salt (sodium chloride)

Salt poisoning is about sodium concentration. When blood sodium climbs fast, osmosis drags water out of neurons; then, as the body rehydrates, the brain swells and cerebral edema develops. That is why correcting sodium too quickly is itself dangerous and why correction has to happen slowly under veterinary control. The Merck Veterinary Manual puts toxicosis at 2-3 g/kg of sodium chloride and the acute oral lethal dose in dogs at roughly 4 g/kg. For a 22 lb (10 kg) dog that is 20-30 g, about 1.5 to 2 tablespoons of salt, with around 40 g potentially lethal. Two tablespoons of soy sauce holds roughly 2.5 g of salt, which is not an acute lethal dose, but routinely seasoning a small dog's food is a genuine chronic hazard. In the US the classic exposures are homemade salt dough ornaments and play dough, rock salt and ice melt tracked in on paws in winter, sea water gulped at the beach, table salt, broths and bouillon cubes. GI signs appear within hours and neurologic signs over 3-24 hours: excessive drinking and urination, vomiting, diarrhea, loss of appetite, then ataxia, head pressing, circling, tremors, seizures and coma. Call your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 immediately. Never withhold water, and do not force large volumes of water or induce vomiting at home.