Misdiagnosis of Crohn’s disease as appendicitis: A case report

Abstract

BACKGROUND

Crohn’s disease (CD) is a chronic inflammatory disease of the intestinal tract that can alternate between disease phases and remission. Currently, endoscopy is the gold standard for diagnosis of CD and evaluation of its activity and complications. However, gastrointestinal ultrasound (GIUS) is a valuable technique in the management of CD because it is noninvasive, convenient, and highly accurate, sensitive, and specific.

CASE SUMMARY

A 15-year-old female presented with recurrent right lower quadrant abdominal pain that had persisted for 2 weeks. Initial GIUS and computed tomography revealed significant edema of the appendix and ascending colon wall, thickening, and multiple lymphadenopathies of the mesentery. Clinicians suspected appendicitis involving the adjacent bowel, and laparoscopic appendectomy was performed. The pathological diagnosis was acute simple appendicitis. However, the patient’s symptoms persisted and aggravated with the occurrence of hematochezia. Follow-up GIUS revealed persistent edema of the ascending and transverse colon walls, intestinal polyps, and local luminal stenosis. CD was suspected and confirmed by endoscopy.

CONCLUSION

CD should be suspected with persistent right lower quadrant abdominal pain. GIUS is essential for initial evaluation, before the confirmatory endoscopy, to assess CD-typical signs like bowel edema and thickening.

Key Words: Crohn’s disease; Gastrointestinal ultrasound; Misdiagnosis; Endoscope; Case report

Core Tip: Crohn’s disease (CD) is a chronic inflammatory condition that can affect any part of the gastrointestinal tract. In recent years the incidence of CD has increased. Gastrointestinal ultrasound (GIUS) features in patients with CD are specific and include segmental bowel wall thickening, mesenteric edema and thickening, and bowel stenosis. When the identifications of these features are combined with clinical symptoms, a high diagnostic accuracy can be achieved. The use of GIUS for the initial diagnosis and evaluation of disease activity and complications in patients with CD is increasingly common.

INTRODUCTION

Crohn’s disease (CD) is a chronic inflammatory disease of the gastrointestinal tract and can affect individuals of all ages; although, the peak incidence occurs between the ages of 15 years and 25 years[1]. CD is associated with reduced dietary fiber intake, smoking (including secondhand smoke), dysbiosis of the gut microbiota, and immune system deficiencies[2]. It has an insidious onset and can affect any part of the gastrointestinal tract, with the terminal ileum and colon being the most involved sites.

Typical clinical symptoms of CD include right lower quadrant abdominal pain, chronic diarrhea, fatigue, anorexia, weight loss, and hematochezia. Approximately 50% of cases exhibit extraintestinal manifestations such as skin disorders and arthritis. One-third of CD patients develop complications such as fistulas, intestinal stenosis, and abscesses. When abscesses develop, patients may present with a high fever.

To diagnose CD several modalities are employed to ensure accurate disease management. Typical laboratory abnormalities in CD include anemia, thrombocytosis, and elevated C-reactive protein levels[3]. The gold standard for diagnosing CD is endoscopy followed by biopsy[4]. Segmental inflammatory lesions and longitudinal or serpiginous ulcers are typical endoscopic features. When ulcers intermingle with nodular edematous mucosa, a cobblestone appearance is observed[5].

Recently, gastrointestinal ultrasound (GIUS) has become more common for the initial imaging of patients with CD. GIUS findings for CD are relatively specific and include segmental bowel wall thickening, mesenteric edema and thickening, polyp formation, and luminal stenosis. GIUS has several advantages including no radiation exposure and high repeatability in intestinal disease diagnosis. As the primary imaging modality for diagnosis and follow-up, especially for adolescents, GIUS holds significant value in the diagnosis and management of CD[6].

Cases of CD involving the appendix are uncommon. Mostyka et al[7] retrospectively analyzed 100 ileocolic CD specimens and found that only 10 had inflammation around the appendix. The clinical manifestations of CD in the ileocecal region are similar to acute appendicitis. Both will present as right lower abdominal pain. Moreover, differential diagnosis based on clinical symptoms and imaging is difficult when there are no signs of intestinal jumping edema or complications like stenosis[8].

