Discover the latest advancements in feline infectious peritonitis (FIP) treatment and diagnosis in veterinary medicine, featuring expert insights on effective strategies and alternatives.
In recent years, notable strides have been made in treating feline infectious peritonitis (FIP), particularly in 2024, with GS-441524 becoming available in the US and Wedgewood becoming the first US veterinary compounding pharmacy to offer molnupiravir.1,2
On this week's episode of The Vet Blast Podcast presented by dvm360, our host Adam Christman, DVM, MBA, and guest Kelly Chappell, DVM, DACVIM (Small Animal), talk more about the current state of treating FIP in veterinary medicine. They also dive into the struggles of definitively diagnosing this disease in clinical practice, as well as available treatments and alternatives.
Below is a partial transcript, edited lightly for clarity.
Adam Christman, DVM, MBA: [Because] we can very rarely obtain a definitive diagnosis of [FIP] in clinical practice, what testing and tools can we use for a more presumptive FIP diagnosis?
Kelly Chappell, DVM, DACVIM (Small Animal): It's such a good question, and I will say the diagnosis of FIP is still the bane of my existence. As happy as I am that we can treat it, diagnosis is still super frustrating. As most people know, definitive diagnosis is really going to be with that histopathology and immunohistochemistry, which requires us to get surgical samples, [requiring] surgery and anesthesia. [And] most of the time, we're not going to put these sick cats through [that], so [we're often] relying on a more presumptive diagnosis.
I often think about it as a building block system, as I'm often trying to check a certain number of boxes to make myself feel like I'm fitting into that presumptive diagnosis. One of the first building blocks that I'll look at is the signalment and vitals. FIP can occur [at] any age [for cats], but we definitely see it in cats [younger] than 2 years—most commonly pure-breed cats. Male cats are also slightly overrepresented in some studies.
Fever is really common in cats with FIP, [occurring in] about 70% of cats with FIP. In a 2017 study that looked at cats with fevers, FIP was the most common condition diagnosed in cats referred for fever. So whenever I see a young cat with a fever, it always picks [up] my little FIP flags.
One of the next building blocks I'll commonly look at is a chemistry panel, looking at the globulins, albumin-globulin ratio, and bilirubin. The globulin number itself could be [within] a normal range but still have an abnormal albumin-globulin ratio. So if my [chemistry] panel doesn't automatically calculate my albumin-globulin ratio, I'm always calculating that. [An] albumin-globulin ratio greater than 0.8 has a really high negative predictive value, meaning it's really helpful in ruling out FIP. So if I have a cat where maybe I have FIP on my differential list, and it's greater than 0.8, I feel pretty good to bring it lower down on my differential list. An albumin-globulin ratio less than 0.6—and especially less than 0.4—again, is another thing that piques my flags up for FIP in those cats.
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