JA, Laframboise GG, Reid KR, et al. Optimal treatment of descending necrotising mediastinitis. Thorax 1997;52:702-8. |
|16.||Sumi Y, Ogura H, Nakamori Y, Ukai Tasaki O, Kuwagata Y, et al. Nonoperative catheter management for cervical necrotizing fasciitis with and without descending necrotizing mediastinitis. Arch Otolaryngol Head Neck Surg 2008;134:750-6. |
|17.||Min HK, Choi YS, Shim YM, Sohn YI, Kim J. Descending necrotizing mediastinitis: A minimally invasive approach using video-assisted thoracoscopic surgery. Ann Thorac Surg 2004;77:306-10. |
|18.||Hirai S, Hamanaka Y, Mitsui N, Isaka M, Mizukami T. Surgical treatment of virulent descending necrotizing mediastinitis. Ann Thorac Cardiovasc Surg 2004;10:34-8. |
|19.||Singhal P, Kejriwal N, Lin Z, Tsutsui R, Ullal R. Optimal surgical management of descending necrotising mediastinitis: Our experience and review of literature. Heart Lung Circ 2008;17:124-8. |
|20.||Landers S, Beck A, Maurer J, Hürtgen M, Silomon M. Tracheobronchial necrosis. Following descending necrotizing mediastinitis. Anaesthesist 2007;56:1237-41. |
|21.||Deu-Martín M, Saez-Barba M, López Sanz I, Alcaraz Peñarrocha R, Romero Vielva L, Solé Montserrat J. Mortality risk factors in descending necrotizing mediastinitis. Arch Bronconeumol 2010;46:182-7. |
|22.||Ridder GJ, Maier W, Kinzer S, Teszler CB, Boedeker CC, Pfeiffer J. Descending necrotizing mediastinitis: Contemporary trends in etiology, diagnosis, management, and outcome. Ann Surg 2010;251:528-34. |
[Figure 1], [Figure 2]