A mother recently called the office, concerned about her toddler who’d swallowed the opening tab on the top of a soda pop can while the family was travelling over the Christmas period. She was concerned and took her child to a clinic where an abdominal x-ray was taken. The radiologist stated that she couldn’t see any foreign body in the child’s intestines but added the caveat that aluminum can’t easily be seen on an x-ray. Despite many years in practice, this surprised me and upon searching further I discovered that aluminum is only weakly radio opaque and easily missed (demonstrated in the radiographs above¹).

The reason? Aluminum has a low atomic number (13) and low radiodensity compared to that of soft tissues (7.5). The child was well and Mom was advised to survey the stools and call back if her little one became ill.

A ballpoint pen?

The vast majority of foreign bodies ingested by toddlers pass through the intestines without causing any damage. However, never underestimate the ability of a two-year-old to swallow almost anything, as was demonstrated recently at my hospital, the Montreal Children’s. This child managed to swallow a ballpoint pen without perforating her esophagus! The radiograph below shows this remarkable feat.

While both these cases had a benign outcome, they remind us of other less merciful ingestions: button batteries and magnets. These can be much more serious, and may be missed because the ingestion wasn’t witnessed and the child presented with non-specific abdominal symptoms initially. A recent paper,³ in a retrospective study, demonstrated that serious morbidity and even fatalities occur more frequently with button battery ingestion, usually in kids under age three. The authors examined data from three sources: the National Poison Data System (NPDS), the National Battery Ingestion Hotline (NBIH) and the medical literature, as well as fatal cases or those of major morbidity from the NBIH. Between 1985 and 2009, 56,535 battery ingestions were reported to the NPDS, giving an incidence of 6.3-15.1 per million population, of which 68% were kids younger than 6 years. The authors analyzed the 8,648 cases reported to the NBIH, covering the period July 1, 1990 to September 30, 2008. There were 13 fatalities and 73 major outcomes. Sixty-two percent of the 8,648 cases reported to the NBIH were kids under 6. Although the annual incidence didn’t change over the 25 years of data, the morbidity and mortality has increased 6.5 fold in the last three years of the study. The authors attributed this to the increased number of large (> 20 mm) lithium batteries in use. 20 mm is slightly larger than an American penny (19 mm) and close to that of a nickel (21 mm). In the 1990-93 period, the number of lithium batteries was about 1.3% but this increased to 24% in 2008.

The 20 mm-sized lithium batteries marked CR2032 are most often implicated in adverse outcomes. (CR stands for the lithium manganese chemistry, 20 = the diameter and 32 = 3.2 mm, the height). These batteries are more likely to lodge in the esophagus and unless removed within two or so hours can cause considerable tissue damage including perforation, T-E fistula, severe esophageal burn with stricture and stenosis. The tissue damage is caused not by leakage from the battery, but by the electrolytic current generated by these 3V batteries. The current causes hydrolysis of tissues and the formation of hydroxide at the negative pole of the battery. It’s the hydroxide that causes the tissue damage. The newer the battery the worse the outcome, as a new battery is 3 times more likely to be associated with significant tissue damage. The authors suggest the mnemonic of “negative-narrow-necrotic” in helping to predict the outcome. The negative pole of the lithium battery is at the narrow end of the battery, where the most hydroxide is formed, and therefore the tissue adjacent to this pole will suffer the most necrosis. The authors provide a useful algorithm for clinical decision making in the case of ingestion, one you may wish to study. In short, lithium button batteries are most often associated with severe outcomes in young children and any child suspected of having ingested one needs to be assessed quickly — if the battery is lodged in the esophagus it must be removed within 2 hours to avoid serious tissue damage or fatality.

Magnetic pull

Magnets are equally dangerous. They may entrap intestinal mucosa if more than one is swallowed and this can lead to intestinal perforation and other GI damage. Kids can get their hands on magnets from the fridge door, where many parents use them to affix notes and pictures, or little fingers might discover them in toys or jewellery.⁴

Unless the child was observed swallowing magnets, they usually don’t present until some days later, with abdominal symptoms. Keep an even higher index of suspicion when confronted with an autistic child with abdominal symptoms.

Putting the above into perspective, most objects such as coins, etc. swallowed by kids, pass through the intestines easily. Management is expectant observation and of course stool inspection. In those rare cases where a child has ingested a lithium button battery or several small magnets, we need to act urgently.

References

1. Valente, JH et al. Aluminum foreign bodies: do they show up on X-ray?. Emerg Radiol (2005) 12:30-31.
2. Image taken from The National Post, August 5, 2011.
3. Litovitz,T et al. Emerging battery-ingestion hazard: clinical implications. Pediatrics 2010;125;1168. DOI:10.1542/peds.2009-3037. Available on-line: http://pediatrics.aappublications.org/content 125/6/1168.full.html.
4. Naji, H et al. Bowel injuries caused by ingestion of multiple magnets in children: a growing hazard. Pediatric Surgery International. Published online 29 November 2011. DOI 10.1007/s00383-011-3026-x.