Case Presentation:
A 24-year-old woman presented to the hospital with “5 weeks of hell” from a sharp right upper quadrant and rib pain, nausea, and daily episodes of diarrhea and bilious emesis. She lost 16 lbs over this time, putting her BMI at 17.4. Initially, her labs and imaging from multiple visits to the ED showed no acute process. Pregnancy test, UA, CBC, CMP, liver/gallbladder/pancreas U/S, and CXR were all normal. Her symptoms were attributed to an exacerbation of her IBS potentially secondary to her anxiety and PTSD, which are due to childhood sexual abuse.
Her pain continued and she sought out a gastroenterologist who ordered a right upper quadrant U/S, HIDA scan, and abdomen/pelvic CT. All were normal. The gastroenterologist initially concurred with the working diagnosis of IBS exacerbation. The patient returned a few days later for a UGI series which showed dilation of the third portion of her duodenum and proximally. During an EGD, the gastroenterologist found it difficult to cannulate the patient’s jejunum due to duodenal tortuosity. Gastric biopsy showed mild chronic gastritis and negative H. pylori. A CTA showed possible 70% celiac artery occlusion with dissection. She then came to our hospital for potential emergency surgery.
Vascular surgery and radiology at the tertiary care center reviewed her CTA and ruled the celiac artery dissection finding as motion artifact. A repeat CT showed compression of the third portion of her duodenum by the SMA with loss of her fat pad and the patient was diagnosed with SMA syndrome. The patient was made NPO and was started on NJ feedings and IV analgesics. The patient’s pain resolved and she was able to avoid surgical intervention by slowly gaining proper weight via NJ feeds. She was discharged home with appointments for follow-up care.
Discussion:
Superior mesenteric artery syndrome is a condition where the SMA obstructs the third portion of the duodenum secondary to diminished fat pad between the SMA and duodenum in anorexics. As it is exceedingly rare, with an estimated incidence of 0.1-0.3%, it is frequently a diagnosis of exclusion. This case recognizes an organic etiology for abdominal pain in a patient who might otherwise have been misdiagnosed due to her other psychiatric and GI comorbidities, thus highlighting the importance of avoiding premature closure.
Conclusions:
It is often difficult to separate organic and non-organic etiologies for GI complaints, especially in a patient with preexisting IBS, PTSD, and anxiety disorder. Although the SMA syndrome seen in this patient is rare, it was a predictable etiology of her GI symptoms given her low BMI and change in symptoms from baseline. Early recognition of this syndrome is essential for timely therapy and avoidance of dehydration and malnutrition.