Introduction

Gastrointestinal foreign bodies are commonly encountered in both primary care and emergency veterinary practice. Whereas some ingested objects may pass without incident, others can result in gastrointestinal obstruction. Associated clinical signs are nonspecific and include vomiting, anorexia, lethargy, diarrhea, and abdominal pain.¹ The majority of ingested objects are chemically inert, and the main mechanism of tissue injury is ischemic necrosis.

Like dogs and cats, small children have a propensity to ingest nonfood objects. Ingestion of disk batteries is a documented cause of severe injuries and death in children, to such an extent that a national task force was established in 2012 to address the issue.² A disk or button battery is defined as a battery with a diameter that is greater than its height, and they are found in remote controls, watches, toys, calculators, and other electronics.^3,4 Disk batteries cause damage by generating current within adjacent tissue. Although laboratory studies have documented disk battery injuries in animal species, complications from naturally occurring disk battery ingestion in small animals have not been previously reported. This report documents a case of gastrointestinal perforation due to disk battery ingestion in a dog.

Case Report

A 7 yr old 5.27 kg (11.6 lb) spayed female shih tzu was presented for evaluation of anorexia of 4 days duration and a 1-day history of black stool. The dog had been examined by a veterinarian 2 days prior to presentation for evaluation of vomiting and anorexia. The owner described the vomit as thin yellow liquid. There was no observed foreign body ingestion, but the dog did have a history of chewing on foreign objects.

Complete blood count and serum chemistry performed at the prior veterinary visit revealed moderate mature neutrophilia (14,400 cells/µL; reference range, 2,060–10,600 cells/µL), with no other clinically significant abnormalities. The dog was presumptively diagnosed with dietary indiscretion and treated conservatively with an antiemetic injection. The vomiting resolved, but the dog remained anorexic and developed black stool 2 days after initial treatment and was presented for another examination.

Physical examination revealed mild hypothermia at 37.0°C (98.6°F). The dog was depressed with pale mucous membranes. The dog was nonpainful on abdominal palpation. Rectal examination revealed black-colored stool. No other abnormalities were noted. Survey abdominal radiographs were performed (Figure 1). The radiographs revealed a moderate loss of serosal detail with dilated loops of bowel. Two round, disk-shaped, metallic-opacity foreign objects were present within the bowel. The dog was given a presumptive diagnosis of small intestinal foreign body obstruction. Referral to a 24 hr emergency and specialty clinic was recommended but was declined by the client due to financial constraints and inability to travel the approximately 100-mile distance to the closest specialty facility.

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The dog was placed under general anesthesia, and an exploratory laparotomy was performed. Anesthetic monitoring included continuous electrocardiogram, pulse oximetry, and temperature measurements, and oscillometric blood pressure every 5 min. Balanced electrolyte IV fluid support was delivered at a rate of 5 mL/kg/hr. The patient was hypotensive throughout anesthesia despite the administration of 10 mL/kg fluid boluses. She was moderately hypothermic despite the use of an IV fluid line warmer and circulating warm water blanket. Upon entering the abdominal cavity, approximately 30 mL of cloudy red fluid was removed by suction. The serosal surfaces and parietal peritoneum were diffusely hyperemic with petechiation. The ileocolic junction was found to have circumferential full-thickness necrosis and perforation with dark brown to black discoloration. Fibrinous adhesions with necrotic material were found in the right limb of the pancreas with a large defect in the adjacent mesentery. A large accumulation of fibrin and necrotic debris was found at the root of the mesentery. A small mesenteric rent was found in the mesojejunum. Two foreign objects were palpated in the descending and transverse colon; no other foreign objects were detected. The liver, spleen, gallbladder, and kidneys were normal in appearance. The colonic serosa overlying the more proximal foreign object was hyperemic in appearance. The objects were milked from the colon out the rectum and anus and were found to be disk-type batteries. An ileocolic resection and anastomosis was performed without complication. The abdomen was thoroughly lavaged with sterile saline prior to closure, and the abdomen was closed routinely.

The patient recovered from anesthesia and was extubated. Approximately 10 min after extubation, the dog experienced respiratory arrest, followed by cardiac arrest. Cardiopulmonary resuscitation was performed but was unsuccessful. A necropsy was not performed.

