Diagnosis of Severe Acute Lower Gastrointestinal Bleeding with CTA
Case
A 31-year-old white man presented to the ED with abdominal and rectal pain accompanied by multiple episodes of bloody diarrhea. He stated he had mild rectal pain the previous night but was pain-free and in his usual state of health the morning of his presentation. Approximately 2 hours before presenting to the ED, however, he began experiencing mild stomach pain, then bloody diarrhea which he described as bright red and “filling the toilet bowl with blood.” He had no history of inflammatory bowel disease or other gastrointestinal (GI) disorder, no recent travel, no complaints of nausea or vomiting, and no infectious symptoms. He described a remote history of external hemorrhoids, and review of his family history was significant for multiple paternal relatives with aortic aneurysms. He was not taking any medications and was a nonsmoker with a normal body mass index (24.3 kg/m2).
Upon arrival at the ED, the patient’s vital signs were: heart rate, 112 beats/min; and blood pressure, 139/102 mm Hg; respiratory rate and temperature were normal, as was the patient’s oxygen saturation on room air. Physical examination was notable for no subjective or objective findings of orthostatic hypotension; increased bowel sounds and diffuse mild abdominal tenderness; and no external hemorrhoids, fissures, or rectal tenderness. Laboratory evaluation was significant for hemoglobin (Hgb), 15.0 g/dL; blood urea nitrogen (BUN)-to-creatinine (Cr) ratio, 11.6; and anion gap, 17 mEq/L.
Upon initial presentation, there was some concern for an infection. However, as the patient continued to have bowel movements consisting almost entirely of frank blood and did not have any infectious signs, a vascular etiology was more strongly considered. Given the patient’s relatively stable vital signs, BUN-to-Cr ratio of less than 20, and lack of orthostatic hypotension, there was low concern for an upper GI etiology, and endoscopy was not obtained emergently. The patient instead underwent abdominal computed tomography angiography (CTA), which identified active extravasation and contrast pooling within the cecum and appendix (Figure 1).
Shortly after the patient returned from imaging, repeat laboratory studies were performed, demonstrating an Hgb drop from 15.0 g/dL to 12.3 g/dL, and surgical services was emergently consulted. The surgeon recommended that embolization first be attempted, with surgery as the option of last resort given the poor localization of the bleed on CTA and the long-term consequences of colonic resection in a young, otherwise healthy man.
Interventional radiology was consulted, and the patient was brought immediately to the angiography suite, where he was found to have “active extravasation arising from a distal descending branch off the right colic artery” (Figure 2). Coil embolization resulted in complete resolution of the hemorrhage.
Later that evening, the patient’s Hgb continued to drop, reaching nadir at 7.3 g/dL, and he continued to have severe hematochezia. His falling Hgb was thought to be indicative of the degree of hemorrhage he had sustained prior to embolization, and the clearance of such blood as the source of his ongoing hematochezia. Following transfusion of 2 U of packed red blood cells (PRBCs), the patient’s Hgb improved to 12.0 g/dL, and he did not experience any significant bleeding for the remainder of his hospital stay.
The following morning, the patient underwent an extensive colonoscopy (extending 25 cm into the terminal ileum), which was unable to detect any signs of arteriovenous malformations, angiodysplasia, or any other possible source of bleeding. After 24 hours with stable vital signs and Hgb levels, the patient was discharged home with close surgical and gastroenterological follow-up, with possible genetic testing for connective tissue diseases. The diagnosis at discharge was spontaneous mesenteric hemorrhage of unknown etiology.
Discussion
Acute lower GI bleeding has an estimated annual hospitalization rate of 36 patients per 100,000, or about half the rate for upper GI bleeding.1,2 The majority of patients (>80%) will have spontaneous resolution and can be worked up nonemergently.
