**Background:** Inflammatory bowel disease (IBD) is a lifelong immune-mediated disorder with increasing global incidence in children. Type 1 diabetes (T1D) is one of the most common autoimmune diseases in childhood. While children with IBD or T1D are known to be at higher risk for other immune-mediated conditions, data on the specific correlation between T1D and IBD remain conflicting. Diagnosis of both conditions can be delayed due to symptom underestimation, low clinical suspicion, and healthcare system barriers. This case highlights the importance of recognizing concurrent autoimmune diseases even when classic symptoms are absent.
**Methods:** A previously healthy 12-year-old Caucasian boy presented for a routine pediatric evaluation at a peripheral secondary hospital outpatient clinic. His recent history included intermittent abdominal pain and diarrhea over two months and an intended weight loss of approximately 7 kg over four months. Vital signs were normal; BMI was 15 kg/m². Initial laboratory findings showed hypochromic microcytic anemia (hemoglobin 9.4 mg/dL, mean corpuscular hemoglobin 20.5 pg, mean corpuscular volume 67.5 fL) with normal ferritin (70 ng/mL), elevated C-reactive protein (5.7 mg/dL; normal <0.5 mg/dL), increased fasting blood glucose (107 mg/dL), and hypoalbuminemia (3.2 g/dL). Extended workup included fecal occult blood test (positive), fecal calprotectin (530 mg/kg), Crohn serology (anti-Saccharomyces cerevisiae antibody positive/pANCA negative), abdominal ultrasonography (bowel wall thickening with hyperemia), oral glucose tolerance test (fasting glucose 110 mg/dL, 2-hour glucose 113 mg/dL), glycated hemoglobin (7.1% on two occasions), and islet autoantibody testing (anti-insulin and islet cell antibodies positive; tyrosine phosphatase, GAD, and zinc transporter 8 antibodies negative). Magnetic resonance enterography and ileocolonoscopy with biopsies were performed after referral to a pediatric gastroenterologist.
**Key Results:** The patient was diagnosed with both Crohn disease and autoimmune type 1 diabetes. MRE showed involvement of the terminal ileum and active inflammatory changes throughout the colon without fistulas, abscesses, or stenoses. By the time of endoscopy (2 months after referral), the patient had deteriorated clinically and biochemically: hemoglobin 8.8 g/dL, erythrocyte sedimentation rate 67 mm/h, serum albumin 3 g/dL, fecal calprotectin 1300 mg/kg, unintended additional weight loss of 3 kg, and an asymptomatic perirectal tag. Ileocolonoscopy revealed wall thickening of the terminal ileum with aphthous lesions and colonic involvement with loss of vascular pattern, friability, and ulcerations, consistent with moderate endoscopic activity. Histology confirmed CD. Induction therapy with partial enteral nutrition and oral prednisolone was started, with infliximab added 4 weeks later after immunization update. At week 6 of induction therapy, the patient remained normoglycemic and HbA1c decreased to 5.9%.
**Clinical Implications:** This case demonstrates that T1D can present asymptomatically and be discovered incidentally during evaluation for other conditions. The co-occurrence of CD and T1D, while rare, should be considered when evaluating children with suspected IBD or diabetes. Early diagnosis of presymptomatic T1D prevents progression to ketoacidosis, which is associated with poorer long-term glycemic control. The improvement in glycemic status following anti-TNF therapy (infliximab) suggests a potential beneficial effect on glucose metabolism, as previously described in young adult patients. The case also highlights significant diagnostic delays due to organizational barriers (MRE performed 1 month and endoscopy 2 months after referral), which contributed to clinical deterioration. Increased awareness among general pediatricians and improved healthcare system coordination are needed to reduce diagnostic delays in pediatric IBD and concurrent autoimmune conditions.