A complicated case of primary aortojejunal fistula: A case report

Abstract

Background

Aortoenteric fistulas are rare and life-threatening pathology characterized by an abnormal connection between the aorta and the gastrointestinal tract.

Case presentation

The patient is a 61-year-old male who initially presented with hypogastric pain, hematemesis, and melena. Computed tomography angiography (CTA) revealed an abdominal aorta aneurysm but not a fistula. Imaging modalities were inconclusive in the diagnosis. The patient became unstable hemodynamically and was transferred to the operation room. The definitive diagnosis of aortoenteric fistula was confirmed during surgical exploration. Urgent surgery was performed; however, the patient experienced a cascade of complications, including rebleeding, intestinal leakage, and hemodynamic instability due to aortic bleeding. Despite rigorous interventions, the patient expired due to multiple organ failure 53 days after the first repair surgery.

Clinical discussion

There is no definite imaging method due to the lack of guidelines, and the absence of exact findings has led to intraoperative diagnosis in up to 50 % of cases. This is one of the modalities of choice to examine suspected aortoenteric fistulas. Many authors prefer Computed tomography (CT) with intravenous contrast for suspected AEF despite its limitations in clarity. Others recommend CT angiography as the preferred modality. It is worth noting that, as reported in a comprehensive retrospective review, the mortality rate is approximately 46 % within 60 days after AEF repair surgery.

Conclusion

This report adds to the limited data about primary aortojejunal fistulas, an extremely rare type of aortoenteric fistulas which has been reported in only a few cases. Understanding the importance of promptly suspecting, diagnosing, and intervening is crucial, emphasizing the importance of sharing such cases for medical guidance and better patient outcomes.

Highlights

• •Many authors prefer CT with IV contrast for suspected AEF, despite its limitations in clarity.
• •EVAR has emerged as the preferred treatment for hemodynamically unstable patients with active bleeding.
• •The rare and potentially fatal nature of AEFs underscores the importance of fast diagnosis.

1. Introduction

Aortoenteric fistulas (AEFs) are a seldom-seen but fatal occurrence, first described by Sir Astley Cooper in 1829 [1]. AEFs are defined as abnormal linkage between the lumen of the aorta and that of the gastrointestinal (GI) tract with an incidence rate of 0.1 % to 0.08 % [2]. Fistulization can occur either primarily, when no prior intervention has been performed on the aorta, or secondarily, developing after both open and endovascular aortic reconstruction even through a thrombosed graft [3,4]. The primary type is even rarer, with an incidence rate ranging between 0.04 % and 0.07 %, as indicated by autopsy studies, while the secondary type has a higher incidence rate, reported to be approximately or below 1 %. Both primary aortoentric fistulas (PAEFs) and secondary aortoentric fistulas (SAEFs) predominantly affect men with a male-to-female ratio of 3:1 and mean ages of 64 and 67 years, respectively [5,6]. Abdominal aortic aneurysm (AAA) is identified as the most prevalent risk factor for AEFs, accounting for the primary etiology of 67 % of PAEF cases. Aneurysms with atherosclerotic origin represent 73 % of cases, while infectious and inflammatory conditions cause the rest. The pathophysiology involves mechanical thinning of the aorta and outermost intestine due to repeated rubbing during each pulsation and GI peristalsis, leading to erosion and linkage between the two lumens. Less common causes of PAEFs include metastatic tumors, radiation therapy, foreign body ingestion, tuberculosis, and infections such as appendicitis or diverticulitis [3,7]. The most common communication is the celiac aorta and the duodenum, especially the third portion at a rate of 83 %. PAEFs can uncommonly involve different segments of the GI tract, such as the stomach, ileum, colon and appendix, or rarely affect the jejunum, with an incidence rate of only 4 % [8]. The most common initial presentation among cases is upper GI bleeding manifesting with hematemesis, melena and hematochezia.

