Acute appendicitis is a common cause of abdominal surgery in children, and is the result of appendiceal luminal obstruction and subsequent inflammation. The clinical presentation is often variable, allowing imaging to play a central role in disease identification and characterization. Ultrasound is often the modality of choice for diagnosis of appendicitis in children. Ready availability and lack of ionizing radiation are attractive features of sonography, though operator dependence is a potential barrier. Computed tomography (CT) was historically the preferred modality in children, as in adults, but recent awareness of the risks of radiation has reduced its usage. The purpose of this article is to detail the imaging findings of appendicitis in children. The discussion will focus on typical signs of appendicitis seen on ultrasound, CT, and magnetic resonance imaging. Considerations for percutaneous drainage by interventional radiology will also be presented. Finally, the evolution of imaging algorithms for appendicitis will be discussed.

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L’appendicite aiguë est la pathologie abdominale aiguë courante et la plus fréquente parmi celles qui nécessitent une intervention chirurgicale rapide. L’imagerie occupe une place croissante dans son diagnostic parce qu’elle tente d’éviter simultanément les appendicectomies inutiles et les perforations appendiculaires compliquées de péritonite tout en recherchant des pathologies alternatives. Si plusieurs techniques d’imagerie sont disponibles – dont la radiographie sans préparation de l’abdomen (dont la performance est faible) et l’imagerie par résonance magnétique (peu disponible, en particulier en urgence) – l’ultrasonographie (US) et la tomodensitométrie (TDM) occupent des positions centrales. Nos études ont investigué la performance de ces dernières, en considérant notamment la réduction de la dose d’irradiation et le recours aux contrastes artificiels. En effet, l’irradiation liée à l’usage de la TDM est à considérer puisque les patients souffrant d’appendicite aiguë sont jeunes (en moyenne 30 ans) tout comme le recours aux contrastes associé à des coûts, de l’inconfort et des risques. Enfin, la performance de ces techniques étant susceptibles d’être influencée par la corpulence des patients et leur quantité de graisse intra-abdominale, l’influence de ces paramètres sur la performance a été évaluée.<p><p>A travers quatre études, nous avons montré que l’US et la TDM sans contraste IV ou entérique ont des performances similaires quant au diagnostic d’appendicite aiguë et de pathologies alternatives, indépendamment de l’expérience du radiologue et de la corpulence du patient. Néanmoins, les examens non concluants (sans diagnostic d’appendicite aiguë ni de pathologie alternative mais où l’appendice n’est pas vu) sont plus fréquents en US qu’en TDM. L’appendice normal, dont la visualisation permet d’exclure le diagnostic d’appendicite aiguë, est plus fréquemment visible en TDM qu’en US, mais en TDM la reproductibilité quant à considérer la même structure comme étant l’appendice dépend du lecteur. L’injection IV de contraste iodé n’augmente pas la proportion d’appendices détectés mais la reproductibilité d’un lecteur particulier. Aucune caractéristique du sujet ni de son appendice, y compris son environnement abdominal, ne permet de prédire cette reproductibilité. La performance de la TDM est constante quelle que soit la dose d’irradiation ou le recours au contraste IV et/ou entérique, indépendamment de la corpulence du patient. La hiérarchie de l’information apportée par les signes évocateurs d’appendicite aiguë n’est pas influencée par la dose; l’infiltration de la graisse péri-appendiculaire et le diamètre appendiculaire en étant les signes les plus prédictifs, malgré le moindre rapport signal/bruit de l’image générée à faible dose. La fréquence de visualisation de l’appendice est aussi indépendante de cette dose. L’exactitude du diagnostic dépend principalement du lecteur mais pas du contraste – quelle qu’en soit la voie d’administration (orale ou IV) – ni de la dose d’irradiation. Le genre du patient influence cependant cette exactitude, le diagnostic étant plus fréquemment correct chez l’homme que chez la femme, en particulier dans les pathologies alternatives.