The Vet Vault 3.2.1.

How Cats With Haemolysis Will Trick You, When Azotaemia is Not CKD, and Is It Septic or Not (ie, Should I Cut?)

Hubert Hiemstra

May 30, 2025

Before we start, just a few things I’m excited about:

Wānaka conference, 10–15 August. Only 16 tickets left. (We were planning the snowman building competition and the almost inevitable snowball battle that will follow in a sponsor meeting with Hills, IDEXX and Credabl this week…)
This

That’s the Onsen in the ryokan where we are hosting Vets On Tour ’26 - Nozawa Onsen, Japan. It’s going to be epic!

Speaking of travel - on Wednesday the 4th I’m co-hosting a lunch time QnA session with Credabl about airline points to try and figure out how to get free flights (or business upgrades!) when you spend money. If you travel a lot (or spend a lot of money!) you should join in.

A new soft tissue surgeon to answer case questions on our Specialist Support space.Welcome Dr Carla Appelgrein!

3 Clinical Pearls.

1. How Cats with Haemolysis Will Trick You

From Episode 193 in the Medicine Feed - With Dr Rachel Korman

Step one when working up an anaemia case is to classify the anaemia. And if we’re trying to figure out whether our patient has been bleeding out, breaking down red blood cells, or just not making any new ones, we want to know if our anaemia is regenerative or non-regenerative, right? So you look for retics, variable cell sizes, and all the other markers of regeneration. But here’s yet another way that cats will knock your diagnostic plan off the coffee table, just to watch it smash…

Let’s start with this: Yes, cats do get IMHA. It should be on your DDx list for an anaemic cat.
Now, you’d expect a haemolytic anaemia to be strongly regenerative, right? (Can you guess what’s coming?)
BUT, when the feline immune system turns on its own red blood cells, it does it differently: it goes right into the bone marrow to target erythroid precursors.
This means that many immune-mediated haemolytic anaemia cats will present with a non-regenerative anaemia, because those retics never even make it out of the bone marrow.
Oh, and just for fun – cats don’t really do spherocytes either!

(If you’re confused about how you should work up the anaemic cat, you should definitely listen to this episode!)

2. The Hidden Link: GI Disease and Renal Disease

From Episode 190 in the ECC Feed - With Dr Bing Zhu

Let’s just jump straight into this 🤯 pearl with a quote:

"I can't tell you the number of times that I’ve pulled these dogs off their renal diet, put them onto a novel protein or a hydrolysed protein diet, treated their gut disease, and then they become non-azotaemic.”

Wait, what?

Here’s what:

Low-grade GI disease can lead to chronic inflammation and acute kidney injuries. Dr Bing sees this as a fairly common reason for ongoing AKI that can look like CKD. (Let me say that again - it’s not azotaemia because the kidneys are chronically cooked, it’s ongoing azotaemia from ONGOING ACUTE kidney episodes.)
Typical case: Dog with life-long low grade GI disease, e.g., occasional random vomit, soft poos from time to time, variable appetite. Owners think it's just normal for their dog.
- Routine bloods in later life reveals azotaemia - we think it's CKD, so we start it on a renal diet (high fat, low protein, non-hydrolysed).

"Guess what’s bad for dogs with gut disease? High fat, non-hydrolysed protein renal diets. Two months later, their creatinine gets worse and they're told, oh yeah, your dog just has really bad kidney disease.”

These patients actually have repeated, low-grade AKIs secondary to unrecognised intestinal disease. In these cases, addressing the underlying disease (e.g., novel protein or hydrolysed protein diet with the appropriate immunosuppressive for chronic GI disease) will stop the damage to the kidneys and resolve or at least massively improve the azotaemia.

I told you… 🤯

3. Is it Septic or Not? (i.e. Should I Cut?)

With Dr Claire Sharp from the Advanced Surgery Podcast

You know how, when you’re trying to figure out whether that effusion in your GI surgery case is septic, or just inflammatory, we reach for glucose and lactate levels in the effusion to help us decide? Well, I have some bad news… Dr Claire Sharpe gave us an absolute masterclass in all things peritonitis, and here’s what she had to say:

Lactate and glucose to help you differentiate are totally off the cards. Several studies have shown this.
When an animal has already had abdominal surgery, there’ll be low glucose and high lactate in the abdominal fluid, just because of the inflammatory response to the surgery.
This is because the inflammatory cells eat glucose and make lactate, whether there is sepsis or not. (Yes, that means that you’ll see the same changes in inflammatory conditions like pancreatitis.)
“There's some diagnostic merit to glucose and lactate differentials in the naïve ‘off the street’ peritonitis case, but there's zero merit to glucose and lactate differentials in the patient that's already been cut.”

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2 Other things

“You never truly need what you want.
That is the main and thoroughgoing key to serenity.”
Albert Ellis
“Perhaps the reason we so often experience happiness only in hindsight, and that any deliberate campaign to achieve it is so misguided, is that it isn’t an obtainable goal in itself, but only an after-effect. It’s the consequence of having lived in the way that we’re supposed to, by which I don’t mean ethically correctly, but fully, consciously engaged in the business of living.”
Tim Kreider

1 Thing to think about.

“Now tell me a vet story.”

