Hi everyone, thank you for joining me this evening. My name's Sophie McMurra. I'm a registered veterinary nurse and also a veterinary technician specialist or VTS in small animal internal medicine.

I work at North West Veterinary Specialists where I'm the head nurse of the internal medicine department and I have a particular interest in endo endocrinology. I also have a Facebook or Instagram page if you like internal medicine, just head over and follow veterinary nurse medicine geek for any internal medicine updates. And today I have the pleasure of speaking to you about feline hyperthyroidism.

So Hyperthyroidism is an endocrine disease of the thyroid gland, which causes an excess in production of T3 and T4, which are thyroid hormones. It's actually the most common endocrine disease that we see in cats, and it's common in many different locations across the world, including the UK, which is where I am, New Zealand, Australia and North America. And it's less common in places such as Hong Kong and Spain.

Now, the prevalence in older cats who present to the veterinary clinic in those common areas make up around 10% of the population who presents to the veterinary clinic, so hyperthyroidism is very common indeed. And typically we see a benign adenomatous hyperplasia, or also known as an adenoma. This makes up around 98% of cases, so typically they are a benign disease.

But we can see a very small amount of cases, less than 2%, can be a thyroid carcinoma. And although this is a disease of the thyroid gland itself, it very quickly becomes a systemic disease causing many diseases of concurrent, concurrent issues throughout the body, because the thyroid hormones affect every tissue and every different organ, so we will, very quickly end up with a multi-systemic disease. And around 70% of patients have both glands which are affected.

And typically the disease free lobe does start to atrophy, and that's because of that typical negative feedback loop which we'll talk about in a moment. If the, the hypersecretion is coming from one lobe. It's feeding back to say we don't need any more thyroid hormone produced, and then there's no thyroid stimulating hormone being released and therefore nothing is stimulating that other non-ceased lobe, so it's just started to atrophy because it's not being used.

Now I'll just touch briefly on a little bit of anatomy and fizz, because I think it is very important to just refresh your knowledge on anatomy and fizz, because if you remember these parts, then you can quite easily figure out the rest if you, if you do forget certain areas. So, as you're aware, there are 2 thyroid glands, both located either side of the larynx, and they are microscopically made up of thousands of tiny follicles, and this is where your thyroid hormones are produced. You can also see functional ectopic thyroid tissue, and ectopic just means when something is in an abnormal place or an abnormal position.

And this can go down and be found in the thoracic inlet or even the mediastinum. However, this is less common. Now I've just mentioned about that negative feedback loop, so we have all endocrine diseases are controlled by a negative feedback loop, and the one that's specific for us today is for the thyroid glands.

So the hypothalamus releases thyrotropin, releasing hormone or TRH. This then goes to the anterior pituitary gland, which stimulates the release of thyroid stimulating hormone. As it says on the tin, this then stimulates the thyroid gland.

To, To produce the thyroid hormones. Once that level has reached a desired level. It will feed back to the hypothalamus to say we don't need any more, our levels are fine, and that is what the negative feedback loop means.

Now we have two main thyroid hormones that we produce and they, they contain, they're iodine containing hormones. So we have thyroxine, which is T4, and this is a pro hormone, and we have T3, which is the active form. But what do all of these mean?

So our free T4 is not yet bound to any protein. So this can still be utilised by the tissues in the body. We then have total T4.

Usually if something says total, it means it's bound to proteins. So the total T4 is bound to proteins, and this is less reliable to look at for diagnostics because it will do whatever your proteins do. It's not independent, it's bound to the Proteins.

So if your proteins fluctuate, maybe if you've got dehydration or any other condition that will cause alterations in your protein levels, your total T4 will do the same. So it's not specific to the thyroid gland itself, so we shouldn't use that as a diagnostic tool, as in the first instance anyway. And then we have total T3, which is the active form of the hormone.

Now I'll just briefly touch on, there is quite a long list of what our thyroid hormones actually do in the body. So they are absolutely vital for the function of our body and of many of our systems. So they play a big role in the maintenance of body temperature.

