Abbas, Mazen I.*; Oliva-Hemker, Maria†; Choi, Joon‡; Lustik, Michael§; Gilger, Mark A.||; Noel, R. Adam¶; Schwarz, Kathleen†; Nylund, Cade M.#
*Department of Pediatrics, Tripler Army Medical Center, Honolulu, HI
†Division of Pediatric Gastroenterology and Nutrition, Johns Hopkins University School of Medicine, Baltimore, MD
‡Department of Pediatrics, Walter Reed National Military Medical Center, Bethesda, MD
§Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, HI
||Pediatric Gastroenterology and Nutrition, Baylor College of Medicine, Houston, TX
¶Department of Pediatrics, Section of Pediatric Gastroenterology, Louisiana State University Health Science Center, New Orleans, LA
#Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD.
Address correspondence and reprint requests to Mazen I. Abbas, DO, MPH, Department of Pediatrics, Tripler Army Medical Center, 1 Jarrett White Road, Honolulu HI 96859 (e-mail: firstname.lastname@example.org).
Received 15 January, 2013
Accepted 29 March, 2013
The views expressed in this article are those of the authors and do not reflect the official policy or position of the US Army, the US Air Force, the US Navy, the Department of Defense, or the US government.
The authors report no conflicts of interest.
See “Magnet Ingestion by Children” by Sahn and Mamula on page 1.
Foreign body ingestion by children remains a serious public health problem in the United States. Young children are an especially vulnerable population because they explore the world with their mouths, have less developed chewing and swallowing ability, and may have unwitnessed ingestions. Children ingesting foreign bodies tend to be younger than 5 years and with a male predominance (1). In 2011, the American Association of Poison Control documented 95,705 incidents of foreign-body ingestions by patients younger than 20 years, with 74,725 occurring in children younger than at least 5 years (2). Fortunately, many foreign bodies pass spontaneously through the gastrointestinal tract without any complications. The morbidity from these ingestions is dependent upon several factors, including the type of object ingested, duration since ingestion, and the site of impaction along the gastrointestinal tract (1).
In the last decade there have been many reports documenting significant morbidity to children related to magnet ingestions, particularly when multiple magnets were swallowed (3–10). Historically, the ingested magnets were made of iron and were found in children's toys such as construction sets and kitchen items such as refrigerator magnets. Recently there has been an increase in the availability of high-powered, small rare earth magnets sold as adult desk toys, sculpting pieces, puzzles, or desk accessories that have made their way into the hands, and ultimately mouths, of children and adolescents. These magnets, which are often sold in sets of dozens to hundreds of pieces, are small (usually <1 cm), round and 5 to 10 times stronger than plain iron magnets and contain iron, boron, and neodymium powders (8,9). Most single-magnet ingestions are benign and result in no significant morbidity; however, ingestion of multiple magnets or magnets combined with other metallic objects is more likely to result in medical complications that would require treatment with endoscopy and/or surgery. These complications have been reported to include intestinal perforation (3,4), peritonitis, intestinal fistulas (4), volvulus (5), small bowel obstruction (6), or large intestinal resection leading to short bowel syndrome and possible death (7,10).
There have been no published epidemiologic studies of magnet ingestion in the United States. Our study objective was to determine the epidemiology of pediatric magnet ingestion–related emergency department (ED) visits in the United States using the National Electronic Injury Surveillance System (NEISS).
Data Source and Study Population
Developed by the US Consumer Product Safety Commission (CPSC) in 1973, the NEISS is a stratified national probability sample of >100 hospitals that includes 7 children's hospitals. These hospitals were selected because they contained 24-hour EDs with at least 6 beds. NEISS uses 5 hospital sizes as stratification variables (small, medium, large, very large, and children's); then within these strata the hospitals are selected with geographic diversity, although all of the selected EDs treat children. Each participating ED enters data daily into the NEISS, including information regarding patient demographics, diagnosis, affected body region, type of product involved, and disposition (11). Additionally, there is a narrative section that provides brief details of the event that led to the ED visit. NEISS allows for creating estimates using statistical weights and variables, and thus enables the tracking of product-related injuries in all US geographic regions (12–14). The database also allows the user to choose from a large list of consumer product codes for each reported case. When it comes to magnet-related injuries, however, NEISS instructs users to choose another product code if the magnet is a component of that product, or to enter it as a kitchen gadget code if the magnet is of unknown or unspecified origin, or to consider it as a toy and code as such (14).