<p><p>En conclusion, comme les techniques US et TDM que nous avons investiguées ont des performances équivalentes, les risques associés à l’irradiation et au contraste doivent intervenir dans leur choix. L’US, utilisée en première intention, devrait être complétée par la TDM si son résultat n’est pas concluant. Dans ce cas, la TDM devrait être réalisée, toujours à basse dose d’irradiation, d’abord sans puis, si nécessaire, avec contraste IV et/ou oral.<p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2016-09-14T18:04:46Z No. of bitstreams: 1 samiraelhassan_dissert.pdf: 845797 bytes, checksum: 9cdbef0eb8a8206334b32172283744d7 (MD5) / Made available in DSpace on 2016-09-14T18:04:46Z (GMT). No. of bitstreams: 1 samiraelhassan_dissert.pdf: 845797 bytes, checksum: 9cdbef0eb8a8206334b32172283744d7 (MD5) Previous issue date: 2014-09-23 / Introduction: Acute appendicitis is the process of the inflamation of the appendix and it is the most frequent cause of acute abdomen. About 50% of patients with acute appendicitis show classic clinical findings. The others have atypical manisfestations which make diagnosis more difficult, such as in pregnant women, women of childbearing age, and patients younger than ten and more than fifty years of age. At the time of surgery, approximately 35% of the cases are in the advanced phase with perforation and local abscesses. Methods of diagnosis such as ultrasonography and computed tomography can help in the diagnosis of acute appendicitis minimizing surgical delay and reducing appendix perforation and unnecesarry appendectomies. Patients with typical signs and symptoms of acute appendicitis should be assessed and undergo appendectomy. Those with atypical presentation should have image exams. First, they should have an ultrasonography. If the exam doesn't present clearly or if it isn't conclusive, computed tomography should be performed. Objetive: Determine sensitivity and specificity of ultrasonography and computed tomography of patients suspected of having acute appendicitis. Verify a positive diagnosis of acute appendicitis by computed tomography when ultrasonography results are negative in patients suspected of acute appendicitis. Casuistic and method: Prospectively, we analyzed 60 patients, from January of 2006 to May of 2007, between 2 and 90 years old, of both sexes, from the Surgery Department of the Hospital de Base de São Jose do Rio Preto who have been sent to the Radiology Department (Ultrasonography and Tomography Unit) of the above mentioned hospital. The ultrasonography exams were done with a graded compression technique. The computed tomography exams were realized with colonic contrast administered rectally. The conventional axial images of 5 mm of thickness were taken from the pelvic region. Afterwards, iodine contrast was given intravenously and tomographic sections were taken by the helical technique with 5mm of thickness in the pelvic region. After this, other sections of 10mm of thickness were taken of the entire abdomen. Results: Of 60 patients that had ultrasonography, 40 (66.67%) presented positive exams for acute appendicitis. The ultrasonography sensitivity for acute appendicitis was 100%, while the specificity was 83.33%. Of 27 patients that underwent computed tomography, 19 (70.37%) presented negative exams for acute appendicitis. The sensitivity of computed tomography to acute appendicitis was 100%, and the specificity was 33.33%. Conclusion: The diagnosis of acute appendicitis by imaging methods helps to reduce the frequency of unnecessary appendicetomies, frequent complications because of delayed diagnosis, the costs of exams, and long hospital stays. / Introdução: A apendicite aguda é o processo inflamatório do apêndice cecal e a causa mais