They play a huge role in the rate of metabolism, and not only from our food, but from many different energy sources, how we utilise the energy from our metabolism so that we can use it as energy in all of our cells, so it regulates that cell metabolic rate. It encourages synthesis of proteins as energy, carbohydrates, and they also play an important role in our glycemic control as well, so it helps to keep our blood sugars within the normal range. It breaks down fast, and the thyroid gland is actually the only endocrine gland to store its own hormone in large quantities.

T4 can only be made by the thyroid glands themselves, and the T4 is converted into its active form, which, as we mentioned before, is T3, by other tissues around the body. So it's produced by the thyroid but then activated in the liver, the kidneys and also in the muscle. Now we don't fully understand the causes of hyperthyroidism in cats, but we do have a few suspicions, and there are a few contributing factors that we can, we can mention.

It could be an infectious cause, an immunological your own body's own immune system causing it. It could be environmental. Think of those, the places where we see it commonly versus the ones where the disease is not common at all.

It could certainly be nutritional, and we'll delve into that a little bit more later on. Genetics can play a part and some studies have shown that canned cat food can be a cause of hyperthyroidism. Goitrogenic compounds may be present in calf food, so we know that iodine is important and is contained within our our thyroid hormones.

So if these cans have too much or too little amounts of iodine, it can stimulate or it can alter the synthesis of the thyroid hormone itself. And then the chemicals that they use to line the cans or the tins can go into the food during the storage, so that can play a big part in the onset of a hypothyroidism. Now with regards to signalment, the age range here is vast, so anything from 4 to 20 years.

But the average age is around 12 to 13 years of age. And any cat under 10 years of age, it's very uncommon to see this disease, but it's not impossible. Our most common cats that we see, domestic short hairs, domestic long hairs are most commonly affected.

And we mentioned genetics may play a small part. Pedigrees including your Siamese or your Himalayan cats seem to be less affected in many studies. And it does also seem to be more prevalent in males as well.

So the clinical signs that we see for hyperthyroidism are very similar to those that we see for many different diseases that your old cat can present to the veterinary clinic with. Weight loss, commonly seen in a large number, so 88%. And this is despite polyphasia.

So I always remember having a hyperthyroid cat in the clinic and I brought out, there was a tin of cat food, and they can become very ravenous with their food and also get quite, not aggressive because they're not, they're not trying to be aggressive, but very determined and very, they can have like a, a hyper aesthetic. Behaviour when they see things like food, and this cat actually started to try to eat the food through the tin, it was actually starting to bite the tin itself, so it can get very ravenous. 83% of patients will have a thyroid glia, and one of the tips that I've learned from some of our medics is rather than just trying to feel for individual nodules in the area of the thyroid, if you do each each side individually, so use your thumb, start at the very top, just underneath the chin or the jaw bone, go right the way down.

And then also into the thoracic inlet and then back up and then do the second side individually. And if you, you can't always feel a goitre, but if you do this and run your thumb down, you may just feel a pop or move slightly as a small nodule underneath your thumb. So you have a greater chance of finding that goitre.

And also, as we mentioned before, you can get ectopic, Glands or tissue and also if the the thyroid gland gets big enough, it just starts to naturally drop into the thoracic inlet. So if it is quite big, you may need to go right the way down and feel in that thoracic inlet as well. If it does go too far down, obviously you won't be able to feel it, and that's where our imaging comes in.

Some patients can get very hyperactive with their their behaviour, and they can get restless, they can get a poor coat quality, so I think it tends to separate and almost become a little bit greasy. They can get patchy fur, it can get matted, sometimes they will stop grooming or other times they will have excess grooming. And I also tend to think they have issues with their claws as well, they stop shedding their claws, so they almost become a little bit long and overgrown.

PUPD we can quite commonly see. Vomiting tends to be intermittent rather than continual and less commonly so we will see diarrhoea. And that abnormal or anxious behaviour is some of that what I've just mentioned about the behaviour around food or maybe around handling these cats as well.

They can seem much more anxious than your normal relaxed cat. And they do seem to have a reduced tolerance to stress and they can open mouth breathe very, very easily. So we do have to be very careful with these patients.

