Okay. So here we go. Taking all that information and all that we've learned this morning, I know it's a lot, we're going to go through some clinical cases and see what we're going to do. All right, so this is Jett. He is a 12 year old male, neutered domestic shorthair cat and he has a one month history of PUPD, weight loss and a good appetite. So here are our results. I'm going to give you a second to look at them. This is our serum chemistries. And then we're also going to take a look at our urinalysis because we did that as well. All right. So on the right here, we have our summary and we're going to go through our interpretation. So we have hyperglycemia with glycosuria and ketonuria. We have a mild hypercholesterolemia, a mild ALP increase, and we have a total T4 in the upper half of the reference range. So what are we going to do next? Do we think this cat is hyperthyroid? Or do we think that something else is going on? So we I am going to vote for thinking that this cat is not hypothyroid, hyperthyroid, but I'm more concerned about this glucose and and especially the ketones in the urine. So I'm going to run a fructosamine level. My fructosamine is 478 which is increased which supports my diagnosis of diabetes mellitus. All right. So we run a fee, free T4 because this total T4 is in the upper half of the reference range. And of course, just to keep things interesting, the free T4 is right at the upper end of the reference range as well. The free T4 is at 50. So what are we going to do? Are we going to treat this cat for hyperthyroidism or not? Well, I would say not. What I would do first is treat this cat for its diabetes mellitus and then recheck a total T4 plus or minus of free T4 in 4 to 6 weeks, once I've controlled the diabetes. That's hopefully going to make it a little bit easier to interpret those findings. 

All right. Let's talk about Prince. Prince is a nine year old male, neutered miniature schnauzer. He has a two month history of lethargy, polyuria, polydipsia and alopecia. And here are his lab results. All right. And then we'll take a look at his urine. Okay. And then on the right again we have his, just a brief summary of the pertinent findings. And so when we look at this, we're going to say that Prince has a mild hyperglycemia with a mild glycosuria, he has hypercholesterolemia, he has a significant increase in his alkaline phosphatase that's the most markedly increased liver enzymes, and otherwise he has a mild to moderate increase in the rest of his liver enzymes. His total T4 is less than 0.5 and he has isosthenuria, proteinuria, glycosuria which we already talked about bacteriuria. So what are we going to do next? Are we going to run to fructosamine because he's hyperglycemic? Are we going to run a free T4 and a TSH because his total T4 is less than 0.5? Or are we going to run a low dose dexamethasone suppression test or an ACTH stimulation test? Which one of those three are you going to do in this case? All right, well. I think if we run a fructosamine it's likely to be low yield. He really has a pretty mild increase in his glucose and a mild glycosuria, and so it's really insufficient to explain his clinical signs. So I'm going to put a fructosamine kind of off my list at this moment in time. What about a free T4 and a TSH? So the question here is, do we think that this dog's lethargy, PUPD, and alopecia could be due to hypothyroidism? And do we think that all of these lab values can similarly be explained by hypothyroidism? Well, the increase in our liver enzymes, our isosthenuria, proteinuria, and bacteriuria, are pretty inconsistent with hypothyroidism. And my worry in this case is that if I run a free T4 and a TSH in a dog that's sick for another reason, it's going to be very difficult to interpret those results. And so probably what's a better choice is figuring out the primary disease and then reevaluating our thyroid hormone levels if we need to. So then what about a low dose dexamethasone suppression test or ACTH stimulation test? I think that's a very good idea in this case. The dog has clinical signs that are consistent with hyperadrenocorticism and also has consistent clinical pathology findings. So the dog has isosthenuria, proteinuria, bacteriuria, and we know these dogs are predisposed to urinary tract infections and an increase in his liver enzymes. So in this case, we're going to move forward with testing for hyperadrenocorticism. 

Okay, Let's talk about Poppy. Poppy is our 15 year old female spayed domestic shorthair cat. She has a one month history of anorexia, vomiting and weight loss. Here are her lab values. And we just going to look at her serum chemistries today. Okay, so here are our significant serum chemistry findings. So the ALT is significantly increased. And we also have hyperbilirubinemia, and we have an increase in our ALP, which suggests primary liver disease. We have an increase in our CK. And remember we talked about that being fairly common in cats who are stressed when they're in the hospital. So I would be worried about stress. And then we have a total T4 in the upper half of the reference range. So do we think that this cat could be hyperthyroid? Do we think the hyperthyroidism could explain everything? Well, remember, this is anorexic and cats with hyperthyroidism are typically polyphagic, so this is inconsistent. I also wouldn't expect to see a total bilirubin of 0.9 in a cat with hyperthyroidism. So this is also inconsistent. But we're going to run a free T4 and we find the our free T4 is at 25 which is within the reference range. So, you know, as I mentioned, if we think that this could be hyperthyroidism, this really doesn't support that, right? Although this total T4 is in the gray zone our free T4 is normal and we have evidence of other disease. So what we're going to do is we're going to pursue further testing and treatment for this cats liver disease. We could repeat a total T4 in the future, you know, maybe in 1 to 2 months once we fix this cat's underlying disease. But we're not going to look at the thyroid anymore in her case based on the information we have at this moment in time. 

All right. Then we have Cookie. Cookie is a, I think Cookie is our last case, and she is a four year old female spayed mixed breed dog with a two month history of waxing and waning anorexia and vomiting and weight loss. So here is her CBC. And here are her serum chemistries. Right. So here are the abnormal findings on our CBC. So we have a mild normocytic, normochromic, non regenerative anemia. And we have a normal leukogram, but we've got to ask ourselves the question again, is this normal in a sick dog that is potentially stressed? So we have a lack of a stress leukogram. Our lymphocytes are relatively increased, our lymphocyte to ratio, neutrophil ratio is almost 5050, which is not normal. So as I mentioned already, the normal distribution is usually about 85 to 15, something like that. So this is pretty off. And you can look at lecture one if you want more information about that. And then we're going to look at our serum chemistries. So we have high end of normal calcium. And if we correct our calcium for our albumin, which is low, we get a total calcium of 12.8, which is technically increased. Remember, we're always going to do an ionized calcium if we wanted to look at this more. We have hyperkalemia and if we do a sodium potassium ratio, it's 25.7 and less than 27 to 1 is suggestive of Addison's disease or hypoadrenocorticism. If you remember from last week, we have an increased anion gap and we have a decreased TCO2 which suggests that we have a high anion gap metabolic acidosis. We have hypoproteinemia, hypoalbuminemia, hypocholesterolemia. 

All right, so what are we going to do next? Our sodium potassium ratio is suggestive of hypoadrenocorticism. We've also got some other findings on our clinical pathology results that suggest that. We're going to do an ACTH stimulation test. Our pre is 0.5 and our post is 0.7, which is very nice because that helps us diagnose hypoadrenocorticism. Just want to draw your attention to the fact that her T4 is also less than 0.5, five. Now, this is a four year old dog with a clinical history that is inconsistent with hypothyroidism, and we're not seeing other changes that would suggest that hypothyroidism is a primary problem. So this is most consistent with sick euthyroid syndrome. I would encourage you not to perform further thyroid testing because that's going to just complicate the picture further. And one of the other problems with this is that if we start this dog on steroids for the hypoadrenocorticism, our total T4 may still be difficult to interpret. So this is a really tricky one. All right.