frequente de abdome agudo. Cerca de 50% dos pacientes com apendicite aguda apresentam quadro clínico clássico. Os demais apresentam manifestações atípicas, o que dificulta o diagnóstico, principalmente gestantes, mulheres em idade reprodutiva, pacientes com menos de 10 anos e com mais de 50 anos de idade. Em aproximadamente 35% dos casos, a apendicite já está em fase adiantada, com perfuração e abscesso local, no momento da cirurgia. Métodos de diagnóstico, ultrassonografia e tomografia computadorizada, podem auxiliar no diagnóstico da apendicite aguda, minimizando o atraso na cirurgia, com subsequente redução do risco de perfuração do apêndice cecal e de apendicectomias negativas. Pacientes com sinais e sintomas típicos de apendicite aguda devem ser prontamente avaliados e conduzidos à apendicectomia. Aqueles, com apresentação ou achados atípicos, devem realizar exames de imagem. Objetivo: Determinar em pacientes com suspeita de apendicite aguda a relação dos resultados do US e TC com os sinais e sintomas clínicos, a sensibilidade e a especificidade da ultrassonografia e da tomografia computadorizada e a positividade da tomografia computadorizada, quando o ultrassom for negativo. Casuística e Método: Foram analisados, prospectivamente, 60 indivíduos no período de janeiro de 2006 a maio de 2007, com idade entre 2 a 90 anos, de ambos os gêneros, procedentes do Departamento de Cirurgia do Hospital de Base de São José do Rio Preto-SP e encaminhados para o setor de ultrassonografia e de tomografia computadorizada do Departamento de Radiologia, no referido hospital. Os exames de ultrassom foram realizados com a técnica de compressão gradual. Os exames de tomografia computadorizada foram realizados com contraste colônico via retal. Foram realizadas imagens axiais convencionais de 5 mm de espessura na região pélvica. Posteriormente, foi administrado contraste iodado endovenoso e foram realizados cortes tomográficos pela técnica helicoidal com 5 mm de espessura na região pélvica. Em seguida, foram realizados cortes tardios de 10 mm de espessura em todo o abdome. Resultados: Dos 60 pacientes que realizaram US, 40 (66,67%) apresentaram exames positivos para apendicite aguda. A sensibilidade do US, para apendicite aguda, foi de 100%, a especificidade de 83,33%. Dos 27 pacientes submetidos à TC, 19 (70,37%) apresentaram exames negativos para apendicite aguda. A sensibilidade da TC, para apendicite aguda foi, de 100%, a especificidade de 33,33%. Conclusão: O diagnóstico da apendicite aguda, por métodos de imagem, contribui para a redução na frequência de apendicectomias negativas, de complicações decorrentes do atraso do seu diagnóstico, dos custos com exames e das internações prolongadas.

Abstract Epidemiological and clinical data suggest that acute appendicitis might have two different forms with different disease severities. Uncomplicated and complicated acute appendicitis appear to be distinct entities instead of consecutive events. Appendicitis does not always inevitably progress to perforation and most cases are uncomplicated by nature. This supports the importance of an accurate differential diagnosis between uncomplicated and complicated acute appendicitis enabling treatment optimization. This thesis consists of three studies. The first study evaluated the possibility to differentiate between uncomplicated and complicated appendicitis using only clinical symptoms and laboratory markers with a special focus on predicting the presence of an appendicolith without the use of modern imaging. We found neither sufficiently reliable to accurately estimate the severity of acute appendicitis or to determine the presence of an appendicolith, supporting the use of computed tomography imaging to assess the disease. The second study focused on clarifying the histopathological differences between uncomplicated acute appendicitis and acute appendicitis presenting with an appendicolith; a calcified deposit of faecal material in the appendiceal lumen. It’s presence has been shown to predict