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BACKGROUND: Clinical reasoning is at the core of medical practice and entangled in a conceptual confusion. The duality theory in probability allows to evaluate its objective and subjective aspects. OBJECTIVES: To conduct a systematic review of the literature about clinical reasoning in decision making in medical education and to propose a "reasoning based on the Bayesian rule" (RBBR). METHODS: A systematic review on PubMed was conducted (until February 27, 2022), following a strict methodology, by a researcher experienced in systematic review. The RBBR, presented in the discussion section, was constructed in his undergraduate dissertation in Philosophy at Minas Gerais Federal University. Heart failure was used as example. RESULTS: Of 3,340 articles retrieved, 154 were included: 24 discussing the uncertainty condition, 87 on vague concepts (case discussion, heuristics, list of cognitive biases, choosing wisely) subsumed under the term "art", and 43 discussing the general idea of inductive or deductive reasoning. RBBR provides coherence and reproducibility rules, inference under uncertainty, and learning rule, and can incorporate those vague terms classified as "art", arguments and evidence, from a subjective perspective about probability. CONCLUSIONS: This systematic review shows that reasoning is grounded in uncertainty, predominantly probabilistic, and reviews possible errors of the hypothetico-deductive reasoning. RBBR is a two-step probabilistic reasoning that can be taught. The Bayes theorem is a linguistic tool, a general rule of reasoning, diagnosis, scientific communication and review of medical knowledge according to new evidence.

FUNDAMENTO: O raciocínio clínico está no centro da prática médica e emaranhado em uma confusão conceitual.A teoria da dualidade da probabilidade permite analisar seus aspectos objetivos e subjetivos. OBJETIVOS: Fazer revisão sistemática da literatura sobre o raciocínio clínico para tomada de decisão na educação médica e uma proposta chamada "Pensamento Conforme a Regra de Bayes" (PCRB). MÉTODOS: A revisão sistemática foi realizada na base PubMed até a data de 27/02/2022, seguindo metodologia rigorosa, por pesquisador experiente em revisão sistemática. A proposta PCRB, apresentada na discussão, foi elaborada no trabalho de conclusão de graduação em Filosofia na Universidade Federal de Minas Gerais. Usou-se a insuficiência cardíaca como exemplo. RESULTADOS: De 3340 artigos encontrados, incluíram-se 154 artigos: 24 tratando da condição de incerteza; 87 tratando de conceitos vagos (discussão de casos, heurística, lista de vieses cognitivos, escolha com sabedoria) incluídos sob o termo 'arte'; e 43 discutindo a ideia geral de raciocínio indutivo ou dedutivo. PCRB oferece regras de coerência e reprodutibilidade, inferência sob incerteza e regra de aprendizado, e pode, por meio da perspectiva subjetiva sobre a probabilidade, incorporar aqueles termos vagos classificados como 'arte', bem como argumentos e evidências. CONCLUSÕES: A revisão sistemática mostra que o raciocínio é fundado na incerteza, predominantemente probabilístico; além de mostrar algumas possibilidades de erro do pensamento hipotético-dedutivo. O PCRB é um pensamento probabilístico em duas etapas que pode ser ensinado. A regra de Bayes é uma ferramenta linguística, uma regra geral de raciocínio, de diagnóstico, de comunicação científica e de revisão do conhecimento médico conforme novas evidências.

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Resumo Fundamento O raciocínio clínico está no centro da prática médica e emaranhado em uma confusão conceitual.A teoria da dualidade da probabilidade permite analisar seus aspectos objetivos e subjetivos. Objetivos Fazer revisão sistemática da literatura sobre o raciocínio clínico para tomada de decisão na educação médica e uma proposta chamada "Pensamento Conforme a Regra de Bayes" (PCRB). Métodos A revisão sistemática foi realizada na base PubMed até a data de 27/02/2022, seguindo metodologia rigorosa, por pesquisador experiente em revisão sistemática. A proposta PCRB, apresentada na discussão, foi elaborada no trabalho de conclusão de graduação em Filosofia na Universidade Federal de Minas Gerais. Usou-se a insuficiência cardíaca como exemplo. Resultados De 3340 artigos encontrados, incluíram-se 154 artigos: 24 tratando da condição de incerteza; 87 tratando de conceitos vagos (discussão de casos, heurística, lista de vieses cognitivos, escolha com sabedoria) incluídos sob o termo 'arte'; e 43 discutindo a ideia geral de raciocínio indutivo ou dedutivo. PCRB oferece regras de coerência e reprodutibilidade, inferência sob incerteza e regra de aprendizado, e pode, por meio da perspectiva subjetiva sobre a probabilidade, incorporar aqueles termos vagos classificados como 'arte', bem como argumentos e evidências. Conclusões A revisão sistemática mostra que o raciocínio é fundado na incerteza, predominantemente probabilístico; além de mostrar algumas possibilidades de erro do pensamento hipotético-dedutivo. O PCRB é um pensamento probabilístico em duas etapas que pode ser ensinado. A regra de Bayes é uma ferramenta linguística, uma regra geral de raciocínio, de diagnóstico, de comunicação científica e de revisão do conhecimento médico conforme novas evidências.

