A 17-year-old male presented with a one-week history of abdominal pain and dysuria. He described the abdominal pain as sharp and localized to the infraumbilical and right inguinal regions. He reported a decrease in appetite. He lost approximately 15 kg over the preceding five months. He had no fever. He had normal bowel movements without blood or mucus. His past medical history was significant for recurrent anterior abdominal wall abscesses. The initial abscess occurred five months prior and he was treated with intravenous (IV) antibiotics at an outside facility. At that institution, computed tomography (CT) of the abdomen was reported as demonstrating significant bowel wall thickening of the TI with adjacent inflammatory stranding. After the antibiotic course was completed, a repeat CT showed resolution of the abdominal wall abscess but persistence of the bowel wall abnormality. Two months later, he developed a second episode of abdominal wall abscess formation that required percutaneous surgical drainage and antibiotic therapy (amoxicillin and metronidazole). Aspirated serous fluid contained few leukocytes and was sterile. After this second episode, he underwent esophagogastroduodenoscopy (EGD) and colonoscopy at the outside institution. The EGD was normal and colonoscopy revealed erythema with ulcerations in the TI. Histopathology confirmed severe chronic inflammation of TI. He was prescribed an oral 5-aminosalicylic acid for inflammatory bowel disease. He was not compliant with taking this medication. His abdominal pain slightly improved for a brief period of time. A follow-up colonoscopy was planned at the other institution but he was admitted to our hospital with the current presenting symptoms.
On admission, his vital signs were within normal limits. Physical examination revealed a soft, non-distended abdomen with mild tenderness in the infraumbilical and right inguinal regions. A small area of erythema and induration, approximately 2 cm in diameter, was present just inferior to the umbilicus. There was minimal guarding but no rigidity or rebound. No umbilical discharge was noted. Laboratory evaluation demonstrated elevated inflammatory markers and normal hemoglobin, platelet count, albumin, and urinalysis. The CT of the abdomen revealed a rim enhancing ovoid shaped fluid collection in the midline of the suprapubic region (just below the umbilicus) measuring 10.5x3x2.5 cm (Fig. 1A). This abscess cavity contained multiple small foci of gas tracking from the umbilicus to the superior-ventral aspect of the urinary bladder wall. Contiguous with the ovoid fluid collection and just lateral to the right rectus abdominis muscle, there was a smaller abscess approximately 1.5 cm in diameter. The CT also revealed significant thickening of the wall of the distal ileum that was in close contiguity with the urachal remnant suggesting the presence of an enterourachal fistula (Fig. 1B). The prior CT performed at the outside hospital at the time of initial presentation was reviewed at our institution and revealed a patent urachus at the same location of the current ovoid shaped abscess (Fig. 1C). He was started on IV piperacillin-tazobactam. He underwent EGD and colonoscopy. EGD was normal. Colonoscopy revealed severe erythema and ulceration in the TI and colon appeared normal. Biopsies from TI revealed chronic severe ileitis with architectural distortion. The colonic biopsies were normal. Magnetic resonance enterography (MRE) confirmed the CT scan findings and clearly demonstrated a fistula from the TI to the urachal remnant abscess (Fig. 1D). Quantiferon-TB gold test was negative and chest radiograph was normal. He was diagnosed with fistulizing CD based on the endoscopic, histologic, and MRE findings. Induction therapy for CD with prednisone was initiated. Percutaneous drainage of the abscess was performed. The aspirated fluid was purulent with neutrophilic predominance and no organism was cultured. He completed two weeks of IV piperacillin-tazobactam and two weeks of oral ciprofloxacin and metronidazole therapy. At the completion of the antibiotic course, a CT scan with sinogram (contrast administered through the drainage catheter) showed no residual fluid collection and no significant filling of the abscess cavity with contrast. The drainage catheter was removed. Repeat MRE showed interval improvement of the TI thickening, complete resolution of the anterior abdominal abscesses, and a blind-ended fistula from the TI without communication to the urachal remnant. His inflammatory markers slowly normalized. Prednisone was gradually weaned and he was started on azathioprine for maintenance therapy. He was referred for a colorectal surgical consultation and underwent laparoscopic exploration of the abdomen. The old abscess cavity was identified and noted to be tightly adherent to the anterior abdominal wall and in close proximity to the inflamed TI. Ileocecectomy with primary anastomosis and complete resection of the abscess cavity was performed. The enterourachal fistula could not be identified and likely obliterated with the medical management. Resection of the urachal remnant could not be simultaneously done due to dense adhesions. Histopathology of the resected specimen confirmed active CD. A repeat colonoscopy ten months after the surgery revealed the CD in remission. He had no recurrence of abscesses during the follow up. A complete resection of the urachal remnant has been planned.