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Acute Aortic Pathology, Munchausen Syndrome, and Confirmation Bias
The Journal of Emergency Medicine, Vol. 45, No. 6, pp. e183–e186, 2013 Copyright Ó 2013 Elsevier Inc. Printed in the USA. All rights reserved 0736-4679/$ - see front matter
http://dx.doi.org/10.1016/j.jemermed.2013.05.067
Clinical Communications: Adults ACUTE AORTIC PATHOLOGY, MUNCHAUSEN SYNDROME, AND CONFIRMATION BIAS Mario Gaudino, MD,* Giuseppe Nasso, MD,† Vito Romano, MD,† Claudio Pragliola, MD,* Alessandro Di Cesare, MD,* Giuseppe Speziale, MD,† and Massimo Massetti, MD* *Division of Cardiac Surgery, Department of Cardiology, Catholic University, Rome, Italy and †Department of Cardiac Surgery, Anthea Hospital, Bari, Italy Reprint Address: Mario Gaudino, MD, Department of Cardiac Surgery, Catholic University, L.go Gemelli 1, 00168 Rome, Italy
, Abstract—Background: Munchausen syndrome is a psychiatric disease characterized by pathological lying and malingering. Patients who are affected can set up such complex and compelling clinical scenarios that they can lead to a bias in the diagnostic process and even to unnecessary surgery. Case Reports: Two cases of Munchausen syndrome misrepresenting acute aortic dissection are reported. The two cases occurred at two different institutions where there was considerable expertise in the management of aortic pathology. In both patients, a wrong diagnosis of acute aortic syndrome was made, leading to unnecessary surgery. Conclusions: Retrospective analysis of the clinical events and the diagnostic process suggests that a confirmation bias played a major role in determining the misdiagnosis. The same mistake is likely to have occurred in the only other case reported in the literature. Ó 2013 Elsevier Inc.
They are usually able to furnish a plausible and detailed history to credibly support their clinical symptoms, and they often travel to multiple sites in order to seek medical attention. We report two cases of patients affected by the Munchausen syndrome who simulated an acute aortic dissection. The complex and compelling clinical scenarios set up by the patients and the limited available information on the pathology (only one case has been previously described in the literature) led, in both cases (treated in different institutions), to a bias in the diagnostic process and to unnecessary surgery.
, Keywords—aortic dissection; Munchausen syndrome; confirmation bias
A 40-year-old man presented at the emergency department (ED) of Catholic University at 6:30 am, complaining of very severe retrosternal pain radiating to the back, shortness of breath, and tachycardia. He reported a strong family history for aortic dissection and a confused anamnestic diagnosis of collagenopathy and ‘‘aortic dilatation,’’ although with no records to support these assertions. Urgent contrast-enhanced computed tomography (CT) scan of the aorta was performed and a diagnosis of acute aortic dissection was made (Figure 1A). The patient was transferred to the operating room for emergency surgery. At operation, the aorta appeared normal with minimal dilatation and
CASE REPORTS Case 1
INTRODUCTION Munchausen syndrome is a psychiatric disease characterized by pathological lying and malingering (1,2). Patients affected by this disorder may fabricate entirely or partially a medical history, present false medical records, and selfinduce real tissue pathology or abnormal laboratory tests.
RECEIVED: 29 September 2012; FINAL SUBMISSION RECEIVED: 27 January 2013; ACCEPTED: 1 May 2013 e183
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M. Gaudino et al.
