scott@vtx-cpd.com

Replying to Serena Cutbill 23/08/2024 - 15:27

No problem.

Let me know if you have any other questions.

Scott 🙂

Replying to Samantha T. 21/08/2024 - 21:35

Welcome Sam!

I never knew the 4 dogs thing! That is something I will hold against you in the future!

Thanks again for your contribution to the course!

Scott 🙂

Replying to Maria W. 15/08/2024 - 19:30

Hi Maria,

I think overall, a single shot of dexamethasone probably isn’t massively problematic. The biggest concern, in my opinion, would be its impact on cardiac disease, particularly in cats. I’ll ask Liz to weigh in on this more, as she might have additional insights.

Even if the underlying cause is infectious, like bronchopneumonia, I don’t think steroids would have a hugely detrimental effect—in fact, in some cases, they might actually be beneficial. And, of course, dexamethasone is likely to be helpful in most cases of inflammatory airway disease, as it effectively addresses the inflammation that causes the breathing issues.

So, while dexamethasone can treat a number of conditions affecting the airway, the only strong contraindication I see would be related to cardiac concerns.

Hope that helps clarify things!

Best regards,

Scott 🙂

Replying to Hannah Willetts 07/08/2024 - 21:38

Hi Hannah,

Thanks for your question—it’s a really important aspect of managing Addison’s patients, especially during a crisis.

When dealing with hypovolemic hyponatremia in an Addisonian crisis, the priority is to address the hypovolemia and restore circulating blood volume. Hartmann’s solution (or any balanced crystalloid) is generally appropriate for this. The key here is that while you’re correcting the hypovolemia, the hyponatremia often begins to correct itself as the sodium concentration normalizes with the fluid resuscitation.

You’re correct that sodium correction should generally be done slowly to avoid the risk of osmotic demyelination syndrome (ODS). However, in an acute Addisonian crisis, the immediate priority is the patient’s circulation, and fluid resuscitation can be life-saving.

I’ve also spoken with one of our ECC specialists about this. The consensus is that your initial fluid resuscitation isn’t likely to significantly impact sodium levels in a way that would cause harm, so you’re generally safe to administer your fluid boluses and complete the fluid resuscitation as you normally would. The real focus should be on the longer-term or medium-term fluid plan, where you need to be mindful of avoiding rapid changes in sodium levels. But overall, with Addisonian crisis patients, when they respond well to treatment, everything tends to stabilize relatively quickly, and we usually see very few issues with rapid sodium correction.

It’s worth noting a case report published in Frontiers in Veterinary Science (2022), where a 6-year-old Chihuahua with Addison’s disease developed hindlimb ataxia and seizures after a rapid correction of hyponatremia, which was presumed to be due to ODS. This dog had been diagnosed with hypoadrenocorticism 10 days prior and presented with neurological signs including generalized tonic seizures and hindlimb paresis three days after the sodium correction. The neurologic signs resolved completely after appropriate treatment, but this case underscores the importance of being cautious with the rate of sodium correction, particularly in the medium to longer-term management of these patients.

To summarize the approach:

Initial Fluid Bolus: Start with an initial bolus of Hartmann’s (10-20 ml/kg) over 15-30 minutes to rapidly correct hypovolemia. Monitor the patient closely during this time.

Assess Response: After the bolus, reassess the patient’s hydration status and continue with maintenance fluids at a rate calculated based on ongoing losses, maintenance requirements, and any additional deficits. If sodium is critically low, consider using 0.9% saline after the initial stabilization, but this is less common unless the sodium is dangerously low and there’s a need for a more controlled correction.

Monitoring: Regularly monitor the patient’s electrolytes (particularly sodium) and adjust the fluid rate/type accordingly. If sodium starts to rise too quickly (>0.5 mmol/L/hr), slow the rate of fluid administration and consider switching to a lower sodium-containing fluid like Hartmann’s to allow for a more gradual correction.

In essence, your initial fluid resuscitation is critical and should be done promptly and effectively. It’s typically in the later stages of treatment, once the crisis is stabilized, that you need to be more cautious with sodium correction.

I hope this helps clarify the approach. Please feel free to reach out if you have any more questions!

Best regards,

Scott 🙂

Hello!

I have another great question:

“Hello,

I have a few questions from the otitis lesson regarding treatment of ear infections;

1) At present, my main approach to treatment of otitis externa is to commence medicated drops based on cytology for 2 weeks then see the patient back for repeat cytology to assess response. If cytology is clear I carry on drops for one week past clinical cure. If infection is still present, I carry on for another two week block of treatment and perform cytology again. If by this point I have a particularly stubborn infection, I would recommend sending a sample for C&S to ensure I am using the most appropriate medicated drops. Is this sensible overall? Most of my patients will end up being on one month’s worth of drops before I reach the stage of clinical cure and I sometimes worry it’s a lot of antibiotic/anti fungal exposure for commensals that could encourage resistance in the future.

2) Alongside drops, more often than not I will get owners to clean the ears 2-3 times per week. I don’t want them to clean too much incase it macerates the inside of the canal. Similarly, I don’t want it performed too little and the drops can’t penetrate the ear canal properly. Is this appropriate use of cleaning?

3) On the topic of cleaning, there are so many different products available to use. I tend to reach for epi-otic as my ‘go to’ cleaner and will use Triz-Nac in cases of pseudomonas or a suspected ruptured ear drum. Some owners will come back saying a certain cleaner has caused visible irritation to the animal when applied. Do you have a particular set of criteria you follow when choosing a cleaner?

Thanks so much!”

Scott 🙂

Hey! Just wanted to give you an update on this patient and some of the results!

Radiography Findings:

Thorax:

We found an irregular, well-defined soft tissue lesion (~15 cm) in the cranioventral mediastinum, slightly to the left, displacing the left cranial lung lobe caudally.
The adjacent sternebrae and ribs looked normal.
There was evidence of pleural effusion, shown by fissure lines, scalloping lung margins, widened lumbophrenic and costophrenic angles, increased lung opacity, and an opacified cardiac silhouette.
The cardiovascular structures appeared normal.
We also noted multifocal ventral spondylosis at the thoraco-lumbar vertebral column.
Assessment:

Cranioventral mediastinal mass
Pleural effusion
Likely thymic neoplasia; less likely a pulmonary mass in the left cranial lung lobe
Once we had the radiographic findings, we performed an ultrasound-guided FNA of the mass, and here’s what we found:

Cytology Report:

Specimens:

Chest mass and axillary lymph node (11 slides)
Pleural effusion (4 mL in a red top tube)
Microscopic Description:

Chest Mass and Axillary Lymph Node:

High cellularity with many erythrocytes, intermediate to slightly large lymphocytes, rare mitotic figures, small lymphocytes, and segmented neutrophils.
No infectious agents observed.
Interpretation:

Consistent with lymphoma.
We recommend considering immunophenotyping by flow cytometry for further characterization, prognostication, and treatment options.
Pleural Effusion Analysis:

Appearance: Cloudy
Color: Orange
WBC Count: 2.77 x10^9/L
RBC Count: 0.02 x10^12/L
Total Protein: 18 g/L
Specific Gravity: 1.018
Microscopic Description:

Modest cellularity with macrophages, small and intermediate lymphocytes, eosinophils, non-degenerate segmented neutrophils, well-differentiated mast cells, and pyknotic nucleated cells.
No infectious agents or neoplastic cells observed.
Interpretation:

Consistent with modified transudate.
The effusion is most likely caused by the chest mass (lymphoma) increasing hydrostatic pressure and/or causing lymphatic obstruction.
Let me know if you have any questions.

Best,

Scott 🙂