That’s typically the last request (order?) from my seven-year-old at bedtime. The lights go off, and he turns around for a back tickle and a veterinary adventure from my past. I cast back into the memory banks for a story with just the right level of gore to keep it exciting – ideally one with a happy ending.

Here’s the story I tried to tell a couple of nights ago:

It’s the story of my first – and to this day, most impressive – dystocia case. I was a few months qualified, working in a small rural clinic where I lived in an apartment attached to the clinic, and my patient had 22 pups inside her that needed to come out.

Oh, and it was a sole charge role.

And of course it was at night. By the time I saw her at 10 pm, she had delivered two or three pups over the preceding 12-hour period. I’m foggy on the details of why I didn’t do a Caesarean – I’m guessing the owners didn’t want to pay for one, but it’s just as likely that I was simply too scared to do a solo C-section. Whatever the reason, I admitted her and spent the rest of that night trying to coax 20 puppies out of a 50 kg Mastiff.

What followed was a haze of oxytocin and glucose drips and calcium and KY. Lots of KY. But pup by pup, we were getting there. By 3 am I felt that we both needed a break. I put her in a cage and crawled off to bed for a nap. An hour or so later my alarm dragged me out of bed, and I went back into the clinic to resume my midwifery. But here’s where the story gets interesting – because my patient was nowhere to be found! Some numpty had failed to properly shut the cage.

I panicked, as you do. Probably cried a bit. In the end, she wasn’t that hard to find – it was a small clinic, and she was a big dog. The bigger challenge, though, was finding the four or five pups that she had deposited, like Easter eggs, throughout the clinic! That last jab of oxytocin, or the calcium, or something was obviously finally working, because suddenly she was popping like a Nerf gun at a 10-year-old’s birthday party.

I won’t go into all the details of the rest of the night, but somehow we managed to get all of the pups out of her – most of them alive!

It’s a funny story, right? Young vet, big conundrum, bad decisions, mistakes, resolution, happy ending. We all have stories like that. But somehow, this time when I told it, I wasn’t laughing.

_______

I said that it was the story I tried to tell my seven-year-old, but I never got to finish it. Because midway through the telling, a lump in my throat forced me to stop. I was suddenly deeply and inexplicably sad.

It took me a while to make sense of this sudden emotion: at the root of it was empathy. Empathy for that foolish young vet, chasing around a confused dog – both of us covered in lube and placental fluids – hoping, squeezing, praying for those puppies to come out. Telling that story snuggled up to my son took me right back there, reliving what young Hubert had felt that night. Not heroic. Not stimulated or challenged or in a growth mindset. Definitely not laughing. Just overwhelmed. Scared of fucking up.

And extremely alone.

I wish I could give that guy a hug and tell him – “you poor thing.”

_______________

I realise now how much is wrong with that story. But I’m still not sure what to make of it. I used to believe – still believe – that experiences like that teach valuable life skills and more than a few coping mechanisms. Sink or swim – and if you don’t sink, you swim away with healthy doses of resilience, self-reliance, persistence, and MacGyverism. Maybe even a bit of perspective.

But now, after thinking this over with the benefit of a bit more wisdom and the hindsight of almost 25 years in practice, I wonder if it also instilled some less-than-ideal traits – like corner-cutting, being OK with low standards, discounting, and undervaluing. And how well have some of those “coping mechanisms” really served mI? Like, where is the line between self-reliance and arrogant resistance to asking for help? When does resilience cross over into a crippling lack of vulnerability? (It’s taken me 25 years to even admit to myself that I was not, in fact, OK.)

Experiences like these also almost certainly contributed in no small part to tainting my relationship with veterinary science – and to the growing desire I had for the first five years of my vet career to be anything but a vet. I’m wary of crying wolf by using the word ‘trauma’, but for many of us, there is a traumatic element in situations like these that, when unrecognised and unaddressed, can leave fingerprints.

When it’s “sink or swim” and you don’t sink, the alternative is not always swimming – sometimes it’s a near-drowning. It can take a long time to fully recover from the emotional aspiration pneumonia that results from events like these.

——————

So what’s the point of this story? I’m not entirely sure. The obvious thing is to not leave our recent grads unsupported. By all means, put them in situations where they need to problem-solve. Let them do hard things. But never in a situation where they feel alone.

I like to think that jobs like my first one don’t really exist anymore. I hope I’m right.

But maybe the main thing to think about is the importance of developing some empathy for yourself. You’ll have rough days – hopefully with more support than I had – but they’re kind of inevitable in this job. The ability to review what happened almost as an outsider - to observe yourself in those situations with love and patience, especially when things don’t have a happy ending – not as a victim, but as someone who is simply trying their best – is illuminating and quite freeing.

“You poor thing. I wish I could give you a hug.” (Just try not to wait 25 years!)

Much love,