A 5.5-year-old castrated Boston terrier was presented with a peracute history of tetraparesis. About 2 hours before presentation, the dog had jumped off a bed and fallen to one side. According to the owners, their dog had difficulty getting up, especially when using his left limbs, but had not cried out or appeared to be in pain. The dog had a medical history of osteoarthritis, and dental extractions had been performed within the past year. The only medications on record were a daily glucosamine–chondroitin supplement and monthly heartworm and flea preventatives. The dog’s vaccinations were up-to-date.