Occasionally we can see weakness, lethargy, anorexia depending on the stage at which the patient presents and how the disease has manifested within each patient as well. So if they do have multisystemic involvement, they could also present in, in these ways to more lethargic and anorexic rather than the the typical hyperactive and polyphagic. These patients are not usually dehydrated, so we do just need to have this in the back of our minds to be cautious with fluid therapy and especially if they do develop cardiac disease, which we'll delve into in a moment, so we can very quickly fluid overload these patients.

OK, so before we do anything with these cats, careful handling is absolutely paramount. So firm handling or even gentle handling just depends on the individual patient. If they are not coping and it's getting them stressed, this can be fatal.

So we need to assess the individual cat if we need to do bloods, place an IV, do any diagnostics on this patient, we need to consider chemical restraint. So they have a heightened metabolic state and possibly even cardiac disease. We can tip them over the edge very, very easily.

So just don't stress them out would be my, my biggest take home tip from, if you take anything from this whole talk. Don't stress them out and consider the use of sedation if and when needed. Now, your physical examination of these patients can often reveal a low bodily condition score.

Sometimes that thyroid mass, they can typically be tachycardic, usually we see a tachycardia of above 240 beats per minute and that typical poor coat quality, that. All of those things together just screams hyperthyroidism. However, it also screams many other different diseases of the older cat, so we need to have it on our differential list, but we do need to, you know, consider all of the other conditions that all cats can present with.

You also might see feel small kidneys on abdominal palpation. Dehydration or potentially not dehydration depending on what stage they've presented, and we can also see things like heart murmurs, gallop rhythms and weakness including ventroflexion of the neck. And excess thyroid hormone can affect our cardiac output, and we'll talk about this in more detail.

It also affects our peripheral vascular tone and our renal blood flow, so therefore our glomerular filtration rate. So we can, we're starting to see the many different systems that this thyroid, or excessive thyroid hormone can affect. And I'm just quickly going to mention apathetic hyperthyroidism where they can present more depressed and anorexic, and it's typically associated with congestive heart failure or other non-thyroidal illnesses.

So be aware of that as well, in case they do have any concurrent illnesses and hyperthyroidism also comes along with that. So typically when we start to investigate, haematology is not usually affected, they might have a mild to moderate raise in our hepatic enzymes, but generally they don't have any clinical significance. Aotemia is a really important one, so.

If they have an elevation in their urea or creatinine, this is significant because you may have found chronic kidney disease in these patients, but. Even if it's within the normal range, typically these patients will have that reduced muscle mass, which should reduce our creatinine value. If it's within the normal range, that's abnormal for these cats because it shouldn't be within the normal range because it, we know that our creatinine should reflect our total muscle mass, so.

Consider that as significant because we need to. We need to see if these patients do have a chronic kidney disease or any kind of kidney disease alongside because hyperthyroidism increases our renal perfusion, increases glomerular filtration rate, and can quite often mask mask kidney disease itself. So pay attention if your urine and creatinine is, top end of normal or even within that normal range when the patient suggests that it shouldn't be.

Oops. So when we're looking at your ear and creatinine, we could also assess it alongside our urine specific gravity. So assess our hydration status, we know that we need to always assess USG alongside hydration status to tell us what our normal range should be.

So if it's between 1008 and 1020 and we have an increase in our renal values, then we should be suspicious of renal insufficiency. And we should be looking at the kidney's concentrating ability. And usually when we do treat hyperthyroidism, if you are suspicious of kidney disease, you may start to unmask it.

And sometimes we may even need to lower our anti-thyroid medication or even discontinue in order to reserve renal function. So it's, it's a balancing act of, of the different diseases. And I've mentioned a few of these things before, but the other part that I want to mention is typically a cat who presents with chronic disease.

Quite commonly we get anaemia of chronic disease in cats. Patients with hyperthyroidism might have a mild increase or high end of normal PCV. Now that's abnormal in a cat with, or it could be deemed as abnormal in a cat with chronic disease because they quite often get an anaemia.

But this should alert a suspicion of hyperthyroidism because the increase in oxygen demand. Induces the release of erythropoietin by the kidneys, so that is why we see that higher PCV or that normal PCV rather than an anaemia, which we would see alongside many other chronic issues. And then we come to cardiac disease.

