Systemic sclerosis and small bowel involvement: A systematic review of diagnostic approaches and current evidence

Small bowel involvement represents a common and clinically significant manifestation of systemic sclerosis (SSc). Pathogenesis is multifactorial, and diagnosis remains challenging due to non-specific symptoms, limited diagnostic tools, and a lack of standardized management strategies.

A systematic search of PubMed and Embase was conducted to identify studies evaluating small bowel involvement in patients with SSc using objective tests and patient tissue. A qualitative synthesis was performed due to the anticipated heterogeneity in study designs, interventions, and outcomes.

Of the 24 studies included, 9 (37.5%) evaluated small bowel motor function using manometry, 12 (50%) employed other objective diagnostic methods, and 7 (29.2%) reported histopathological findings. Manometric studies showed a high prevalence of motor abnormalities: absent or impaired phase III complexes (median 50.3%, IQR,22.5%-81%), reduced phase III migration velocity (31.3%, IQR,18%-53%), diminished contraction amplitude (median 62.5%, IQR,40%-75%), and abnormal postprandial responses (median 60.6%, IQR,50%-90%). No correlation was found between esophageal and small bowel involvement when both were assessed by manometry(5 studies). Transit studies (breath tests, capsule endoscopy, and whole-gut scintigraphy) showed variable performance; however, whole-gut scintigraphy identified clinically relevant associations, including a strong link with increased mortality (HR 4.57; 95% CI: 1.58-13.24). Histopathological results identified smooth muscle atrophy, enteric neuropathy, and vascular fibrosis in the pathogenesis of small bowel involvement.

In SSc, small bowel involvement is frequent and associated with decreased contractile amplitude and delayed transit time. There is a critical need for standardized diagnostic approaches to enable early recognition and guide management.