Figure 1. Preoperative computed tomography scan and operative finding of Patient no. 1. The artifact that led to the falsepositive diagnosis is evident in (A) (arrow) and the operative finding of normal aorta is shown in (B).
no signs of wall hemorrhage or dissection (Figure 1B). The ascending aorta was opened and inspected and no signs of intimal tear or dissection were found. The operation was terminated and the postoperative course was uneventful. Postoperative in-depth talks with the family revealed that the patient frequently sought medical attention for variable, usually dramatic, symptoms and was particularly interested in medical information through the Internet or the specialized press. The reported family history of aortic deaths and collagenopathy were denied by the relatives. The patient refused psychiatric evaluation and was discharged from the hospital. Case 2 A 23-year-old man presented at 2:30 am to the ED of Anthea Hospital with a complaint of 10/10 retrosternal and intrascapular pain that began 2 h earlier. He reported a history of aortic surgery and a strong family history of death due to aortic dissection. At physical examination, the scar of a previous sternotomy was evident and sternal wires were found on chest x-ray study. An urgent contrastenhanced CT scan of the aorta was performed and a diagnosis of acute aortic syndrome was made (Figure 2). The patient was transferred to the operating room and an urgent median sternotomy was performed. After division of the adhesions from previous surgery, the ascending aorta and arch appeared normal. In addition, no signs of previous aortic surgery were found. Intraoperative epiaortic ultrasound revealed normal aortic wall. The operation was terminated and the postoperative course was uneventful. Extensive talks with relatives revealed that the patient’s brother died a few years before from aortic dissection, and since then the patient developed a form of fixation on this pathology. The scar of the previous sternotomy was due to another exploratory surgery performed the year before in
another institution for the same reason. The patient was referred to the psychiatric ward for treatment. However, 18 months after the episode, we received an urgent call from another hospital describing the same clinical scenario with the same patient. When confronted with his history, he left the hospital against medical advice. For the purpose of the present study, the CT scans of the two patients were submitted for examination by two different radiologists from the same institutions, who were blinded to the clinical context. Both reviewers denied the presence of acute aortic pathology and correctly recognized the cause of the false-positive interpretations (motion artifacts in the first patient and adhesions from previous surgery in the second). DISCUSSION Munchausen syndrome is a psychiatric factitious disorder that was first described in 1951 by Asher, who took
Figure 2. Preoperative computed tomography scan of Patient no. 2. The artifact that led to the false-positive diagnosis is marked by an arrow.
Munchausen Aortic Pathology
inspiration from the historical figure of Baron Karl von Munchausen (1720–1797) (1). Typical features of Munchausen patients include pathological lying; frequent requests for medical attention; and recurrent, feigned, or simulated illness. Supporting elements are borderline or antisocial personality traits, deprivation in childhood, equanimity for diagnostic procedures, equanimity for treatments or operations, evidence of self-induced physical signs, knowledge of or experience in the medical field, multiple hospitalizations, multiple scars, and unusual or dramatic presentation of illness (2). From a psychodynamic standpoint, Munchausen patients put in place conscious manipulations due to underlying unconscious motivations; the relationship between conscious and unconscious aspects is complex, with behaviors (such as falsification of, or self-inducted, injuries) that might be partly conscious but not wholly under the patient’s control (2). Patients usually express at the same time both love and hatred for their caregivers, who are often idealized and to whom they delegate their self-destructiveness. The treating physicians often end up being overwhelmed by the patient’s sense of urgency and emergency (2). Acute aortic dissection was first described by Morgagni more than 200 years ago. It is the most common acute aortic condition requiring urgent or emergent surgical therapy with an estimated incidence of 5 to 30 per 1 million people per year; the typical patient is a hypertensive man in his seventh decade (3). The clinical spectrum of presentation is broad (although sharp chest pain is reported by the great majority of patients) and symptoms can mimic other conditions, such as myocardial infarction and stroke. Diagnosis requires contrast CT scan or transthoracic/transesophageal echocardiography and, once a dissection has been demonstrated, emergent surgical repair is the only therapy when the ascending aorta is involved (although with a not negligible in-hospital mortality). Hopkins and coauthors in 2006 were the first and to date the only authors to report a case of Munchausen syndrome misrepresenting acute aortic dissection (4). In their report, the patient was entered into an acute dissection fast-track protocol, submitted to intensive pharmacological treatment as well as cardiologic and cardiac surgical evaluation, and to transesophageal echocardiography before the fictitious nature of the disorder became evident. Of note, as demonstrated by the evidence of sternal wires at the admission chest x-ray, he had previously succeeded in presenting his history to the point of being submitted to exploratory sternotomy. In our two cases, according to current practice, the protocol for acute aortic syndromes management included CT scan as the first-line examination.
