Severe pancolitis presenting as sacroiliitis: a case report on the gut-joint axis in ulcerative colitis
A single case documents severe UC-related pancolitis presenting without gastrointestinal symptoms, with sacroiliitis as the initial manifestation, treated with upadacitinib with normalization of inflammatory markers within 2 months — favorable direction for treatment, with no possibility of causal generalization.
| Population | 32-year-old male without gastrointestinal symptoms, with MRI-confirmed bilateral sacroiliitis and colonoscopy/histopathology-confirmed severe UC pancolitis |
|---|---|
| Intervention | Upadacitinib 45 mg/day (reduced to 30 mg after 2 months) |
| Comparator | — |
| Outcome | CRP normalization; ESR normalization; Fecal calprotectin normalization; Fecal lactoferrin normalization; Low back pain resolution; MRI sacroiliitis improvement; Absence of gastrointestinal symptoms |
Summary of findings
| Outcome | Effect | 95% CI | Certainty | Clinical relevance | Notes |
|---|---|---|---|---|---|
| CRP normalization | absolute reduction 100 mg/L to 0.04 mg/L at 12mo; in the IC, n=1 | — | Very low | — | 1 studies |
| ESR normalization | absolute reduction 70 mm/h to 5 mm/h at 2mo; in the IC, n=1 | — | Very low | — | 1 studies |
| Fecal calprotectin normalization | absolute reduction 8001 ug/g to <20 ug/g at 6mo; in the IC, n=1 | — | Very low | — | 1 studies |
| Fecal lactoferrin normalization | absolute reduction 1000 ug/g to <6.25 ug/g at 6mo; in the IC, n=1 | — | Very low | — | 1 studies |
| Low back pain resolution | complete resolution reported at 2mo follow-up; in the IC, in the scale score reported, n=1 | — | Very low | — | 1 studies |
| MRI sacroiliitis improvement | qualitative improvement on repeat MRI at 2mo; in the quantitative metric reported, n=1 | — | Very low | — | 1 studies |
| Absence of gastrointestinal symptoms | symptom-free reported at 12mo; in the validated GI score reported, n=1 | — | Very low | — | 1 studies |
Context
Extraintestinal manifestations occur in 25–40% of IBD patients; subclinical sacroiliitis has an 11% prevalence in this population. UC and axial spondyloarthritis share immune pathways (IL-23/IL-17, TNF-α, JAK), making JAK inhibitors therapeutic candidates for both conditions. Case reports document atypical presentations that may delay diagnosis.
What the study showed
CRP decreased from 100 mg/L to 1 mg/L at 2 months and to 0.04 mg/L at 1 year. ESR decreased from 70 mm/h to 5 mm/h at 2 months, remaining at 5–6 mm/h through 1 year. Fecal calprotectin decreased from 8,001 μg/g to <20 μg/g at 6 months. Fecal lactoferrin decreased from 1,000 μg/g to <6.25 μg/g at 6 months. Back pain and gastrointestinal symptoms absent at 1-year follow-up. No 95% CI or comparator — observation in n=1.
How it was done
Single case report, observational, no control group, no randomization, no blinding. Single patient followed for 12 months after upadacitinib initiation. UC diagnosis confirmed by colonoscopy (UCEIS 7, Mayo Score 6) and histopathology (Nancy grade 2); sacroiliitis confirmed by MRI and ASAS criteria.
Effect magnitude
Absolute CRP reduction from 100 mg/L to 0.04 mg/L (99.96% reduction) and fecal calprotectin from 8,001 μg/g to <20 μg/g (>99.7% reduction) in 1 patient — no 95% CI, no controlled comparator, no calculable effect size.
Risk of bias
N=1 precludes any statistical or causal inference. No comparator, randomization, or blinding. Formal risk of bias tools (RoB 2, ROBINS-I) are not applicable to case reports; publication bias toward favorable cases is inherent. HLA-B27 negativity and absence of prior GI symptoms make this an atypical case, reducing applicability.
What this study does NOT prove
This study does not prove causality between sacroiliitis and UC, nor upadacitinib efficacy in the UC-AxSpA overlap population. A single case does not support treatment recommendations or generalization to other patients.
In clinical practice
In young patients with sacroiliitis and elevated inflammatory markers without a clear cause, IBD screening with fecal calprotectin and lactoferrin is cost-effective before colonoscopy. Upadacitinib has regulatory approval for moderately-to-severely active UC and axial spondyloarthritis; its selection in overlapping cases should follow institutional protocols and cardiovascular/infectious risk assessment.
Limitations
N=1 precludes any statistical or causal inference. No comparator, randomization, or blinding. Formal risk of bias tools (RoB 2, ROBINS-I) are not applicable to case reports; publication bias toward favorable cases is inherent. HLA-B27 negativity and absence of prior GI symptoms make this an atypical case, reducing applicability.
What is still missing
Randomized clinical trials evaluating upadacitinib specifically in patients with UC-AxSpA overlap, with articular and intestinal outcomes as co-primary endpoints, are needed to establish efficacy and safety in this population.
Technical appendix
Version history
- 1.0 · 2026-09-14 — Auto-generated under Evidence Standard v1.0