Acute canine gastroenteritis

Symptoms an owner can spot at home

• Vomiting, once, repeatedly, or a mix of food and bile
• Diarrhea, soft, watery, or with fresh blood or mucus
• Reduced appetite for 24-48 hours
• Mild lethargy

When to see a vet

• Repeated vomiting for more than 24 hours, or any vomiting in a small-breed or toy dog, dehydration escalates quickly
• Any vomiting or diarrhea in a puppy under 6 months (parvo rule-out)
• Blood in vomit or diarrhea, black tarry stool, or a distended abdomen
• Known or suspected toxin ingestion, foreign body, or dietary indiscretion in a deep-chested breed (bloat rule-out)
• Lethargy, collapse, pale gums, or refusal to drink water

What it is

Acute gastroenteritis is a syndrome of sudden gastric and intestinal irritation. Common causes include dietary indiscretion (garbage, fatty scraps, new treat), abrupt food change, viral or bacterial infection (parvovirus, salmonella, campylobacter), parasites (giardia), foreign material, drug reactions, and pancreatitis. Idiopathic acute hemorrhagic diarrhea syndrome (AHDS) is a distinct severe presentation with profuse bloody diarrhea and rapid hemoconcentration that needs aggressive fluid therapy.

Most healthy adult dogs with a single episode of vomiting or a day of soft stool recover with supportive care and short-term dietary management. The escalation triggers above are the ones that separate 'wait 24 hours' from 'go to the vet today'.

Treatment overview

This is editorial overview, not a treatment plan. Uncomplicated cases are typically managed with a short fast (4-12 hours in adults, no fasting in puppies), then a bland highly-digestible diet (boiled chicken and rice or a veterinary GI formulation) for 3-5 days before transitioning back to the regular diet. Rehydration, anti-nausea class medication, and probiotics are used when indicated. In-hospital IV fluid therapy is needed for dehydrated, hypoproteinemic, or non-responsive patients.

What owners can do

• Transition diets over 7-10 days, not overnight.
• Secure trash and human food; the 'garbage gut' presentation is largely preventable.
• Keep fatty scraps off the plate, high-fat table food is a major pancreatitis trigger.
• Maintain parvo and core vaccine schedule; adult AHDS is not the same as parvo, but parvo remains the highest-priority differential in puppies.
• Deworm on schedule and pick up feces promptly.