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In fact, the reported specificity and sensitivity of CT scan for the diagnosis of acute aortic dissection are 90% to 100% and 83% to 94%, respectively, with even better results achieved by the scanners of recent generations, and data from the International Registry of Acute Aortic Dissection show that CT is the most used diagnostic modality for patients with suspected acute aortic pathology (5 7). Although a false-positive result of a CT scan in the evaluation of acute aortic syndrome has been described previously, the cause of a false positive is usually recognized at a second review of the scan and only rarely leads to inappropriate treatment (8,9). It is then surprising that CT evaluation (performed by two different and independent teams) led to a false-positive diagnosis and to unnecessary surgery in both cases. Both cases occurred in large institutions with considerable expertise in the management of acute aortic pathology. It also must be noted that in the only other case of Munchausen simulating aortic dissection described in the literature, as well as in our second case, a falsepositive diagnosis has previously occurred at least once (as demonstrated by the presence in both of sternal wires), leading to an inordinately high incidence of false-positive diagnosis in this type of case (4). All of these considerations lead us to believe that the clinical context factitiously set up by the patients can increase the risk of misdiagnosis considerably. The interpretation of medical data and information in a way biased to fit existing beliefs or expectations has been widely recognized. Bias of this type has been reported in forensic medicine, otorhinology, and clinical medicine, and has been shown to have particular relevance in disciplines based on subjective visual assessment, such as pathology and radiology (10 14). Confirmation bias, in particular, is related to the expectation of the observer to see what he or she expects or wants to see, rather than to objectively evaluate what is present, a scenario that fits perfectly with our cases (15). In fact, all the described Munchausen-aortic patients were young (aged 20 40s), presented a detailed and plausible history (including a family history of collagen disorders or previous surgery on the aorta) and dramatic clinical symptoms. Possibly by design, all cases (including that reported in the literature) presented to the ED late at night or in the early morning, contributing to the creation of a compelling scenario. All patients were retrospectively reported by the treating physicians to be odd, ingratiating, and trying to support and confirm the misdiagnosis. In this setting, the psychological pressure exerted on the physician can increase the possibility of confirmation errors in the interpretation of CT scan false positives. The fact that in both our cases an a posteriori re-evaluation of
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the CT images by a third reviewer blinded to the clinical context led to the correct diagnosis lends support to this hypothesis. The limited information available on the condition (only one case reported to date) increases the risk of misdiagnosis. CONCLUSIONS In conclusion, we describe two of the three cases reported in the literature, to date, of Munchausen syndrome simulating acute aortic pathology. In both cases, the limited available information on the disease and the compelling scenario factitiously set-up by the patient led to a bias in the diagnostic process and to inappropriate surgery. Emergency physicians, radiologists, cardiologists, and cardiac surgeons must be aware of the possibility of such an occurrence in order to correctly manage it and avoid unnecessary and potentially harmful treatments (16). Knowledge of this rare condition is the best and probably only means to avoid misdiagnosis and unnecessary surgical treatment. When in doubt, the emergency physician should not hesitate to ask for multidisciplinary consultation and blinded imaging re-evaluation.
REFERENCES 1. Asher R. Munchausen’s syndrome. Lancet 1951;1:339–41. 2. Cremona-Barbaro A. The Munchausen syndrome and its symbolic significance: an in-depth case analysis. Br J Psychiatry 1987;151: 76–9.
