Round 1
A 68-year-old man with severe COPD presents with worsening dyspnea, wheezing, and chest tightness after several days of productive cough. EMS administers nebulizers en route, and the ED team quickly labels the case a COPD exacerbation. Steroids and bronchodilators are started immediately. Over several hours, he becomes increasingly diaphoretic and hypotensive. Repeat ECG later demonstrates evolving inferior ST elevations, though clinicians continue focusing on respiratory failure because the patient “looked pulmonary from the start.”
Anchoring and Premature Closure
Anchoring: The team fixated early on COPD exacerbation.
Premature closure: Diagnostic reconsideration stopped despite new contradictory data.
A 40-year-old man with chronic GERD presents with substernal burning discomfort after dinner. Symptoms partially improve with antacids in triage. The team reassures him that the pain is reflux-related. He later develops diaphoresis and worsening chest pressure, but providers remain reassured by the initial GI response.
Representativeness: MI was dismissed because the presentation did not fit the “classic” crushing chest pain stereotype.
Anchoring: Early reflux framing dominated subsequent thinking.
A 45-year-old woman presents with fatigue, constipation, weight gain, and depressed mood. She is referred for psychiatric evaluation and antidepressants are started. Months later, laboratory testing reveals severe hypothyroidism.
Fundamental attribution error: Symptoms were attributed to psychological causes instead of medical disease.
Premature closure: Evaluation stopped before exclusion of organic causes.
During flu season, a 55-year-old man presents with fever, malaise, and cough. Clinicians rapidly diagnose influenza after a clear CXR without further evaluation and start supportive therapy only. He continues to deteriorate with worsening mentation and persistent fevers. Blood cultures later grow Staphylococcus aureus.
Availability bias: Recent flu prevalence distorted diagnostic reasoning.
Anchoring: Initial viral diagnosis persisted despite worsening signs.
33-year-old woman presents to the ED with severe abdominal pain, tachycardia, and repeated vomiting. She has multiple prior visits for chronic abdominal pain and carries a chart diagnosis of “cyclic vomiting syndrome.” During evaluation she appears anxious and repeatedly requests IV pain medication. Providers attribute the current presentation to another exacerbation and delay imaging because previous CT scans have been negative. Several hours later she develops worsening hypotension and peritoneal signs from a perforated viscus.
Diagnostic momentum: Previous diagnostic labels strongly shaped interpretation of the current presentation.
Fundamental attribution error: Behavioral factors and assumptions about pain medication seeking overshadowed objective clinical deterioration.
A patient with recurrent ED visits for abdominal pain undergoes repeated negative imaging over several years. During a new admission, clinicians avoid additional workup because “everything has already been done.” The patient is later found to have mesenteric ischemia.
Yin-yang out, diagnostic momentum
Prior negative evaluations do not eliminate the possibility of new disease.
A postpartum woman develops progressive dyspnea and orthopnea. Clinicians repeatedly attribute symptoms to anxiety and sleep deprivation from caring for a newborn.
Attribution error: Symptoms were psychologized.
Representativeness: Serious cardiac disease was considered unlikely in a young woman.
A patient admitted for “CHF exacerbation” develops fever, hypotension, and rising lactate. Teams continue aggressive diuresis despite worsening shock physiology.
Initial diagnostic framing persisted despite contradictory evidence.
A stable patient with mild viral upper respiratory symptoms insists on antibiotics. Despite low suspicion for bacterial infection, broad-spectrum antibiotics are prescribed “just in case.” The patient later develops severe Clostridioides difficile colitis.
Commission bias
The urge to “do something” may lead to unnecessary or harmful interventions.
During M&M conference, a team harshly criticizes a resident for not diagnosing necrotizing fasciitis earlier. Retrospectively, subtle skin findings seem significant, although the patient initially lacked hypotension, crepitus, or severe laboratory abnormalities.
Hindsight bias
Outcome knowledge inflates perceived predictability of events.