The purpose of this case report was to summarize the experience of misdiagnosing ileocecal CD as appendicitis and to emphasize the important role of GIUS in the follow-up of CD.

CASE PRESENTATION

Chief complaints

A 15-year-old female presented with gradually intensifying right lower quadrant abdominal pain that had begun 2 weeks prior to presentation, without any obvious cause and accompanied by nausea, vomiting, and hematochezia.

History of present illness

In the previous 2 months, the patient had experienced recurrent episodes of right lower quadrant abdominal pain without an obvious cause. The pain progressively worsened but would be slightly alleviated with rest. One month prior, GIUS had revealed appendiceal fecalith, significant edema, thickening of the appendix and ascending colon wall with surrounding exudation, and multiple lymphadenopathies of the mesentery. Abdominal computed tomography (CT) had then confirmed these findings. As a result, the clinical diagnosis of “acute appendicitis with localized peritonitis” was made and a laparoscopic appendectomy was performed. During the operation the appendix had been found to be enlarged to 1 cm in diameter and 8 cm in length with congestion and edema; a small amount of purulent exudate was also noted around it. The mesenteric lymph nodes of the surrounding intestine had been noted to be significantly enlarged and the cecum to have marked edema. The postoperative pathological diagnosis was simple appendicitis. Throughout the course of this case, the patient did not experience fever, chest tightness, nor chest pain.

History of past illness

The patient was previously healthy and denied any history of trauma, allergies, or infectious diseases.

Personal and family history

There was no significant personal or family history of medical conditions.

Physical examination

The patient’s vital signs were stable: Temperature was 36.1 °C; heart rate was 136 beats per minute, regular, and with no murmurs; and blood pressure was 91/66 mmHg. The patient was conscious and alert. Breath sounds were clear in both lungs without any dry or wet rales. The abdomen was soft and flat, with tenderness in the right lower quadrant. The liver and spleen were not palpable below the costal margin. Bowel sounds occurred 5 times per minute. There was no edema in the lower extremities.

Laboratory examinations

The following laboratory parameters were abnormal: Platelet count: 447.0 × 10⁹/L (reference range: 125.0-350.0 × 10⁹/L); hemoglobin: 82.0 g/L (reference range: 120.0-140.0 g/L); and high-sensitivity C-reactive protein: 79.1 mg/L (reference range: 0.0-10.0 mg/L). Other biochemical markers and routine blood tests did not reveal any significant abnormalities.

Imaging examinations

Postoperative recurrence GIUS revealed significant edema and thickening of the bowel wall in the terminal ileum, cecum, ascending colon, and splenic flexure of the transverse colon (Figure 1A-C). Non-contrast CT confirmed an edematous and thickened terminal ileum, cecum, ascending colon, and splenic flexure of the transverse colon (Figure 1D-F). There was a nodular protrusion into the lumen of the ascending colon (Figure 2A-C) with local luminal stenosis (Figure 2D and E). The surrounding mesenteric tissue showed edema and thickening with encasement (Figure 2A). CD was considered on the basis of these findings.

Figure 1 Imaging examinations. A-C: Gastrointestinal ultrasound imaging showed uneven edema and thickening of the ascending colon, transverse colon, and splenic flexure colon walls (triangle), along with punctate calcifications within the mesenteric lymph nodes due to long-term inflammatory infiltration (arrows); D-F: Computed tomography imaging showed edema and thickening of the ascending colon, ileocecal region, and splenic flexure colon walls (orange dashed lines).

Figure 2 Gastrointestinal ultrasound imaging examinations. A-C: Inflammatory polyps of the colon with abundant blood flow signals (arrows), and edematous and thickened mesentery (light blue areas); D and E: Luminal stenosis caused by thickening of the ascending colon wall (arrows); Cross-sectional view of the bowel (D); Wide-scene imaging (E).