The term “ingested object” in the diagnosis query field was applied for the study period. Querying for the term “magnet” in the narrative sections of all of the collected cases, we identified magnet-related ED visits during the study period. We further manually reviewed each case narrative to determine whether there was documentation that the magnets may have been the recently manufactured rare earth magnets, which are generally small and/or round, compared with traditional magnets. This analysis included querying for any magnets that were round (eg, spherical, ball, or pebble shaped) and/or small sized (eg, <1 cm diameter, “pebble,” small, tiny). We further queried to determine whether there was potential for multiple magnets to have been ingested. All magnet ingestions that did not fit the small and/or round category were included in the “other magnets” category. Narratives sections that had only the term “magnet” but no additional description were listed in a “no-description” category. Additional data collected included date of ED visit, age, sex, type of product(s) ingested, location of ingestion, and ED disposition. All children younger than 18 years during the study period were included. The institutional review board at the Uniformed Services University for the Health Sciences approved the study.
We calculated projected estimates by using NEISS-supplied weights and variance variables. Age categories (0–4 years old and 5–17 years old) were based on those published by the US Census Bureau and population estimates were obtained from the US Census Bureau (15). All of the statistical analyses were calculated using SAS 9.2 (SAS Institute, Cary, NC). The Taylor series linearization method was used in calculating all national estimates and proportions confidence intervals (16). Means, percentages, and standard deviations were calculated and chi-square analysis was used to compare age, race, sex categories, and ED dispositions for patients who ingested small and/or round magnets and those not described as small and/or round magnets. Furthermore, a linear regression model was used to conduct trend analysis over time for only all magnets ingested.
Of the 588,226 (95% CI 477,231–699,219) national calculated estimate of childhood ED visits for suspected foreign body ingestions during 2002–2011 (estimates were derived from 23,304 reported ED visits), there were an estimated 16,386 (95% CI 12,175–20,598) suspected magnet ingestion–related ED visits among children younger than 18 years (estimates were derived from 678 reported ED visits for magnet ingestion). Following NEISS instructions, most suspected ingestions were reported as kitchen gadgets or toys (Fig. 1). In 2002, the estimated number of visits for magnet ingestion was 327 (95% CI 68–585) compared with 2770 (95% CI 1784–3756) in 2011, representing an average annual increase of 75%. The rate of ED visits for suspected magnet ingestion had a statistically significant increase from 0.45/100,000 (95% CI 0.09–0.80) to 3.75/100,000 (95% CI 2.39–5.06) during the same 10-year period, an 8.5-fold increase (P < 0.01). Although there was an overall trend of increase during the study period, there was a decrease noted from 2007 to 2009 in the estimated cases and rate. This trend reversed in the last 3 years, with a 34% increase in the number of estimated cases (Fig. 2).
The majority of patients reported to have possibly ingested magnets were boys (59.4%) and 54.7% were younger than 5 years (mean age 5.0 years ± 0.14) (Fig. 3). Patients identified as “white” accounted for 8769 cases (95% CI 6999–10,540) compared with only 701 cases (95% CI 403–999) whose race was identified as “black.” A large percentage of patients, however, did not identify a race or the race was not recorded (32%). Although location was unknown in 25% of the patients, the majority of ingestions occurred in the home (73%). An overwhelming majority of the visits resulted in the patient being released from the ED after being examined and/or treated directly from the ED (96%) (Table 1).
Magnet ingestion–related ED visits that were described as small and/or round magnets accounted for an estimated 7159 ED visits based on 275 reported visits (Table 2). On the contrary, 278 visits (6343 estimated visits) did not describe the suspected magnet ingested and were excluded from further analysis, and another 125 were described as something other than small and/or round (2883 estimated visits) and thus were listed as “other magnets.” Patients suspected of ingesting small and/or round magnets were more likely to be older than 5 years when compared with those ingesting another type of magnet (mean age 5.6 years ± 0.23 vs 3.7 years ± 0.29; P < 0.001) (Table 2). Further stratification of those who ingested small and/or round magnets into groups, including those suspected of ingesting multiple small and/or round magnets and those ingesting a single magnet, also demonstrated that those patients who were suspected to have ingested multiples were more likely to be older than 5 years (mean age 7.1 years ± 0.56 vs 5.0 years ± 0.23; P < 0.001).
