Impedance measurements and high-resolution manometry help to better define rumination episodes

Background. Rumination syndrome is a disorder of unknown etiology characterized by regurgitation of recently ingested food. We aimed to improve the diagnosis of rumination syndrome by classification of separate rumination symptoms using (1) an ambulatory manometry/impedance (AMIM) measurement and (2) a single-catheter high-resolution manometry/impedance (HRIM) measurement. Methods. A total of 96 symptoms during AMIM and 37 symptoms during HRIM were analyzed in five patients with clinically diagnosed rumination syndrome. Key results. AMIM identified rumination events in 85 out of 96 reported symptoms (symptom index (SI): 89%). Of these events, 63% were non-acidic and would have been missed by pH-metry. HRIM identified 32 out of 37 reported symptoms (SI: 86%). Upper esophageal sphincter (UES) relaxation was observed during all rumination events identified by HRIM and could be an additional criterion in the definition of rumination events. Conclusions. Impedance measurement and high-resolution manometry contribute to a more detailed description of rumination events. Rumination events defined as gastric strain, common cavity phenomenon, retrograde esophageal fluid flow, and UES relaxation show a high SI when measured with AMIM or single-catheter HRIM.