Presentations

Abstract

Introduction: Large cell neuroendocrine carcinoma of the colon is a rare and aggressive type of cancer associated with a poor prognosis as it tends to be metastatic at the time of initial diagnosis (1). Clostridium Septicum (C. septicum) bacteremia has a well-established association with right-sided colonic malignancy (2, 3) C. septicum aortitis is a rare complication of bacteremia with C. Septicum and carries a poor prognosis (4). We present a gentleman with persistent C. Septicum bacteremia complicated by aortic dissection in the setting of a newly diagnosed large cell neuroendocrine tumor of the colon.

Case Information: 59-year-old male with a past medical history of hypertension, Type II Diabetes, and schizophrenia presents to the ED with abdominal pain, acute hypoxic respiratory failure, and septic shock refractory to fluids. CT abdomen/pelvis showed pericecal stranding. Respiratory status continued to worsen requiring intubation. CTA chest to evaluate for pulmonary embolism revealed Type A and B aortic dissection. Repeat CT abdomen/pelvis was concerning for contained cecal perforation. Repeated blood cultures were positive for C. septicum. Antibiotics were narrowed to IV Piperacillin/Tazobactam to which the organism was sensitive. The patient underwent repair of his cecal perforation, with pathology showing large cell neuroendocrine carcinoma of the colon with lymph node invasion. The patient remained bacteremic for several weeks despite antibiotic therapy. Repeat CT scan showed an area of myonecrosis in the left gluteal region. Initial transthoracic echocardiogram was concerning for new vegetation and aortic regurgitation. Transesophageal echocardiogram 17 days later was negative for vegetation but did show moderate to severe aortic regurgitation. MRI was suspicious for embolic phenomena. Indium tagged white blood cell scan showed positive uptake in the distribution of the thoracic descending aorta. In the setting of metastatic large cell neuroendocrine tumor and numerous comorbidities, goals of care discussions were initiated with the patient's next of kin.

Discussion/Clinical Findings: Bacteremia from Clostridium Septicum is rare, usually observed in the setting of hematologic or colonic malignancy, with at least one case report describing its occurrence in the setting of colonic neuroendocrine adenocarcinoma (3, 5, 9). There are few case reports describing aortitis and endocarditis in individuals with C. septicum bacteremia. Both aortitis and endocarditis carry a poor prognosis, mortality has been reported at 50-100% and 33.3% respectively (6, 7). Seeding of the aorta from C. Septicum usually presents with periaortic gas infiltration with subsequent rapid progression to acute aneurysm and aortic dissection, however, 7% of cases report an absence of periaortic gas (8, 10). Due to the scarcity of cases described, there are no established guidelines for the management of C. Septicum aortitis. One review investigating C. Septicum aortitis concluded that early open aortic repair vs. endovascular aortic repair is the best way to improve the odds of survival in patients eligible for high-risk vascular surgery (4). Additionally, the authors note that antibiotic therapy may be considered to "bridge" high-risk patients to eventual surgery (4). The same group found that antibiotic therapy without surgical or endovascular therapy had a six-month mortality rate of 100% in patients with C. Septicum aortitis (4).

Conclusion: Clinicians should be aware that Clostridium septicum bacteremia is associated with hematologic and colonic malignancy, and that an extensive search for cancer should be initiated whenever a patient presents with bacteremia from this organism. Endocarditis and aortitis are rare complications of C. Septicum bacteremia, and both carry a poor prognosis. Antibiotics may be used to bridge patients who are too ill to undergo immediate surgical repair or may be used as long-term therapy in those seeking palliative therapy over a long-term cure. Early identification, antibiotic administration, and surgical intervention are key to giving patients the best chance for recovery.