Abstract Background Clinical reasoning is at the core of medical practice and entangled in a conceptual confusion. The duality theory in probability allows to evaluate its objective and subjective aspects. Objectives To conduct a systematic review of the literature about clinical reasoning in decision making in medical education and to propose a "reasoning based on the Bayesian rule" (RBBR). Methods A systematic review on PubMed was conducted (until February 27, 2022), following a strict methodology, by a researcher experienced in systematic review. The RBBR, presented in the discussion section, was constructed in his undergraduate dissertation in Philosophy at Minas Gerais Federal University. Heart failure was used as example. Results Of 3,340 articles retrieved, 154 were included: 24 discussing the uncertainty condition, 87 on vague concepts (case discussion, heuristics, list of cognitive biases, choosing wisely) subsumed under the term "art", and 43 discussing the general idea of inductive or deductive reasoning. RBBR provides coherence and reproducibility rules, inference under uncertainty, and learning rule, and can incorporate those vague terms classified as "art", arguments and evidence, from a subjective perspective about probability. Conclusions This systematic review shows that reasoning is grounded in uncertainty, predominantly probabilistic, and reviews possible errors of the hypothetico-deductive reasoning. RBBR is a two-step probabilistic reasoning that can be taught. The Bayes theorem is a linguistic tool, a general rule of reasoning, diagnosis, scientific communication and review of medical knowledge according to new evidence.

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INTRODUCTION: There are few drugs with proven efficacy in cutaneous leishmaniasis (CL), and pentavalent antimonial derivatives are still the main first-line therapeutic agents worldwide, despite their recognized high toxicities. Randomized controlled clinical trials assessing the efficacy and safety of new therapeutic modalities are of high priority, and the definition of the design of such trials raises debate about the use of placebo as a comparator. To support the use of placebo as a comparator, two main points need to be addressed: 1--the cure rate without any therapeutic intervention and 2--the damage caused by CL and its impact on patients. OBJECTIVE: The aim of this study was to systematically assess the spontaneous cure rate for American CL and to broaden the discussion about placebo use in CL trials. METHODS: The PRISMA guidelines for systematic reviews and the Cochrane manual were followed. The sources used were the PubMed and LILACS databases. Studies were included if they reported cure rates using placebo or no treatment in American CL. RESULTS: Thirteen studies of a total of 352 patients were ultimately included in this review. The summarized global cure rates for all Leishmania species according to the intention-to-treat analyses performed at approximately three ("initial cure") and nine ("definitive cure") months after "no treatment" or placebo use were 26% (CI95%: 16 to 40%) and 26% (CI95%:16 to 38%), respectively. Notably, a significantly lower cure rate was observed for L. braziliensis infection (6.4%, CI95%:0.2 to 20%) than for L. mexicana infection (44%, CI95%:19 to 72%), p = 0.002. Of note, relapse occurred in 20% of patients with initial healing (CI95%:9.2 to 38.9%). CONCLUSION: These results clearly demonstrate a low spontaneous cure rate following no-treatment or placebo use, confirming that this strategy for the control group in CL studies expose patients to greater morbidity, especially for CL caused by L. braziliensis. Therefore, from this point, the crucial question to consider regarding placebo use is the seriousness of the suffering caused by this disease.

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The aim of this study was to evaluate the accuracy of invasive and non-invasive tests for diagnosis of visceral leishmaniasis (VL) in a large series of human immunodeficiency virus (HIV)-infected patients. In this delayed-type cross-sectional study, 113 HIV-infected symptomatic patients were evaluated by an adjudication committee after clinical follow-up to establish the presence or absence of VL as the target condition (reference test). The index tests were recombinant K39 antigen-based immunochromatographic test (rK39), indirect fluorescent antibody test (IFAT), prototype kit of direct agglutination test (DAT-LPC), and real-time polymerase chain reaction (qPCR) in peripheral blood. Compared with parasitological test and adjudication committee diagnosis or latent class model analyses, IFAT and rk39 dipstick test presented the lowest sensitivity. DAT-LPC exhibited good overall performance, and there was no statistical difference between DAT-LPC and qPCR diagnosis accuracy. Real-time PCR emerges as a less invasive alternative to parasitological examination for confirmation of cases not identified by DAT.

