SESSION TITLE: Infectious Disease Student/Resident Case Report Posters II
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Anterior mediastinal abscesses are uncommon without preceding trauma or instrumentation. Few structures reside in this space and common pathologies include teratoma, lymphoma, thymus, thyroid, and germ cell tumors. Non-traumatic mediastinal abscesses can occur from direct extension along fascial planes from odontic or retropharyngeal infections, following osteomyelitis of ribs or vertebrae or by hematogenous or lymphangitic spread from distant sites.
CASE PRESENTATION: A 55-year-old man with no past medical history presented with left-sided chest and shoulder pain. The left upper sternal area was notable for a non-tender area of induration. Patient denied fever, chills, or weight loss. There was no history of trauma or surgery in the area. Two weeks prior he underwent chiropractic manipulation of the lower back for pain and a short taper of corticosteroids for left shoulder pain. Labs were significant for a leukocytosis of 24,000/μL with 82% granulocytes. A chest radiograph revealed a large anterior mediastinal mass. A non-contrast computed tomography showed a 5 x 6.3 cm mass encasing the left proximal clavicle and extending from the anterior mediastinal space to the chest wall. He underwent fine needle aspiration (FNA) which revealed purulent fluid that was negative for malignancy. Fluid from the FNA cultured positive for methicillin-sensitive Staphylococcus aureus. Subsequent blood cultures grew the same. Patient then underwent surgical evacuation including thorascopic decortication as well as prolonged antibiotics with eventual complete resolution. Work-up including gallium scan and transesophageal echocardiogram failed to reveal a source for the infection.
DISCUSSION: Organisms that have been implicated in anterior mediastinal abscesses include atypical and typical tuberculosis, actinomyces, and syphilis among others but Staphylococcus is the most common. There has been only one previous report of an anterior mediastinal abscess without antecedent trauma/instrumentation or infection at a distal site. This was reported in 1945 and a causative organism was not clearly identified. This case illustrates how an infectious process can mimic a tumor. No primary site identified, nor cardinal signs of infection was present.
CONCLUSIONS: Staphylococcus aureus is a highly virulent pathogen and a leading cause of bacteremia with significant morbidity and mortality. Early recognition and treatment is essential in avoiding potentially lethal complications.
Reference #1: Akkasilpa S, Osiri M, Ukritchon S, Junsirimongkol B, Deesomchok U. Clinical features of septic arthritis of sternoclavicular joint. J Med Assoc Thai. 2001;84(1):63-68. PubMed
Reference #2: Michael Aronovitch and Arthur M. Vineberg. Two Cases of Anterior Mediastinal Abscess. Can Med Assoc J. 1945 November; 53(5): 455-458
Reference #3: G. Ralph Corey. Staphylococcus aureus Bloodstream Infections: Definitions and Treatment. Oxford Journals Medicine Clinical Infectious Diseases Volume 48, Issue Supplement 4 Pp. S254-S259
DISCLOSURE: The following authors have nothing to disclose: Judette Polynice, Robert Holladay, Justin Ardoin, Adam Wellikoff
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