Further diagnostic work-up

Colonoscopy revealed mucosal hyperplasia, elevation at the terminal ileum, and patchy hyperplasia of the mucosa in the ileocecal region, colon of the hepatic flexure, ascending colon, and transverse colon with a cobblestone appearance (Figure 3A). Longitudinal or serpiginous ulcerative lesions, which were friable and prone to bleeding, were visible between the mucosa (Figure 3B). The lesions were segmental and distributed in a skip pattern, whereas the remaining intestinal mucosa appeared normal without congestion, erosion, or ulcers. No abnormal hyperplasia was observed. Biopsies were taken from different sites of the intestine. Pathological results revealed chronic inflammation of the mucosa in the ileocecal region, ascending colon, and transverse colon as well as lymphocytic aggregation and granuloma formation (Figure 3C).

Figure 3 Endoscopic images and intestinal mucosa biopsy histopathology images. A: Edematous and irregularly hyperplastic intestinal mucosa with a cobblestone appearance under colonoscopic view (arrow); B: Discontinuous creeping ulcers of the intestinal mucosa under colonoscopic view, with normal-appearing mucosa between the ulcers (arrow); C: Histopathological examination revealed lymphocytic aggregation (× 10 magnification, hematoxylin-eosin staining).

FINAL DIAGNOSIS

On the basis of the colonoscopic findings, histopathological results of the biopsies, GIUS features, and clinical symptoms, the final diagnosis was established as CD.

TREATMENT

After a definitive diagnosis was established, the patient was placed on a semiliquid diet and received intravenous methylprednisolone (40 mg/day) for anti-inflammatory treatment. After 1 week the patient received oral methylprednisolone tablets (32 mg/day) for another 3 days. The patient’s abdominal pain significantly improved.

OUTCOME AND FOLLOW-UP

The patient’s vital signs were stable with no abdominal pain, nausea or vomiting, or hematochezia. The abdomen was soft and without tenderness, and bowel sounds were heard 5 times per minute. The patient was discharged with instructions to continue oral methylprednisolone tablets (32 mg/day), monitor the color of the stool, maintain a lukewarm liquid diet, and seek medical attention promptly for any discomfort.

DISCUSSION

In recent years, the incidence of CD has significantly increased globally[6], and early and accurate diagnosis is crucial for ensuring effective treatment. Similar to the clinical symptoms of CD, many intestinal diseases can present with right lower quadrant pain, such as appendicitis, ulcerative colitis, and colon cancer. However, each of these diseases has relatively specific characteristics. For example, appendicitis typically presents with migratory right lower quadrant abdominal pain, tenderness, and rebound tenderness at McBurney’s point. However, it is often not accompanied by nausea, vomiting, diarrhea, and changes in bowel habits[9]. Ulcerative colitis primarily affects the rectum and colon with clinical manifestations of mucopurulent bloody stools and tenesmus[10]. Colorectal cancer commonly occurs in middle-aged and elderly populations and may appear on ultrasound as a structure with a disorganized bowel wall and a mass-like echoic appearance[11]. When the right lower quadrant pain is suspected to be caused by an intestinal disease, clinicians must carefully distinguish and meticulously evaluate patients through epidemiology, imaging, blood tests, and timely endoscopy.

In our case, the patient’s clinical symptoms and initial imaging findings from GIUS and CT were insufficient to diagnose CD. However, the presence of anemia in the patient was indicative of CD. Chronic gastrointestinal bleeding is observed in CD due to intestinal ulcers and nutrient malabsorption, which can lead to anemia. However, acute appendicitis has a rapid onset and is characterized by edematous and thickened bowel walls due to inflammation. It does not involve intestinal ulcers and, therefore, does not cause gastrointestinal bleeding or anemia. In this case, if the clinician noticed anemia, CD should have been considered even if the clinical symptoms and imaging findings were atypical. This was the reason for the misdiagnosis in this case. Therefore, when diagnosing diseases, clinicians should act as detectives, paying attention to the minutiae of clinical information.