perforation and failure of conservative treatment. This study evaluated the histopathological findings of computed tomography diagnosed uncomplicated acute appendicitis and appendicolith appendicitis without perforation. Acute appendicitis presenting with an appendicolith was histopathologically different from uncomplicated acute appendicitis on all the assessed histological parameters, indicating the potentially complicated nature of appendicolith appendicitis. The third study was a randomized, multicentre clinical trial comparing interval appendectomy with follow-up with magnetic resonance imaging after successful initial non-operative treatment of complicated acute appendicitis presenting with a periappendicular abscess. The study hypothesis was that an interval appendectomy might not be necessary based on the previously reported low appendicitis recurrence rate after a periappendicular abscess. The original study hypothesis was left unresolved, as an unexpectedly high rate of appendiceal neoplasms was detected in the study population and the study was prematurely terminated. The neoplasm rate after a periappendicular abscess in this prematurely terminated study was high (20%). All the neoplasms were detected in patients over 40 years of age, strongly supporting an interval appendectomy for all patients over 40 years of age if this rate of neoplasms is validated in future studies. / Tiivistelmä Aiemmat tutkimukset viittaavat siihen, että on olemassa kaksi erillistä akuutin umpilisäkkeen tulehduksen muotoa: komplisoitumaton ja komplisoitunut. Nämä muodot eivät ole toistensa jatkumo: umpilisäkkeen tulehdus ei aina johda umpilisäkkeen puhkeamiseen, vaan valtaosa umpilisäkkeen tulehdustapauksista on komplisoitumattomia. Oikean hoitotavan valinta edellyttää tarkkaa erotusdiagnostiikkaa tautimuotojen välillä Tämä väitöskirjatyö koostuu kolmesta osatyöstä. Ensimmäisen osatyö selvitti, onko komplisoitumaton ja komplisoitunut umpilisäkkeen tulehdus mahdollista erottaa ilman kuvantamista kliinisin löydöksin ja laboratoriokokein painottaen ulostekiven olemassaolon ennustamista. Umpilisäkkeen tulehduksen vaikeusasteen tai ulostekiven olemassaolon ennustaminen ei ollut mahdollista pelkästään kliinisten löydösten tai laboratoriokokeiden perusteella. Tämä korostaa tietokonetomografian merkitystä taudin vaikeusasteen arvioinnissa. Toinen osatyö selvitti histologisia eroja komplisoitumattoman umpilisäkkeen tulehduksen ja ulostekiven sisältävän äkillisen umpilisäkkeen tulehduksen välillä. Ulostekiven tiedetään ennustavan umpilisäkkeen puhkeamaa ja konservatiivisen hoidon epäonnistumista. Tutkimuksessa selvitettiin histologisia löydöksiä potilailla, joilla oli tietokonetomografiatutkimuksella varmistettu komplisoitumaton äkillinen umpilisäkkeen tulehdus tai ulostekiven sisältävä äkillinen umpilisäkkeen tulehdus ilman puhkeamaa. Tutkimuksessa todettiin, että ulostekiven sisältävät tulehtuneet umpilisäkkeet poikkeavat kaikkien tutkittujen parametrien osalta komplisoitumattomasta umpilisäkkeen tulehduksesta. Tämä tukee käsitystä ulostekiven sisältävän umpilisäkkeen tulehduksen komplisoituneesta luonteesta. Kolmas osatyö oli randomoitu monikeskustutkimus, jossa verrattiin toisiinsa rauhallisessa vaiheessa tehtyä umpilisäkkeen poistoa ja seurantaa magneettiresonanssikuvauksella potilailla, joilla oli onnistuneesti hoidettu konservatiivisesti umpilisäkkeen ympäryskudoksen paise. Hypoteesina oli, että myöhempi umpilisäkkeen poisto ei ole tarpeen, koska tulehduksen uusiutumisen riski umpilisäkkeen vieruskudoksen paiseen hoidon jälkeen on aiemmin raportoitu matalaksi. Tutkimushypoteesi jäi avoimeksi, koska tutkimuksen aikana havaittiin runsaasti umpilisäkkeen kasvaimia, mikä johti tutkimuksen ennenaikaiseen keskeyttämiseen. Umpilisäkkeen kasvainten ilmaantuvuus oli 20 %, kaikki yli 40-vuotiailla potilailla. Mikäli tutkimuksen tulokset vahvistuvat tulevissa tutkimuksissa, kaikille yli 40-vuotiaille potilaille tulisi suositella umpilisäkkeen poistoa sairastetun umpilisäkkeen vieruskudoksen paiseen jälkeen.