On the other hand, hemodynamic instability and syncope are the second and third most frequent symptoms. Herald bleeding is another finding that indicates upcoming massive GI bleeding and hemodynamic instability in the next 6–24 h and should always raise suspicions of PAEF. It is noteworthy that clinical signs may be absent or not sufficiently specific [3]. Moreover, there are other conditions that can mimic AEFs, such as retroperitoneal fibrosis, infected aortic aneurysm, infectious aortitis, and perigraft infection without fistulization, leading to misdiagnosis [9]. Understanding fatality and rarity of PAEFs, early diagnosis and management are crucial. Reporting comprehensive data and different clinical manifestations help in providing timely susception and management. In the following, we are reporting a rare case of aortojejunal fistula that presented with hypogastric pain and gastrointestinal bleeding according to SCARE guidelines [10].

2. Case presentation

We present a case of a 61-year-old male admitted to our department with complaints of hypogastric pain, hematemesis, and melena who presented the night before admission. He had no past medical history except benign prostatic hyperplasia, which was on medication. He used no other medications. He was addicted to opiates and smoked 40 cigarettes daily but denied any alcohol consumption. He had no food or drug allergies, no prior surgeries, and no notable family history. Upon arrival, his blood pressure measured 105/70 mmHg, without showing orthostatic hypotension, and his heart rate remained steady at 90 beats per minute. He had a body temperature of 36.88 °C and a respiratory rate of 18 breaths per minute. The oxygen saturation level was 96 % without the use of supplemental oxygen. An abdominal examination revealed no tenderness or guarding, and a rectal examination showed melaena. No other abnormalities were detected during the physical examination. Initial laboratory examination reported hemoglobin 8.7 g/dL, white blood count 9.7 × 10³/μL (polymorphonuclear 58 %, lymphocytes 35 %, monocytes 7 %), platelet count 211 × 10³/μL. In the first hours of admission, we hydrated the patient with intravenous fluids to prevent upcoming hemodynamic instability. Nasogastric washing was bloody, while the initial chest X-ray and electrocardiogram were normal. Afterwards, endoscopy was performed up to the second portion of the duodenum, revealing only one large clean-based ulcer in the bulb of the duodenum but not a hemorrhage or clot. Abdominal ultrasound indicated an elongated aneurysmal dilation of the aorta, and for better evaluation, spiral thoraco-abdominal CTA was performed. It revealed a fusiform abdominal aorta aneurysm with an axial diameter of 60 × 62 mm with circumferential mural thrombosis and an aneurysm located 1 cm distal to the origin of the renal artery.

