But which is the more likely culprit?*  That kind of depends on both your patient and your geographic location.

If this had been in my native Virginia – I’d “assume/ guess” metastatic cancer  (since my patient population is usually older, high rate of smoking, other risk factors for cancer).

But luckily (who ever thought I’d be saying luckily) in my current location (Northern Mexico) in this patient (with multiple risk factors for infectious disease but no asbestos exposure) - tuberculosis is the more likely diagnosis.

* Prior to formal tissue pathology results, which confirmed tuberculosis in this patient.

** I apologize for the lack of formal references, but I was unable to find any comprehensive literature (available as free articles).

Radiology Reference on-line article

Sternotomy incisions, along with clamshell/ hemi-clamshell incisions may be utilized for large anterior mediastinal tumor resections, which places patients at the same risk of mediastinitis as traditional cardiac surgery procedures.

Blunt trauma can include injuries such as an esophageal tear that allows bacterial/ food/ fluids to seep from the torn esophagus into the chest.   In rare cases, it can occur due to the spread of an infection affecting the head /neck.  Recently, there have been several case reports of mediastinitis resulting from necrotizing fascitis which is particularly devastating, with cases originating as dental infections.

If untreated, mediastinitis can rapidly progress to sepsis (a systemic bloodstream infection causing numerous serious sequelae) and death.  Mortality related to the development of mediastinitis ranges from 21 – 60% (depending on sources).

Additional Risk Factors for the development of mediastinitis

Any condition that delays or impedes healing can promote the development of mediastinitis - particularly in post-surgical patients.  This includes diabetes, patients taking immunosuppressive therapies (such as Rheumatoid arthritis treatments, COPD and other patients on prednisone (and other steroids), transplant recipients and cancer patients receiving chemotherapy.)  This is why care of sternotomy or large chest incisions should be taken very seriously. 

Prevention of mediastinitis in patients with sternotomy incisions:  (s/p thymectomies, mediastinal mass resections etc.)

Patients should be sure to follow all lifting or movement restrictions (sternotomy precautions) and report any drainage from their incisions.  Patients should also contact their surgeons if they develop any wound dehiscence (wound edges come apart) or development fluctuance or swelling around the surgical site.  Fever following discharge from the hospital should be reported to the surgical service, particularly if it accompanies any signs of wound breakdown.

Patients with diabetes or elevated serum blood glucose need to be aggressive in the treatment of hyperglycemia.  Even patients who were previously well controlled on oral agents may require basal or correction insulins post-operatively to prevent elevated glucose, and increased risk of infection. 

Large breasted female patients, or obese males should wear a support bra to keep gravity from pulling breast tissue apart, and placing stress on the healing incision.  This is one of the most common reasons for poor wound healing of sternotomies.  (This will also significantly reduce post-operative pain.)

Post-thoracic surgery patients receiving radiation early in the course of their surgical recovery are also at risk, even from smaller procedures such as mediastinoscopies and Chamberlain procedures.  Aggressive surveillence and regular inspection of all wounds may help detect early signs of superficial infection/ wound breakdown to prevent the development of more serious complications.

Do not apply creams, lotions or ointments to incisions without speaking to your surgeon.  Avoid overly harsh anti-bacterial soaps and scrubs.  These products may actually damage the delicate tissues and promote infection.

Diagnosis may require CT scans of the chest to detect the development of a fluid collection within the chest.

Treatment of Acute Mediastinitis

Early treatment and surgical debridement of infected material (dead tissue, pus, etc) are essential for optimal results.  Intravenous antibiotics are a crucial part of this treatment to help prevent / and treat possible sepsis.  In patients presenting with more advanced infection – fluid resuscitation and treatment of underlying sepsis and sepsis related complications (organ failure) may be required along with other supportive measures.  Urgent evacuation of mediastinal space should remain a priority, even in the critically ill and unstable patient to prevent further spread of infection, particularly if necrotizing organisms are suspected.

* Sternotomy or the surgical division of the sternum was actually first adopted by a thoracic surgeon to access the anterior chest and mediastinum almost fifty years prior to its use in cardiac surgery.  Sternotomy remains one the primary ways (along with clamshell and hemi-clamshell incisions) that surgeons can access the anterior mediastinum for large tumor resections.

Additional References and Information about Mediastinitis

New York Times article on mediastinitis

Banazadeh M.  (2011).  Successful management of acute necrotizing mediastinitis with trans-cervical drainage.  Ann Thorac Cardiovasc Surg. 2011 Oct 25;17(5):498-500. Epub  2011 Jul 13. 

