The Vet Vault 3.2.1.

Effusion pro tip, quick and easy osteosarcoma diagnosis, why you might want to keep some desmopressin on the shelf, and are 'wellness screens' just a money-making exercise?

3 Clinical Pearls.

1. Effusion pro tip.

From ep 182 on the medicine feed. With Dr Holly Brown and Jessica Wilson Hess.

• I feel like a fool for not thinking of this sooner, but now I know… In case you also didn’t know this:

  • You DO know that understanding how cellular an effusion is, and identifying the types of cells present, is crucial to determining the nature of the effusion and its possible causes..

  • So you send it off, or, if you need an answer immediately, you perform a rough-and-ready manual cell count. 🙄

  • But did you know that your in-house CBC machine is totally capable of doing this for you, and will give you a much more accurate answer.

  • Pro tip: The machine is expecting a blood sample, so when you give it a fluid with low cellularity it will have a hissy fit and spit out lots of exclamation marks and ‘invalid’ results. Stay calm, ignore its outburst, and just look at the WBC and RBC counts - that’s all you care about.

2.  Quick and easy osteosarcoma diagnosis.

From a case on our specialist support space.

• Someone posted a radiograph of a suspicious looking bone lesion in our support space a few weeks ago to ask our specialists what they thought. Surgeon Dr Mark Newman said it looked like bad news and definitely needed a workup. Then oncologist Dr Penny Thomas added this bit of wisdom about a sensible next step to get an answer:

  • FNA of bony neoplasias have a 60-80% success rate in getting you a diagnosis.

  • What this looks like for me practically is, while I have the patient sedated for rads, if I see a suspicious lesion, I stick some needles into it. (It’s easier than you think - the affected bone is usually soft as.)

  • Dr Penny’s how to guide:

    • Use imaging to direct where you go. You want to be central in the mass, not peripheral, as there will be a lot of reactive change around these masses.

    • Aim for a big lucent area, which will allow you to go quite deep.

    • Use a 23-gauge needle first. If not having much luck (ie you smear what you get, and there’s nothing exciting to see) try a 22-gauge needle next.

    • Don't apply suction to the syringe initially to avoid excessive blood contamination. If you find that you are not getting a good enough sample, then attempt again by applying suction on the syringe.

3. Two Other reasons why an ECC clinic might want to keep some desmopressin on the shelf.

From episode 121 on the ECC stream. With Prof Kate Hopper

When we recorded this masterclass on treating patients with sodium abnormalities Prof Kate mentioned that you can use desmopressin to prevent sodium levels from coming up too fast when you’re trying to fix a severe hyponatraemia. I nodded along like I knew what she was talking about. And then, as soon as we stopped recording, I went down a Google rabbit hole to remind myself what desmopressin is. Here’s what I learnt, including some cool uses for it:

• It’s a synthetic analogue of the natural occurring hormone vasopressin, which (and this always confuses me!) is the same thing as antidiuretic hormone, or ADH.

• We could have an entire textbook chapter on ADH, but in terms of therapeutics, you’d know vasopressin as a vasopressor for use in vasodilatory shock, because it constricts blood vessels very effectively. (Presses the vasos…)

• Desmopressin, on the other hand, you might recognise as the drug we use to treat central diabetes insipidus. (Recall that central DI is where the body cannot produce sufficient ADH, leading to PU/PD.)

  • Note that desmopressin lacks the vasoconstrictory effects of naturally occurring vasopressin.

Are you with me so far? Good. Now, two uses beyond DI for desmo:

1. Like Prof Kate said: You’re trying to slowly bring up the hyponatraemic patient’s sodium to prevent sudden brain shrink. But when you check electrolytes an hour later the sodium has shot up much faster than you want. Crap! No worries - give it some desmopresson so that the kidneys hold back more free water, thereby quickly diluting that sodium again.

2. Von Willebrand’s disease! I can’t find out why, but randomly desmopressin can also increase levels of von Willebrand’s factor. So when that Doberman’s emergency surgery is going horribly messy, desmo might get you out of trouble!

(Random fact - in human med they also use desmo for bad bed wetting. Keep that in mind for when you get older!)

2 Other things

1. “Begin with this question: ‘What are you hiring yourself to do?’

   Are you making that choice because your labor is cheap and convenient, or because it’s the place of maximum leverage? It’s often easier to be busy than it is to be productive.

   Busy is a morally superior distraction. Busy gets us off the hook. Busy is a great place to hide.”

   - Seth Godin

2. “'If you want to learn something, read about it.

   If you want to understand something, write about it.

   If you want to master something, teach it!”

   - Yogi Bhajan

   (I can concur Yogi, as evidenced by the above post about desmopressin!)

1 Thing to think about.

 Here’s something I think about a lot: how do we practise a high standard of medicine without doing unnecessary things? How do we take great care of our patients without succumbing to fear-based practice or the pressures of running a financially successful business? Basically, where is the line between good medicine and ‘do you want fries with that?’

---

Several conversations on the clinical podcasts have made me think long and hard about wellness profiles (none more so than this one. My question is this: do wellness profiles make scientific sense?

