[Impact of abdominal ultrasound on the identification of the site of infection in the emergency department - Analysis whether it makes sense to perform abdominal ultrasound examination for the identfication of the site of infection if medical history and clinical examination do not indicate an abdominal focus.].

 A very high number of patients presenting in emergency departments suffer from an unknown infection or rather fever. If diagnostic imaging is necessary ultrasound can be performed. Whether ultrasound is superior to medical history and clinical examination considering the significantly enhanced technology in recent years and hence has to be performed in patients without abdominal symptoms with non-obvious focus cannot be answered by review of the literature. The objective of this study was to evaluate the relevance of abdominal ultrasound in the determination of the site of infection and to analyse whether an abdominal ultrasound for the identification of the source of infection is dispensable in patients in whom history and clinical examination do not indicate an abdominal focus.  All patients undergoing an ultrasound between 2013/04 and 2013/07 in the emergency department of the university hospital of Regensburg were retrospectively analysed. 500 abdominal ultrasound examinations were performed for identifying an abdominal site of infection. These cases were analysed whether medical history and clinical examination were indicating an abdominal focus. Furthermore, on the basis of patient record and medical report the result of the performed ultrasound, final diagnosis, clinical parameters (lab results, fever) were retrospectively analysed.  Based on the medical report in 208 (41.6 %) of the 500 reviewed cases there has been an abdominal focus. In 122 of these patients (59.0 %) abdominal ultrasound identified the abdominal focus correctly. In 206 patients (99.0 %) medical history and in 152 patients (73.1 %) clinical examination indicated an abdominal focus. A subgroup analysis regarding immunocompromised patients revealed that in 25 of 38 patients (65.8 %) an abdominal focus was determined via abdominal ultrasound. In patients with unremarkable medical history and clinical examination (23 examinations) no abdominal focus could be found via abdominal ultrasound.  An urgent examination of the abdomen via ultrasound is dispensable in patients in whom history (provided complete history) and clinical examination (i.e. particularly no immunosuppression) do not indicate an abdominal focus.