Name your poison.

—Pet MD

Last Sunday afternoon, leaning in a doorway at the Martha’s Vineyard Hebrew Center, waiting for State Senator Julian Cyr and State Representative Dylan Fernandes to speak, my cell phone, muted in my pocket, buzzed frantically. Stepping outside to take the call, I learned that Poosky, a middle-aged Jack Russell terrier, had been missing overnight. His owner had just found him, lying trembling, unable to stand, in the yard. “I think he might have been poisoned,” his dad said. “Or gotten into a rotten deer carcass out in the woods.” I headed back to office, leaving my fellow citizens to carry on the democratic process.

Poosky was in rough shape, very depressed, barely able to lift his head. He was twitching and shaking constantly. Despite having been outside all night in midwinter, his temperature was elevated, probably due to the constant muscle tremors. He was vomiting and dehydrated. His heart was racing. Whatever Poosky had eaten, this was hypovolemic shock and he needed immediate intravenous fluids. Once the catheter was in place and fluids started, the next step was to try to pin down the cause, so we could tailor treatment to fit.

“I’m just taking blood for tests,” I said, guiding a needle into Poosky’s vein and drawing back on my syringe. Whoa. Look at that. I had never seen blood that color come out of an animal before. It was creamy dark reddish-pink, almost like a strawberry milkshake. Could this be cyanide poisoning? I immediately wondered. The signs could be consistent. Symptoms of cyanide toxicity can include rapid breathing and heart rate, vomiting, muscle spasms, drooling, and cherry-red blood and mucous membranes. If you are a murder mystery fan, you know cyanide smells of bitter almond, but the ability to detect that scent is genetically determined in people, so the fact that I didn’t notice an odor didn’t rule it out.

Where would Poosky encounter cyanide? It’s present in tiny amounts in apple seeds, and the inner kernels of peach pits. It’s in a wide range of plants, such as cherry tree leaves, especially when wilted. It’s in construction and industrial products. It can be released from burning materials, including wool, cotton, plastics, Styrofoam, rubber, and vinyl, causing cyanide toxicity in smoke-inhalation victims. But Poosky clearly hadn’t been in a fire, and it was extremely unlikely he could have happened upon (or ingested) a significant dose of cyanide out in the forest.

Watching him twitch, my next thought was bromethalin toxicity. For many decades, the main types of rodent poison marketed to the general public contained anticoagulants — substances that interfere with normal blood clotting, leading to fatal hemorrhage. Nasty, but a type of poison we can often treat successfully if Fido eats it. New regulations, however, have made anticoagulant baits less accessible to homeowners, replacing them with bromethalin, a poison much harder to treat. Symptoms in dogs can include elevated temperature, hyperexcitability, muscle tremors, seizures, incoordination, vomiting, paralysis, and coma. While I was trying to figure things out, Poosky upchucked again, blood-tinged brown vomitus coming not just from his mouth, but streaming out his nose as well. Despite the lack of definitive diagnosis, it was time for antivomiting drugs, intravenous medications to stop the tremors, and antibiotics in case of aspiration pneumonia.

His dad sat monitoring the IV while I started lab work. Spinning down Poosky’s blood, the reason for the odd color became apparent. Blood separates into two components, cells, and fluid (called serum or plasma). Serum is normally fairly clear, and can have a faint straw-colored tinge. After eating, especially high-fat foods, fat in the blood can give the serum a milky appearance called lipemia. Poosky’s serum didn’t look like milk. It looked like heavy cream. Excessive fat in the blood, called hyperlipidemia, usually occurs secondarily to metabolic illness such as diabetes, hypothyroidism, or Cushing’s disease, but it can also occur with acute pancreatitis. Hang on. We’ll get back to this later. Hyperlipidemia can interfere with the functioning of my in-house laboratory machines, so I could not complete all the labs I wanted, but I was able to see that Poosky’s liver and kidneys were both impacted by his illness. And his phosphorus levels were sky-high. Another oddity. Why were his phosphorus levels so elevated? Could this be cholecalciferol toxicity?

Cholecalciferol. Yet another rodent poison. This one actually consists of lethal doses of vitamin D. Symptoms can include weakness, vomiting, constipation or diarrhea, blood in stool or vomit, drooling, elevated temperature, and kidney failure. Lab tests usually show markedly elevated phosphorus and calcium. Poosky had many consistent clinical signs. His phosphorus was high … but his calcium was normal. Cholecalciferol wouldn’t explain the hyperlipidemia. But pancreatitis wouldn’t explain the high phosphorus. My head was spinning with possibilities.

Making a diagnosis is often like doing a jigsaw puzzle. You need to put together enough pieces of the puzzle to start to see the big picture. Poring over my texts, sifting through information gathered, I suddenly realized that some puzzle pieces I had put in as part of the blue sky were actually part of the blue water. In other words, I had been repeatedly misled by one thing that looked like another.

My reading reminded me that hyperlipidemia can falsely elevate phosphorus. So this initially worrisome lab result was probably not real. Strawberry-milkshake blood? Hyperlipidemia, not cyanide. Most likely history? Not rodent poison, but ingestion of rotten deer meat. Poosky’s owner said this had been a problem before in their neck of the woods, where hunters sometimes left behind remnants of their kill. The puzzle was coming together. A presumptive diagnosis of acute pancreatitis with concurrent hemorrhagic gastroenteritis, due to “dietary indiscretion,” exacerbated by exposure when Poosky became too sick to make it home and spent the night outside. Oh, but then there was a question about wild-mushroom toxicity. No! Enough! Tune in next time to learn more about pancreatitis, and how we treated Poosky. Don’t worry. The story has a happy ending.