The analysis of 1199 accidental paediatric foreign body and chemical substance ingestions over thirteen years (2005–2017) at a German University Medical Centre revealed a significant increase in the annual case rate of 80% to about 11 per 10.000 children in the catchment area. This has also been reported in the United States with an annual increase of 91.5% from 9.5 in 1995 to 18 per 10.000 children with FBI in 2015 . In contrast, considerably less FBI have been reported at Chiang Mai University in Thailand (only 194 cases from 2006 to 2017) with a population comparable to Ulm. This cannot be explained by different age limits (< 15 versus < 18 years) and the inclusion of ingestion of chemical substances in our study. Thus, other factors e.g. difficult access to medical care, fewer harmful items in the household, or better parental care may influence the observed lower frequency of FBI. The increase in our study affects all categories of objects and substances, many of them are increasingly used in German households. We observed an alarming increase of lithium button battery ingestions in infants which is associated with hospitalisation and major complications. This trend was already previously reported in comparable studies from the U.S. [23, 24].
Ingestion of foreign bodies or chemical substances is frequent among children below six years around the world [2, 3, 6, 25, 26]. A variety of foreign bodies is ingested of which coins appear the most common in our cohort like in many other studies [2, 7, 25, 27, 28]. However, the share was lower in our study (18%) compared to 49 to 88% reported by others, which may also reflect changes over time, differences in referral, selection and inclusion of the patients or classification and localization of objects as well as different diets and habits of the populations [2, 26, 28–30]. A retrospective observational study from Japan reported cigarettes be the most frequent FB (17%) in a cohort of younger children (median age 1 year 3 months) compared to only 2.3% registered cases in our study although the smoking prevalence in both countries are equivalent (WHO statistics data). In addition, the Yen coins are equivalent in size of 5 Cent to 2 Euro coins and should thus be as attractive for ingestion by toddlers . Furthermore, the frequency of FBs in different categories vary between study populations, e.g. on second position fish bones were reported in Hong Kong , toys in the U.S., plastics in Japan , and metallic objects in our study reflecting differences in the surrounding of children, the regional or cultural habits and age-dependent preferences in the investigated populations. The ingestion pattern also differs by sex, age and season (e.g. Christmas decoration)[7, 32]. We found, that girls are at risk for hazardous ingestion of sharp objects in our population. Another study showed that it is 2.5 times more likely that girls ingest jewellery or hair products compared to boys . Here we also report relevant liquid ingestions of potential harmful cleanser (12.3%), acid (2.7%) or base (0.6%). Caustic ingestions in children are mostly accidental and the severity depends on the type and quantity of the ingested substance .
A carefully obtained history, the type of ingestion and the level of suspicion will determine the course of action to avoid severe and life-threatening complications. In this study about sixteen percent of all patients required hospitalisation which is slightly more than in similar studies reporting around ten percent . Twenty-two percent of patients with coin ingestion and more girls were hospitalized. The highest rate of complications was observed for button battery, glass and food ingestions. Others reported an increased prevalence of complications after sharp FB ingestion and a 4 to 8-fold increase of complications if the endoscopic retrieval of the oesophageal FB was performed later than 24 to 48 h after ingestion . Serious complications and fatal outcomes have been reported for button battery ingestions [15, 16, 22]. Although we observed an annual increase of total cases and hazardous ingestions the number of patients admitted to the hospital was constant. In fact, the hospitalisation rate for coin ingestions was considerably lower in our cohort than the 55% reported in a European study .
In 2010, we implemented an algorithm for the diagnostic and therapeutic procedure at our hospital considering age of the patient, symptoms, size, type and location of radiopaque and radiolucent FB based on an interdisciplinary consent of the departments of radiology, paediatrics and adolescent medicine (including paediatric intensive care and paediatric gastroenterology), and ENT . This may potentially influence the practice of admissions at our hospital and partially explain the constant number of hospitalized patients. In addition, the complication rate could be reduced by two percent from 6.8% before 2010 to 4.8%.
The majority of children are presented if a caregiver witnessed the ingestion of a FB or harmful substance by the child, an object is missing, or the child is symptomatic . Presenting symptoms varied from the type and location of the ingested FB in our cohort, e.g. gagging, pain and coughing was frequently observed after coin ingestion. In contrast, a primary association with vomiting and drooling was reported in other studies after coin ingestions . Patients with oesophageal FB mainly present drooling, vomiting and dysphagia especially if the FB is located in the first narrowing . Still, most patients have a normal physical examination . In children the diagnosis of FB ingestion may be complicated if the ingestion was not observed or the child is asymptomatic. Like in other studies about half of the patients were asymptomatic .