Currently, endoscopy remains the gold standard for assessing the severity of CD and evaluating treatment response[1]. However, it is invasive and may not be well tolerated by patients, especially adolescents. GIUS is a cross-sectional imaging modality and has many benefits in the management of CD due to its low cost, repeatability, and lack of radiation exposure. Numerous studies have demonstrated that GIUS is comparable in sensitivity and specificity to enteric CT and magnetic resonance imaging for diagnosing CD, assessing disease activity, and detecting complications when performed by experienced operators[2,12,13].

The normal bowel wall appears as a five-layer structure on an ultrasound. It consists of the following layers: A hyperechoic mucosal-lumen interface; the submucosa; the serosa; the hypoechoic mucosal layer; and the muscular layer[14]. The representative and effective signs of CD on GIUS are bowel wall thickness (BWT), vascularity and layering structure, presence of mesenteric inflammatory fat, motility of the bowel, and enlargement of mesenteric lymph nodes[15]. Among these indicators, BWT is the most reliable indicator. The BWT is obtained by measuring the bowel wall in both the longitudinal and transverse planes multiple times with a high-frequency probe and calculating the average value. The overall sensitivity of BWT for diagnosing CD can reach 0.85 (95%CI: 83%-87%), and the overall specificity can reach 98% (95%CI: 95%-99%)[16]. The European Crohn’s and Colitis Organization and European Society of Gastrointestinal and Abdominal Radiology consensus recommends a threshold of 3 mm of bowel wall inflammation in both the small and large intestines[17].

GIUS has several advantages in dynamically evaluating CD activity. It is convenient and highly repeatable, and it matches endoscopic assessment in diagnostic accuracy. Sævik et al[18] developed a simple ultrasound scoring criterion using BWT and bowel wall flow to predict CD activity. They used the simplified endoscopic activity score for CD as a reference standard. In the validation cohort their model had an area under the receiver operating characteristic curve of 0.92. Allocca et al[19,20] retrospectively analyzed BWT and bowel wall flow for predicting the endoscopic activity of CD and prospectively validated it with an accuracy of 0.80. Kucharzik et al[21] monitored disease activity in patients with CD after pharmacological treatment with GIUS and reported significant differences in ultrasound parameters before and after treatment.

CD is a long-term chronic condition, and intestinal stenosis is a major complication of the disease. In this case, panoramic ultrasound imaging clearly showed the internal diameter and length of the intestinal stenosis. This is difficult to achieve with cross-sectional CT. Lu et al[22] observed that the specificity of GIUS for diagnosing intestinal stenosis was 86%-100%. Intestinal stenosis is caused by fibrosis of the bowel wall, and studies have shown that the mean strain ratio of fibrotic stenotic bowel segments is higher than that of nonfibrotic ones. Ultrasound elastography has the ability to assess intestinal wall fibrosis and offers a new diagnostic approach for bowel stenosis[23].

GIUS can serve as an alternative to endoscopy for assessing postoperative recurrence in patients with CD. When complications occur, approximately 70% of patients with CD require surgery, and 30% of these patients experience recurrence after surgery[24]. The European Crohn’s and Colitis Organization recommends that patients with CD who have undergone surgery due to complications should receive follow-up endoscopy within 6-12 months after surgery to detect recurrence[16]. Two meta-analyses by Barchi et al[25] and Rispo et al[26] evaluated the effectiveness of GIUS in detecting postoperative recurrence and reported an area under the receiver operating characteristic curve of 0.93 and an accuracy of 0.875.

In this study our patient was evaluated by GIUS twice. GIUS detected segmental edema and thickening of the bowel wall and mesentery and clearly visualized intestinal polyps. The diagnostic information obtained was far more detailed than with CT, and these details were particularly helpful for diagnosing CD.

CONCLUSION

A thorough full abdominal GIUS examination detecting the typical signs of segmental bowel wall edema, stenosis, and polyp formation combined with gastrointestinal symptoms, such as abdominal pain, diarrhea, and hematochezia, can accurately diagnose CD.

ACKNOWLEDGEMENTS

The authors express gratitude to the staff of the Nanxun People’s Hospital for their assistance. Without their efforts in interprofessional collaboration for data collection and patient treatment, this case report would not have been possible.