In today's households batteries of all types can be found — alkaline, disc and rechargeable — and all present risks to pets who are exposed to them.
Alkaline batteries contain potassium hydroxide and thus have a very high pH. Ingestion of alkaline or caustic substances, like the contents of batteries, can cause liquefactive necrosis of tissues.
Disc or button batteries can be found in watches, hearing aids, small electronic devices or toys. When chewed open they have the same caustic injury concern as alkaline batteries, but when swallowed intact they do have additional concerns.
Depending on the size of the battery and the size of the patient, obstruction of either the esophagus or trachea (if aspirated) is a possible, but not common, concern. Furthermore, if the battery is retained in the esophagus it can cause burns due to its ability to emit a small electrical current.
Batteries that are leaking or stuck in the esophagus can either be removed by endoscopy or, if in the stomach, removed via gastrotomy. If the battery is in the stomach adding extra fiber to the diet and monitoring for the passage of the battery is a reasonable approach, particularly if the battery appears intact or is a disc battery.
Radiographs may be indicated if whole batteries or large pieces of the cases were ingested to determine the location of the battery and if they are moving through the GI tract. In some cases, it can also be determined if the batteries are leaking or not.
While most battery ingestions are mild and do little harm to the animal, some do great damage and need considerable care and treatment. Always call your veterinarian if suspect your pet has chewed or swallowed a battery. The Pet Poison Helpline has more information.