“The problem with wellness profiles is, how far do you need to go when you do find something abnormal? You may miss something bad, or get an abnormal result for something that’s nothing.”
— Prof Jill Maddison

Let’s explore that question

But first: I sat down at my desk hoping to write a quick post on this, but as an outline of what needs to be covered started taking shape, I realised that it’s actually quite a big topic if you want to unpack it properly. (In fact, I think I’m in over my head. Luckily, I know some smart people who can help us!) So here’s the plan: we’ll do this as a series of posts over the next few weeks. Here’s what I’d like from you:

1. Tell me if you care. Is it:

   • “Great topic, Hugh—I look forward to reading the next few posts!”

   • or “Who cares?! Get back to questioning existence.”

2. If we do go down this rabbit hole, I would love your input. Invariably, there will be a fair bit of my own bias and opinion. There’s an old saying that I like:
   “Opinions are like a$$holes; everybody has one, but everyone doesn’t need to see yours.”
   Well, I want to see yours.

---

Ok, in the spirit of Simon Sinek: let’s start with why. Why would we run any diagnostic test on seemingly well animal?

How about this: we want to screen for asymptomatic or unrecognised underlying problems with the hope of:

• Catching issues early.

• Treating them before they cause unnecessary suffering or become life-threatening crises.

• Increasing the chances of effectively treating and hopefully curing something.

Does that sound right?
(A cynic might say it’s a great way to improve practice turnover, but we’re not cynics—we’re scientists. Right?!)

---

So here’s the first thing to consider: what are conditions that can theoretically be clinically silent that could lead to a catastrophic event, or avoidable suffering, where earlier recognition would have had an impact on the outcome?

Here’s what I can come up with:

Cancers

• The ruptured splenic mass springs to mind, mainly because I dealt with another one this week. If I picked that up 3 months earlier we could have prevented the crisis, had a much less pressurised conversation, and potentially could have cut that bastard out before it burst and spread cancer cells all over the abdomen. Right?

• Same thing can be applied to any mass with the potential of causing an acute bleed. Even the heart base mass that inevitably ends up as the crisis pericardial effusion case could potentially be disarmed (not fixed, just controlled) with targeted radiotherapy.

So cancers, right. If we can catch them, maybe we can fix them. Let’s think about other common cancers:

• If you found lymphoma before those golf balls appeared on your patient’s neck, would you have a better chance of achieving remission?

• Ditto osteosarcoma. If we picked it up in the pre-clinical stage, could we chop off the leg or chemo it into oblivion, or at least extend pain-free life by preventing a pathological fracture?

• Any other internal (ie something that you couldn’t find on a thorough clinical exam) soft tissue cancer that could potentially be surgically cured before it spreads.

Metabolic Conditions

Is there any benefit to finding and instituting treatment for the following conditions before they start causing clinical signs?

• Diabetes: If the owner is astute enough to see the PU/PD and weight loss, then you have plenty of time to start treating, right? But then, we all know that not all owners are that observant, which is why we see plenty of cases where the first evidence of diabetes is an episode of DKA. So maybe early warning makes sense.

• Cushing’s… Well there’s a rabbit hole! Nobody drops dead from Cushing’s. So is there any point in confusing ourselves checking ALP levels randomly? You could also argue that Cushing’s can cause low grade suffering before the owner gets annoyed by the panting and the pissing, or that picking it up early could prevent a cruciate rupture, diabetes, or random death from a clot or some other life-shorting condition. (ACVIM Consensus Statement on Hyperadrenocorticism)

• The yin to Cushing’s yang—the great pretender, the sneaky disease: is an early diagnosis of Addison’s worth an annual electrolyte panel in the right breed? (Or even a sneaky stimulation test so we can address Cushing’s at the same time?)

• Kidneys: We have multiple ways to assess kidney function, and IRIS tells us that starting management in the preclinical stages can slow disease progression, improve quality of life, and potentially extend survival time. (IRIS Guidelines)

• Let’s not talk about the liver. It will only make you cry. (Just listen to that link I shared above.)

Cardiovascular Disease

• For mitral valve disease, we know that we’d only start treating once we hit stage B2. So you’d check for a murmur before you reach for the probe, right? (EPIC Study Official Site)

• If you had a Doberman, or another breed predisposed to dilated cardiomyopathy (DCM), then it might be worth knowing about it before you hear a murmur or see clinical signs. (PROTECT Study Summary)

• Cats and their hearts… a long chat about this led me to believe that only a scan (or the onset of clinical signs) will tell you what’s really happening in your feline patient’s heart. Screening echocardiograms for your committed clients, anyone?

Miscellaneous

There are many ways for your patients to get sick and die—more so for some breeds than others. So maybe non-specific markers of "trouble brewing" could be useful.

---

OK, your turn. I’m sure I’m missing heaps. Tell me:

1. What other conditions are we missing?

2. Do you run health screening tests?

3. If so, what tests do you routinely run?

Pop it in the comments or reply to me. I’ll send this to a few smart people for their input.

Next week, we’ll compare some common tests with the list we’ve compiled to figure out what’s genuinely useful.
(This might just turn into a quest for the ‘Sensible, Science-Based Wellness Profile!’)

Much love,
Hugh

---

How to connect with us:

Listen

Learn

Connect

If you are finding these emails useful - do us a favour and forward it to a friend who you think would like it too.

And if you are that friend who had this forwarded to them and you want to get more of these emails, then …

---