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Replying to Mónica P. 14/04/2024 - 08:27

Hello Mónica,

I hope you are well. I have popped some thoughts below:

1. Thyroglobulin autoantibodies (TgAA) are specific for dogs are used to diagnose autoimmune thyroiditis, which can lead to hypothyroidism. The test should be specific for veterinary use and not cross-react with human antibodies. I would double check with the lab you are using, but the veterinary labs I checked with are canine specific.

2. Fasting for Thyroid Hormone Testing: No, thyroid hormone levels do not need to be tested after fasting. Unlike some other tests, such as cholesterol, fasting does not significantly affect thyroid hormone levels. This is the protocol I have always used. I am often testing thyroid values along with other parameters, so my patients might be fasted for other reasons. I also found some evidence in human medicine that there may be an effect:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4171896/

I will chat to Yvonne regarding this question as she will have the most up to date lab based information.

3. Here are the conversions for TSH:

1 ng/ml = 1 µg/L
0.5 µg/L = 0.5 ng/ml

I do not have a table, I am afraid.

4. Since phenobarbital can affect thyroid hormone levels, it’s best to test thyroid function before starting phenobarbital therapy if possible. If a patient is already on phenobarbital, testing can still be done, but the results should be interpreted with caution, knowing that phenobarbital could potentially affect the results. Ultimately, it often will come down to clinical suspicion. I would have to be VERY clinically suspicious that these patients had hypothyroidism before starting treatment.

5. The frequency of levothyroxine (T4) administration depends on the individual patient. While some guidelines recommend once daily dosing for T4 levels above 7.5 µg/dL, others may suggest adjusting the dosage. In practice, once daily dosing is often practical and effective, especially for owner compliance. However, I find that the majority of dogs do better on twice daily dosing overall.

6. The maximum recommended dosage of levothyroxine is usually around 0.8 mg twice daily. In giant breed dogs, dosages should be individualized based on the patient’s response to treatment and monitoring of thyroid hormone levels. I am comfortable increasing this dose further as long as I am confident that we have an accurate diagnosis and the patient requires the higher dose. I would be monitoring carefully.

7. Successful response in dogs treated once daily is associated with a median peak TT4 concentration (6 hours after administration) of approximately 4 mcg/dL (50 nmol/L). Values below 2.7 mcg/dL (35 nmol/L) are usually associated with an inadequate clinical response, and an increase in dosage is indicated. Markedly increased peak TT4 concentrations >7 mcg/dL (>90 nmol/L) occasionally occur. Although dogs are usually resistant to severe clinical thyrotoxicosis, such values should prompt a decreased dosage.

Regarding the Dogue de Bordeaux case, it’s true that some breeds, including the Dogue de Bordeaux, can have lower thyroid hormone concentrations compared to other breeds, so interpreting the results should take this into consideration.

Feel free to ask if you have any more questions or need further clarification!

Scott 🙂

Replying to Hayley O. 16/04/2024 - 21:15

Hey Hayley.

Thanks for the brilliant questions:

1. Any amount of protein on a urine dipstick can be a reason for further investigation, especially if other clinical signs or laboratory abnormalities are present. However, a threshold of 1+ or greater on the dipstick is often used to raise concern for proteinuria. It really does depend on the case. I would not be rushing to perform UPC in all cases, especially if you are treating/managing other problems. I would want to demonstrate that it was a persistent abnormality before investigating further. This is the same for UPC; it is really important to demonstrate that it is a persistent and consistent finding.

2. It’s generally advisable to confirm persistent proteinuria with a urine protein-to-creatinine ratio (UPCR) from at least one home caught first-morning sample (a more concentrated sample) before initiating further diagnostics or treatment. If the UPCR is borderline, it’s recommended to retest in 2-4 weeks to assess for persistence or resolution. This timeframe allows for monitoring without unnecessary delay in case intervention is needed. It also gives time to resolve any concurrent disease processes.

3. Proteinuria can occur in intact animals, but it is not considered a normal finding. It should be quantified and further investigated, especially if persistent or associated with other abnormalities.

4. Quantification of proteinuria is ideally done by UPCR on a first-morning sample. If cystocentesis is performed for another reason, such as collecting a urine culture, the urine can be analysed for protein at the same time. However, if the animal is not showing clinical signs and the proteinuria is only detected on dipstick, it’s reasonable to start with a UPCR from a voided sample and proceed based on those results.

I hope that helps!

Scott 🙂

Replying to Talia C. 16/04/2024 - 16:49

I also think it is a really good way of assessing the urethra.

We often perform a rectal to assess the prostate, but you can get a good idea of urethral thickening in many dogs.

I am always surprised by the number of owners that do not report melena, but the rectal exam says otherwise!

Scott 🙂

Replying to Karen McPherson 16/04/2024 - 16:08

Hello Karen!

It is so lovely to see you here! This feels like a Kilmarnock reunion! We can exchange stories from the night shifts… although I am not sure all of them are appropriate for a public forum! 🙂

Thank you so much for joining the course! Please let us know if you have any questions.

Scott 🙂

Replying to Talia C. 16/04/2024 - 14:50

Hello Talia.

Really interesting that you mention the pregabalin, I have never used that specifically:

https://pubmed.ncbi.nlm.nih.gov/35466408/

I wonder if people will start to use this over the standard gabapentin?

Scott 🙂

Replying to Elle P. 15/04/2024 - 16:03

You got it! 🙂

Thank you for being brave!

This ECG shows a common ECG abnormality that is found in dogs in the ICU setting. It represents a mainly sinus rhythm with frequent ventricular premature complexes or VPCs (shown by the black arrows).

You can tell that the main rhythm is sinus because there is a P wave for every QRS and the QRS complexes following the P waves are tall and narrow, being positive in lead II. The VPCs on the other hand seem to disrupt the rhythm and don’t look like the normal QRS complexes. They are much wider and are negative in lead II (bizarre looking). There is no P wave before them.

VPCs can be seen in many situations. They can be found in dogs with cardiac disease, but they can be equally present in dogs that have systemic disease e.g. IMHA, splenic disease and so on. Cytokines disrupt the heart’s normal electrical activity and this can result in VPCs or even ventricular tachycardia.

Scott 🙂

Replying to Jennifer M. 15/04/2024 - 21:18

Jenny!!!!!

Welcome. Thank you so much for joining the course!

I think I will start a ‘tales from the nightshift’ thread so we can share stories from our OOH days!

Thanks again!

Scott 🙂