Dataset for: Urine Sodium Concentrations are Predictive of Hypoadrenocorticism in Hyponatremic Dogs: A Retrospective Pilot Study

Objectives: The purpose of this study was to determine if a urine sodium concentration could be used to rule out hypoadrenocorticism as the cause of hyponatremia in hyponatremic dogs. In the hyponatremic state, sodium should be conserved at the level of the renal tubule; with expected urine sodium concentrations are < 30 mmol/L. However, in the case of aldosterone deficiency due to hypoadrenocorticism, sodium is inappropriately lost into the urine, resulting in urine sodium concentrations > 30 mmol/L. Methods: Medical records of hyponatremic dogs (serum sodium < 135 mmol/L) that had urine sodium concentrations measured were reviewed. Twenty hyponatremic dogs were included; 11 with a diagnosisdiagnosed with of classical hypoadrenocorticism and 9 with non-adrenal causes of hyponatremia. A Wilcoxon sum rank test was used to compare results between groups. Results: No dog with hypoadrenocorticism had a urine sodium concentration < 30mmol/L. Urine sodium concentration in dogs with hypoadrenocorticism was significantly higher (median 103 mmol/L, range: 41-225), than in dogs with non-adrenal illness (median: 10 mmol/L, range: 2-86) (p < 0.0005). Serum sodium concentrations were not significantly different between dogs with hypoadrenocorticism and dogs with non-adrenal illness. Clinical Significance: These results suggest that urine sodium concentrations can be used to prioritize a differential diagnosis of hypoadrenocorticism in hyponatremic dogs. A urine sodium concentration < 30 mmol/L in a hyponatremic dog makes classical hypoadrenocorticism an unlikely cause of the hyponatremia. Due to the small sample size in this study, results should be interpreted with caution. A larger follow-up study would be valuable.

研究目的：本研究旨在探讨尿钠浓度能否用于排除低钠血症犬的低肾上腺皮质功能减退症（hypoadrenocorticism）病因。在低钠血症状态下，机体应在肾小管水平保留钠，此时预期尿钠浓度应＜30 mmol/L。但当低肾上腺皮质功能减退症引发醛固酮缺乏时，钠会异常随尿液丢失，导致尿钠浓度＞30 mmol/L。
研究方法：本研究回顾性分析了经尿钠浓度检测的低钠血症犬（血清钠＜135 mmol/L）的临床病历资料，共纳入20只低钠血症犬，其中11只确诊为经典型低肾上腺皮质功能减退症，9只存在非肾上腺源性低钠血症。采用Wilcoxon秩和检验（Wilcoxon sum rank test）进行组间结果比较。
研究结果：所有确诊低肾上腺皮质功能减退症的犬尿钠浓度均未低于30 mmol/L。低肾上腺皮质功能减退症犬的尿钠浓度（中位数103 mmol/L，范围41~225 mmol/L）显著高于非肾上腺源性疾病犬（中位数10 mmol/L，范围2~86 mmol/L）（p＜0.0005）。两类犬的血清钠浓度无显著差异。
临床意义：本研究结果显示，尿钠浓度可用于辅助确定低钠血症犬的低肾上腺皮质功能减退症鉴别诊断优先级。若低钠血症犬的尿钠浓度＜30 mmol/L，则经典型低肾上腺皮质功能减退症作为其低钠血症病因的可能性极低。鉴于本研究样本量较小，解读结果时需谨慎，后续开展更大样本量的随访研究具有重要临床价值。