scott@vtx-cpd.com

Replying to Lara Brunori 16/12/2024 - 11:16

Good news!

Hope you are managing some time off over the festive period!

Scott 🙂

Replying to Talia C. 17/12/2024 - 07:04

Hi Talia,

I completely agree that urine cultures in these cases can be tricky. I wouldn’t recommend routinely culturing these patients every time. Instead, my decision to reculture would usually depend on clinical signs and the presence of comorbidities. For example, in asymptomatic patients with conditions like chronic kidney disease or diabetes, I might consider reculturing, but there’s certainly a lot of debate around this.

Unless the patient is systemically unwell or showing specific symptoms that warrant further investigation, I don’t think routine reculturing is necessary. I’d focus more on clinical indicators and ongoing monitoring strategies like creatinine, SAA, and ultrasound, which you’re already doing. This targeted approach helps balance the need for thorough care with cost considerations and avoids unnecessary interventions.

Best,

Scott 🙂

Replying to Talia C. 17/12/2024 - 07:17

Dear Talia,

Urine protein dipstick tests are more sensitive for detecting albumin than globulin, which is important to keep in mind when interpreting results. Dipstick results must always be evaluated in the context of urine specific gravity (USG) and pH. In concentrated urine, such as with a USG of 1.050 or higher, or in the presence of a high pH, even a “2+” result may not be clinically significant due to the higher risk of false positives. Conversely, in dilute urine, particularly with a USG of 1.015 or lower, even a “1+” result becomes more concerning and may indicate clinically significant proteinuria.

When dipstick-detected proteinuria is identified, further quantitative analysis with a urine protein-to-creatinine ratio (UPC) is recommended. This is particularly important if proteinuria persists, such as with “++” or “+++” readings, which should always be repeated. Any “+” result in urine with a USG less than 1.012 warrants additional assessment with UPC. Additionally, if globulinuria is suspected or if there is a high urine pH, confirmation via UPC becomes necessary as the dipstick may not provide an accurate representation. It is also important to note that USG alone does not accurately predict significant proteinuria.

It is essential to place results in the context of USG and pH, as these factors influence the significance of the findings. Dilute urine with even mild proteinuria, as well as persistent “++” or higher readings, should prompt further evaluation with UPC.

I hope that helps!

Scott 🙂

Replying to Talia C. 10/12/2024 - 06:42

Dear Talia,

Thank you for sharing this challenging and case. The lack of Pu/Pd and the relatively high urine specific gravity (USG) do make the diagnosis of hyperadrenocorticism (HAC) less clear-cut, especially since Pu/Pd is a hallmark feature in the majority of Cushing’s cases. However, the presence of clinical signs such as polyphagia, alopecia, and a pot-bellied abdomen, coupled with the adrenal nodules and elevated alkaline phosphatase (ALP), certainly raises the suspicion for HAC.

The low-dose dexamethasone suppression (LDDS) test results, while supportive of HAC, do carry a risk of false positives, especially in dogs without classic clinical signs. This makes it even more important to interpret these results within the broader clinical context. While the urinary cortisol-to-creatinine ratio (UCCR) was elevated, it is worth noting that UCCR has a lower specificity for HAC, and the high USG (1.041) further challenges the diagnosis, as lower USG is often expected in Cushingoid dogs due to impaired concentrating ability.

Given these nuances, the Cushing’s Risk Predictor Tool published by the Royal Veterinary College (RVC) could be a valuable next step. This tool integrates multiple clinical and laboratory findings to provide a percentage likelihood of HAC, and it may help refine the diagnostic certainty in this case. The adrenal nodules, while consistent with HAC, could also represent incidental age-related changes, functional changes secondary to another condition, or even a different type of neoplasia.

Blood pressure monitoring is another key consideration here, as adrenal changes and HAC can predispose dogs to systemic hypertension. While the systolic blood pressure (SBP) of 155 mmHg is mildly elevated, stress could be a factor, so I’d recommend repeat measurements to confirm whether intervention is necessary.

Overall, while the LDDS test suggests HAC, the absence of Pu/Pd, high USG, and the nuanced clinical picture raise the possibility of a false positive. If you remain uncertain, it would not be unreasonable to hold off on starting treatment for HAC immediately and instead continue monitoring clinical signs and rechecking key parameters. Using the RVC’s predictive tool could provide additional clarity in this decision-making process.

This is undoubtedly a tricky case, and your cautious approach is well justified. Please let me know if you’d like to discuss further or explore additional diagnostic or management strategies.

Best regards,

Scott 🙂

Replying to Talia C. 04/12/2024 - 19:58

Hi Talia,

You’ve raised some excellent points and highlighted the key challenges in this case, particularly Siichba’s young age and the uncertainty around the stone composition. I’ll share what we’ve done so far and my evolving thoughts.

I agree that simply extending the antibiotic course without addressing the calculi as a nidus of infection is unlikely to fully resolve the issue. While Clavaseptin has good coverage, I’ve transitioned Siichba to a fluoroquinolone to improve penetration into the urinary tract and stones, particularly given the persistent E. coli infection. This choice will be reassessed pending final culture sensitivities.

Determining the stone composition has indeed been challenging. The association between E. coli and struvites makes it tempting to focus on dissolution, but without definitive analysis, we’re balancing probabilities. Given Siichba’s young age and the likelihood of struvite stones in young cats, I’ve started a dissolution diet (feline c/d). This will continue for two weeks, after which I plan to transition to feline i/d to ensure nutritional adequacy for a growing kitten while supporting urinary health. We’re monitoring urine pH to assess dietary impact, and if calcium oxalate becomes a stronger suspicion, I may consider potassium citrate to alkalinize the urine.

To manage the marginally elevated ionized calcium, I introduced 1 gram of soaked chia seeds daily into Siichba’s diet. I hoped this would help reduce calcium availability and minimize calcium precipitation in the urine. It’s a bit of an outside-the-box approach, and I’d love your thoughts on whether this was the right move! If the urinalysis confirms acidic urine with calcium oxalate, I might pivot to other strategies like citrate supplementation.

Hydronephrosis and partial obstruction of the left kidney are concerning, and I completely agree that quick action is essential to preserve renal function. While Siichba’s bloodwork doesn’t yet show signs of renal insufficiency, I’ve implemented close monitoring with serial ultrasounds and bloodwork to track progression. If the obstruction worsens, a ureteral stent or SUB will likely be our next steps.

To manage pain and improve comfort, I’ve started buprenorphine and Prazosin to help relax the ureteral smooth muscle and encourage stone passage. Siichba is also on IV fluids to maintain hydration and dilute urine, reducing the risk of further stone aggregation.

While the ultrasound findings are detailed, I’m still considering a contrast-enhanced CT to better visualize the ureteral anatomy and obstruction.

I’ll keep you posted on Siichba’s progress, and I completely agree that a discussion on ureteral calculi and stents would be a fantastic topic. Thank you for your input, and I’d love to hear your thoughts on some of the management choices, particularly the use of chia seeds.

Best,

Scott 😊