After observing the patient for 36 h in the gastrointestinal ward, the hemoglobin level dropped to 6.4 g/dL, and his general condition started to deteriorate. His level of consciousness decreased, manifesting as drowsiness. Then, he became hemodynamically unstable due to GI bleeding, and his blood pressure decreased to 85/60 mmHg. Emergent endoscopy indicates backflow of fresh blood from the duodenum in stomach without definite site of bleeding identified. Bed side emergency ultrasonography revealed no free fluid in abdominal cavity. Due to the patient's unstable hemodynamic condition, we were suspicion to massive bleeding from the duodenal ulcer, so an urgent exploratory surgery was performed. A duodenotomy was executed, but we noticed that the massive bleeding is originating from distal of the duodenotomy site, rather than from the ulcer itself. We found the aortic aneurysm and an aortoenteric fistula in the proximal jejunum. The aneurysm was successfully excluded using an 18 mm Dacron tubular graft by vascular surgeon. Resection of the site of the fistula at the jejunum was performed successfully due to patient unstable hemodynamics we decided to perform a damage control surgery and postpone the remaining surgical procedures for a second-look surgery. Therefore, we used two linear staples to close the duodenum's 4th portion and the jejunum downstream of the fistula. A tissue sample from the resected area was sent for pathology analysis. The pathology findings were mucosal edema, congestion and serosal abscess consisting of an inflamed fistula tract. Then the patient was transferred to The Surgical Intensive Care Unit. A second- look surgery performed one day later while patient was on low dose inotrope and relatively stable, with no evidence of bleeding or ischemia observed. A side-to-side duodenojejunal anastomosis performed, connecting the jejunum distal to the fistula with the first and second segments of the duodenum, and a jejunostomy tube inserted. Patient got stable after the second surgery and he was extubated and transferred to the ward 8 days post surgery. Unfortunately, two days later, he encountered potential surgery complications. Due to massive Bloody discharge from the surgery site and abdominal catheter, we decided to perform an exploratory surgery. We found disruption of the jejunoduodenal anastomosis and bleeding of the gastroduodenal artery (GDA). Therefore, reanastamosis of the small bowel and GDA ligation were done for him. Unfortunately, reanastomosis failed and the patient developed a controlled enterocutaneous fistula. In response, we used total parental nutrition. In the subsequent days, the patient continued to be hemodynamically unstable, requiring multiple blood product transfusions and oxygen supplementation through a ventilator. Few days later, intraperitoneal bleeding was recurred. Emergency angiography was performed, which revealed bleeding from one of the branches of the superior mesenteric artery. Consequently, angioembolization was conducted emergently. We didn't find any specific reason for this episode of bleeding. We considered various infections and conditions like diverticulitis, pancreatitis, vasculitis, tuberculosis, syphilis, tumors and radiation therapy to find the cause of the fistula. However, our evaluations didn't confirm any of these as the actual reason. Despite management of hematologic issues, including DIC (disseminated intravascular coagulation) and anemia, correcting electrolyte imbalances, and antibiotic therapy, due to multiple organ failure, his hemodynamic status did not improve, and he expired within three days.

3. Discussion

Fistula formation between the aorta and the GI tract has remained a rare and challenging entity since it was described in the 19th century. AEFs are categorized as primary and secondary. PAEF is predominantly a complication of AAA accompanied by atherosclerotic conditions in more than two-thirds of cases. Other etiologies include tumor, radiation therapy, foreign body, tuberculosis, syphilis and infection such as diverticulitis. Since the 1970s, effective treatment for tuberculosis and syphilis has eliminated the risk associated with PAEFs, although immunocompromised cases are still somewhat at risk. SAEFs are more common and occur in cases with previous surgical interventions on the aorta, affecting up to 66 % of patients undergoing AAA reconstruction [11,12]. Before 1960, PAEFs were the most common type, but during three decades, the SAEF incidence rate rose [8], possibly due to the development of surgical aortic reconstruction techniques. PAEFs impact the duodenum in up to 80 % of cases: third portion (55–60 %), fourth portion (5–8 %), second portion (3 %), and first portion (<1 %). Less than 4 % of PAEFs affect the jejunum, and approximately 2 % involve the ileum. The stomach is impacted in 4 % of cases, while the sigmoid colon is affected in 4 % as well. In another 2 % of cases, the descending or ascending colon is involved [13]. To the best of our knowledge, aortojejunal fistulas are extremely rare, and only a few cases have been reported yet. According to Kehagias, D., et al., the most common symptom leading patients to the emergency department is upper GI bleeding presenting with hematemesis, hematochezia and melena. Other less common symptoms are abdominal pain, syncope, fever and hemodynamic instability [3]. The classic triad of gastrointestinal bleeding, abdominal pain, and a pulsing abdominal mass only occurs in 25 % of cases. The term ‘herald bleed’, defined as an initial minor bleeding followed by a hemorrhage-free interval, warns us about an upcoming massive bleeding episode commonly within 6–48 h and should always raise suspicion for AEFs. This definition holds true for our case as well. It is noteworthy that clinical signs may be absent due to unclear reasons, making diagnosis more difficult [12,14].

Computed tomography (CT) with intravenous contrast is now the modality of choice to examine suspected aortoenteric fistulas. Its widespread availability, short acquisition time, high resolution, and high detection rate of 60 % make it a better modality than MRI for diagnosing AEFs. While CT scans expose patients to ionizing radiation, causing health issues, their benefits outweigh their costs. Based on the consensus among the majority of authors, we recommend it as the preferred diagnostic approach when challenging suspected AEFs. Pathognomonic signs for diagnosing PAEF include the detection of air within the aortic wall and contrast in the gastrointestinal tract. Indirect signs include thickening of the bowel wall over an aneurysm or disruption of the aortic fat cover. These markers make CT the most sensitive diagnostic method for PAEF [9,12].

