Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, frequently presents with musculoskeletal extraintestinal manifestations (EIMs), such as arthritis and enthesitis, affecting up to 50% of patients. These can be subclinical and are often underestimated by physical examination alone. Musculoskeletal ultrasound (MSK-US) is a sensitive, non-invasive tool for detecting both clinical and subclinical inflammation. Despite its benefits, there is no standardized MSK-US protocol specifically for IBD patients. This study aims to develop a structured MSK-US assessment protocol, evaluate its effectiveness in detecting musculoskeletal involvement, and investigate its relationship with IBD disease activity.

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic, immune-mediated condition primarily affect the gastrointestinal tract. However, up to 30-50% of IBD patients develop extraintestinal manifestations (EIMs), with the musculoskeletal system being the most commonly affected. These manifestations may precede or follow gastrointestinal symptoms and contribute significantly to patient morbidity and quality-of-life reduction.

The musculoskeletal manifestations in IBD include peripheral arthritis, axial spondyloarthritis (SpA), enthesitis, dactylitis, and sacroiliitis. These features overlap with those seen in the spondyloarthritis spectrum and may present subclinically. Clinical examination alone may underestimate the true burden of inflammation, especially enthesitis and tenosynovitis.

Musculoskeletal ultrasound (MSK-US) has emerged as a sensitive, non-invasive, and reproducible imaging modality to detect both clinical and subclinical inflammation. It can visualize synovial hypertrophy, joint effusion, enthesitis, bursitis, and tenosynovitis, along with power Doppler (PD) signal indicative of active inflammation. MSK-US is particularly valuable in early disease detection and monitoring therapeutic response.

Studies have shown that a significant proportion of IBD patients have subclinical MSK involvement detectable only through imaging. In one study, up to 84% of asymptomatic IBD patients had at least one entheseal abnormality on ultrasound, reinforcing the utility of screening in high-risk populations.

Despite the increasing use of MSK-US, there is a lack of standardized scanning protocols specifically tailored for IBD patients, leading to variability in clinical practice and research. Protocol development can improve diagnostic accuracy, facilitate longitudinal monitoring, and aid in clinical decision-making and treatment stratification.

Given the high prevalence of MSK involvement in IBD, and the proven efficacy of ultrasound in detecting both clinical and subclinical inflammatory changes, the implementation of a structured MSK-US protocol for IBD patients is essential. This study aims to standardize the ultrasound assessment of musculoskeletal findings in IBD, evaluate its diagnostic yield, and explore associations with disease activity.

Inclusion Criteria:

• patients diagnosed with inflammatory bowel disease (Crohn's disease or ulcerative colitis)
• Patients without a definite diagnosis of inflammatory arthritis, to focus on subclinical musculoskeletal involvement.

Exclusion Criteria:

• Patients with a prior clinical diagnosis of inflammatory arthritis or other rheumatologic diseases.
• Patients with complicated or severe comorbidities that may interfere with musculoskeletal evaluation or study participation (e.g., severe infections, malignancies).

The study population will consist of patients 18 years old or older confirmed diagnosis with IBD attending gastroenterology or IBD specialty clinics. Participants may be either symptomatic or asymptomatic for musculoskeletal complaints, allowing for the detection of both clinical and subclinical inflammatory findings.