A patient with known migraine disorder presents with “the worst headache of my life.” Because she has visited multiple times previously for migraines, clinicians rapidly administer migraine therapy and defer neuroimaging initially. Hours later she develops progressive confusion and neck stiffness.
Anchoring: Providers fixated on prior migraine history.
Availability bias: Familiarity with prior benign headaches distorted risk assessment.
A 24-year-old previously healthy woman presents with pleuritic chest pain and mild tachycardia after a 14-hour car ride home from vacation. The resident argues against pulmonary embolism because “she’s too young and healthy,” favoring costochondritis after a normal chest X-ray. D-dimer is not ordered. She returns 18 hours later with worsening hypoxia and syncope.
Base-rate neglect
Clinicians may underestimate disease probability when patients do not fit demographic expectations, even when risk factors are present.
A 35-year-old woman with chronic abdominal pain presents again with worsening pelvic pain and vomiting. Her chart prominently documents IBS and anxiety. Imaging later reveals ovarian torsion.
Diagnostic momentum: Previous labels became “sticky.”
Anchoring: Providers fixated on prior benign explanations.
A young athlete collapses during basketball practice. Coaches report poor hydration and the ED attributes the episode to heat exhaustion. Despite family history of sudden cardiac death, further cardiac testing is deferred.
Representativeness: Clinicians favored the common sports dehydration narrative.
Premature closure: Concerning family history was not pursued adequately.
A 72-year-old nursing home resident presents with confusion and foul-smelling urine. Antibiotics are started for UTI. Overnight she develops aphasia and right arm weakness, but clinicians continue attributing symptoms to delirium.
Anchoring: UTI diagnosis framed all future symptoms.
Search satisficing: Clinicians stopped looking once one abnormality was found.
A 41-year-old woman presents with episodic headaches, diaphoresis, hypertension, and palpitations. A trainee suggests pheochromocytoma, but the team dismisses it as “too rare.”
Why?
Providers retreated from a dangerous rare diagnosis because it seemed inconvenient or unlikely.
A young man presents with recurrent hemoptysis, sinus symptoms, and acute kidney injury. One intern suggests vasculitis, but the attending favors atypical pneumonia because “we can’t chase zebras on every patient.” ANCA testing is deferred until the patient later requires dialysis.
Zebra retreat, framing effect
Fear of appearing “overly academic” can suppress consideration of dangerous uncommon diseases.
A diabetic patient presents with nausea, abdominal pain, and fatigue. Providers diagnose viral gastroenteritis because glucose is only mildly elevated initially.
Representativeness: Clinicians expected “classic” DKA findings.
Premature closure: Evaluation ended before full metabolic assessment.
A 41-year-old woman presents with recurrent abdominal pain, episodic hypertension, diaphoresis, and palpitations. A resident briefly mentions pheochromocytoma, but the team dismisses it as “too rare” and avoids ordering further testing because endocrinology access is limited and the workup is expensive.
Zebra retreat
Rare diagnoses should not be abandoned solely because they are inconvenient, unfamiliar, or statistically uncommon.
Multiple consultants agree a patient’s symptoms are “functional” without independently reassessing the patient.
Group consensus reinforced diagnostic assumptions without fresh evaluation.
A septic patient becomes progressively hypotensive overnight. The covering physician delays vasopressors because the blood pressure is “not quite low enough yet” and worries about ICU complications from central line placement. The patient arrests several hours later.
Omission bias
Failure to intervene can itself represent an active cognitive error.
A patient with chronic back pain and numerous prior negative evaluations presents with new neurologic sensory deficits described as numbness and pin and needle sensations all across the right side of the body. Providers document “chronic pain syndrome” and defer imaging. Later develops hemi-paralysis on the right and facial droop. Extensive workup later shows Lupus with CNS involvement.
Why?
Yin-yang out: Extensive prior workups led clinicians to stop reconsidering disease.
Diagnostic momentum: Previous labels dominated interpretation.
