Endoscopic ultrasound: a powerful tool to modify treatment algorithms in opioid-induced achalasia

Abstract

Background: Opioid use in the U.S. has increased dramatically over the last 15 years, recently being declared a public health emergency. Opioid use is associated with esophageal dysmotility lending to a confusing clinical picture compared to true achalasia. Patients exhibit symptoms and elicit diagnostic results consistent with esophageal motility disorders, in particular type III achalasia. Modified therapeutic strategies and outcomes become challenging. Differentiating true achalasia from opioid-induced achalasia is critical. Conventional surgical interventions, i.e., myotomy, are ineffective in the absence of true achalasia. We assess the utility of esophageal muscle layer mapping with endoscopic ultrasound (EUS) in distinguishing primary from opioid-induced achalasia.

Methods: From 2016 to 2019, patients with abnormal manometry and suspected achalasia underwent esophagogastroduodenoscopy and EUS mapping of esophageal round muscle layer thickness. Maximum round layer thickness and length of round muscle layer thickness > 1.8 mm were collected and compared between opioid users and non-opioid users using Wilcoxon Rank sum test.

Results: 45 patients were included: 12 opioid users, 33 non-opioid users. Mean age 56.8 years (range 24-93), 53.3% male patients. Mean BMI in the opioid-induced achalasia group was 30.2 kg/m², mean BMI in the primary achalasia group 26.8 kg/m² (p = 0.11). In comparing endoscopic maximum round layer thickness between groups, non-opioid patients had a thicker round muscle layer (2.7 mm vs 1.8 mm, p = 0.05). Length of abnormally thickened esophageal muscle (greater than 1.8 mm) also differed between the two groups; patients on opioids had a shorter length of thickening (4.0 cm vs 0.0 cm, p = 0.04). Intervention rate was higher in the non-opioid group (p = 0.79). Of the patients that underwent therapeutic intervention, symptom resolution was higher in the non-opioid group (p = 0.002), while re-intervention post-procedure for persistent symptomatology was elevated in the opioid subset (p = 0.06). Patients in the opioid group were less likely to undergo invasive treatment (Heller). As of 2017 all interventions in the opioid group have been endoscopic.

Conclusion: Endoscopic ultrasound is an essential tool that has improved our treatment algorithm for suspected achalasia in patients with chronic opioid usage. Incorporation of EUS findings into treatment approach may prevent unnecessary surgery in opioid users.

Keywords: Achalasia; Endoscopic ultrasound; Esophageal dysmotility; Foregut; Motility.