The Vet Vault 3.2.1.

Cholestyramine and rat bait, more FIP treatment news, sneaky snakes and getting to know your amygdala.

Mar 01, 2024

I think I left my leap year plan a too late… Shout out to Rory who just recently learnt that some people wear contacts for fashion, not vision (how many times have you been flabbergasted by people with purple eyes until you learnt this Rory?), and Gythrie for learning the important lesson to not allow clients to dictate how you manage your patients, especially when it clashes with your standards and values. Great lesson.

I have to admit - was quite excited to see what you’ve been learning about, so I’ll make that a standing invitation: every time you have a lightbulb moment at work, or you see something non-vet related that changes your perspective - share the love. Message me within substack, or send me an email. I’d love to learn with you.

Ok, back to normal non-29th-of-Feb programming:

3 Clinical pearls.

1. Cholestyramine and rat bait

From episode 149 on the ECC feed with Nick Merwood and Kasra Ahmadi.

Remember a few newsletters ago I told you what I’d learnt about using cholestyramine as a decontaminant for toxins that undergo enterohepatic recirculation? Here’s an important thing to know about cholestyramine and anticoagulant rat baits:

Cholestyramine would, in theory, work as a decontamination for most anticoagulant rodenticides. Potentially very useful news.

BUT

It is also great at catching Vitamin K as it’s cycled between the liver and gut, and then holding it’s hand all the way out the poop hole, instead of into your patient’s clotting cascade.
In other words, as you’re starting to experiment with cholestyrmaine in your toxin cases, don’t be tempted to give it to your rat bait patient that is already on Vit K.

2. MORE FIP treatment options

From episode 151 on the medicine feed with Dr Sally Coggins.

A while ago I wrote about Dr Sally’s insights on Molnupiravir - another (much cheaper) drug that seems to work very well in treating FIP. Great news, but sourcing the drug sounded like a fair pain in the… well, the same place where cholestyramine takes Vit K!

However, since recording that episode, there’s been some more good news for Australian and UK vets:

EIDD, the prodrug of Molnupiravir, is now available in a tablet formulation through BOVA.
EIDD is significantly cheaper than GS or Remdes, even through official channels.
GS is also now available in a liquid formulation through BOVA, because, you know, cats and tablets.
BOVA pricing in Australia, as of Feb 2024 (All prices are ex GST):
- Rem: $99 per vial.
- GS tabs: $480 for 10 and $795 for 20 tabs. (and less if you order more)
- GS liquid: 50mg/ml – 25ml = $790. (Similar to the tabs.)
- EIDD 20 = $200.
- In practical terms that translates to EIDD pricing for treating a 3kg cat at 15mg/kg for 84 days comes to approx $1,260. (Based on ¾ of a tablet BID.)

Note that EIDD does not have the data behind it that proves efficacy and lack of side-effects that Remdes or GS has, so these should still be your recommended first choice therapy.

(And no, I’m not sponsored by BOVA, although if they are reading this, feel free to send me money!)

3. Brown snake lesson

Not from an episode, but from one of my own cases. (Although we do have a great Australian snake episode with Dr Ellie Lester back in episode 27 on the ECC stream.)

I may have gotten a bit over-confident with making calls on suspected snake bite cases based just on clinical signs, but a case last week gave me a good wake up call.

My doggo had an altercation with a large Eastern Brown (as evidenced by the 2m dead brown snake that accompanied the dog to our clinic!). Dog presented an hour after the event with 0 clinical signs. The owner made it clear that he had a very hard financial limit (way below the cost of a vial of antivenom), so I just ran PT/PTT, which was normal. A recheck 1 hour later still showed no clinical signs. I suggested we repeat clotting times and maybe a few more bloods, but to be honest, I was pretty confident that after 2 hours my patient would be showing signs of envenomation if it had been bitten. I know that, in theory, it can take up to 12-24 hours for signs to show, but I was feeling pretty optimistic. The owner declined further testing and opted to take the dog home. (I was very clear that we were not out of danger and on what to look for, but I didn’t really believe my own advice.) My shift ended and I went home.

