TL;DR: Ingesting a hearing aid battery is a life-threatening emergency that can cause severe internal chemical burns within two hours; contact a veterinarian immediately.
What happens if my dog swallows a hearing aid battery?
Hearing aid batteries, typically small button-style cells (zinc-air or lithium), are common household items that dogs may accidentally ingest. When a dog chews or swallows these batteries, the moist environment of the mouth, esophagus, or stomach can trigger an electrochemical reaction or cause the battery to leak caustic materials.
Is it a medical emergency if my dog eats a battery?
Urgency Level: High. Ingesting a hearing aid battery is a medical emergency that requires immediate veterinary attention. These batteries can cause severe tissue necrosis and deep chemical burns within just two hours of contact with internal membranes. Even if the battery is "dead," it often retains enough residual charge to cause significant damage to your dog's digestive tract.
How does a photo of the battery help with medical triage?
- Safely take a photo of the battery packaging or the remaining battery from the pair to show your veterinarian.
- Identifying the exact type (lithium vs. zinc-air) helps the medical team determine the level of corrosive risk.
- Providing the battery size helps the vet determine if it is small enough to pass or likely to cause a physical obstruction.
- Knowing the specific voltage and diameter allows the medical team to prepare the correct surgical or endoscopic equipment before you even arrive.
Clinical Context (Merck Veterinary Manual)
Ingestion of alkaline batteries, commonly from hearing aids, poses a risk of gastrointestinal tract corrosive injury and foreign body obstruction in dogs. Alkaline gel causes liquefactive necrosis of tissues on contact, resulting in burns. Lithium disk batteries may lodge in the esophagus and generate a current against the esophageal walls, resulting in circular ulcers. If the battery was swallowed intact without chewing, emesis may be induced for expulsion, unless the battery casing is possibly punctured, in which case emesis is contraindicated due to the risk of alkaline gel leakage. Radiographs should be performed to determine the location of the battery; however, some disk batteries do not show up well. Administering 20 mL boluses of tap water every 15 minutes will decrease the severity and delay the development of current-induced esophageal ulceration. Batteries that do not pass through the pylorus within 48 hours of ingestion are unlikely to pass on their own and may require surgical or endoscopic removal. Batteries that have been punctured should be surgically removed to prevent gastric or intestinal ulceration. Serial radiography to verify battery location is recommended until the battery is expelled.
Chapter: Toxicology, Gastroenterology, Surgery
Source: The Merck Veterinary Manual, 11th Edition (Page 3003)