To characterize persistent abdominal pain in children with inflammatory bowel disease (IBD) by examining factors such as disease type, activity and location, psychosocial factors, and genetics.

The investigators hypothesize that by using patient pain and psychological assessments in addition to analysis of blood, stool and colonic biopsies, we can better characterize factors that predispose children and adolescents with IBD to have persistent and/or disproportionate abdominal pain.

This is a prospective longitudinal inception cohort pilot study. The study will hopefully provide information about why there is persistent abdominal pain in children with IBD by examining factors such as disease type, activity and location, psychosocial factors, and genetics. Fifty newly diagnosed pediatric IBD patients, age 8-17 years will be enrolled into the study. There will be 2 control groups as well: pain control population: 20 patients with irritable bowel syndrome (IBS) or functional abdominal pain (FAP) diagnosis who have no evidence of bowel inflammation will serve as a pain control population for patients with no active inflammation. To serve as a control population for patients with no abdominal pain or inflammation, the investigators will include 10 patients with no gastrointestinal symptoms, who undergo colonoscopy for various reasons such as painless rectal bleeding, polyp surveillance, etc. The investigators anticipate completing enrollment in 12 months and allowed another 12 months for follow-up.

The study participants will be seen every 3 months for a year and they will have the following procedures/test performed:

1. Standard of care blood and stool samples
2. Pediatric Ulcerative Colitis Activity Index (PUCAI) or Pediatric Crohn's Disease Activity Index (PCDAI)

They will have an endoscopy performed at diagnosis then at 12 months from enrollment.

A magnetic resonance enterography (MRE) will be done at diagnosis.

The following pain and anxiety tests will be performed throughout the study:

Pain:

Pain Severity Duration Scale (PSDS) Pediatric Catastrophizing Scale-Child/Parents (PCS-C/P) Pain Burden Interview (PBI) Adolescent Pediatric Pain Tool (APPT)

Anxiety:

Revised Children's Anxiety and Depression Scale (RCADS-25) Children's Somatization Index (CSI-24) Adult Responses to Children's Symptoms (ARCS)

Blood, rectal biopsies and stool specimens will be obtained throughout various time points of the study to look at hematology, sed rates, C-reactive protein, genomic DNA, colon RNA, stool microbiome and stool calprotectin.

In summary, the investigators will be examining:

1. Relationship between clinical factors and persistent abdominal pain in patients with IBD

   1. Disease type
   2. Location of disease at diagnosis
   3. Extent of disease at diagnosis
   4. Markers of inflammation at diagnosis and over the course of follow up
   5. Active disease vs. inactive disease over the course of follow up

2. Relationship between psychosocial factors persistent abdominal pain, and remission status, specifically in patients with:

   1. Inactive IBD vs. active IBD
   2. Inactive IBD vs. IBS/FAP
   3. We will compare the parental report to patient report in the above mentioned groups

3. Relationship between gene expression, microbiome, persistent abdominal pain, and remission status, specifically in patients with:

   1. Inactive IBD vs. active IBD
   2. Inactive IBD vs. IBS/FAP
   3. Inactive IBD vs. controls with no abdominal pain

Inclusion Criteria:

• Age ≥ 8 years or < 18 years (achieved 8th birthday but not yet their 18th birthday)
• IBD established by standard criteria
• Anticipated availability for follow up for ≥ 1 year
• Informed consent/assent

Exclusion Criteria:

• Prior abdominal surgery unrelated to IBD
• Active gastrointestinal infection at time of diagnosis (e.g., C. difficile)
• Other co-morbidities that contribute to abdominal pain (e.g., Familial Mediterranean Fever, metabolic disease)
• Preexisting chronic pain disorder (e.g., fibromyalgia)

The study participants will be recruited from the GI clinic here at Connecticut Children's Medical Center