So, we mentioned before, tachycardia typically sitting above 240 beats per minute, and they often have a powerful apex beat, so as you pick the patient up, you can feel the heart pounding in the thorax. We can see a systolic murmur typically between a grade 1 and 3, a gallop rhythm and also some other arrhythmias as well. If you link up your ECG, we can see atrial and ventricular abnormalities.

And thyrotoxic cardiomyopathy is a cardiac disease caused by the toxic effects of the thyroid, hormones can be seen in cats, and the most common one is hypo hypertrophic cardiomyopathy phenotypes or HCM. Now it depends how they present and when they present, it could be asymptomatic or it could be causing life threatening congestive heart failure and it could also be coming along with a pulmonary edoema and a pleural effusion. Usually once we start anti-thyroid medication, these side effects will reverse and we don't commonly see dilative thyrotoxic diseases, so it doesn't often dilate the the the.

Cardiac muscle itself. However, we do often see a dilation of the ventricular areas of the heart, so. Alongside that we get decreased myocardial contractility.

And once that does, once the, the ventricles and everything do dilate, it can quite easily become irreversible depending on how, how progressive this, this disease is and what later stage that we have, the patient has presented in. And we can also see hypertension, so I've just mentioned a load of different things caused by the heart, and we know that our cardiac output determines our blood pressure, cardiac output, stroke volume, vasodilation or vasoconstriction, so systemic vasoconstriction. All of these things have a really important, role in maintenance of blood pressure.

And all of these are maybe abnormal with hyperthyroidism, so this activates the RAS system, so the Renin angiotensin aldosterone system which can shoot up their blood pressure in return. And these cardiac abnormalities are usually directly correlated with the effects of the thyroid glands in the thyroid hormone in excess amounts. And the heart is just compensating to the changes in the alterations in the peripheral tis tissue perfusion.

Some of the things we may see a lower urinary tract infection, these are common but often asymptomatic. And when we are looking at our diagnostics for diagnosing hyperthyroidism, ideally we want to do a cystocentesis and send off a full urinalysis for culture and sensitivity. We can also see some gastrointestinal disorders with this disease as well.

And we can get an increased intestinal motility. So we get polyphagia or anorexia, we can get weight loss with vomiting and diarrhoea, and an increase in volume and frequency of defecation because we just have an increase in our intestinal motility. Now these can also be signs of intestinal neoplasia.

So abdominal, the abdomen should be carefully palpated and looking for any enlarged lymph nodes or thickening of the gastrointestinal tract which can also be seen on abdominal ultrasound. Now in order to diagnose hyperthyroidism, typically we will see an increase in our total, sorry, in RT4. And we look at this to diagnose hyperthyroidism.

Some patients can have a normal T4 within the top or normal reference range due to occult hyperthyroidism. Or any other non-thyroidal illness causing the suppression of T4. So your thyroid 6 syndrome, we know exists and this is basically the suppression of the thyroid gland caused by any other chronic disease.

So if we do think that this patient has another concurrent disease, we should consider controlling that and treating it prior to testing the thyroid gland because we may get an abnormally low reading. And if we don't treat this disease, it's not really a disease that can go untreated for very long because progression will lead to severe metabolic compromise, potentially heart disease, and the patient can also die as well, so it can be a fatal disease. Now there are other tests available.

T3 suppression tests, which we don't really do. Radionucleotide scanning is used to image, these cats, and it can be great for looking at abnormal tissue, so ectopic thyroid tissue, which you can see on this image here is also in the the mediastinum area. And this will also point us in the correct direction towards what treatment options we have available, because if we do have ectopic thyroid tissue, then surgery is no longer an option.

This can also help locate metastatic spread from a thyroid carcinoma as well. OK, so now that we know we've diagnosed hypothyroidism, we also need to treat it. So we have our first option is radioactive iodine.

This is a very effective treatment and it's safe. And it's also considered the treatment of choice in most cats. It is also useful for patients with ectopic thyroid tissue and also carcinoma as well.

So how does it work? So we usually administer subcutaneously IV or oral I131. Radioiodine treatment.

