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：本研究旨在明确尿钠浓度（urine sodium concentration）能否用于排除低钠血症犬的肾上腺皮质功能减退症（hypoadrenocorticism）病因。在低钠血症（hyponatremia）状态下，机体应在肾小管（renal tubule）层面保留钠离子，此时预期尿钠浓度应<30 mmol/L。然而，当肾上腺皮质功能减退症引发醛固酮（aldosterone）缺乏时，钠离子会异常随尿液流失，导致尿钠浓度>30 mmol/L。
研究方法：回顾性分析了经检测尿钠浓度的低钠血症犬（血清钠<135 mmol/L）的病历记录。最终纳入20只低钠血症犬，其中11只确诊为经典型肾上腺皮质功能减退症，9只低钠血症由非肾上腺疾病引发。采用威尔科克森秩和检验（Wilcoxon sum rank test）对两组结果进行比较。
研究结果：所有肾上腺皮质功能减退症犬的尿钠浓度均未低于30 mmol/L。肾上腺皮质功能减退症犬的尿钠浓度显著高于非肾上腺疾病犬，其中前者中位数为103 mmol/L，范围41~225 mmol/L，后者中位数为10 mmol/L，范围2~86 mmol/L（P<0.0005）。两组犬的血清钠浓度无显著差异。
临床意义：本研究结果提示，尿钠浓度可用于对低钠血症犬的肾上腺皮质功能减退症鉴别诊断进行优先级排序。若低钠血症犬的尿钠浓度<30 mmol/L，则经典型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。由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追踪研究具有重要价值。