Predictive Factors for the Existence of Foreign Body following Fish Bone Ingestion: A Prospective Study

Abstract

Objectives To look at the factors that will affect the likelihood of a fish bone (FB) in throat and help to improve the use of oesophagogastroduodenoscopy (OGD). Methods It was a prospective cohort study of patients who attended the Accident and Emergency Department of Queen Elizabeth Hospital because of having foreign body sensation after eating fish in the period of 15th May 2008 to 15th February 2009. A pro forma was designed for the collection of information on various clinical parameters to be studied. Direct laryngoscopic examination (DL) and OGD findings were recorded. Tracing through the computerised Clinical Management System or telephone enquiry for the clinical outcome was employed for patients who refused or defaulted OGD. The primary outcome measured was the predictive power of the sharp pricking sensation symptom, radiographic finding and full visualisation by DL on the presence of FB. The data were analysed by logistic regression. Results The findings of 259 patients were analysed: 94 FBs were found; 83 (88.3%) FBs were lodged at a level above the hyoid bone; 73 FBs (77.7%) were removed by DL and 21 (22.3%) by OGD. Sharp pricking sensation was the only significant predictive factor for the presence of FB (OR=8.27; 95% CI=2.66, 25.76; p<0.01) in the group of patients requiring OGD whereas positive radiological finding (p=0.07) and full visualisation by DL (p=0.36) were not. Full visualisation by DL alone could not reliably rule out the presence of fish bone. Two FBs were missed. Conclusion The presence of definite sharp pricking sensation is a significant independent predictor for the presence of fish bone whilst full visualisation by DL and positive X-ray findings are not significant predictors.