The European Society of Paediatric Gastroenterology and Nutrition (ESPGHAN) and European Society of Gastrointestinal Endoscopy (ESGE) recommend x-ray examination in all patients with suspected FB ingestion even without symptoms . In our study, medical imaging was performed in half of the patients as nearly half of the objects were radiopaque. Imaging is important to confirm the presence, type, number and localisation of FB as well as detect complications e.g. perforation and guide the further management and follow-up if indicated . X-ray of the chest and abdomen was frequently performed and detected the FB and its localization in 86%. Girls received significantly more medical imaging, particularly x-ray, inter alia due to ingestion of sharp objects. In fact, we observed an annual increase particularly of x-ray investigations. Although hand held metal detectors (HHMD) have been shown to detect the majority of metallic FB and their localisation we did not use them in our department at that time . It is proved that HHMD have a high sensitivity in detection of coins and seem to be a good early screening tool for a faster triage in the emergency room setting which may potentially reduce radiation exposure [39, 40].
The primary management was awaiting spontaneous passage for the most FBI, interventional removal was performed in 126 cases. The indication and timing of medical intervention to remove a foreign body was based on the location, size and type of the FB, duration of impaction, and patient symptoms according to our in-house standard with special attention towards button battery and magnet ingestion . Initial localisation and size of the FB are determining factors of the likelihood of a spontaneous passage [2, 10]. Coins logged in the oesophagus may pass spontaneously if they are located in the distal one third of the oesophagus .
Removal of FB was mainly performed by rigid and flexible endoscopy according to the localization of the FB and symptoms of the patient and was successful in 81% and 90%, respectively. High success rates for rigid and flexible endoscopy have been reported in retrospective studies for oesophageal FB in children and adults with low rate of complications [12, 36, 42, 43]. The management of foreign body, food and toxic substance ingestions needs to be adapted for infants, e.g. smaller endoscopes with less than 6 mm diameter in children below ten kilo and paediatric-trained endoscopists are required [19, 44]. An algorithm on the usage of retrieval tools in foreign body ingestion and food impaction has been published . Oesophageal food impaction is a frequent finding and requires special attention . Removal is performed either en bloc or by a piecemeal approach using various grasping devices and after examining the oesophagus distal of the bolus also the push technique . Food impaction is frequently associated with oesophageal pathology e.g. oesophageal atresia and eosinophilic esophagitis [47–49]. In addition, like in our study bowel obstruction or oesophageal perforation and fistulation by plants may require surgery. Magnet ingestion are rarely registered but frequently need surgery, especially children with neurological or psychiatric diseases have an increased risk [50, 51]. There is an alarming increase of magnet ingestions in emergency departments according to data from the National Electronic Injury Surveillance System (NEISS) .
We found a very low necessity of surgical interventions (0.3% of all, 2% of hospitalized cases, 3% of removed FB) in our cohort in contrast to 18% of hospitalized cases reported by others although providing paediatric surgery twenty-four-seven . Some surgical interventions in historic cohorts may be prevented by experienced endoscopic removal nowadays . After caustic ingestions in children mostly mild oesophageal lesions (88%) were identified and severe oesophageal lesions were associated with the presence of signs and symptoms (e.g. oral lesions, vomiting, dyspnoea, drooling, dysphagia, and hematemesis) . Thus, endoscopy like in our study cohort could be avoided in absence of signs and symptoms .
This study again confirms the poor awareness of caregivers concerning the hazards of toys and household products for young children. In our study 9% of the children were presented more than 24 hours following ingestion, compared to 22% in a study from Pittsburgh of children who underwent esophagoscopy for suspected FB . The lack of awareness for harmful situations requiring emergency care and prompt intervention may lead to serious complications, e.g. as observed with button batteries, pins and magnets . Preventive measures, e.g. pressure on manufactures to package items appropriately for children below three years of age, effectively reduced toy ingestions in the U.S. in 2011 . Furthermore, food and toys should not be marketed together to prevent children from ingestions of toys. Legal measures to protect children from the growing problem of unintentional button battery ingestion are required and should include child-resistant packaging for batteries, child-resistant closure of all consumer products that use button batteries, and warnings regarding the potential danger of ingestion [54, 55].
At the end, few limitations of this study should be underlined. Firstly, in a retrospective study design the conditions may not ideal and lack some relevant information not available from the electronic patient file. In addition, we only captured patients presented at our hospital which - as in many other studies - underrates the real frequency of accidental ingestions in children. In addition, comparability among related studies is limited as patient selection and categorization of objects may differ and age groups vary .