This is then taken up by the follicular epithelial cells of the thyroid gland, and this concentrates the level in the affected gland itself. Radiation is then emitted from that area from the the affected gland and it destroys local tissue. But it also spars your parathyroid tissue and it spares the other thyroid glands, so it's very clever.

And the aim is to cause a normal thyroid level or e thyroidism, while avoiding over suppression or hypothyroidism. So they, they titrate it or they, they do very careful calculations to make sure that it doesn't over suppress the glands and it just destroys exactly how much we need. The treatment is successful in over 90% of patients and it has an overall survival time of between 2 and 4 years.

So the long-term prognosis is excellent. And the thyroidism can be achieved anything between week 1 and week 12. So as with all of these treatments, we need to weigh up the pros and cons, so there are a few side effects.

However, once we Sorry, I should, I should have said there are a few side effects there. I've read that wrong. Once we .

Have had this treatment, then there's no need for any oral medication, which is great for the owner and it's also curative as well. The disadvantages are that there are only a few centres that carry out this procedure, so it's not readily available all across the UK or all across the world. It can be expensive.

If it does go wrong or it unmasks kidney disease, it's irreversible. It could cause hypothyroidism, and the patient also needs to quarantine for days or weeks depending on the policy of the individual site. Now patients along along with many of the other treatment options, they do need to be pre-treated with anti-thyroid medication first, and this will allow us to just make sure that we're not going to unmask any kidney disease.

And there is a lower reoccurrence rate with this of 2% following the procedure, which is great, very low indeed. Now the most common choice that we tend to see in the UK is the oral or transdermal medication which you can see here, we tend to have methimazole or or carbimazole. And the advantages of this is that it's easy to administer if the patient can be tableted.

If they can't be tableted, then we have the transdermal medication, which is very useful. It's also cheap and you can also stop it if you do unmask kidney disease. Now there are potential side effects that come along with these drugs, cytopeniaass can occur.

We can also get facial pruritus and excoriations as well as bone marrow suppression. So this doesn't suit all patients. And the side effects do seem to be the same with both drugs regardless of which one you use.

And one thing to remember is that you cannot crush anti-thyroid medication because it reduces the effectiveness of the drug. And then we also have surgical thyroidectomy, which is also curative. This can be performed once the patient has been controlled again for 1 to 2 months on anti-thyroid medication, and this will just make sure that they are stable enough for anaesthesia.

Once your normal T4 levels and renal values have been documented, you can then go ahead and be deemed a safe for surgery. Surgery is not an option for ectopic thyroid tissue or thyroid carcinoma. And again, advantages and disadvantages, it's curative in 80% of cases.

It can be quick if you in the experienced hands of a surgeon. It's relatively inexpensive given that it's just a one-off payment and there's no need to orally medicate long term for the rest of the patient's life. Disadvantages are that it obviously does carry an anaesthetic risk.

You can develop hypothyroidism, hypoparathyroidism, and you can also get things like laryngeal paralysis if the surgery is affects the the laryngeal nerves. And if there are any bits of tissue left behind, you can also get a relapse of the disease. Now, it's very important that we are aware of the side effects or the hypoparathyroidism that can occur postoperatively, and this can be a serious complication.

And when I say postoperatively, it doesn't just mean in that initial post-op period. This can take between 3 and 5 days to develop post-surgery, so the whole veterinary team needs to be aware of what signs to look out for and if the patient is discharged during that time, the owner education is absolutely vital so that the owner knows what they're looking out for and can detect any early signs of hypoparathyroidism if it were to occur. And this can happen due to, it's a reduction in the parathyroid hormone secretion, causing a hypocalcemia, which is where the side effects come from.

And this can just be interference from the surgery itself. We know how small that parathyroid gland is, and if it's been interfered with a little bit too much during the removal of the the thyroidectomy, then these signs can occur. Now the most common ones that we look out for are facial twitching, lethargy, weakness, and muscular tremors, and it can even get bad enough to cause seizures or convulsions.

Now when we're looking at monitoring our calcium, it's very important that we are looking at our ionised calcium. And this is typically Measured on our electrolyte machines such as your epoch, and they can also be the machines that measure your blood gas analysis will also do often your electrolytes as well. So that is typically ionised calcium.