Our study is the first to report national estimates of ED visits for magnet foreign body ingestion by children younger than 18 years. We showed that from 2002 to 2011 there were >16,000 ED magnet-related visits, and that such visits increased >8-fold. This increased incidence coincides with the growing availability of magnets, especially high-powered magnets being sold as toys for both children and adults.
In 2002, 24 cases of injury from the ingestion of small neodymium magnet ingestions were reported from a children's hospital in the United Kingdom (8). The Centers for Disease Control and Prevention reported 20 cases of magnet ingestions in children occurring from 2003 to 2006, with 75% of the cases developing intestinal perforations (10). As a result, the CPSC issued their first warning in 2007, noting that serious injury could occur to children swallowing >1 magnet or a magnet and another metal object. In 2009, the commission banned the sale of high-powered rare earth magnets to children younger than 14 years (17,18). Our data show a dip in the rate of magnet ingestion visits to the ED from 2007 to 2009 (Fig. 2), which may have been the result of the initial CPSC warning. The increasing incidence noted in the most recent 3 years, however, suggests new sources of exposure for children. Coincidentally, around 2009 several manufacturers began producing sets containing hundreds of tiny high-powered magnets sold as adult desk toys. These sets have become popular and are being sold widely, leading to increased potential exposure for children.
Reports of ingestions have been noted not only in the expected toddler age range, as confirmed by our study, but also in older children and adolescents who unintentionally swallowed or inhaled high-powered magnets used to mimic nose and tongue piercings. Our data show that detectable ED visits for small and/or round magnet ingestions tend to be from older children and adolescents. Tavarez et al (9), in a single-center retrospective study, reported similar findings, with multiple magnet ingestions having a mean age of 9 ± 3.6 years that were predominantly girls (62%). This may be partially explained by use of these magnets as jewelry or to simulate piercings.
The challenge posed by multiple magnet ingestions is dramatically different from single magnet ingestions because of the significant attractive force between the 2 magnets. When ingested alone, a magnet tends to move through the intestine without much difficulty, although there have been rare reports of a magnet getting lodged in the appendix or other pockets within the intestines (19). On the contrary, when ingested in multiple quantities, or exposed to another ingested metal object, significant complications can occur. Reports of magnet ingestions in children have described complications including erosion of the gastrointestinal mucosa, intestinal perforation, peritonitis, fistulas, and intestinal loss from resection (3–10). Multiple magnet ingestion has been reported to be associated with perforation rates as high as 50% (9). One institution has even implemented ferromagnetic screening before magnetic resonance imaging, after having a 5-year-old child undergoing a neck study for torticollis develop intestinal perforations from the undisclosed ingestion of multiple high-powered small magnets (20).
The concern by many health care providers of the significant complications associated with magnet ingestions has prompted the development of algorithms to help the medical community evaluate and manage patients with magnet ingestions (21). This concern has been echoed by the CPSC, which recently filed administrative complaints against 2 manufacturers of rare earth high-powered magnet adult toys and issued a notice of proposed rulemaking aimed at developing a new federal standard for small, high-powered magnet sets (22–24).
Our study does have some limitations. First, the NEISS database only contains records of patients who have been treated in EDs, thus visits to other acute care facilities, physician offices, and small medical centers are excluded, leading to an underestimation of the true number of pediatric magnet ingestions. Second, the ED reports are for suspected ingestions and do not differentiate actual documented ingestions. Third, because there is no NEISS product code for magnets, the information regarding ingestion needed to be obtained by reviewing individual case narratives, which were incomplete in many instances, and did not always fully describe the magnet or the number of magnets ingested. This limitation also most likely leads to an underestimation of the numbers. Fourth, estimates were determined based on sampling and weights and variables determined by the NEISS, and the data to determine visit rates required calculations based on US Census Bureau historical and vintage estimates. Furthermore, sample size of actual cases for older children or those ingesting multiple magnets were small (<30 cases/year) and have limitations to deriving national estimates. Fifth, evaluations and treatments in the ED do not identify the type of treatments rendered (eg, endoscopy). Finally, we cannot determine whether the trend of increased magnet ingestion visits was because of increased exposure severity, better public awareness of foreign body ingestion in children, or increased access to health care.
In conclusion, this study is the first to describe estimates for magnet ingestion–related ED visits in the United States. It is important for parents and health care providers to be aware of the potential hazards associated with magnet ingestion and the recent increase trend of ED visits for these suspected ingestions.
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