<p>The aim was to identify diagnostic difficulties for acute abdominal pain at the emergency department and during hospital stay. A total of 3349 patients admitted to Mora Hospital with acute abdominal pain of up to seven days duration, were registered prospectively for history and clinical signs according to a structured schedule. The preliminary diagnosis from the attending physician at the emergency department, any investigations or surgery and final diagnosis were registered at a follow-up after at least one year. </p><p>There were no differences in diagnostic performance between physicians with 0.5 to 5 years of medical experience. The information collected and a careful examination of the patient was more important than formal competence. The main differential diagnostic problem was non-specific abdominal pain; this was the same for diagnoses requiring surgery. Patients originally diagnosed as not needing surgery had a median delay before operation of 22 hours (mean 40 hours, with 95% confidence interval of 30-50 hours), compared to 8 hours (mean 15 hours, 95% confidence interval of 12-28 hours) for patients with the same final follow-up diagnosis as the preliminary diagnosis. Constipation was a diagnostic pitfall, as 9% of the patients considered constipated required surgery for potentially life threatening reasons and 8% were later found to have an abdominal malignancy. Both the preliminary diagnosis and the discharge diagnosis were less reliable for elderly patients than for younger patients. Elderly patients often had specific organ disease and arrived at the emergency department after a longer history of abdominal pain. </p><p>This study confirms that assessment of suspected appendicitis can still be based on clinical judgements combined with laboratory tests. Classical clinical findings indicating localised inflammation, such as isolated pain in the right iliac fossa, rebound tenderness, right-sided rectal tenderness, pain migration to the right iliac fossa, local guarding and aggravation of pain when moving, were reliable for predicting acute appendicitis. A CT scan can be saved for the more equivocal cases of acute abdominal pain. A generous strategy regarding CT scan among elderly patients with acute abdominal pain, even in the absence of pronounced signs of an inflammatory intra-abdominal process, is recommended.</p>

The aim was to identify diagnostic difficulties for acute abdominal pain at the emergency department and during hospital stay. A total of 3349 patients admitted to Mora Hospital with acute abdominal pain of up to seven days duration, were registered prospectively for history and clinical signs according to a structured schedule. The preliminary diagnosis from the attending physician at the emergency department, any investigations or surgery and final diagnosis were registered at a follow-up after at least one year. There were no differences in diagnostic performance between physicians with 0.5 to 5 years of medical experience. The information collected and a careful examination of the patient was more important than formal competence. The main differential diagnostic problem was non-specific abdominal pain; this was the same for diagnoses requiring surgery. Patients originally diagnosed as not needing surgery had a median delay before operation of 22 hours (mean 40 hours, with 95% confidence interval of 30-50 hours), compared to 8 hours (mean 15 hours, 95% confidence interval of 12-28 hours) for patients with the same final follow-up diagnosis as the preliminary diagnosis. Constipation was a diagnostic pitfall, as 9% of the patients considered constipated required surgery for potentially life threatening reasons and 8% were later found to have an abdominal malignancy. Both the preliminary diagnosis and the discharge diagnosis were less reliable for elderly patients than for younger patients. Elderly patients often had specific organ disease and arrived at the emergency department after a longer history of abdominal pain. This study confirms that assessment of suspected appendicitis can still be based on clinical judgements combined with laboratory tests. Classical clinical findings indicating localised inflammation, such as isolated pain in the right iliac fossa, rebound tenderness, right-sided rectal tenderness, pain migration to the right iliac fossa, local guarding and aggravation of pain when moving, were reliable for predicting acute appendicitis. A CT scan can be saved for the more equivocal cases of acute abdominal pain. A generous strategy regarding CT scan among elderly patients with acute abdominal pain, even in the absence of pronounced signs of an inflammatory intra-abdominal process, is recommended.

Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-04-12T14:56:26Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Júlio F. A. Flôres.pdf: 3515655 bytes, checksum: 1e8754bf324f0131dfff4b0f1146868f (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-04-12T14:57:01Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Júlio F. A. Flôres.pdf: 3515655 bytes, checksum: 1e8754bf324f0131dfff4b0f1146868f (MD5) / Made available in DSpace on 2018-04-12T14:57:01Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_Júlio F. A. Flôres.pdf: 3515655 bytes, checksum: 1e8754bf324f0131dfff4b0f1146868f (MD5) Previous issue date: 2018-02-08 / Background. Acute appendicitis is a public health issue: its morbidity increases significantly if not diagnosed and treated in a timely manner and its complications may result in patient’s death. Several diagnostic methods and several instruments have been investigated and many have been validated by medical practice and medical teaching about appendicitis’ diagnosis. Alvarado’s criteria are part of this group; thus, their semiotic simplicity could justify their usage in the education of early-years medical students through the employment of a platform largely used by individuals of the corresponding age. Objectives. To develop a digital form composed of Alvarado’s Criteria for the diagnosis of acute appendicitis; to determine the form validity when applied by early-years medical students. Methods. An electronic form was developed using digital platform Google© Forms. Early-years medical students, after a lecture about the disease, evaluated abdominal pain syndrome patients selected by active search in medical records and responded to Alvarado’s Criteria digital form, deciding or not for the acute appendicitis hypothesis. These data, tabulated in Microsoft© Excel electronic spreadsheet, were then compared by the researcher to similar data contained in medical records, and confirmed or not the diagnosis of acute appendicitis. Variables were arranged in 2 x 2 tables and were submitted to subsequent statistical analysis. Results. An electronic form was developed using digital Google© Forms platform. This form was integrated by cloud computing to Microsoft© Excel electronic spreadsheet for the compilation of data concerning the Score of Alvarado. After a brief introductory lecture, early-years medical students were invited to fill the form out, by using their smartphones. Subsequently, they were supposed to indicate in the form which patients would carry the diagnosis of acute appendicitis among those with abdominal pain. For a sample of 211 patients, electronic application of Alvarado’s Criteria by students demonstrated sensitivity of 80%, specificity of 81%, positive predictive value of 17% and negative predictive value of 98% in the diagnosis of acute appendicitis. The accuracy of the studied method was 81%. Frequency of appendicitis (4%) in the observed population corresponded to usual described medical literature prevalence values for the disease. Conclusions. Results pointed to the feasibility of the employment of the digital platform and demonstrated that the validity of the inserted Alvarado Criteria could be satisfactorily measured when applied by medical students of initial years. / Justificativa. Apendicite aguda é uma questão de saúde pública: sua morbidade aumenta significativamente se não diagnosticada e tratada em tempo hábil e suas complicações podem resultar em morte do paciente. Diversos métodos diagnósticos e instrumentos vêm sendo investigados e muitos têm sido validados, dentro do ensino e da prática da Medicina, para o diagnóstico da doença. Os Critérios de Alvarado fazem parte desse grupo. Destarte, sua simplicidade semiótica poderia justificar seu ensino a estudantes de anos iniciais do Curso de Medicina, com a utilização de plataforma de utilização disseminada entre indivíduos da faixa etária correspondente. Objetivos. Desenvolver formulário digital contendo os Critérios de Alvarado para o diagnóstico de apendicite aguda; determinar a validade da aplicação do formulário por parte de estudantes dos anos iniciais do curso de graduação de Medicina. Métodos. Desenvolveu-se formulário eletrônico com a utilização da plataforma digital Google© Forms. Estudantes de Medicina, após preleção sobre a doença por parte do pesquisador, avaliaram pacientes com síndrome dolorosa abdominal, escolhidos por busca ativa em prontuários, decidindo ou não pela hipótese de apendicite aguda ao preencherem o questionário digital montado com os Critérios de Alvarado. Os dados, tabulados pelo sistema em planilha Microsoft© Excel, foram então cotejados com informações obtidas em prontuários pelo pesquisador, confirmando ou não o diagnóstico de apendicite aguda. As variáveis foram agrupadas em tabelas 2 x 2 com análise estatística subsequente. Resultados. Desenvolveu-se formulário eletrônico com a utilização da plataforma Google© Forms, integrando-a na nuvem com planilha do Microsoft© Excel para a compilação de dados referentes ao Escore de Alvarado. Após instrução inicial, alunos de anos iniciais do Curso de Medicina foram convidados a preencher o formulário, com a utilização de seus smartphones, na tentativa de indicar, entre pacientes com dor abdominal, quais os portadores de apendicite aguda. Para uma amostra de 211 pacientes, a aplicação eletrônica dos Critérios de Alvarado pelos estudantes demonstrou possuir sensibilidade de 80% e especificidade de 81%, valor preditivo positivo de 17% e valor preditivo negativo de 98%. A acurácia do método estudado foi de 81%. A frequência de apendicite (4%) nos pacientes observados correspondeu ao valor usualmente citado na literatura para prevalência da doença. Conclusões. Os resultados apontaram que o desenvolvimento da plataforma digital foi factível e demonstraram que a validade dos critérios de Alvarado inseridos pôde ser medida satisfatoriamente quando empregados por estudantes de Medicina de anos iniciais.