The initial imaging modality remains controversial among authors. PAEFs can present the same as other GI bleeding conditions; therefore, it is important to rule out more common causes, such as gastric ulcers commonly encountered in the emergency department. As suggested by the guidelines of the American College of Gastroenterology and the German Society of Gastroenterology, esophagogastroduodenoscopy (EGD) is the preferred modality for diagnosis and therapy when there is suspicion of ulcer bleeding [15,16]. While endoscopy is effective in excluding other common causes of GI bleeding, it rarely reveals the presence of a fistula. Moreover, endoscopy can only visualize the duodenum up to its second portion. It may also accidentally disrupt a clot and cause sudden severe bleeding. Supporting the idea of upper endoscopy preference in the initial stages, we performed upper endoscopy as the first modality, but it did not provide a diagnosis of bleeding origin or the existing fistula [4]. Magnetic resonance imaging (MRI) has the same sensitivity and specificity as CT scans, but it is less available in emergency settings. As a result, it is not a frequently used modality in these cases. Ultrasonography can rarely indicate AEFs because the presence of bowel gas causes shadowing, obscuring the underlying aortic aneurysm [9]. Ct angiography is another modality used with a diagnostic sensitivity of 40 %–90 % and specificity of 33 %–100 %. Some authors describe CT angiography as well suited for the diagnosis of AEF due to its possible benefits over regular CT with contrast dye. These include clearer images that show smaller blood vessels more accurately and the ability to better show changes in the shape of the aorta. The most frequent findings are air pockets near the aorta, no fatty space between the aorta and digestive tract, swelling of the intestinal wall around the aorta, and extravasation of contrast medium from the aorta to the intestinal lumen [12,17].

It is worth noting that there is no clear imaging method due to the lack of guidelines, and the absence of exact findings has led to intraoperative diagnosis in up to 50 % of cases. We faced the same challenge, and our imaging modality (US and CTA) revealed the presence of the duodenal ulcer and the AAA but not a fistula. Therefore, we have a suspicion that the most probable origin for bleeding is the duodenum. Although the discovery of an AAA increased our suspicion of an AEF being present, we definitively diagnosed an aortojejunal fistula only upon exploring the area. If the diagnosis is clear or strongly suspected, emergency surgery should be performed promptly, as it is the approach of choice to treat PAEFs. Without surgical interventions, the mortality rate is 100 %, while performing surgical interventions carries a mortality rate of 30–40 %. During surgery, it is essential to control bleeding, repair the intestinal defect, restore proper blood flow to the distal area, and control possible infections. In situ aorta repair with prosthetic grafts in cases without systemic sepsis or gross contamination should be performed, as we did in our case using a Dacron tubular graft. Using antibiotic-soaked grafts can improve outcomes [3,12,18]. When there is severe peritonitis or localized contamination, extra-anatomic bypass, commonly axillofemoral bypass, should be performed to re-establish distal blood flow. In situ repair of the aorta results in a higher survival rate compared to the extra-anatomic bypass method, with rates of 65 % and 53 %, respectively. Primary repair of the gastrointestinal tract at the affected site, the jejunum in our case, should be performed. After surgery, patients should receive intravenous broad-spectrum antibiotics for up to 6 weeks based on culture results [18,19].