The ones that you will read on your biochemistry machines are typically total calcium, which we said before, your total calcium are bound to proteins, so that will reflect what your protein is doing rather than what your, your calcium is doing. And if we do see a deficiency, we may need to supplement the calcium either orally or IV along with vitamin D to help with the absorption of that calcium. And it can take weeks or months to recover depending on the severity.

And then we do also have dietary therapy or dietary treatment that is available, however, it's very new to the market. So the data is also very limited. We do have some prescription diets available now by some of the the different diet companies such as Hills.

And the reason this works is because iodine is essential for thyroid hormone production and therefore if we restrict it in the diet, it can reduce our thyroid concentrations. So when this is fed as the sole source of diet, then your thyroidism can be achieved within 3 weeks. And when I say the sole food source, I mean if the patient is a hunter.

And goes outdoors and catches one bird or one mouse, that's enough to restart this cycle all over again. So we need to be selective with what patients we put on this diet because it does not suit all patients. And if they are outdoor cats who hunt, then you may not get the desired effect by this if they are hunting because even one meal can reset the whole the whole process.

However, it may be suitable for patients with concurrent disease who have limited treatment options. And if you do have a cat who lives in a multi-cat household, what we should advise is that all cats are fed the iodine and restricted diet, but the other cats should be fed 1 teaspoon of a normal commercial diet appropriate to their life stage, which should maintain adequate iodine levels and prevent hypothyroidism being caused by, by us putting them on that diet or iatrogenic hypothyroidism. The long term effects of iodine and restricted diets is limited, so the data is still limited because it's still in progress, it's very new, but it does bring some concerns, so.

Until we have more data, we don't know what the long term effects, long term effects may be. And then advantages and disadvantages as we've just mentioned, there's limited data and it may not be suitable for all cats, especially if they are outdoor hunters. Advantages is that it's cheap, it's easy to administer if they'll eat it, it can be quite palatable.

You don't need any oral medication and it can be stopped if you do unmask kidney disease. And just to mention another treatment option is the ethanol infusion. So you would administer this ultrasound guided into the thyroid gland itself, and this causes tissue necrosis and eventually e thyroidism.

Usually just a single unilateral injection, ultrasound guided is enough to have the desired effect. And then I mentioned earlier that we should not stress these cats out because it could be fatal and that we may need to use chemical restraint. And the patient may also need to undergo a variety of other diagnostic procedures.

In order to investigate this disease and look for concurrent diseases, so anaesthetic considerations are absolutely paramount that we are aware of these, and we need to take them into consideration when we're looking at anaesthetizing or even sedating these patients. Now ideally we may need, we should be stabilising them on thyroid medication prior to anaesthesia. However, the timing of this is not always appropriate.

So because they have that increase in that metabolic rate, that means they also have a higher oxygen demand. This leaves the patients more susceptible to tissue hypoxia. So we should always be providing oxygen by flow by, or intubating and providing 100% oxygen to these patients if they do undergo a sedation or an anaesthetic.

Have a multi parameter linked up to these patients, ideally with a pulse oximeter to measure that tissue perfusion. Along with that metabolic rate, they will also metabolise their drugs at a faster rate. So if depends on what procedures the patient is undergoing, you may want to carefully select those drugs and also have a top up ready in case they do suddenly metabolise those drugs faster than your typical patient and require a top up.

Have a glucometer to hand because the glucose demand is also increased, if you think about how increased that metabolic demand is across the whole body on every system, the heart, the metabolic rate of everything going on, that requires energy. And that energy is given in the form of glucose, so we do have a faster glycemic turnover. So take a blood glucose when you first sedate or anaesthetize the patient and then you deem whenever the next reading is necessary, and definitely take one in recovery as well.

So keep one to hand in your recovery, in your anaesthetic box. Carbon dioxide is produced at a much greater rate because that oxygen the cardiac output is much faster, so the gaseous exchange is exchanging at a faster rate in the lungs. You can see the heart disease that we mentioned earlier, hypertrophic cardiomyopathy, so they often get dilation in the ventricles along with a reduced contractility, which means that thrombus formation is much more likely in the ventricles, which can be thrown.

