Mediastinitis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Anthony Gallo, B.S. [2]
Overview
Mediastinitis is inflammation or infection of the tissues in the mid-chest, or mediastinum.[1] This disorder is rare, but is most often observed among patients following chest surgery or endoscopy. Mediastinitis may occur at any age.[2] It may be classified according to cause into 2 groups: acute or chronic (sclerosing or fibrosing). Acute mediastinitis is usually bacterial and due to rupture of organs in the mediastinum. Chronic sclerosing (or fibrosing) mediastinitis, while potentially serious, is caused by a long-standing inflammation of the mediastinum, leading to growth of acellular collagen and fibrous tissue within the chest and around the central vessels and airways. Life threatening causes of mediastinitis include esophageal perforation. Common causes of mediastinitis include trauma, beta-hemolytic streptococcus, forceful or constant vomiting, and median sternotomy. If left untreated, fibrosing mediastinitis may progress to sepsis and subsequently, death. The presence of mediastinitis among patients following chest surgery is observed to have a particularly poor prognosis; there is a serious risk of mortality.[3] Common complications of mediastinitis include sepsis and spread of the infection. Symptoms of mediastinitis include chest pain, malaise, and shortness of breath.[4] Common physical examination findings of mediastinitis include clinical signs of sepsis, tachycardia, and tachypnea.[5] CT scan may be diagnostic of mediastinitis. On CT scan, findings suggestive of mediastinitis include the presence of calcified mediastinal mass. The mainstay of therapy in acute mediastinitis secondary to cardiothoracic surgery includes clindamycin and ceftriaxone. The preferred regimen for preoperative prophylaxis against acute mediastinitis includes either a second generation cephalosporin or vancomycin. Aggressive surgical debridement is recommended among patients with descending necrotizing mediastinitis.
Historical Perspective
Chronic mediastinitis was first described by Dr. Thomas T. Whipham, MD, a British physician, in 1899.[6]
Classification
Mediastinitis may be classified according to cause into 2 groups: acute or chronic (sclerosing or fibrosing).[7]
Pathophysiology
Mediastinitis is the inflammation or infection of the mediastinum.[1] The pathogenesis of the infection remains unknown; radiographic, serologic, and/or histopathologic evidence of prior Histoplasma capsulatum infection, histoplasmosis, or chronic granulomatous disease is always observed.[8] Additionally, mediastinitis may also present as the result of Staphylococcus aureus or Staphylococcus epidermidis infection following chest surgery.[9]
Causes
Esophageal perforation is a life-threatening cause of mediastinitis. Common causes of mediastinitis include infection, trauma, endoscopy, and forceful vomiting.
Differential Diagnosis
Mediastinitis must be differentiated from superior vena cava syndrome and Hodgkin's lymphoma.[10]
Natural History, Complications and Prognosis
If left untreated, fibrosing mediastinitis may progress to sepsis and subsequently, death. Common complications of mediastinitis include sepsis and spread of the infection. Patients with mediastinitis following chest surgery have a poor prognosis.[3]
Diagnosis
History and Symptoms
Symptoms of mediastinitis include chest pain, malaise, and shortness of breath.
Physical Examination
Common physical examination findings of mediastinitis include clinical signs of sepsis, tachycardia, and tachypnoea.[5]
Laboratory Findings
Laboratory findings consistent with the diagnosis of mediastinitis include positive confirmation of organisms found upon culture of the mediastinum, including Staphylococcus aureus and Histoplasma capsulatum.[11]
CT
On CT scan, the appearance of mediastinitis can be variable and dependent on the pattern of involvement. Typically, the disease affects the middle mediastinum and may demonstrate mediastinal or hilar mass, infiltrative regions of soft-tissue attenuation which obliterate normal mediastinal fat planes and encase or invade adjacent structures, or calcifications of the central mass or associated lymph nodes (especially if there has been preceding histoplasmosis).[12]
MRI
On MRI, mediastinitis is characterized by mediastinal or hilar mass or soft-tissue attenuation. Pattern of involvement is essentially similar to CT scan for mediastinitis.[12]
Treatment
Medical Therapy
The mainstay of therapy in acute mediastinitis secondary to cardiothoracic surgery includes clindamycin and ceftriaxone. The preferred regimen for preoperative prophylaxis against acute mediastinitis includes either a second generation cephalosporin or vancomycin.
