S3782 Fragmented Vessels: A Case Report and Literature Review of Segmental Arterial Mediolysis
Bibliographic record
Abstract
Introduction: Segmental Arterial Mediolysis (SAM) is a rare disease that can cause acute abdominal pain and shock due to complications like arterial aneurysmal rupture or thrombosis. Often underreported or misdiagnosed, SAM is characterized by distinct arteriopathy leading to dissecting aneurysms. SAM mainly occurs in the splanchnic vasculature in the elderly population and its diagnosis is difficult due to non-specific GI symptoms including abdominal pain, nausea/vomiting, and bloody stools. Histologic examination is gold standard for diagnosis, revealing dissecting aneurysms and medial wall necrosis. However, obtaining arterial tissue biopsies during acute events is not often attainable therefore CTA is crucial in helping establish Our case serves to bring awareness to SAM as a possible cause of abdominal pain in the elderly, emphasize diagnostic challenges, and advocate for routine use of Computed Tomography Angiography (CTA) in abdominal pain work-ups to enhance detection. We present a case of an elderly woman diagnosed with SAM after thorough evaluation, underscoring the importance of early recognition to prevent life-threatening complications. Case Description/Methods: A 60-year-old woman presented to the ED with sudden epigastric pain, nausea, and vomiting. Elevated vital signs and abdominal tenderness were noted. Lab tests showed elevated white blood cells, hemoglobin, and lactate. CTA showed a partially thrombosed aneurysm in the hepatic artery. SAM was diagnosed by vascular surgery. Despite no dissecting aneurysms, the pain was attributed to bowel ischemia secondary to SAM. Conservative management was chosen, with aspirin and apixaban prescribed, and planned vascular follow-up with routine CTA monitoring. Discussion: As mentioned, SAM is a nonatherosclerotic, noninflammatory arteriopathy, often presenting with nonspecific symptoms, making diagnosis challenging yet crucial. Confusing SAM with inflammatory vasculitis and administering steroids or immunosuppressants should be avoided due to ineffectiveness and potential adverse outcomes. Abdominal pain in the elderly comprises a significant percentage of visits to the ED but CTA in the vitally stable patient is not part of the routine work-up. SAM incidence is likely underestimated due to limited CTA use in routine abdominal pain workup, hindering recognition of characteristic segmental and aneurysmal arterial changes. Increased CTA utilization in abdominal evaluations could enhance SAM detection thereby decreasing chances of developing complications.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.007 | 0.006 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.003 | 0.004 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".