gcpriale@hotmail.com / Objective: Identify the frequency of negative appendectomy (NA) and associated factors associated in a private hospital in Lima. Methods: Retrospective study of all appendectomies performed between 2012 and 2013 at a private hospital of Lima-Peru. We reviewed the medical records of patients who underwent appendectomy and had a medical report of emergency. We excluded the ones without pathology reports. Adjusted ORs were calculated with a logistic regression model to identify factors associated with AN. Results: Three hundred seventy-six appendectomies were performed for suspected appendicitis 55.9% in women). The average patient age was 33.4 ± 17.6 years. We identified 28 AN cases of 363 patients (7.7%). We found that pain in right flank (aOR: 5.4; 95%CI: 1.4-20.8), negative Mc Burney (aOR: 3.6; 95%CI: 1.3- 10.5), pain in hypogastrium (aOR: 3.1; 95%CI: 1.1-8.4) and no leucocitosis (aOR: 2.9; 95%CI: 1.2-6.7) were associated factors to AN. Gynecologic conditions (53.6%) and complicated diverticular disease (14.3%) are the most common diagnosis in AN cases. Conclusion: The obtained results indicate that the presence of pain in the right flank, negative Mc Burney, pain in hypogastrium and no leukocytosis are factors that can be taken into account to prevent negative appendectomy. / Objetivo: Identificar la frecuencia de apendicectomías negativas (AN) y los factores asociados en una clínica privada de Lima. Métodos: Estudio retrospectivo de todas las apendicectomías realizadas entre los años 2012 y 2013 en una clínica privada de Lima-Perú. Se revisó las historias clínicas de pacientes apendicectomizados que contaron con historia clínica de emergencia e informe quirúrgico. Se excluyó a aquellos que no contaban con informe anatomopatológico del apéndice. Se calculó los OR ajustados con un modelo de regresión logística para identificar los factores asociados con AN. Resultados: Se realizaron 376 apendicectomías durante el periodo 2012-2013. Se excluyó 13 casos por no contar con registro de historia clínica. La población femenina fue de 55.9%. La media de edad del paciente fue 33.4 ± 17.6 años. En 28 de 363 pacientes (7.7%) se registró una AN. Se encontró que el dolor en flanco derecho (ORa: 5.4; IC95%: 1.4-20.8), Mc Burney negativo (ORa: 3.6; IC95%: 1.3-10.5), dolor en hipogastrio (ORa: 3.1; IC95%: 1.1-8.4), y no leucocitosis (ORa: 2.9; IC95%: 1.2-6.7) son factores asociados a una AN. Las patologías más frecuentemente implicadas en el caso de una AN fueron las de causa ginecológica (53.6%) seguida de enfermedad diverticular complicada (14.3%). Conclusión: Los resultados obtenidos indican que la presencia de dolor en hipogastrio, dolor en flanco derecho, Mc Burney negativo y no leucocitosis son factores que se pueden tener en cuenta para prevenir apendicectomías negativas.

Intestinal microbiota is involved in metabolic processes and the pathophysiology of various gastrointestinal disorders. We aimed to characterize the microbiome of the appendix in acute pediatric appendicitis comparing extraluminal and intraluminal samples. Between January and June 2015, 29 children (3–17 years, mean age 10.7±3.4 years, sex M:F=2.6:1) undergoing laparoscopic appendectomy for acute appendicitis were prospectively included in the study. Samples for bacterial cultures (n=29) and 16S ribosomal desoxyribonucleic acid (rDNA) sequencing (randomly chosen n=16/29) were taken intracorporeally from the appendiceal surface before preparation (“extraluminal”) and from the appendiceal lumen after removal (“intraluminal”). The degree of inflammation was histologically classified into catarrhal, phlegmonous, and gangrenous appendicitis. Seventeen bacterial species were cultivated in 28 of 29 intraluminal samples and 4 species were cultivated in 2 of 29 extraluminal samples. Using 16S rDNA sequencing, 267 species were detected in intraluminal but none in extraluminal samples. Abundance and diversity of detected species differed significantly between histological groups of acute appendicitis in bacterial cultures (P=.001), but not after 16S rDNA sequencing. The appendiceal microbiome showed a high diversity in acute pediatric appendicitis. The intraluminal microbial composition differed significantly depending on the degree of inflammation. As bacteria were rarely found extraluminally by culture and not at all by sequencing, the inflammation in acute appendicitis may start inside the appendix and spread transmurally.