Why the 5 kg Shih Tzu needs a vet tonight
The real danger here isn't just the walnut's high fat content - it's the shell and potential mould. A whole walnut with shell is a triple threat: choking hazard, intestinal blockage risk, and possible tremorgenic toxin exposure if the nut was mouldy. Your dog's small size makes this especially urgent - what might pass through a larger dog could lodge in their narrow intestines.
Right now, the priority is preventing the shell from moving deeper. Don't wait for symptoms - walnut shells don't digest and can perforate the gut. Your vet may induce vomiting (only if very recent) or use imaging to locate the shell. Meanwhile, check your other pets' mouths for shell fragments - cats sometimes carry things without swallowing.
Where walnut shells hide in homes
Walnut shells have a knack for disappearing into carpet piles, vent grates, and under furniture legs. The ridges catch on fabrics, so inspect any area where your pets lounge. Pay special attention to the Shih Tzu's favorite spots - small dogs often hoard finds in bedding or under cushions.
Use a flashlight to check dark corners - shells blend with shadows. Listen for crunching sounds over the next 24 hours even after cleanup. If your larger dog starts sniffing intensely in one spot, investigate immediately - they may have found a fragment you missed.
Two silent symptoms you could miss
Tremorgenic mycotoxins don't always cause dramatic seizures right away. Early signs include exaggerated lip-licking, random muscle twitches (especially in the face), or your dog seeming 'drunk' with mild loss of balance. These may appear 30 minutes to 4 hours after ingestion.
The second stealth symptom is abdominal pain without vomiting. Your dog might stretch into a 'prayer position' with front legs down and rear up, or resist being picked up around the middle. These subtle signs often precede more serious blockage complications by several hours - your window to act is now.
Why your other pets aren't in the clear yet
While your cat and larger dog didn't eat the walnut initially, pets sometimes return to investigate forbidden items hours later. The smell of walnut oil lingers on carpets and paws. Confine all pets to easy-to-clean areas until you're certain no fragments remain.
Watch for secondary exposure - if the Shih Tzu vomits up walnut pieces, another pet might eat that. Clean any vomit immediately using gloves, as tremorgenic toxins remain active in regurgitated material. For the next 48 hours, feed all pets in separate rooms to monitor who's eating normally.
The full verdict, portion guidance and serving notes are collected on the Walnuts food facts page.