Late‐onset rapid gastric emptying: Identification of a new abnormal finding in patients with otherwise normal results on gastric emptying scintigraphy

Background The 4‐h gastric emptying (GE) scintigraphy protocol is the gold standard for assessing GE. Rapid gastric emptying (RGE) is >30% emptied by 30 min and >65% emptied at1 h. We observed that some GE studies demonstrated rapid emptying at a later time although interpreted as normal (NGE) at 4 h. We aimed to establish thresholds to characterize this subset of late‐onset rapid gastric emptying (LRGE). Methods We retrospectively analyzed 4‐h GE studies of 425 patients with upper GI symptoms who fulfilled the criteria for NGE. We recruited 24 normal subjects to establish GE cutoff values (mean +/‐ 2SD) at 1–2, 2–3, and 3–4 h. These thresholds were applied to the 425 patients with NGE. During every GE study, patients graded their postprandial symptoms on a scale from 0 to 4. Key Results The mean upper threshold decrement limits were calculated from the normal volunteers as 67.6% at 1–2 h, 48.7% at 2–3 h, and 27.9% at 3–4 h. After applying these values to the NGE patients, 19 (4.5%) were classified as having LRGE; 6 patients (1.4%) for the 2‐ to 3‐h; and 13 (3.1%) for the 3‐ to 4‐h period. Patients with LRGE had abdominal pain, bloating, nausea, or diarrhea beginning more than 1‐h postprandial. Conclusion 5% of patients classified as “normal” at 4 h had an abnormal GE pattern based on the proposed criteria for LRGE. This highlights the importance of applying these hourly decrement thresholds to identify LRGE as a new diagnostic entity explaining postprandial symptoms. Applying those hourly decrement thresholds led to identification of a new diagnostic abnormality, the entity of late onset rapid gastric emptying (LRGE), which can contribute to post prandial symptoms.