Epilogue: Several hours later, at home, the dog fell to pieces and re-presented for euthanasia.

So my pearl: snake bites will mess with you! I’ll be setting aside pattern recognition-based medicine when it comes to life-threatening conditions in future.

By the way - some great news about our clinical podcasts: we’ve had a test batch of episodes RACE approved, which means that you can now get RACE accredited CE by listening to our podcasts. Now that we have proof of concept we’ll work on getting the rest approved, but for now we have 18.5 hours of CE up for grabs!

“Tomorrow IS the most important day of your life. Every day of your life has been leading up to tomorrow.
But of course, every day of your life has led up to TODAY”
- Trent Dalton, Boy Swallows Universe
Fear disguised as optimism.
“There's no difference between a pessimist who says, ‘Oh, it's hopeless, so don't bother doing anything,’ and an optimist who says, ‘Don't bother doing anything, it's going to turn out fine anyway.’
Either way, nothing happens.”
- Yvon Chouinard, founder of Patagonia

1 Thing to think about.

This episode of the Huberman lab with Professor of Systems Neurobiology, Dr Kay Tye has provided me with multiple things to think about thinking, feeling and doing, and the things that drive it all.

Much of Dr Tye’s research has been around the amygdala - that part, or parts, (we have two of them apparently) of the brain that regulate emotions. Most of us think of fear and ‘there’s a tiger, let’s run!’ when we hear the word ‘amygdala’. But I was fascinated with all the other things I learnt about the amygdala from this conversation. Here are my takeaways:

- It’s not just there to initiate fear in an effort to keep us from doing life-ending things. It’s in conductor of your full choir of emotions; yes, the deep dark voices, but also those happy high notes. It does however skew towards fear, because it’s fear that keeps you alive in the jungle in the short term. Running away from a predator is, in the appropriate circumstances, more urgent than getting food, or even getting laid.

- Its function, from an evolutionary perspective, is to help us pick what’s important by giving it emotional significance.

- Once it has your attention by making you FEEL something, it then ascribes valence to what you’re feeling: is this good or bad? Should I move towards, or move away? (I picture this as kind of a filter: the inputs that are reaching your mind gets filtered by the ‘coloured lens’ of the amygdala, so that when that information is analysed, it’s interpreted in the light of an associated emotion. Are this stuff red light information, or green?)

- Novelty gets the attention of the amygdala. The shiny things stimulate more emotion. The amygdala scans the environment for what’s new and what’s different so that it can decide whether that new thing is a threat.

- It has multiple inputs beyond just external sensory input, including pathways and feedback from within the body. Two inputs that I found interesting are:

Hunger. The amygdala has receptors that are altered by nutritional status, which in turn affects its output to the rest of the brain. Basically, the valence and the amplitude of emotion are directly affected by how hungry you are. (She sites studies where animals loose all fear once they get hungry enough. It seems that when hunger becomes your most immediate existential it eventually trumps fear.)
Social interactions have a huge influence on the amygdala. Those subtle and subconscious social cues directly impact how we interpret all the other information that our brain is receiving. What the people around you are doing can change your filter from green to red, and vice versa.

So what are the practical implications of these facts? For me, its:

- Experience is filtered, and truth can be flexible. If hunger can make you mean, or fearless, and subconscious social cues can inform how we interpret what our eyes are seeing and our ears are hearing, then how many other ways are there that can shape what we believe about ourselves and the world, and how we act?

- Understand negative bias. You’re not weird or overly anxious - it’s normal neurology.

- Clarity on why ‘the first time’ is so scary, or so wonderful, and then why we get so bored eventually. Your amygdala just can’t be bothered to give that thing attention after the 10th or the 50th or the 100th time, so it becomes ‘blah’ - just facts, no feeling. Conversely - that thing that feels so terrifying will eventually be mundane when your amygdala gets tired of it.

- Our connections with the humans around us matter. A lot.

- Hangry is real! It’s not just low blood sugar - it’s a dys-regulated, re-calibrated amygdala. (Has anyone coined the term ‘hadness’ for the other end of the hungry scale yet??)

Much love,

Hugh