Narcotic bowel syndrome misdiagnosed as somatoform pain disorder and presenting with opioid use disorder - A case report

Dear Editor, Narcotic bowel syndrome (NBS) is a rare, centrally mediated disorder characterized by chronic or frequently recurring abdominal pain following prolonged potent opioid use, often worsening with both dose escalation and reduction.[1,2] The pathophysiology involves opioid-induced hyperalgesia and central sensitization, leading to a paradoxical increase in pain sensitivity.[3] We report NBS misdiagnosed as somatoform pain disorder linked with a weaker opioid-tramadol managed successfully with transdermal buprenorphine patches when standard opioid substitution therapies (OST) are not available. A 37-year-old male presented repeatedly with intermittent severe excruciating upper-abdominal pain for two days associated with nausea and vomiting. Physical examination, all investigations including serum amylase and lipase, and computed tomography abdomen were normal on multiple occasions. One year earlier, he had been treated for alcohol dependence syndrome and alcohol-induced acute pancreatitis, managed conservatively with intravenous (IV) tramadol 300 mg/day for 3 days. Oral tramadol 300 mg in divided doses was prescribed in a tapering regimen for 10 days, along with analgesics. He remained abstinent from alcohol thereafter. Two weeks following the acute pancreatitis episode, he intermittently consumed tramadol 50 mg tablets for 2–3 times/day for 2 months to alleviate abdominal discomfort. Subsequently, escalated to approximately eight to ten tablets daily, a pattern he maintained for the last 3–4 months. He experienced abdominal pain, tremors, and restlessness on missed doses due to unavailability and sought hospitalizations (4–5/month). Over the next 6 months, he had multiple emergency admissions with similar pain and was repeatedly administered IV tramadol 300–450 mg/day for 3–4 days, tapering regimen as mentioned before, along with analgesics, despite normal investigations. After exclusion of organic causes, a psychiatric evaluation was sought. A provisional diagnosis of persistent somatoform pain disorder was made as per the International Classification of Diseases-10,[4] and duloxetine up to 60 mg/day was prescribed. Oral tramadol was prescribed by the medical gastroenterologist in a tapering regimen. During the index admission, based on craving, withdrawal symptoms, salience, and socio-occupational dysfunction, opioid dependence syndrome was considered. Clonidine 0.4 mg/day, tramadol 200 mg/day, ketorolac 60 mg/day with duloxetine 60 mg/day, and clonazepam 6 mg/day were administered. The Clinical Opiate Withdrawal Scale (COWS) score reduced from 24 to 5, and abdominal pain subsided significantly. The patient was discharged with a weekly tapering regimen. However, upon decreasing the dose of tramadol to 100 mg/day, all his symptoms mentioned earlier recurred (COWS Score = 22), warranting re-admission. NBS was considered according to the ROME IV criteria.[5] He was initiated on buprenorphine (5 mg) transdermal patch treatment due to the non-availability of the standard OSTs. Within 24 hour, his symptoms completely resolved. The patch was tapered over a 2-week period, and the patient remained asymptomatic for 3 months. This case illustrates the diagnostic challenge of NBS in the presence of a prior organic gastrointestinal illness, leading to misattribution of symptoms to a somatoform disorder. Tramadol, a mild opioid, can cause NBS, especially with repeated parenteral exposure. Escalating opioid dose and sudden reduction perpetuates central sensitization, resulting in worsening abdominal pain and recurrent hospitalizations. The dramatic response to buprenorphine supports opioid-induced hyperalgesia as the primary mechanism. Buprenorphine’s partial agonist activity may attenuate hyperalgesia while preventing withdrawal, making it a practical option when standard OSTs are unavailable. This approach is especially relevant in resource-limited Indian settings. NBS should be considered in patients citing chronic intermittent abdominal pain worsening with opioid dose reduction or escalation. Prompt diagnosis and treatment of NBS, including the use of buprenorphine patches, can be effective, particularly when standard OSTs are unavailable. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.