NU652 Unit 4 Diagnostic Error Review, Ischemic Bowel Example

A Stomach Bug That Was an Embolus: A Diagnostic Error Case Review of Acute Mesenteric Ischemia in a 74-Year-Old Woman Who Had Stopped Her Anticoagulant

[Student Name]

Purdue University Global

NU652: AGACNP Acute Care Diagnosis and Management II

Unit 4 Diagnostic Error Case Review

[Instructor Name]

[Date]

The patient and every clinician are composite and identified by role; times and values are bracketed.

Definition

A 2015 National Academies report defines diagnostic error as the failure to establish an accurate and timely explanation of the patient's health problem, or to communicate that explanation to the patient (National Academies of Sciences, Engineering, and Medicine, 2015). This case met both parts. The explanation was wrong and late, and the patient left the first visit told that she had a stomach bug, with no instruction that would have brought her back sooner. The review treats the communication failure as its own finding, since it is the part most easily overlooked.

Summary

Mrs. [B.] is a [74]-year-old woman with atrial fibrillation and hypertension who stopped her apixaban [two] weeks before the event because of its cost, without telling her clinicians. She developed sudden severe pain around her navel at [06:00], vomited twice and had one loose stool. At the first emergency visit her abdomen was soft and only mildly tender, and she was discharged with ondansetron. She returned at [04:30] the next morning with a distended, rigid abdomen. CT angiography showed an embolus in the superior mesenteric artery. At laparotomy, [80] cm of necrotic small bowel was resected. She survived and was discharged on day [12].

Timeline

1. [09:10], day 1. Emergency department triage: pain [9] of 10, pulse [104] and irregular, blood pressure [148/86], temperature [37.2]. Triaged as moderate acuity.

2. [10:05]. Clinician assessment: pain described as severe and constant, abdomen soft with mild periumbilical tenderness. Anticoagulant history not asked; the medication list, last updated [eight] months earlier, still showed apixaban.

3. [10:40]. White count [14.8]; lipase, liver tests and creatinine normal. Lactate not ordered. Pain improved to [6] after intravenous morphine.

4. [12:15]. Discharged with a diagnosis of gastroenteritis, ondansetron and general return precautions. The pain was noted as "better with medication."

5. [04:30], day 2. Return by ambulance: pain [10], abdomen distended and rigid, pulse [128], blood pressure [96/58], lactate [5.8] mmol/L.

6. [05:40]. CT angiography: embolic occlusion of the superior mesenteric artery beyond the middle colic branch, with thickened, poorly enhancing small bowel.

7. [07:15]. Laparotomy, embolectomy and resection of [80] cm of small bowel.

Classification of Contributing Factors

Graber et al. (2005) sorted the causes of 100 diagnostic errors in internal medicine into no-fault, system-related and cognitive factors, and found that most errors involved both of the latter, with premature closure the single most common cognitive cause. This case fits that pattern.

Cognitive factors:

1. Premature closure. Gastroenteritis was accepted after vomiting and one loose stool, and alternatives were not reconsidered when the pain was described as severe with a soft abdomen. Pain out of proportion to the examination is the classic early sign of mesenteric ischemia, and it was documented as a reassuring finding.

2. Faulty data gathering. The anticoagulant history was not taken, so the most important risk factor in the chart, atrial fibrillation without anticoagulation, was never assembled.

3. Misjudging salience. The irregular pulse and the white count were recorded but not linked to an embolic source. Improvement after morphine was read as evidence of a benign cause.

System-related factors:

1. The medication list was [eight] months old and was not reconciled at triage.

2. No emergency department pathway prompted consideration of mesenteric ischemia in patients over [60] with atrial fibrillation and severe abdominal pain.

3. Lactate was not part of the standard abdominal pain order set.

4. Discharge instructions were generic and did not name worsening pain or distension as reasons to return at once.

No-fault factors: the early examination was genuinely soft, and early mesenteric ischemia can present that way. That makes the case hard, but it does not make it unavoidable, because the history and risk factors were available.

What Should Have Happened

The World Society of Emergency Surgery guideline describes acute mesenteric ischemia as uncommon, with mortality still around 50 percent when untreated, and stresses that early diagnosis and timely treatment are what reduce it (Bala et al., 2022). The guideline recommends CT angiography without delay when the diagnosis is suspected, and warns that a normal lactate does not exclude it. In Mrs. [B.]'s case, suspicion needed only three facts that were available at [10:05]: age over 70, atrial fibrillation and severe pain with a soft abdomen. A CT angiogram that morning would likely have found the embolus before the bowel died. The morphine deserves a separate comment, because it shaped the discharge. Analgesia does not hide a surgical abdomen in the way older teaching claimed, and giving it was right. The error was in the interpretation: a pain score that fell from [9] to [6] after an opioid was recorded as improvement and used as a reason to discharge. For a patient whose pain was already out of proportion to her examination, a partial response to morphine says little about the cause. What it did was make the chart look reassuring to the clinician who wrote the discharge, and to anyone who read the note later.

Recommendations

1. Reconcile anticoagulants at triage for every patient with a history of atrial fibrillation.

2. Add a prompt to the abdominal pain pathway: in patients over [60] with atrial fibrillation or known vascular disease and severe pain, consider CT angiography before discharge.

3. Include lactate in the abdominal pain order set for older adults, with the caveat that a normal value does not exclude ischemia.

4. Require a diagnostic time-out before discharging any patient whose pain needed an opioid: what else could this be, and what would make me wrong?

5. Replace generic return precautions with specific ones for abdominal pain in older adults.

Cognitive strategies such as a deliberate pause to consider alternatives are among the approaches proposed to reduce errors of premature closure (Croskerry, 2003). The fourth recommendation builds that pause into the discharge process rather than leaving it to individual memory.

Communication and Disclosure

The error was disclosed to Mrs. [B.] and her son on day [three] by the attending emergency physician and the surgeon. They were told what was missed, why it mattered and what the department is changing. The review recommends that disclosure be documented and that the patient receive a written summary, since the National Academies definition makes communication part of the diagnosis itself.

References

Bala, M., Catena, F., Kashuk, J., De Simone, B., Gomes, C. A., Weber, D., Sartelli, M., Coccolini, F., Kluger, Y., Abu-Zidan, F. M., Picetti, E., Ansaloni, L., Augustin, G., Biffl, W. L., Ceresoli, M., Chiara, O., Chiarugi, M., Coimbra, R., Cui, Y., . . . Moore, E. E. (2022). Acute mesenteric ischemia: Updated guidelines of the World Society of Emergency Surgery. World Journal of Emergency Surgery, 17, Article 54. https://doi.org/10.1186/s13017-022-00443-x

Croskerry, P. (2003). The importance of cognitive errors in diagnosis and strategies to minimize them. Academic Medicine, 78(8), 775-780. https://doi.org/10.1097/00001888-200308000-00003

Graber, M. L., Franklin, N., & Gordon, R. (2005). Diagnostic error in internal medicine. Archives of Internal Medicine, 165(13), 1493-1499. https://doi.org/10.1001/archinte.165.13.1493

National Academies of Sciences, Engineering, and Medicine. (2015). Improving diagnosis in health care. The National Academies Press. https://doi.org/10.17226/21794