3. Hopkins RA, Harrington CJ, Poppas A. Munchausen syndrome simulating acute aortic dissection. Ann Thorac Surg 2006;81:1497–9. 4. Hagan PG, Nienaber CA, Isselbacher EM, et al. The international registry of acute aortic dissection (IRAD). JAMA 2000;283:897–903. 5. Firstenberg MS, Crestanello JA, Sai-Sudharkar CB, et al. Ascending aortic dissection: look again before you leap. Ann Thorac Surg 2008;85:1782–4. 6. Yoshiba S, Akiba H, Tamakawa M, et al. Thoracic involvement of type A aortic dissection and intramural hematoma: diagnostic accuracy—comparison of emergency helical CT and surgical findings. Radiology 2003;228:430–5. 7. Hagan PG, Nienaber CA, Isselbacher EM, et al. The international Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000;283:897–903. 8. Batra P, Bigoni B, Manning J, et al. Pitfalls in the diagnosis of thoracic aortic dissection at CT angiography. Radiographics 2000;20: 309–20. 9. Ghio A, Merienne S, Giovanni A. Context influence on the perception of dysphonia: when the knowledge of the patient’s clinical state can modify the results of perceptual voice quality assessment. Rev Laryngol Otol Rhinol 2011;132:9–17. 10. Sibbad M, Panisko D, Rodrigo B, et al. Role of clinical context in resident’s physical examination diagnostic accuracy. Med Educ 2011;45:415–21. 11. Lebreton G, Litzler PY, Bessou JP, et al. Acute aortic syndrome: a ‘‘last glance’’ before incision. Interact Cardiovasc Thorac Surg 2010;11:357–9. 12. Dror IE, Hampikian G. Subjectivity and bias in forensic DNA mixture interpretation. Sci Justice 2011;51:201–8. 13. Fandel TM, Pfnur M, Schafer SC, et al. Do we truly see what we think we see? The role of cognitive bias in pathological interpretation. J Pathol 2008;216:193–200. 14. Egglin TKP, Feinstein AR. Context bias: a problem in diagnostic radiology. JAMA 1996;276:1752–5. 15. Nickerson RS. Confirmation bias: a ubiquitous phenomenon in many guises. Rev Gen Psychol 1998;2:175–220. 16. Lauwers R, Van De Winkel N, Vanderbruggen N, et al. Munchausen syndrome in the emergency department mostly difficult, sometimes ease to diagnose: a case report and review of the literature. World J Emerg Surg 2009;4:38.
http://dx.doi.org/10.1016/j.jemermed.2013.05.067
Clinical Communications: Adults ACUTE AORTIC PATHOLOGY, MUNCHAUSEN SYNDROME, AND CONFIRMATION BIAS Mario Gaudino, MD,* Giuseppe Nasso, MD,† Vito Romano, MD,† Claudio Pragliola, MD,* Alessandro Di Cesare, MD,* Giuseppe Speziale, MD,† and Massimo Massetti, MD* *Division of Cardiac Surgery, Department of Cardiology, Catholic University, Rome, Italy and †Department of Cardiac Surgery, Anthea Hospital, Bari, Italy Reprint Address: Mario Gaudino, MD, Department of Cardiac Surgery, Catholic University, L.go Gemelli 1, 00168 Rome, Italy
, Abstract—Background: Munchausen syndrome is a psychiatric disease characterized by pathological lying and malingering. Patients who are affected can set up such complex and compelling clinical scenarios that they can lead to a bias in the diagnostic process and even to unnecessary surgery. Case Reports: Two cases of Munchausen syndrome misrepresenting acute aortic dissection are reported. The two cases occurred at two different institutions where there was considerable expertise in the management of aortic pathology. In both patients, a wrong diagnosis of acute aortic syndrome was made, leading to unnecessary surgery. Conclusions: Retrospective analysis of the clinical events and the diagnostic process suggests that a confirmation bias played a major role in determining the misdiagnosis. The same mistake is likely to have occurred in the only other case reported in the literature. Ó 2013 Elsevier Inc.
They are usually able to furnish a plausible and detailed history to credibly support their clinical symptoms, and they often travel to multiple sites in order to seek medical attention. We report two cases of patients affected by the Munchausen syndrome who simulated an acute aortic dissection. The complex and compelling clinical scenarios set up by the patients and the limited available information on the pathology (only one case has been previously described in the literature) led, in both cases (treated in different institutions), to a bias in the diagnostic process and to unnecessary surgery.
