By: Mallory Chavannes, MD
Case Presentation
An 8 year old child presents with one month of intermittent, lower cramping mild abominal pain, worse with eating (particularly dairy), 2-3 episodes of loose, diarrheal bowel movements daily, occasionally with blood, arthralgias of the knees and ankles bilaterally without arthritis, occasional mouth sores, and intermittent low grade fevers at night two to three times per week. Laboratory evaluation and stool studies performed by the pediatrician are significant for elevated inflammatory markers (CRP 79 mg/L and ESR 80 mm/hr, a normal hemoglobin but with a low MCV, and an elevated fecal calprotectin to > 3000 mcg/g concerning for possible inflammatory bowel disease. After the initial history, intestinal ultrasound is performed during the visit.
Initial Intestinal Ultrasound Assessment
In this case, intestinal ultrasound is used early in the initial consultation as a diagnostic screening tool. In the right lower quadrant, the terminal ileum is followed proximally. This intestinal ultrasound demonstrates mild to moderate thickening of the bowel wall in the ascending colon and cecum. The video loop then demonstrates significant inflammation in the terminal ileum, beginning immediately at the ileocecal valve. There is increased bowel wall thickness, bright surrounding inflammatory fat, and reactive lymphadenopathy, characterized by the classic "wink" or "blink" sign of hypoechoic circles that flash in and out of the video loop as the terminal ileum is tracked proximally. This appears to be a relatively short segment of ileal inflammation, roughly 8-10 cm.
Correlation of IUS with Ileocolonoscopy
Intestinal ultrasound is then utilized to facilitate discussion with the family. We already know that this child has Crohn's disease based on the intestinal ultrasound. In this age group, outside of tuberculosis, there is almost nothing that mimics these imaging findings with the clinical history other than Crohn's disease. Next diagnostic steps, and the importance of mucosal and histologic evaluation for confirmation of the Crohn's disease diagnosis, are discussed with the family. The family agrees to proceed with a diagnostic endoscopy and ileocolonoscopy urgently.
Treatment Course
The patient is initially trialed on exclusive enteral nutrition, however they cannot tolerate it. They begin diet therapy with the Crohn's disease exclusion diet and shortly thereafter, they initiate treatment with adalimumab for anti-tumor necrosis factor therapy.
Intestinal Ultrasound Monitoring: 2 Months
Intestinal ultrasound is repeated 2 months later and does not show a significant treatment response.
The intestinal ultrasound examination demonstrates inflammation in the ascending colon and terminal ileum characterized by increased bowel wall thickness and hyperemia. Subjectively, the surrounding inflammatory fat appears less bright in signal compared to the diagnostic intestinal ultrasound examination. Given these findings, and the fact that the patient had a clincial response but not remission, adalimumab treatment was escalated to weekly from every other week.
Intestinal Ultrasound Monitoring: 6 Months
Intestinal ultrasound is performed again, 6 months after treatment initiation, and 4 months after treatment optimization. Now we can see a significant decrease in the bowel wall thickness of the terminal ileum, restoration of the bowel wall architecture, and improvement in inflammatory fat. However, there is subtle luminal narrowing and fecalization of intestinal contents of the terminal ileum several centimeters from the ileocecal valve proximally. There appears to be the beginning of proximal dilation suggestive of early stricture formation.
Intestinal Ultrasound Monitoring: 10 Months
Intestinal ultrasound demonstrates very mild persistent bowel wall thickening in the terminal ileum, however there is luminal narrowing with continued fecalization of contents proximally without any evidence of proximal dilation.
Treat-To-Target Ileocolonoscopy at 1 Year
The patient then undergoes treat-to-target ileocolonoscopy to correlate findings with his most recent 10 month intestinal ultrasound examination and guide further management decisions.
Treat-to-target ileocolonoscopy demonstrates healing of the ascending colon and distal terminal ileum, with a single stricture with ulceration at 25 cm proximal to the ileocecal valve, correlating well with intestinal ultrasound findings. The patient remains on treatment with adalimumab weekly.
Flare Presentation at 16 Months
4 months after treat-to-target ileocolonoscopy, the patient presents with worsening fatigue, intermittent chills and nausea. However, there are no overt gastrointestinal symptoms. Laboratory and stool evaluation is unrevealing, with a normal CBC, inflammatory markers, therapeutic adalimumab level, and a fecal calprotectin < 100 mcg/g. Intestinal ultrasound is performed next.
Intestinal ultrasound examination now demonstrates stricture formation with significant proximal dilation, concerning for progression of stricturing Crohn's disease. Both a MRE and small bowel follow-through are performed and are normal, in discordance with the findings on intestinal ultrasound.
Case Resolution
The patient ultimately undergoes an exploratory laparotomy and is found to have a 2-3 cm stricture, 20 cm proximal to the ileocecal valve and an additional 1-2 cm stricture in the mid-ileum. Both of these strictures are resected and the patient has an uncomplicated postoperative course.