Surgical Therapy
Aggressive surgical debridement is recommended among patients when combined with broad spectrum antibiotics that provide coverage against MRSA, beta-lactamase producing gram-negative organisms, and anaerobes.
Prevention
Effective measures for the primary prevention of mediastinitis include nasal decolonization, hand hygiene, and antibiotic prophylaxis. Effective measures for the secondary prevention of mediastinitis following sternotomy include reporting wound discharge to physician and aggressive treatment of hyperglycemia.
References
- ↑ 1.0 1.1 Koksal D, Bayiz H, Mutluay N, Koyuncu A, Demirag F, Dagli G; et al. (2013). "Fibrosing mediastinitis mimicking bronchogenic carcinoma". J Thorac Dis. 5 (1): E5–7. doi:10.3978/j.issn.2072-1439.2012.07.03. PMC 3548007. PMID 23372962.
- ↑ Abboud CS, Wey SB, Baltar VT (2004). "Risk factors for mediastinitis after cardiac surgery". Ann Thorac Surg. 77 (2): 676–83. doi:10.1016/S0003-4975(03)01523-6. PMID 14759458.
- ↑ 3.0 3.1 Mediastinitis: a potentially lethal infection. Thoracics (2012). http://thoracics.org/2012/03/03/mediastinitis-noncardiac-surgery/ Accessed on September 25, 2015.
- ↑ Lewandowski B, Pakla P, Wołek W, Jednakiewicz M, Nicpoń J (2014). "A fatal case of descending necrotizing mediastinitis as a complication of odontogenic infection. A case report". Kardiochir Torakochirurgia Pol. 11 (3): 324–8. doi:10.5114/kitp.2014.45685. PMC 4283893. PMID 26336443.
- ↑ 5.0 5.1 Acute Mediastinitis Following a Laparotomy for Small Bowel Obstruction. Journal of Current Surgery (2014) http://jcs.elmerpress.com/index.php/jcs/article/view/252 Accessed on September 28, 2015
- ↑ The Lancet. Google Books (2015). https://books.google.com/books?id=Zxw6AQAAMAAJ&pg=PA947&lpg=PA947&dq=the+lancet+mediastinitis+1896&source=bl&ots=izLFx5SXRB&sig=mXN15zc74xrPIn00rWnfoZ_NQ9Y&hl=en&sa=X&ved=0CB0Q6AEwAGoVChMIgPPf0aiByAIVAW0-Ch3LpgUe#v=onepage&q=lancet%20mediastinitis%201896&f=false Accessed on September 18, 2015
- ↑ Mediastinitis. Wikipedia (2015) https://en.wikipedia.org/wiki/Mediastinitis Accessed on September 21, 2015
- ↑ Histopathologic Overlap between Fibrosing Mediastinitis and IgG4-Related Disease. International Journal of Rheumatology (2012). http://www.hindawi.com/journals/ijr/2012/207056/ Accessed on September 25, 2015
- ↑ Konvalinka A, Erret L, Fong IW (2006). "Impact of treating Staphylococcus aureus nasal carreiers on wound infections in cardiac surgery". J Hosp Infect. 64 (2): 162–8. PMID 16930768.
- ↑ Kang DW, Canzian M, Beyruti R, Jatene FB (2006). "Sclerosing mediastinitis in the differential diagnosis of mediastinal tumors". J Bras Pneumol. 32 (1): 78–83. PMID 17273573.
- ↑ CDC/NHSN Surveillance Definitions for Specific Types of Infections. CDC (2015). http://www.cdc.gov/nhsn/PDFs/pscManual/17pscNosInfDef_current.pdf Accessed on September 21, 2015
- ↑ 12.0 12.1 Fibrosing mediastinitis. Radiopedia.org (2015) http://radiopaedia.org/articles/fibrosing-mediastinitis Accessed on October 2, 2015