What is the diagnosis and management for a patient with an inflamed and edematous terminal ileal loop, hepatomegaly, and grade 1 fatty liver disease, suspected to have inflammatory bowel disease (IBD)?

Diagnosis and Management of Inflamed Terminal Ileum with Hepatomegaly and Fatty Liver

Primary Diagnosis

This presentation most likely represents Crohn's disease with concurrent non-alcoholic fatty liver disease (NAFLD), requiring immediate ileocolonoscopy with systematic biopsies to confirm the diagnosis. 1, 2

Diagnostic Workup

Immediate Endoscopic Evaluation

• Perform ileocolonoscopy with systematic biopsies from at least six segments: terminal ileum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum, obtaining minimum two biopsies per segment including normal-appearing mucosa 1, 2
• Biopsies from both inflamed and normal-appearing areas are essential to characterize the distribution pattern—continuous inflammation suggests ulcerative colitis while patchy distribution with skip lesions indicates Crohn's disease 2
• Even when the terminal ileum appears endoscopically normal, proceed with biopsies, as imaging findings of ileal inflammation despite negative ileoscopy frequently represent active Crohn's disease that may progress (67% show subsequent surgical resection, radiological worsening, or ulcers at follow-up) 3

Critical Diagnostic Considerations

• The diagnostic yield of terminal ileal biopsy is highest (84%) when endoscopic "ileitis" is visualized, but remains valuable even with normal-appearing mucosa when imaging shows inflammation 4, 3
• Histological confirmation through typical microscopic features is mandatory—look for focal crypt irregularities, transmural inflammation, and granulomas (characteristic of Crohn's disease) versus diffuse mucosal inflammation with basal plasmacytosis (characteristic of ulcerative colitis) 1, 2
• Store biopsies from each segment in separate containers to map inflammation distribution, which increases diagnostic accuracy from 66% to 92% 5

Hepatobiliary Assessment

Given the hepatomegaly with grade 1 fatty liver, perform comprehensive hepatobiliary evaluation:

• Order liver function tests immediately, as abnormal liver biochemical tests occur in up to 30% of IBD patients 6
• Screen for primary sclerosing cholangitis (PSC) with MRCP, as PSC is the most common chronic progressive liver disease in IBD, affecting approximately 5% of patients with extensive colitis 1, 6
• Measure fasting lipid panel and assess metabolic risk factors, as NAFLD in IBD is independently predicted by older age, higher BMI, and elevated triglycerides 7
• Perform ileocolonoscopy with biopsies from all colonic segments including terminal ileum regardless of lesion presence, as this is recommended at the time of PSC diagnosis 1

Additional Laboratory Testing

• Complete blood count to assess for anemia and leukocytosis 2
• Fecal calprotectin, which correlates well (r > 0.8) with endoscopic disease activity in IBD 1, 5
• Stool testing for bacterial pathogens (Salmonella, Shigella, Campylobacter, STEC), C. difficile toxin, and parasites to exclude infectious causes 5
• Test for cytomegalovirus (CMV) if there is immunosuppressant-resistant disease, as CMV is associated with reduced therapy efficacy and increased colectomy rates 1

Management Approach

IBD-Specific Management

• Treatment decisions depend on definitive histological diagnosis—the distinction between Crohn's disease and ulcerative colitis fundamentally changes treatment approach and prognosis 2
• If Crohn's disease is confirmed with moderate-to-severe ileal inflammation (mean length 10 cm, severity score 1.6), anticipate that disease may progress and require escalation of medical therapy or surgical intervention 3
• Consider cross-sectional imaging (MR enterography) to assess for proximal small bowel involvement, strictures, or fistulas, which occur in 45%, 32%, and 11% of cases respectively with terminal ileal disease 3

Hepatic Comorbidity Management

• NAFLD screening with transient elastography is reasonable, as NAFLD prevalence reaches 32.8% in IBD patients and is associated with increased risk of chronic kidney disease (10.3% vs 2.3%) and cardiovascular disease (11.3% vs 4.7%) 7
• Initiate weight loss interventions and correct dyslipidemia if NAFLD is confirmed 7
• If PSC is diagnosed, implement annual surveillance colonoscopy (or every 1-2 years in individualized patients without inflammatory activity) regardless of IBD duration, as PSC-IBD has high colorectal cancer risk 1

Critical Pitfalls to Avoid

• Do not rely solely on endoscopic appearance—unequivocal imaging findings of ileal inflammation despite negative ileoscopy represent active inflammatory Crohn's disease in two-thirds of cases 3
• Avoid limiting endoscopic evaluation to sigmoidoscopy unless acute severe colitis is suspected (perforation risk 0.3-1% with full colonoscopy in this setting) 2
• Do not assume hepatomegaly is solely due to fatty liver—PSC represents a distinct phenotype with right-sided predominant inflammation, rectal sparing, and mild disease course that can be endoscopically subtle 1
• Screen for hepatitis B before initiating immunosuppressive therapy, as reactivation is a major concern requiring prophylaxis with entecavir or tenofovir if HBsAg positive 6