Dunbar Syndrome: An Old Cause of a New Clinical Picture in an Older Adult

Abstract

In January 2012, a 73-year-old woman was admitted to the Geriatrics Unit for investigation of a 2-month history of postprandial, diffuse, mainly epigastric, abdominal pain with anorexia and worsening general conditions. She reported undefined weight loss and progressive decrease in hemoglobin levels (~2 g/dL over the last year). Medical history included diabetes mellitus, hypertension, paroxysmal atrial fibrillation, and depressed mood. On examination, her body mass index was 18.7 kg/m2, and her physical examination was within normal limits. Blood tests showed hyposideremic anemia (hemoglobin 9.3 g/dL, mean corpuscular volume 76.0 fL, mean cell hemoglobin 24.2 pg, serum iron 21 μg/dL), moderate renal failure (serum creatinine 1.43 mg/dL, blood urea nitrogen 56 mg/dL, glomerular filtration rate 36 mL/min according to the Modification of Diet in Renal Disease equation); other findings were unremarkable. Gastroscopy revealed hyperemic and edematous mucosa with multiple shallow erosions; histology revealed mild chronic inflammation, without evidence of Helicobacter pylori. Treatment with intravenous iron and pantoprazole 40 mg twice a day was started. Because abdominal symptoms persisted, abdominal echography was performed; ultrasound examination revealed dyshomogeneous echogenicity of the pancreatic parenchyma, compatible with lipomatous involution, in the absence of obvious expansive alterations, and a normal choledochus. Secretin-enhanced magnetic resonance cholangiopancreatography evidenced fatty degeneration of the pancreas with multiple, diffuse cysts of a maximum size of 22 mm, mainly located within the tail, with cystic dilation of the secondary branches. Pancreatic enzyme replacement therapy for chronic pancreatitis was ineffective. Duplex ultrasound revealed stenosis of the celiac trunk exceeding 70%, which raised suspicion of angina abdominis. Computed tomography angiography confirmed severe stenosis of the proximal portion of the celiac axis secondary to compression by the median arcuate ligament with poststenotic dilatation (11 mm; Figure 1). All other vessels, including the superior and inferior mesenteric arteries, were normal. Considering these findings and symptoms, the diagnosis of Dunbar syndrome (deep crossing of the median arcuate ligament with ensuing compression of the proximal celiac axis), also known as median arcuate ligament syndrome or celiac artery compression syndrome, was established, and the woman was referred for laparoscopic treatment. She refused surgical intervention and started a diet of six easy-to-digest meals per day, with only mild improvement of symptoms. Diagnosis of this case was difficult because individuals with Dunbar syndrome are typically aged 20 to 40.1 In this woman, comorbid conditions might be relevant to explain the clinical picture. It is likely that anemia smoothed the beneficial effect of collateralization between the celiac axis and the superior mesenteric artery or that age-related changes in the dorsal spine curvature modulated the compression of the celiac trunk by the arcuate ligament. Progressive stiffening of the arcuate ligament might also play a pathogenetic role; diabetes mellitus and age are both known to promote the nonenzymatic glycosylation of collagen, with ensuing stiffening of tissues rich in low-turn-over proteins, especially fibrous tissues.2 Laparoscopic resection of the arcuate ligament has been substituted for surgical repair, variably consisting of decompression and reconstruction of the celiac axis,2 as the criterion standard remedy for Dunbar syndrome.3 Experience with elderly adults is limited, with only seven cases aged 70 and older in the five most recent series out of 102 individuals.1, 4-7 Age of 60 and older has been recognized as a risk factor for failure of the classical operative procedure,2 but it is unknown whether this might apply also to laparoscopic treatment. In this woman, the diet of six meals per day relieved symptoms only partially. It cannot be excluded that gastritis and pancreatic involution contributed to the clinical picture, but even though the definitive proof, based on the effect of laparoscopic repair, is lacking, the computed tomography angiography findings and the ineffectiveness of other medical therapies are highly consistent with the primary pathogenetic role of celiac artery compression by the arcuate ligament. This report suggests that atherosclerotic and embolic diseases should not be considered the only cause of intestinal ischemia in elderly adults; even a condition typical of younger people should be part of the diagnostic examination. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Laudisio A., Rivera C.: data analyses. Laudisio A., Antonelli Incalzi R.: drafting of the manuscript. Laudisio A., Rivera C., Sansoni I., Antonelli Incalzi R.: study design. All authors: reading and approval of the final manuscript. Sponsor's Role: None.