, Keywords—aortic dissection; Munchausen syndrome; confirmation bias
A 40-year-old man presented at the emergency department (ED) of Catholic University at 6:30 am, complaining of very severe retrosternal pain radiating to the back, shortness of breath, and tachycardia. He reported a strong family history for aortic dissection and a confused anamnestic diagnosis of collagenopathy and ‘‘aortic dilatation,’’ although with no records to support these assertions. Urgent contrast-enhanced computed tomography (CT) scan of the aorta was performed and a diagnosis of acute aortic dissection was made (Figure 1A). The patient was transferred to the operating room for emergency surgery. At operation, the aorta appeared normal with minimal dilatation and
CASE REPORTS Case 1
INTRODUCTION Munchausen syndrome is a psychiatric disease characterized by pathological lying and malingering (1,2). Patients affected by this disorder may fabricate entirely or partially a medical history, present false medical records, and selfinduce real tissue pathology or abnormal laboratory tests.
RECEIVED: 29 September 2012; FINAL SUBMISSION RECEIVED: 27 January 2013; ACCEPTED: 1 May 2013 e183
e184
M. Gaudino et al.
Figure 1. Preoperative computed tomography scan and operative finding of Patient no. 1. The artifact that led to the falsepositive diagnosis is evident in (A) (arrow) and the operative finding of normal aorta is shown in (B).
no signs of wall hemorrhage or dissection (Figure 1B). The ascending aorta was opened and inspected and no signs of intimal tear or dissection were found. The operation was terminated and the postoperative course was uneventful. Postoperative in-depth talks with the family revealed that the patient frequently sought medical attention for variable, usually dramatic, symptoms and was particularly interested in medical information through the Internet or the specialized press. The reported family history of aortic deaths and collagenopathy were denied by the relatives. The patient refused psychiatric evaluation and was discharged from the hospital. Case 2 A 23-year-old man presented at 2:30 am to the ED of Anthea Hospital with a complaint of 10/10 retrosternal and intrascapular pain that began 2 h earlier. He reported a history of aortic surgery and a strong family history of death due to aortic dissection. At physical examination, the scar of a previous sternotomy was evident and sternal wires were found on chest x-ray study. An urgent contrastenhanced CT scan of the aorta was performed and a diagnosis of acute aortic syndrome was made (Figure 2). The patient was transferred to the operating room and an urgent median sternotomy was performed. After division of the adhesions from previous surgery, the ascending aorta and arch appeared normal. In addition, no signs of previous aortic surgery were found. Intraoperative epiaortic ultrasound revealed normal aortic wall. The operation was terminated and the postoperative course was uneventful. Extensive talks with relatives revealed that the patient’s brother died a few years before from aortic dissection, and since then the patient developed a form of fixation on this pathology. The scar of the previous sternotomy was due to another exploratory surgery performed the year before in
another institution for the same reason. The patient was referred to the psychiatric ward for treatment. However, 18 months after the episode, we received an urgent call from another hospital describing the same clinical scenario with the same patient. When confronted with his history, he left the hospital against medical advice. For the purpose of the present study, the CT scans of the two patients were submitted for examination by two different radiologists from the same institutions, who were blinded to the clinical context. Both reviewers denied the presence of acute aortic pathology and correctly recognized the cause of the false-positive interpretations (motion artifacts in the first patient and adhesions from previous surgery in the second). DISCUSSION Munchausen syndrome is a psychiatric factitious disorder that was first described in 1951 by Asher, who took
Figure 2. Preoperative computed tomography scan of Patient no. 2. The artifact that led to the false-positive diagnosis is marked by an arrow.
