COLORECTAL CARCINOMA: A CASE OF MALIGNANT FISTULA FORMATION PRESENTING AS SEPTIC SHOCK

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TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Colorectal carcinoma (CRC) is the third most common cause of malignancy in the United States. Common signs and symptoms include hematochezia, melena, abdominal pain, anemia, and change in bowel habits. Rarely, CRC can present with fistula formation and subsequent infection. Here we highlight a patient with known CRC who presented with intrapulmonary abscesses due to colopleural fistula formation. CASE PRESENTATION: A 57-year-old male with recently diagnosed stage IV colon adenocarcinoma presents with a productive cough of brown, foul-smelling sputum and left-sided chest and abdominal pain for three weeks. Vitals showed tachycardia and hypotension. Exam revealed diminished breath sounds of the left hemithorax and tenderness to palpation of the left chest wall and left upper quadrant. Labs were significant for anemia 6.2 g/dL, leukocytosis 21.3 thou/cmm with bandemia 17%, and peak lactate 20.1 mmol/L. Computed tomography (CT) of the chest, abdomen, and pelvis showed a large gas containing mass within the left lower lobe contiguous with the splenic flexure and chest wall as well as left-side intrapulmonary abscesses and extensive soft tissue gas within the left hemithorax concerning for pleurocutaneous fistula. These findings were consistent with colopleural fistula formation due to extension of his known splenic flexure mass. Patient was fluid resuscitated, transfused one unit of packed red blood cells, and started on vasopressors and broad-spectrum antibiotics. Multidisciplinary discussions determined that patient would require extensive surgical debridement for source control; however, his overall prognosis remained poor given the advanced state of his cancer and poor performance status. A goals of care discussion was held with the patient who declined surgery and opted to pursue hospice care. DISCUSSION: Colopleural fistula formation is an extremely rare complication of CRC with the potential to manifest as serious pulmonary infections arising due to perforation or invasion of nearby tissue. Our patient developed intrapulmonary abscesses and pleurocutaneous fistula with soft tissue gas concerning for necrotizing fasciitis due to colopleural fistula formation. Management involves a multidisciplinary approach and ultimately, requires emergent surgical intervention. Unfortunately, this is not always possible as in our patient who was too far advanced in his disease course making him a poor surgical candidate. CONCLUSIONS: Malignant fistulas associated with CRC can present as life-threatening infections, which require emergent surgical and medical management. It is important for all patients to undergo age-appropriate CRC screening with close follow-up to prevent such dire complications. REFERENCE #1: Lian R, Zhang G, Zhang G. Empyema caused by a colopleural fistula: A case report. Medicine (Baltimore). 2017 Sep;96(39):e8165. doi: 10.1097/MD.0000000000008165. PMID: 28953667; PMCID: PMC5626310. REFERENCE #2: Papagiannopoulos K, Gialvalis D, Dodo I, Darby MJ. Empyema resulting from a true colopleural fistula complicating a perforated sigmoid diverticulum. Ann Thorac Surg. 2004 Jan;77(1):324-6. doi: 10.1016/s0003-4975(03)01378-x. PMID: 14726092. REFERENCE #3: Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer Statistics, 2021. CA Cancer J Clin. 2021 Jan;71(1):7-33. doi: 10.3322/caac.21654. Epub 2021 Jan 12. PMID: 33433946. DISCLOSURES: No relevant relationships by Arjan Ahluwalia, source=Web Response No relevant relationships by Henry Lam, source=Web Response No relevant relationships by Kaitlyn Musco, source=Web Response No relevant relationships by Andres Zirlinger, source=Web Response