Endovascular aneurysm repair (EVAR) has emerged as the preferred treatment for hemodynamically unstable patients with active bleeding because of its good bleeding control rate of 80 % and minimal invasiveness. Although EVAR works well for acute bleeding control, the risk of infection remains. Antoniou et al. reported an incidence rate of 44 % for rebleeding and reinfection after EVAR. This highlights the need for intensive antibiotic therapy or intraabdominal collection drainage if necessary [20,21]. In our case, imaging modalities were not conclusive and because of the presence of a large duodenal ulcer that was revealed in the endoscopy, we thought that the ulcer is the most probable source of the massive bleeding and hemodynamic instability. Thus, we performed the open surgery and duodenectomy instead of EVAR and as the bleeding doesn't stop after the duodenectomy, we found the fistula during the surgery.

As reported in a comprehensive retrospective review, the mortality rate is approximately 46 % within 60 days after AEF repair surgery. Gastrointestinal complications are the most significant factor increasing the mortality rate. Mortality in patients with GI complications has been reported at 77 %, whereas it is 35 % for those without GI complications. Intestinal leakage is noted as the most fatal GI complication, elevating the mortality rate to 83 %, while the rate for mesenteric ischemia is 57 %. Factors such as chronic renal insufficiency, advanced age, and other complications can also contribute to increased postoperative mortality [22]. In our case, we encountered that after repair surgery, gastrointestinal complications, especially intestinal leakage, were the possible culprits behind our patient's deterioration and eventual mortality.

4. Conclusion

In conclusion, primary aortoenteric fistulas, described as rare connection between the aorta and the GI tract, are mainly caused as a complication of abdominal aortic aneurysms. They can rarely affect the jejunum, as reported in only a few cases thus far. This report adds to the limited data on primary aortojejunal fistulas and highlights their multifaceted clinical presentation, diagnostic intricacies, and evolving treatment approaches. The rare and potentially fatal nature of AEFs underscores the importance of promptly suspecting, diagnosing, and intervening. Understanding this issue and documenting and sharing such rare cases play an essential role in assisting both healthcare workers and affected patients.

List of abbreviations

AEF

aortoentric fistula

GI

gastrointestinal

PAEF

primary aortoentric fistula

SAEF

secondary aortoentric fistula

AAA

abdominal aorta aneurysm

RBC

red blood cell

WBC

white blood cell count

CT

computerized tomography

US

ultrasonography

CTA

computerized tomography angiography

GDA

gastroduodenal artery

EVAR

endovascular aneurysm repair

Consent

Written consent to participate was obtained from Kin of the patient included in this study. Informed consent was obtained from Kin of the patient for publication of their clinical data.

A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

Written consent to participate was obtained from Kin of the patient included in this study. Informed consent was obtained from Kin of the patient for publication of their clinical data.

This was a clinical case report; therefore, it was no need to get the ethic code from ethics committee, however we obtained written permission and consent from kin of the patient to present the case and use the pictures. A written copy of the informed consent form is available for submission if necessary.

Funding

None.

Author contribution

Hooman Rezaei and Hamed Ghoddusi Johari designed the study. Farnia Ghasemi Wrote the main manuscript. Farnia Ghasemi, Mohammad Amin Gholami gathered data. Farnia Ghasemi and Mohammad Amin Gholami wrote and edited the final report and reviewed the final draft of the manuscript. All the authors read and approved the final manuscript Hooman Rezaei, Hamed Ghoddusi Johari carried out the patient medical treatment.

Guarantor

Dr. Farnia Ghasemi.

Research registration number

It is no first in man study.

Conflict of interest statement

None.

Appendix. Supplementary data

Fig. S1.

A: axial contrast CT image showing a fusiform abdominal aorta aneurysm with circumferential mural hypodense thrombosis. B: coronal view of the abdominal aorta aneurysm.

Fig. S2.

CT angiography showing an abdominal aorta aneurysm located 1 cm distal to origin of renal artery and 2.5 cm proximal to the aortic bifurcation.

Fig. S3.

Repaired abdominal aorta aneurysm using a tubular dacron graft.

Fig. S4.

The disconnected aortojejunal fistula. The white arrow shows the affected part of jejunum that has been detached and clamped. The yellow arrow shows the abdominal aorta aneurysm. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Availability of supporting data

The data used during the current study are available from the corresponding authors upon reasonable request.