Munchausen Aortic Pathology
inspiration from the historical figure of Baron Karl von Munchausen (1720–1797) (1). Typical features of Munchausen patients include pathological lying; frequent requests for medical attention; and recurrent, feigned, or simulated illness. Supporting elements are borderline or antisocial personality traits, deprivation in childhood, equanimity for diagnostic procedures, equanimity for treatments or operations, evidence of self-induced physical signs, knowledge of or experience in the medical field, multiple hospitalizations, multiple scars, and unusual or dramatic presentation of illness (2). From a psychodynamic standpoint, Munchausen patients put in place conscious manipulations due to underlying unconscious motivations; the relationship between conscious and unconscious aspects is complex, with behaviors (such as falsification of, or self-inducted, injuries) that might be partly conscious but not wholly under the patient’s control (2). Patients usually express at the same time both love and hatred for their caregivers, who are often idealized and to whom they delegate their self-destructiveness. The treating physicians often end up being overwhelmed by the patient’s sense of urgency and emergency (2). Acute aortic dissection was first described by Morgagni more than 200 years ago. It is the most common acute aortic condition requiring urgent or emergent surgical therapy with an estimated incidence of 5 to 30 per 1 million people per year; the typical patient is a hypertensive man in his seventh decade (3). The clinical spectrum of presentation is broad (although sharp chest pain is reported by the great majority of patients) and symptoms can mimic other conditions, such as myocardial infarction and stroke. Diagnosis requires contrast CT scan or transthoracic/transesophageal echocardiography and, once a dissection has been demonstrated, emergent surgical repair is the only therapy when the ascending aorta is involved (although with a not negligible in-hospital mortality). Hopkins and coauthors in 2006 were the first and to date the only authors to report a case of Munchausen syndrome misrepresenting acute aortic dissection (4). In their report, the patient was entered into an acute dissection fast-track protocol, submitted to intensive pharmacological treatment as well as cardiologic and cardiac surgical evaluation, and to transesophageal echocardiography before the fictitious nature of the disorder became evident. Of note, as demonstrated by the evidence of sternal wires at the admission chest x-ray, he had previously succeeded in presenting his history to the point of being submitted to exploratory sternotomy. In our two cases, according to current practice, the protocol for acute aortic syndromes management included CT scan as the first-line examination.
e185
In fact, the reported specificity and sensitivity of CT scan for the diagnosis of acute aortic dissection are 90% to 100% and 83% to 94%, respectively, with even better results achieved by the scanners of recent generations, and data from the International Registry of Acute Aortic Dissection show that CT is the most used diagnostic modality for patients with suspected acute aortic pathology (5 7). Although a false-positive result of a CT scan in the evaluation of acute aortic syndrome has been described previously, the cause of a false positive is usually recognized at a second review of the scan and only rarely leads to inappropriate treatment (8,9). It is then surprising that CT evaluation (performed by two different and independent teams) led to a false-positive diagnosis and to unnecessary surgery in both cases. Both cases occurred in large institutions with considerable expertise in the management of acute aortic pathology. It also must be noted that in the only other case of Munchausen simulating aortic dissection described in the literature, as well as in our second case, a falsepositive diagnosis has previously occurred at least once (as demonstrated by the presence in both of sternal wires), leading to an inordinately high incidence of false-positive diagnosis in this type of case (4). All of these considerations lead us to believe that the clinical context factitiously set up by the patients can increase the risk of misdiagnosis considerably. The interpretation of medical data and information in a way biased to fit existing beliefs or expectations has been widely recognized. Bias of this type has been reported in forensic medicine, otorhinology, and clinical medicine, and has been shown to have particular relevance in disciplines based on subjective visual assessment, such as pathology and radiology (10 14). Confirmation bias, in particular, is related to the expectation of the observer to see what he or she expects or wants to see, rather than to objectively evaluate what is present, a scenario that fits perfectly with our cases (15). In fact, all the described Munchausen-aortic patients were young (aged 20 40s), presented a detailed and plausible history (including a family history of collagen disorders or previous surgery on the aorta) and dramatic clinical symptoms. Possibly by design, all cases (including that reported in the literature) presented to the ED late at night or in the early morning, contributing to the creation of a compelling scenario. All patients were retrospectively reported by the treating physicians to be odd, ingratiating, and trying to support and confirm the misdiagnosis. In this setting, the psychological pressure exerted on the physician can increase the possibility of confirmation errors in the interpretation of CT scan false positives. The fact that in both our cases an a posteriori re-evaluation of