At any minute. So they could throw a clot, and these patients can also present like an ATE, an arterial thromboembolism. The classical presentation of an incredibly painful cat can go off their back legs because they've thrown that thrombus to the, the artery, .

And that can all be caused by the initial issue of hyperthyroidism. And if you do have a multi parameter and you've got a patient on an ECG as well, that would be ideal. You may see some arrhythmias, ventricular arrhythmias may be present and if it's persistent, you may need to also treat it with antiarrhythmic therapy.

We also said about these patients being hypertensive to monitor their blood pressure throughout and you may need, if they are hypertensive beforehand, you may need to treat them before you do anaesthetize them. Now another thing that we often don't consider is the enlargement of that thyroid gland. If you think of how small the trachea is of a cat, it's really tiny so it doesn't take much compression.

Of anything around it to cause an occlusion. So this is Important for both sides, whether you're anaesthetizing and intubating, it may make intubation difficult, but it's also very important if we're not intubating. So keep a very close eye on the patient's ventilation, what's their chest movement like?

Does it look like an obstructive pattern? If we're not anaesthetizing these patients and they are just on flow by oxygen, then this is even more important because they could quickly occlude. If there is some compression of that trachea, it won't take much, like a little bit of mucus to cause a complete occlusion, so just pay.

Pay a lot of attention to the ventilation of these patients. And again, why it's important to have a multi-parameter with a pulse oximeter and all of your other monitoring available. And we've said a few times that hyperthyroidism can also mask kidney disease because of that increasing renal perfusion because of the higher cardiac output, so.

Bear that in mind when you're thinking of your drug choices, what drugs are you going to use? Is it something that we would use in a renal patient? And There are also many other anaesthetic considerations for these patients, but that is probably beyond the scope of today's talk, but I hope those that handful of different considerations are enough to just make you think when you're anaesthetizing or sedating these patients, of how careful we need to be and what things we can look out for, because if we are well prepared before sedating them, then we have a better chance of having a successful recovery.

And when we think of how common this disease is, owner education is very important because. We've mentioned that this condition can present in the same way that many different conditions can, many conditions that can present and occur commonly in our older cats. So quite typically these patients will present for maybe the the vomiting, if they vomited a few times, but typically the the owner will say, oh well, I didn't consider any of the other symptoms relevant because she's she or he is just an older cat.

So the weight loss, the polyphasia, the changes in the hair growth. May just be put down to being an older cat for many owners. So owner education is very important, whether that be through our vaccination clinics that we do, but also nurse clinics are vital to these patients as well, and to the owner to just educate what common diseases we can see in felines as they get older, this being the most common.

And what symptoms to look out for alongside all of those other diseases that we might see, such as diabetes and kidney disease. But if they do have on their radar that weight loss is not normal for an old cat and fair changes and coat changes is not normal, and changes in appetite and demeanour are also not normal, they may present at a much earlier stage. Before the the disease has had a chance to progress into a multi-systemic disease.

So your nurses education and nurse clinics are absolutely vital for for these patients presenting in a more stable condition. And a lot of clinics will also do older cats or geriatric cat clinics, so where you will see any patient over the age of 8 or some people say 10, and you can do your routine biochemistry, haematology, look out for some of these diseases if any symptoms are shown. So when we do diagnose and treat the disease, the prognosis is varied depending on the treatment options.

But typically, as long as we find an appropriate treatment that suits that individual, the prognosis is excellent, as long as we don't have comorbidities such as renal disease alongside. And the survival times can vary, so anything from 2 years if we choose the anti-thyroid medication, up to 4 years from the . The radiation treatment.

OK, so that's all from me. I hope you've enjoyed hyperthyroidism, and I hope you now share my the same thoughts that it is a very complex but also very interesting endocrine disease and it is the most common. So if we are going to choose one disease to to.

Look into and do some extra research on this would be a great topic to choose because it is the most common disease that you will see in in cats across the UK and many different parts of the world. If you do like it, if you do have Instagram or Facebook, please follow my page, Veterinary nurse medicine Geek which I regularly update with bits of interesting internal medicine topics and anything that you might be interested in if you do like internal medicine. That's all from me, thank you very much and enjoy the rest of your evening.