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BACKGROUND: The role of intravascular ultrasound (IVUS) in percutaneous coronary interventions (PCI) is still controversial despite several previously published meta-analyses. A meta-analysis to evaluate the controversial role of IVUS-guided PCI with bare-metal stenting was performed and a previous published meta-analysis was re-evaluated in order to clarify the discrepancy between results of these studies. METHODS: A systematic review was performed by an electronic search of the PubMed, Embase and Web of Knowledge databases and by a manual search of reference lists for randomized controlled trials published until April 2011, with clinical outcomes and, at least, six months of clinical follow-up. A meta-analysis based on the intention to treat was performed with the selected studies. RESULTS: Five studies and 1,754 patients were included. There were no differences in death (OR = 1.86; 95% CI = 0.88-3.95; p = 0.10), non-fatal myocardial infarction (OR = 0.65; 95% CI = 0.27-1.58; p = 0.35) and major adverse cardiac events (OR = 0.74; 95% CI = 0.49-1.13; p = 0.16). An analysis of the previous published meta-analysis strongly suggested the presence of publication bias. CONCLUSIONS: There is no evidence to recommend routine IVUS-guided PCI with bare-metal stent implantation. This may be explained by the paucity and heterogeneity of the studies published so far.

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BACKGROUND: Human visceral leishmaniasis (VL), a potentially fatal disease, has emerged as an important opportunistic condition in HIV infected patients. In immunocompromised patients, serological investigation is considered not an accurate diagnostic method for VL diagnosis and molecular techniques seem especially promising. OBJECTIVE: This work is a comprehensive systematic review and meta-analysis to evaluate the accuracy of serologic and molecular tests for VL diagnosis specifically in HIV-infected patients. METHODS: Two independent reviewers searched PubMed and LILACS databases. The quality of studies was assessed by QUADAS score. Sensitivity and specificity were pooled separately and compared with overall accuracy measures: diagnostic odds ratio (DOR) and symmetric summary receiver operating characteristic (sROC). RESULTS: Thirty three studies recruiting 1,489 patients were included. The following tests were evaluated: Immunofluorescence Antibody Test (IFAT), Enzyme linked immunosorbent assay (ELISA), immunoblotting (Blot), direct agglutination test (DAT) and polimerase chain reaction (PCR) in whole blood and bone marrow. Most studies were carried out in Europe. Serological tests varied widely in performance, but with overall limited sensitivity. IFAT had poor sensitivity ranging from 11% to 82%. DOR (95% confidence interval) was higher for DAT 36.01 (9.95-130.29) and Blot 27.51 (9.27-81.66) than for IFAT 7.43 (3.08-1791) and ELISA 3.06 (0.71-13.10). PCR in whole blood had the highest DOR: 400.35 (58.47-2741.42). The accuracy of PCR based on Q-point was 0.95; 95%CI 0.92-0.97, which means good overall performance. CONCLUSION: Based mainly on evidence gained by infection with Leishmania infantum chagasi, serological tests should not be used to rule out a diagnosis of VL among the HIV-infected, but a positive test at even low titers has diagnostic value when combined with the clinical case definition. Considering the available evidence, tests based on DNA detection are highly sensitive and may contribute to a diagnostic workup.

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Minimum accuracy of HIV diagnostic tests is considered the pillar on which testing strategies for all settings must be based. Systematic reviews and meta-analyses have shown that performance of the same test in different settings may vary according to several factors, resulting in different confidence intervals for sensitivity and specificity. Prevalence of HIV infection may influence observed test accuracy. The purpose of this article is to use the knowledge from meta-analyses of general diagnostic tests to inform the specific field of HIV diagnostic strategies. We propose the 'Bayesian' thinking: considering the pretest probability (i.e., prevalence, risk factors) and understanding test limitations to estimate a post-test probability of HIV diagnosis. Cost-effectiveness analysis, patient preferences and ethical issues must also be considered in HIV testing strategies.

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BACKGROUND: The pathophysiology of cardiovascular disease (CVD) in chronic kidney disease (CKD) remains uncertain, but autonomic dysfunction seems to be involved. The aim of the study is to investigate the cardiac dysautonomia in uremic pediatric individuals through iodine 123 metaiodobenzylguanidine (MIBG) scintigraphy and heart rate variability (HRV) analysis. METHODS AND RESULTS: We divided 40 CKD patients (aged 5-21 years) into 4 groups according to the treatment for CKD: conservative (n = 7), continuous ambulatory peritoneal dialysis (n = 5), hemodialysis (n = 13), and kidney transplantation (n = 15). Planar and tomographic I-123 MIBG images were acquired, and early and late cardiac uptake, cardiac and lung washout, and regional I-123 MIBG uptake were evaluated. Hemodialysis patients showed increased cardiac washout (P = .002), a heterogeneous pattern of I-123 MIBG distribution (P = .036), and lower values of the low-frequency (LF) component of HRV (P = .040). Subjects undergoing continuous ambulatory peritoneal dialysis had reduced lung washout (P = .030). The cardiac washout correlated positively with parathyroid hormone levels and negatively with creatinine clearance. There was a significant negative association between the LF component and cardiac washout. CONCLUSIONS: Uremic cardiac dysautonomia may be characterized by a decreased LF component of HRV, increased I-123 MIBG washout, and a heterogeneous distribution pattern in the left ventricular walls; these abnormalities were not present after kidney transplantation.