A trauma patient is found to have a displaced femur fracture after a MVC. Orthopedics is consulted urgently. Hours later the patient becomes hypotensive from an unrecognized splenic injury.
Once the fracture was identified, clinicians prematurely stopped searching for additional injuries.
A 25-year-old woman presents with pleuritic chest pain and dyspnea shortly after a difficult breakup. She appears anxious and tearful. Providers attribute tachycardia to panic attacks despite recent oral contraceptive use and a long road trip.
Attribution error: Emotional distress overshadowed medical risk factors.
Premature closure: Alternative diagnoses were inadequately explored.
A 36-year-old woman with years of chronic fatigue, diffuse pain, and multiple prior hospitalizations presents again with worsening symptoms and new weight loss. Providers reviewing her chart repeatedly document “extensive prior negative workups” and defer further testing. Months later, she is diagnosed with Hodgkin lymphoma.
Yin-yang out
Diagnostic fatigue can cause clinicians to prematurely stop reassessing evolving illness.
A 68-year-old smoker with weight loss presents with persistent cough. Multiple providers reassure him that lung cancer is unlikely because his chest X-ray is normal and symptoms began after a viral illness. No CT imaging is obtained for months.
Base-rate neglect, premature closure
Common diseases are common—but high-risk populations still deserve Bayesian reasoning.
After a patient dies from missed aortic dissection, M&M reviewers state the diagnosis was “obvious” because the patient had chest pain radiating to the back. However, the presentation also included reproducible chest wall tenderness and a normal initial chest X-ray.
Hindsight bias
Knowing the outcome changes how prior decisions are judged and may distort fair analysis.
A patient with cellulitis remains tachycardic and increasingly hypotensive despite antibiotics. The team attributes deterioration to dehydration rather than reassessing the diagnosis.
The original diagnosis prevented recognition of evolving severe soft tissue infection.
A 72-year-old man with atrial fibrillation is admitted after a minor GI bleed. Anticoagulation is held “to be safe.” Over the next week, no one resumes it despite bleeding resolution. He subsequently develops a large embolic stroke.
Omission bias
Clinicians often perceive harm from action as worse than harm from inaction, even when inaction carries greater risk.
A 52-year-old emergency physician presents to the ED at 2:30 AM with vague chest discomfort, fatigue, mild dyspnea, and intermittent diaphoresis that began while finishing an overnight shift. He appears calm, jokes with staff, and repeatedly minimizes his symptoms, stating, “I’m probably just exhausted and dehydrated.”
Initial vitals show mild tachycardia and borderline hypotension. ECG demonstrates nonspecific ST-T abnormalities unchanged from an ECG performed two years prior. Initial troponin is negative. Because he is a physician known to the department, the case is discussed informally at the nursing station, where several clinicians agree the presentation is “probably stress-related.”
While awaiting repeat labs, he develops transient left leg weakness that spontaneously resolves. A resident briefly raises concern for acute aortic pathology, but the attending dismisses the idea, noting the patient lacks “classic ripping pain,” has equal pulses, and appears too clinically stable. The patient himself strongly prefers discharge and repeatedly reassures staff that he “knows what real sick patients look like.”
A repeat troponin returns minimally elevated but below the institutional MI threshold. The patient is discharged home with outpatient follow-up. Twelve hours later, he returns in cardiogenic shock with tamponade physiology.
Anchoring
The team anchored early on stress/dehydration/exhaustion.
Representativeness Bias
Clinicians dismissed dissection because the patient lacked the stereotypical “tearing chest pain” presentation.
Zebra Retreat
Aortic dissection was considered briefly but abandoned because it felt statistically unlikely and diagnostically inconvenient.
Bandwagon Effect
Multiple clinicians informally reinforced each other’s low-risk interpretation.
Framing Effect
The patient being an emergency physician changed how clinicians perceived risk and severity.
Premature Closure
The diagnostic process stopped once benign explanations appeared plausible.
Overconfidence Bias
The patient’s own medical confidence and the clinicians’ reassurance amplified false certainty.