Usefulness of symptoms in the diagnosis of whooping cough

Objectives: To study the usefulness for the diagnosis of whooping cough of clinical symptoms. The Gold standard test was the deep nasopharyngeal swab and specific culture for bordetella pertussis, parapertussis or bronchiseptica. Desing: Case-control retrospective not random a not blinded study. Setting: An urban health centre. Metods: Definition of case: children who were diagnosed of whooping cough with positive culture or who had contact with infected persons and who presented one or more of the following criteria: cough of more than 14 days, cough in accesses, post-tussive vomiting or final sputum or apnoeas. All the cases took place in the year 2000 and in children who consult in a health centre. Definition of controls: children who in the same period of time presented one or more of the following criteria: cough of more than 14 days, cough in accesses, post-tussive vomiting or final sputum or associated to apneas. All the controls took place in the year 2000 between children who consult in a health centre. In all the children nasopharyngeal specimens were taken and the sample was seeded immediately in specific culture for Bordetella pertussis, Bordetella parapertussis o Bordetella bronchiseptica. The data were taken from clinical histories of the children who fulfilled the criteria of definition of case or control. The data were analysed by means of a leaf of Excel to calculate sensitivity, specificity, predictive positive and negative values as well as positive and negative quotients of probability for each one of the clinical symptoms alone or in combination. It was considered as test of standard reference or ?gold? the specific culture for Bordetella pertussis, parapertussis or bronchiseptica. Main Results: Eleven children were diagnosed of whooping cough by bacteriologic culture or secondary household contacs of cases with positive bacteriologic culture. In this population the percentage of whooping cough was de 24%. The respective Positive likehood ratio for Estridor: 2, Esputum: 1,25, Emeting cough 1,69, tussive acces 1,15. The pretest probability: 0,24.The posttests probability of three symptoms as Esputum+Emeting cough+ Tussive access: 54% and Estridor+Emeting cough+Esputum: 62%. Conclussions: For the diagnosis of whooping coug is necessary the confirmatory bacteriologic test. In many cases its takes a long time and medical staff needs objective data in order to take decisions. So the results of this sutdy can be evaluated for each phyisician for an individual management of each case.