Discussion

To the author’s knowledge, this is the first case report in the small animal veterinary literature of naturally occurring gastrointestinal necrosis and perforation due to disk battery ingestion. Disk battery ingestion is an increasingly documented cause of morbidity and mortality in children. Injury occurs in children when batteries become impacted in the esophagus, allowing prolonged contact with the esophageal mucosa. Reported complications include tracheoesophageal fistulas, esophageal strictures or stenosis, vocal cord paralysis, mediastinitis, cardiac or respiratory arrests, pneumothorax, pneumoperitoneum, tracheal stenosis, aspiration pneumonia, empyema, lung abscess, and discospondylitis.^4–6 Most fatalities occur as a result of arterio-esophageal fistulas causing exsanguination.^2,4 All but 1 of the 43 reported fatalities occurred in children 4 yr of age or younger, with one fatality occurring in a 5 yr old.⁷ Large-diameter (≥20 mm) cells are more likely to become impacted, and 20 mm lithium cells are implicated in the majority of major and fatal outcomes.^2,5,8 Lithium ion batteries can be identified by their imprint codes, which can be referenced at the National Battery Ingestion Hotline (NBIH).⁴ The most commonly encountered imprint code is CR2032M, which represents a 20 mm, 3V cell. This imprint code is implicated in the majority of cases with major and fatal complications.⁵ Injury can progress for days to weeks following battery removal, with tracheoesophageal fistulas occurring up to 9 days following removal, aorto-esophageal fistula reported from 18 to 28 days from battery removal, and esophageal strictures weeks to months from removal.^4,5 Notably, there have been significant increases in both major complications and fatalities due to battery ingestion in recent years, with a 6.7-fold increase in fatalities during the period from 2007 to 2009 compared with 1985 to 1987.⁵ This increase is attributed to the increasing popularity of lithium ion cells.^3–5

With older-generation alkaline batteries, leakage of caustic alkaline contents is an important mechanism of tissue injury.⁹ Unlike alkaline batteries, lithium batteries do not contain corrosive alkaline electrolyte, only a mildly irritating organic electrolyte.^4,10 The most significant mechanism of injury is current conduction through tissue resulting in the generation of hydroxide ions at the negative pole.^5,10 The local accumulation of hydroxide ions then results in caustic tissue injury. The speed of hydroxide generation is determined by the voltage of the battery, with 3V lithium ion batteries generating more current and more rapid damage compared with 1.5V alkaline button batteries. Although spent lithium ion batteries retain less voltage than fresh batteries, they retain enough voltage to cause tissue injury.⁴ An experimental study in dogs showed complete necrosis of the esophageal epithelium after 30 min of contact with a 3V lithium ion disk battery, with full-thickness necrosis extending to the trachea after 1 hr of contact.⁹

The National Poison Control Center and NBIH have established guidelines for the management of disk button battery ingestion in human patients.⁵ Home management with monitoring of stool for battery passage is recommended if the patient is older than 12 yr, the battery ingested is less than 12 mm in diameter, and the patient is asymptomatic. Radiographs are recommended immediately with known or suspected battery ingestion in children under 12 yr of age who have ingested any battery, or older patients who have ingested a cell greater than 12 mm in diameter, to confirm battery ingestion and determine its location. Batteries can be distinguished from coins or other flat, round, radio-opaque foreign bodies based upon the presence of a halo sign, a peripheral radiodense ring caused by summation of the halves of the battery case, or a step-off, which results from the difference between the diameters of the inner and outer case halves (Figure 2).⁴ Immediate emergency endoscopy and battery removal is recommended when the battery is found to be in the esophagus. If the battery is located in the stomach or small intestine and the patient is asymptomatic, home monitoring with potential follow-up radiography is recommended, because it is felt that the battery will likely pass throughout the remainder of the gastrointestinal tract without harm. The amount of tissue damage observed at the time of endoscopic removal determines the extent of treatment and the length and intensity of observation and follow-up testing, which may include hospitalization, serial endoscopy or tracheoscopy, and contrast studies.