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BACKGROUND AND METHODS: In order to study fractal HR dynamics in Chagas disease, we performed detrended fluctuation analysis (DFA)-along with analysis of power-law beta slope (beta index) and standard deviation of N-N intervals (SDNN)-in edited and unedited (with ventricular premature beats - VPBs, only in DFA analysis) series of R-R intervals from Holter monitoring of healthy controls (Group 0, n = 27) and Chagas disease patients with left ventricular (LV) ejection fraction >50% (Group 1, n = 137) and with LV ejection fraction <50% (Group 2, n = 23). RESULTS: When analyzed from the edited R-R interval data, the long-term scaling exponent alpha(2) is altered both among the Chagas patients with and without LV dysfunction. The short-term scaling exponent alpha(1) was higher in Group 1 Chagas patients as compared to controls (P < 0.01) and did not differ between Group 2 and controls. In unedited R-R interval series, alpha(1) was significantly reduced in Group 2 Chagas patients (0.55 +/- 0.002) as compared to controls (0.90 +/- 0.002) and Group 1 (0.91 +/- 0.003) (P < 0.001), but did not differ between Group 1 and controls. Similarly alpha(2) was lower in Group 2 compared to other groups (P < 0.001). SDNN did not differ between the groups, but the beta index derived from 1/f model was reduced both in Group 1 and 2 Chagas patients as compared to controls (P < 0.01). There was strong correlation (rs = 0.82; P < 0.001) between the beta and alpha(2) index from edited series. There was an inverse correlation (rs =-0.63, P < 0.01) between the number of VPBs and alpha(1) index of unedited series. CONCLUSIONS: The long-term fractal HR dynamics altered in chagasic patients with and without LV dysfunction could be an early sign of autonomic dysfunction. Patients with impaired LV function show marked alterations in short-term fractal HR dynamics toward more random behavior, mainly due to frequent ectopy. Prospective studies are necessary to define the value of these indices as predictors of death in Chagas disease.

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Acute myocardial infarction (AMI) is a rare, potentially fatal and often unrecognized complication of blunt thoracic trauma (BTT). Heart injury is diagnosed in less than 10% of all cases of blunt thoracic trauma. Medical literature is scarce in publications about AMI caused by BTT (AMI-BTT). There is no specific protocol on this issue. We describe two cases of AMI-BTT in young patients who were previously healthy and with no risk factors for coronary artery disease. The diagnostic tools and therapeutic approach are discussed based on a literature review. We conclude that the emergency physician should be alert for the possibility of AMI in victims of BTT, regardless of the intensity of the trauma.

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OBJECTIVE: To determine the value of the radiological study of the thorax for diagnosing left ventricular dilation and left ventricular systolic dysfunction in patients with Chagas' disease. METHODS: A cross-sectional study of 166 consecutive patients with Chagas' disease and no other associated diseases. The patients underwent cardiac assessment with chest radiography and Doppler echocardiography. Sensitivity, specificity, and positive and negative predictive values of chest radiography were calculated to detect left ventricular dysfunction and the accuracy of the cardiothoracic ratio in the diagnosis of left ventricular dysfunction with the area below the ROC curve. The cardiothoracic ratio was correlated with the left ventricular ejection fraction and the left ventricular diastolic diameter. RESULTS: The abnormal chest radiogram had a sensitivity of 50%, specificity of 80.5%, and positive and negative predictive values of 51.2% and 79.8%, respectively, in the diagnosis of left ventricular dysfunction. The cardiothoracic ratio showed a weak correlation with left ventricular ejection fraction (r=-0.23) and left ventricular diastolic diameter (r=0.30). The area calculated under the ROC curve was 0.734. CONCLUSION: The radiological study of the thorax is not an accurate indicator of left ventricular dysfunction; its use as a screening method to initially approach the patient with Chagas' disease should be reevaluated.

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Left ventricular dysfunction in Chagas' disease is common but can be difficult to detect. We investigated whether measurement of plasma brain natriuretic peptide (BNP) could identify patients with left ventricular dysfunction who need further investigation or treatment. Among patients with an abnormal electrocardiogram or chest radiograph, a BNP concentration of 60.7 pmol/L or higher has a sensitivity and positive predictive value of 80%, and specificity and negative predictive value of 97%. Measurement of plasma BNP concentration could be a useful method to screen patients with Chagas' disease.

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