Context: Foreign body aspiration (FbA) is a serious problem in
children. Accurate clinical and radiographic diagnosis is important
because missed or delayed diagnosis can result in respiratory
difficulties ranging from life-treatening airway obstruction to chronic
wheezing or recurrent pneumonia. Bronchoscopy also has risks and
accurate clinical and radiographc diagnosis can support the decision
of bronchoscopy.
Objective: To rewiev the diagnostic accuracy of clinical presentation
(CP) and pulmonary radiograph (PR) for the diagnosis of FbA. There is
no previous rewievMethods: A search of Medline is conducted for
articles containing data regarding CP and PR signes of FbA.
Calculation of likelihood ratios (LR) and pre and post test probability
using Bayes theorem were performed for all signs of CP and PR.
Inclusion criteria: Articles containing prospective data regarding CP
and PR of FbA.
Exclusion criteria: Retrospectives studies. Articles containing
incomplete data for calculation of LR.
Results: Five prospectives studies are included with a total of 585
patients. Prevalence of FbA is 63% in children suspected of FbA. If CP
is normal, probability of FbA is 25% and if PR is normal, probability is
14%. If CP is pathologic, probability of FbA is 69-76% with presence
of cough (LR = 1.32) or dyspnea (LR = 1.84) or localized crackles
(LR = 1.5). Probability is 81-88% if cyanosis (LR = 4.8) or decreased
breaths sounds (LR = 4.3) or asymetric auscultation (LR = 2.9) or
localized wheezing (LR = 2.5) are present. When CP is anormal and
PR show mediatinal shift (LR = 100), pneumomediatin (LR = 100),
radio opaque foreign body (LR = 100), lobar distention (LR = 4),
atelectasis (LR = 2.5), inspiratory/expiratory abnormal (LR = 7), the
probability of FbA is 96-100%. If CP is normal and PR is abnormal the
probability is 40-100%. If CP is abnormal and PR is normal the
probability is 55-75%.
Conclusions: This rewiev of prospective studies demonstrates the
importance of CP and PR and an algorithm can be proposed. When
CP is abnormal with or without PR pathologic, the probability of FbA is
high and bronchoscopy is indicated. When CP and PR are normal the
probability of FbA is low and bronchoscopy is not necessary
immediatly, observation should be proposed. This approach should be
validated with prospective study.