Why lethargy and wobbliness demand urgent vet care
Your terrier's symptoms indicate the stagnant water has already disrupted sodium balance severely. Unlike simple stomach upset, the wobbliness means fluid is pressing on brain tissue—a life-threatening emergency. Even if the puddle seemed small, bacteria and toxins in stagnant water speed up electrolyte imbalances.
Do not attempt home remedies like limiting water or offering salty foods. Correcting sodium levels requires IV fluids adjusted precisely to avoid rebound swelling. Your vet will monitor neurological signs and bloodwork hourly during stabilization.
How timing affects treatment options
Since ingestion was yesterday, the delayed onset suggests gradual sodium depletion rather than sudden overload. This changes the vet's approach—they'll likely administer hypertonic saline slower to prevent shocking the system while still reducing brain swelling.
Expect hospitalization for at least 24 hours. Dogs showing neurological symptoms often need anti-seizure medications and oxygen support until sodium normalizes. The wobbliness may persist for days even after treatment.
Why small breeds face greater danger
A terrier's size makes them far more vulnerable than larger dogs to water toxicity. Just 1-2 cups of stagnant water can overwhelm their kidneys' ability to maintain electrolyte balance. Stagnant water compounds this with concentrated toxins that damage kidney filtration.
Watch for subtle changes like excessive yawning or head pressing against walls—these precede seizures in small dogs. Your vet may recommend follow-up kidney function tests after recovery since stagnant water often contains leptospira bacteria.
The risks beyond water intoxication
Stagnant puddles frequently contain blue-green algae, antifreeze runoff, or decomposing organic matter. These cause separate poisonings with overlapping symptoms—another reason your vet will run comprehensive blood panels rather than just addressing sodium.
If your dog develops vomiting or diarrhea after treatment, bring this up immediately. Some puddle contaminants like heavy metals or pesticides require specific antidotes that standard water intoxication protocols won't cover.
The step-by-step response, from the first minute to the vet visit, is in our Water Intoxication (Hyponatraemia) emergency guide.