Mediastinitis: Difference between revisions
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+ | ==Background== |
− | * |
+ | *Infection of the structures in the mediastinum |
+ | **The mediastinum refers to the space between the lungs which contains the heart, thymus, esophagus, and trachea |
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+ | *Confusing nomenclature, and includes mediastinal infections caused by extension of a cervical infection (necrotizing mediastinitis or descending mediastinitis) and mediastinal infection after sternotomy (sternal infection or deep sternal wound infection) |
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− | === |
+ | ===CDC Definition=== |
− | * |
+ | *One of the following: |
− | ** |
+ | **Organisms cultured from mediastinal tissue or fluid |
− | ** |
+ | **Gross anatomical or histopathologic evidence of mediastinitis |
− | ** |
+ | **Fever, chest pain, or sternal instability |
− | * |
+ | *Plus one of the following: |
− | ** |
+ | **Purulence from the mediastinal area |
− | ** |
+ | **Mediastinal widening on imaging |
− | === |
+ | ===Microbiology=== |
− | * |
+ | *Post-cardiac surgery: often mixed |
+ | **[[Staphylococcus aureus]] is by far most common, followed by [[coagulase-negative staphylococci]] |
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+ | **Can also involve other [[Gram-positive cocci]] and [[Gram-negative bacilli]] (including [[SPICE organisms]] and [[Pseudomonas aeruginosa]]) |
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− | == |
+ | === Epidemiology === |
+ | * Post-surgical deep sternal wound infections occur after about 1% of cardiac surgeries |
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+ | ** Incidence increases with the complexity of the operation, and is highest with CABG = valve replacement or aortic surgery |
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+ | ** Risk increases with BMI, diabetes, and number of platelet transfusions |
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+ | ==Clinical Manfestation== |
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+ | === Prognosis === |
+ | * For deep sternal wound infections after cardiac surgery |
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− | * Surgical exploration with debridement |
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+ | ** Mortality is about 15% in the short term, but is also higher than those without infection in the years following surgery |
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+ | ** Mortality is higher when Gram-negatives are isolated |
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+ | |||
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+ | |||
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+ | ==Management== |
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+ | |||
+ | *In general, surgical exploration with debridement should always be performed as quickly as possible |
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+ | *Empiric antibiotics should be broad, including coverage for MRSA and resistant Gram-negatives |
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+ | *Duration of therapy unclear but depends on adequacy of source control, presence of sternal osteitis, and presence of metal or other foreign bodies |
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+ | **Probably somewhere between 3 and 12 weeks |
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+ | **Following sternal resection and pectoral flap: maybe 2 to 3 weeks |
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+ | **After debridement without resection, or with residual bone infection: probably 4 to 6 weeks |
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[[Category:Respiratory infections]] |
[[Category:Respiratory infections]] |
Revision as of 10:12, 7 February 2021
Background
- Infection of the structures in the mediastinum
- The mediastinum refers to the space between the lungs which contains the heart, thymus, esophagus, and trachea
- Confusing nomenclature, and includes mediastinal infections caused by extension of a cervical infection (necrotizing mediastinitis or descending mediastinitis) and mediastinal infection after sternotomy (sternal infection or deep sternal wound infection)
CDC Definition
- One of the following:
- Organisms cultured from mediastinal tissue or fluid
- Gross anatomical or histopathologic evidence of mediastinitis
- Fever, chest pain, or sternal instability
- Plus one of the following:
- Purulence from the mediastinal area
- Mediastinal widening on imaging
Microbiology
- Post-cardiac surgery: often mixed
- Staphylococcus aureus is by far most common, followed by coagulase-negative staphylococci
- Can also involve other Gram-positive cocci and Gram-negative bacilli (including SPICE organisms and Pseudomonas aeruginosa)
- Esophageal rupture: polymicrobial, with oropharyngeal and gastrointestinal flora including anaerobes
- Can also occur from contiguous extension of pneumonia, pancreatitis, subphrenic abscess, or epidural abscess, with the microbiology determined by the source of infection
Epidemiology
- Post-surgical deep sternal wound infections occur after about 1% of cardiac surgeries
- Incidence increases with the complexity of the operation, and is highest with CABG = valve replacement or aortic surgery
- Risk increases with BMI, diabetes, and number of platelet transfusions
Clinical Manfestation
- Usually presents within 30 days of surgery
- Fever, chest pain, drainage from surgical site
- See CDC definition, above
Prognosis
- For deep sternal wound infections after cardiac surgery
- Mortality is about 15% in the short term, but is also higher than those without infection in the years following surgery
- Mortality is higher when Gram-negatives are isolated
Investigations
- CT chest can show evidence, including sternal wire displacement, sternal disruption, free gas, or fluid collections
- Surgical exploration, with fluid sent for culture
Management
- In general, surgical exploration with debridement should always be performed as quickly as possible
- Empiric antibiotics should be broad, including coverage for MRSA and resistant Gram-negatives
- Antimicrobials directed by culture results
- Duration of therapy unclear but depends on adequacy of source control, presence of sternal osteitis, and presence of metal or other foreign bodies
- Probably somewhere between 3 and 12 weeks
- Following sternal resection and pectoral flap: maybe 2 to 3 weeks
- After debridement without resection, or with residual bone infection: probably 4 to 6 weeks