Dajer-Fadel, et al (2012).  Thoracic necrotizing fasciitis due to snake ointment that progressed to a mediastinitis. Interact Cardiovasc Thorac Surg. 2012 Jan;14(1):94-5. Epub  2011 Nov 18.  Story of fatal case of mediastinitis in Mexico City, Mexico.  Please note: photos are fairly graphic.

Kim, et. al. (2011).  Application of radiographic images in diagnosis and treatment of deep neck infections with necrotizing fasciitis: a case report.  Imaging Sci Dent. 2011 Dec;41(4):189-93. Epub  2011 Dec 19.  Discussion of case of serious, necrotizing infection originating from a dental infection- with CT images showing close proximity of infection to thoracic cavity. [Patient in case report did not develop mediastinitis.]

Mahmodlou (2011).  Aggressive surgical treatment in late-diagnosed esophageal perforation: a report of 11 cases.  ISRN Surg. 2011;2011:868356. Epub  2011 Jun 22.  Iran case reports of mediastinitis after esophageal injury.

Saha et. al (2011).  Perils of prolonged impaction of oesophageal foreign bodies.  ISRN Surg. 2011;2011:621682. Epub  2011 Jun 13.  2 Cases (with color photos and CT scans) of mediastinitis after foreign body ingestion.

when fully encapsulated as seen in this ct scan may be difficult to distinguish from lung abscess – but note the compressed lung, which is a characteristic of empyema.

In advanced empyema, a tough, fibrous layer (or peel) forms around the lung and prevents full re-expansion. (This peel has the appearance and texture of rubbery chicken skin.)

thick pleural removed during decortication

In these cases, decortication (or peel removal) is necessary for full recovery.

VATS decortication of a loculated empyema

If the peel isn’t removed, the lung will remain compressed and infection can easily recur.  In VATS surgery, several ports are used (small 2cm incisions) versus a larger thoracotomy incision.  This isn’t always possible; if the infection is severe, or surgeons are unable to free the lung through the smaller incisions.  Sometimes surgeons have to convert to open surgery intra-operatively.  However, VATS is preferable for patients, (if possible).  Smaller incisions mean less injury, less pain leading to fasting healing, and a shorter hospital stay.

advanced empyema requiring open thoracotomy for decortication

Click here to see a video showing a standard thoracotomy incision (with retractors holding it open).

For a related case study on VATS decortication.

As we mentioned in a previous post – empyema is a serious, potentially fatal infection* – in fact - one out of three patients with this condition will die from it.

What’s the difference between empyema and a parapneumonic effusion?  Answer: Pus.

*while this case report features a patient from Uganda, similar cases have been encountered in my practice here in the USA.

References:

Prilozi. 2010 Dec;31(2):61-70.  Indications for VATS or open decortication in the surgical treatment of fibrino-purulent stage of parapneumonic pleural empyema.  Colanceski R, Spirovski Z, Kondov G, Jovev S, Antevski B, Cvetanovski M V.  Article linked in text above, recommending early surgical treatment for better patient outcomes.  However, this study did not compare surgical treatments to medical therapies.

Asian Cardiovasc Thorac Ann 2010;18:337–43. Thoracic empyema in high-risk patients: conservative management or surgery?   Bar I, Stav D, Fink G, Peer A, Lazarovitch T, Papiashvilli M.  Limited study of 119 patients showing benefit in both groups of patients with surgery used as primary management strategy in clinically unstable patients.  (Increased mortality in this limited study of surgical interventions versus medical management can be attributed to the fact that surgery was used as a last resort in the sicker, more debilitated patients by the authors descriptions).

Metin M, Yeginsu A, Sayar A, Alzafer S, Solak O, Ozgul A, Erkorkmaz U, Gürses A.  Treatment of multiloculated empyema thoracis. Singapore Med J. 2010, Mar 51(3): 242-6.  Comparison of VATS, open surgery and conventional treatment for empyema.  Authors recommend VATS for first line treatment.

older references on VATS decortication:

J Thorac Cardiovasc Surg 1999;117:234-8. Video-assisted thoracoscopy in the treatment of pleural empyema: stage-based management and outcome.  Cassina PC et al.  Authors discuss the results of VATS decortication in 45 patients after failed medical treatment and attempted thoracostomy drainage.  Several patients required open thoracotomy due to late organized infectious process.

Ann Thorac Surg 2006;81:309-313.  Video-Assisted Thoracic Surgery for Pleural Empyema.  Wurnig, S. S.,Wittmer, V., Pridun, N., & Hollaus, P. H. (2006).  Linked in text above. Austrian study of 130 patients

Ann Thorac Surg 2003;76:225-30. Minimally invasive surgery in the treatment of empyema: intraoperative decision-making. Roberts, J. R