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Although not reported in human children, the dog of this report developed gastrointestinal perforation at the ileocolic junction. Anatomic differences between canines and humans can account for this difference. Humans have a relatively narrow esophagus, such that an object that can pass through the lower esophageal sphincter is likely to pass through the remainder of the gastrointestinal tract.^3,11,12 In contrast, dogs have a relatively large esophagus and can swallow objects that can pass through the esophagus only to become lodged in the stomach or small intestine.¹³ Retrospective studies of gastrointestinal foreign bodies in dogs have found that the small intestine is the most frequent location of discreet foreign body impaction, with 72% of discrete foreign bodies found in the small intestine at one institution and 66.8 % at another.^1,14 During the 48 mo study period at one of these institutions, 208 gastrointestinal foreign bodies at the level of the stomach or beyond were reported, compared with 10 esophageal foreign bodies.¹⁴

It is possible that the dog in this report developed intestinal perforation as a result of pressure necrosis as opposed to battery-driven hydrolysis. However, the presence of both batteries in the colon at the time of surgery indicates that the batteries were able to pass through the ileocolic junction. The ileocolic sphincter normally remains mildly constricted to slow emptying of ileal contents into the colon and to prevent backflow of colonic contents into the ileum.¹⁵ The batteries may have passed continuously through the small intestine until the ileocolic sphincter prevented passage into the colon, allowing prolonged contact with the ileal mucosa and the generation of electrical current. The black stool observed preoperatively and the dark discoloration observed at the site of perforation are characteristic of battery-driven tissue injury.^9,10 Unfortunately, the batteries found in this case were disposed of before they could be identified by their imprint code. Based upon their size and shape, they were suspected to be hearing aid batteries.

Given the propensity of dogs to chew and ingest foreign objects, the increasing use of lithium ion button cells, and the increasing number of significant and fatal cases of battery ingestion observed in human children, it is reasonable to infer that dogs are currently at increased risk for ingestion of disk batteries. An ingested disk battery can be similar in radiographic appearance to a coin or to a bismuth subsalicylate tablet.^16,17 Without clinician suspicion of battery ingestion and knowledge of the potential for adverse effects, a potentially life-threatening condition may be overlooked or conservative management inappropriately pursued. In children, delay in diagnosis and battery removal is associated with progression of damage and more severe injury.^3,5 The dog in this report displayed clinical signs 2 days before initial evaluation, with an additional 2 days of delay before radiography, diagnosis, and surgery. It is possible that if radiographs had been performed on the day of initial presentation, earlier intervention would have resulted in a better outcome.

Septic peritonitis occurs as a result of bacterial contamination of the abdominal cavity, most frequently from leakage from the gastrointestinal tract, as occurred in the dog in this report. Mortality rates can be high and vary from 20 to 68%.¹⁸ Successful management of septic peritonitis requires aggressive hemodynamic support, surgical exploration to identify and control the source of contamination, and comprehensive postoperative management, including IV crystalloid and colloid therapy, IV antimicrobials, and nutritional support.¹⁸ Given that ingested batteries can quickly result in gastrointestinal perforation, intra-abdominal sepsis should be a significant concern in any animal who is suspected of ingesting a disk battery. Abdominocentesis or diagnostic peritoneal lavage can be performed to investigate potential gastrointestinal perforation. Aggressive preoperative stabilization and referral to a 24 hr facility capable of administering intensive care should be considered in any dog who may have ingested a disk battery.

Conclusion

The difference in gastrointestinal impaction sites between human children and dogs, as well as the wide range of size of canine patients, makes direct adaptation of the NBIH button battery ingestion guidelines to canine patients impractical. The author proposes the following guidelines for disk battery ingestion in dogs: Observed or known disk batteries should be treated as emergencies and abdominal and thoracic radiographs obtained immediately to determine the battery location. Flat, round, metallic objects detected on radiography should be carefully examined for the double halo or step-off signs that indicate a disk battery. If a companion or replacement battery is available, the CR code should be determined and the NBIH consulted. A CR code beginning with the number 20 indicates a 20 mm-diameter cell, which is the size most frequently associated with impaction and tissue destruction in children. A confirmed or highly suspicious disk battery in the esophagus or stomach should be immediately removed by endoscopy. A battery at any location in a dog displaying clinical signs should be removed, either by endoscopy or surgery. Postoperative radiography should be considered to confirm removal of all batteries. If spontaneous passage is deemed possible based upon battery and patient size, conservative management with serial radiography q 12–24 hr may be considered, provided owners are thoroughly educated about the potential negative sequelae to delayed treatment. Following battery removal, patients should be carefully monitored for the development of delayed complications, and repeated diagnostic tests such as endoscopy or contrast radiography should be considered. Application of these guidelines may reduce poor outcomes like that of the dog in this report. In addition, veterinarians should include education about the dangers of battery exposure and ingestion as a part of routine wellness care, particularly at new puppy evaluations. The NBIH publishes guidelines for the protection of children from batteries, available online at http://www.poison.org/battery/tips. These guidelines are equally applicable to pets, and pet owners should be advised to read the guidelines to protect all members of their households.