Biochemical, electrolytic, and cardiovascular evaluations in cats with urethral obstruction
Darlan Henrique Canei1, Mariana Elisa Pereira1, Maria Natália de Freitas2
1Program of Postgraduate in Veterinary Sciences, Faculty of Veterinary Medicine, Federal University of Mato Grosso, Cuiabá - Mato Grosso, Brazil.
Insights
Urethral obstruction in cats causes significant electrolyte and acid-base imbalances, leading to temporary electrocardiographic changes. Cardiac troponin I levels and blood pressure may remain normal despite severe metabolic disturbances.
Area of Science:
- Veterinary Medicine
- Cardiology
- Nephrology
Background:
- Urethral obstruction (UO) is a prevalent condition in feline medicine.
- Severe acid-base and electrolyte disturbances are known to cause electrocardiographic changes in cats.
- The impact of UO on myocardial damage and cardiac troponin I levels is not well-established.
Purpose of the Study:
- To investigate biochemical changes, electrocardiographic findings, troponin I levels, and electrolyte disturbances in cats with UO over a 7-day period.
- To assess the relationship between UO, metabolic derangements, and cardiovascular status.
Main Methods:
- A prospective follow-up study involving 33 cats diagnosed with UO.
- Evaluations included clinical examination, serum biochemistry, electrolyte analysis, blood pressure, and electrocardiography.
- Cardiac troponin I was measured in 16 cats at three different time points.
Main Results:
- Significant changes in creatinine, urea, BUN, glucose, phosphorus, base excess, bicarbonate, and potassium were observed.
- Ionic calcium and blood pH levels increased significantly.
- Electrocardiographic abnormalities were present in 63.63% of cats on admission but resolved subsequently.
- Only one cat showed elevated cardiac troponin I levels.
Conclusions:
- The severity of electrolyte abnormalities correlates with the clinical and cardiovascular status of cats with UO.
- Normal cardiac troponin I, blood pressure, and heart rate do not rule out significant cardiovascular and metabolic abnormalities.
- Hyperglycemia in UO is likely linked to reduced renal clearance, reflecting hyperkalemia and azotemia severity.
- Intensive care can mitigate metabolic and cardiovascular changes, but cardiac and blood gas monitoring is crucial for assessing disease severity.
Background And Aim:
Urethral obstruction (UO) is a common condition in feline medicine. Severe acid-base and electrolyte disorders promote relevant electrocardiographic changes in these animals. Cardiac biomarkers such as cardiac troponin I have been shown to be useful in identifying cats with myocardial disease, but it has not been investigated whether UO leads to myocardial damages. This study aimed to evaluate biochemical changes, electrocardiographic findings, troponin I measurements, and electrolyte disturbances for 7 days in cats with UO.
Materials And Methods:
This follow-up prospective study included 33 cats diagnosed with UO for 7 days. For all cats, clinical examination, serum biochemistry, electrolyte analyses, blood pressure, and electrocardiography were performed. Cardiac troponin I was measured in the serum in 16 cats at 3 different times.
Results:
The mean age of the feline population was 1.83±1.58 years (mean±standard deviation). Creatinine, urea, blood urea nitrogen, glucose, phosphorus, base excess, bicarbonate, and serum potassium decreased significantly (p≤0.05), while ionic calcium and blood pH increased significantly (p≤0.05) at different times. Electrocardiographic abnormalities were observed in 21/33 (63.63%) of the felines on admission day. The electrocardiographic abnormalities were no longer observed on the subsequent days. Only one feline showed changes in troponin I cardiac concentrations.
Conclusion:
This study suggests the sum and severity of electrolyte abnormalities aggravate the clinical and cardiovascular status of these patients. However, cTnI, blood pressure, and heart rate within the reference range do not exclude the presence of major cardiovascular and metabolic abnormalities. The hyperglycemia in felines with UO appears to be associated with decreased renal clearance, which may reflect the severity of hyperkalemia and azotemia. The metabolic and cardiovascular changes of these felines are minimized by the establishment of appropriate intensive care; however, cardiac and blood gas monitoring is essential to assess the severity of the disease.
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