e186
M. Gaudino et al.
the CT images by a third reviewer blinded to the clinical context led to the correct diagnosis lends support to this hypothesis. The limited information available on the condition (only one case reported to date) increases the risk of misdiagnosis. CONCLUSIONS In conclusion, we describe two of the three cases reported in the literature, to date, of Munchausen syndrome simulating acute aortic pathology. In both cases, the limited available information on the disease and the compelling scenario factitiously set-up by the patient led to a bias in the diagnostic process and to inappropriate surgery. Emergency physicians, radiologists, cardiologists, and cardiac surgeons must be aware of the possibility of such an occurrence in order to correctly manage it and avoid unnecessary and potentially harmful treatments (16). Knowledge of this rare condition is the best and probably only means to avoid misdiagnosis and unnecessary surgical treatment. When in doubt, the emergency physician should not hesitate to ask for multidisciplinary consultation and blinded imaging re-evaluation.
REFERENCES 1. Asher R. Munchausen’s syndrome. Lancet 1951;1:339–41. 2. Cremona-Barbaro A. The Munchausen syndrome and its symbolic significance: an in-depth case analysis. Br J Psychiatry 1987;151: 76–9.
3. Hopkins RA, Harrington CJ, Poppas A. Munchausen syndrome simulating acute aortic dissection. Ann Thorac Surg 2006;81:1497–9. 4. Hagan PG, Nienaber CA, Isselbacher EM, et al. The international registry of acute aortic dissection (IRAD). JAMA 2000;283:897–903. 5. Firstenberg MS, Crestanello JA, Sai-Sudharkar CB, et al. Ascending aortic dissection: look again before you leap. Ann Thorac Surg 2008;85:1782–4. 6. Yoshiba S, Akiba H, Tamakawa M, et al. Thoracic involvement of type A aortic dissection and intramural hematoma: diagnostic accuracy—comparison of emergency helical CT and surgical findings. Radiology 2003;228:430–5. 7. Hagan PG, Nienaber CA, Isselbacher EM, et al. The international Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000;283:897–903. 8. Batra P, Bigoni B, Manning J, et al. Pitfalls in the diagnosis of thoracic aortic dissection at CT angiography. Radiographics 2000;20: 309–20. 9. Ghio A, Merienne S, Giovanni A. Context influence on the perception of dysphonia: when the knowledge of the patient’s clinical state can modify the results of perceptual voice quality assessment. Rev Laryngol Otol Rhinol 2011;132:9–17. 10. Sibbad M, Panisko D, Rodrigo B, et al. Role of clinical context in resident’s physical examination diagnostic accuracy. Med Educ 2011;45:415–21. 11. Lebreton G, Litzler PY, Bessou JP, et al. Acute aortic syndrome: a ‘‘last glance’’ before incision. Interact Cardiovasc Thorac Surg 2010;11:357–9. 12. Dror IE, Hampikian G. Subjectivity and bias in forensic DNA mixture interpretation. Sci Justice 2011;51:201–8. 13. Fandel TM, Pfnur M, Schafer SC, et al. Do we truly see what we think we see? The role of cognitive bias in pathological interpretation. J Pathol 2008;216:193–200. 14. Egglin TKP, Feinstein AR. Context bias: a problem in diagnostic radiology. JAMA 1996;276:1752–5. 15. Nickerson RS. Confirmation bias: a ubiquitous phenomenon in many guises. Rev Gen Psychol 1998;2:175–220. 16. Lauwers R, Van De Winkel N, Vanderbruggen N, et al. Munchausen syndrome in the emergency department mostly difficult, sometimes ease to diagnose: a case report and review of the literature. World J Emerg Surg 2009;4:38.