The Vet Vault 3.2.1.

Bile acids and shunts, MORE bile acids, CRP in aspiration, and another lesson learnt from surfing.

Mar 14, 2024

3 Clinical Pearls.

1. Portosystemic shunts: when the bile acids don’t make sense.

From episodes 151 and 152 on the surgery feed, with Prof Karen Tobias.

So you have your ‘usual suspect’ dog breed for a PSS, and you do your BA stim tests. Maybe you have reason to suspect a shunt, or maybe your patient already had surgery for a shunt, and you’re checking if it worked. But the results come back a bit ‘meh.’ Like 60-something - not normal, but not 100+, as you’d expect for a shunt.

Professor Tobias (yes, THE Tobias!) shared these pearls in our discussion about shunt surgery:

Those kinda-maybe-but-not-quite bile acid results are often due to a condition called congenital portal vein hypoplasia.
It’s a non-pathological syndrome where a patient has an underdeveloped portal system, but not an actual shunt.
Affected patients will always have high-ish bile acids.
It affects mostly the same breeds that are likely to have shunts, so small fluffies that like to ride in handbags and love to savage your face.
Prof Karen reckons that two thirds of ‘normal’ Yorkies in the US have it. (She’s likely exaggerating, but you get the point!)

“I would say that the vast majority of our small breed shunt dogs also have that condition, so they'll never have totally normal bile acids. They will never have totally normal ALT.”

2. More bile acid pearls.

From episode 153 on the medicine feed. With Prof Jill Maddison.

Sometimes I feel like the more we learn about a topic, the less certain I am about what I thought I knew. And when I share pearls like these ones about bile acids from our epic liver enzyme discussion with Prof Jill, I almost feel guilty for dragging you into the murk with me! But an uncertain truth is probably better than a confident falsehood, so here we go:

Doing a BA stim test in a jaundiced animal is pointless: it’s not telling you anything that you don’t already know from what your eyeballs are telling you.
“People say that they are a liver function test. It's not.” Whaaat?! Let’s clarify.
- While they do get affected when there is a problem with liver function (billiary obstruction, shunting, and parenchymal disease), they do not quantify the problem at all. Unlike albumin, which, when it starts to go low because of liver disease, tells you that you have less than 20% liver function left.
Bile acids ARE very useful to help you investigate why your other liver enzymes are up, but you can’t entirely trust them…
- A recent RVC study showed that a significant proportion of animals with confirmed liver disease will have bile acids BELOW the reference range. ( I haven't got the figures right in front of me, but I think the study showed that almost half of the cats that had card carrying liver disease had fasting bile acids less than the reference range, and about a third or maybe a quarter of them had a post prandial bile acid less than the reference range.)

“The take home message about bile acids is that they can be really useful in adding to your ‘information stockpile’ when you're chasing liver disease, but you also can't rule out liver disease based on normal bile acids. Which makes it all very frustrating.”

3. Aspiration and CRP.

From episode 151 on the ECC feed, with Dr Simon Cook.

This one is for you Matt, and for anyone else who’d really like to have early warning that their super sick tick paralysis patients have aspirated and have wondered whether CRP could be that, and maybe also a marker to monitor efficacy of treatment.

Simon’s study with aspiration showed that CRP will peak at 24 - 48 hours after an aspiration event.
This occurs regardless of whether infection develops, and it doesn’t seem to be useful to differentiate inflamed lungs from infected lungs.
Its almost always going to be normal at 7 days, and it's always going to be normal by 14 days, BUT
The first thing to normalise will be your clinical findings.

JOMO, not FOMO. (The joy of missing out.)
Every decision to use a portion of our time in a certain way by definition is a decision NOT to use it in an infinity of other possible ways. That can be anxiety inducing, so we try to avoid having to confront this fact by numbing ourselves with distractions and busy-ness, or by convincing ourselves that we don’t have choices.
Our modern obsession with productivity is another way to avoid our responsibility for making choices. We try to convince ourselves that we are infinite.
But missing out is not just unavoidable - it’s arguably what makes things worth doing. It gives meaning to our experience.
Our finitude gives weight to our choices. If you had endless time you’d never do anything.
Instead of complaining that our lives are short, be amazed that you get to live as long as you do, or live at all. Whatever you decided to do today - that’s how you chose to spend a portion of time that you never had any right to expect.
- Oliver Burkeman
Instead of trying to do it all, do something REALLY well, and get meaning out of it.
- Cal Newport, talking about slow productivity, with Tim Ferris.

1 Thing to think about.

The surf has been pumping at Noosa over the last couple of days. If you’ve never witnessed a good day at Noosa, you’re missing out - even if you’re not a surfer. Line upon line of swell wrapping around the points to unload all that violent energy generated by some far-away cyclone over the shallow sand and rock that fringes the national park. It’s there, in that fringe zone, that we wait - a flotilla of surfers who live for days like these, when we can tap into some of that raw energy for our own pleasure.

But all good things come at a price, and the price of a good cyclone swell at Noosa (apart from trying to find parking!) is the sweep. Good waves at Noosa are inevitably accompanied by a conveyer belt of water pushing relentlessly all the way from Granite Bay to Main Beach. Walk the kilometre or so from the car park (or the three or four from wherever you finally found a parking spot! ) to Boiling Pot and jump in with something that will keep you afloat. On a good day, if you just sit there without paddling, you’ll be washed up on Main Beach almost two kilometres away in about 15-20 minutes.

This means that if you’re trying to be in the right spot to snag one of those lovely long waves, you have to paddle hard and paddle non-stop just to stay in one spot. And there are a LOT of other surfers waiting for their bit of cyclone magic, so you’ll often wait 20 or 30 minutes for your wave. That’s a lot of paddling just to keep up, but the reward is worth it.

Here's what I noticed this week: In my eagerness to get more waves, I'd try to stay in the water for as long as possible. But effective paddling turns into flailing within about 40 minutes when you're not a 20-something surf god. I'd try to push through it, begging my 45-year-old shoulders to work a little harder. But eventually I'd have to pause for a breath. I'd sit up on my board to rest my aching shoulders for 30 seconds, or a minute, but while I sit there, I can see the place where I need to be rapidly moving away from me. So I’d start again, but from 50 meters back, paddling/flailing to make up the lost ground… only to need a rest when I get there… It's Sisyphus and the rock! Or worse: my wave would arrive – my moment – but it's hard to paddle into a wave with jelly arms, so I’d stuff up the takeoff or miss that long-awaited, well-deserved wave completely.

Life feels that way sometimes. In the times when opportunities are plenty, there’s usually also a lot of resistance, and the competition is fierce. So you push harder, relentlessly paddling, because pausing is weakness and pausing means losing ground. But you can’t keep pushing, so you do end up slipping backwards, or fail to fully utilise those opportunities.

The better approach, I'm learning, for Noosa, is to jump in at the point, then surf like hell. Paddle ferociously to get onto the wave you want. When you get off that wave, go with the flow for a while - let the current take you to the next break further down the point (because there's always another break). Then paddle like a madman for the next wave. Rinse and repeat until you end up on Main Beach after 4 or 5 good waves – tired, but not spent. Then you take an actual break, not just a few desperate gasps. Take a leisurely walk back to the point. Stop at the taps for a drink. Sit down for a bit and enjoy watching other people ride the quicksilver magic carpet. By the time you get back to the jump-off point, you can start again, frothing, and fresh.

Much love,

Hugh