Changes in Serum Creatinine Levels Can Help Distinguish Hypovolemic from Euvolemic Hyponatremia

Abstract

Background and Objectives: Differentiating between hypovolemic (HH) and euvolemic hyponatremia (EH) is crucial for correct diagnosis and therapy, but can be a challenge. We aim to ascertain whether changes in serum creatinine (SC) can be helpful in distinguishing HH from EH. Materials and Methods: Retrospective analysis of patients followed in a monographic hyponatremia outpatient clinic of a tertiary hospital during 1 January 2014–30 November 2019. SC changes during HH and EH from eunatremia were studied. The diagnostic accuracy of the SC change from eunatremia to hyponatremia (∆SC) was analyzed. Results: A total of 122 hyponatremic patients, median age 79 years (70–85), 46.7% women. In total, 70/122 patients had EH, 52/122 HH. During hyponatremia, median SC levels increased in the HH group: +0.18 mg/dL [0.09–0.39, p < 0.001], but decreased in the EH group: −0.07 mg/dL (−0.15–0.02, p < 0.001), as compared to SC in eunatremia. HH subjects presented a higher rate of a positive ∆SC than EH (90.4% vs. 25.7%, p < 0.001). EH subjects presented a higher rate of a negative/null ∆SC than HH (74.3% vs. 9.6%, p < 0.001). ROC curve analysis found an AUC of 0.908 (95%CI: 0.853 to 0.962, p < 0.001) for ∆SC%. A ∆SC% ≥ 10% had an OR of 29.0 (95%CI: 10.3 to 81.7, p < 0.001) for HH. A ∆SC% ≤ 3% had an OR of 68.3 (95%CI: 13.0 to 262.2, p < 0.001) for EH. Conclusions: The assessment of SC changes from eunatremia to hyponatremia can be useful in distinguishing between HH and EH.

Epidemiology and outcomes of hyponatremia in patients with COVID-19—A territory-wide study in Hong Kong

“…Patients were further classified into mild, moderate, and severe hyponatremia if their serum sodium level ranged from 130 to <135 mmol/L, 125 to <130 mmol/L, and <125 mmol/L, respectively. The volume status of patients with hyponatremia was further evaluated by the percentage change of serum creatinine from hyponatremia to eunatremia as described by Ruiz-Sánchez et al ( 29 ). In essence, a percentage change of creatinine above 10% indicates hypovolemic status, while a change below −3% indicates euvolemic status.…”

Clinical manifestations and associated factors in acquired hypoaldosteronism in endocrinological practice

“…SNa was corrected for glycemia ( 18 ) when the latter was ≥ 140 mg/dL. Hyponatremia was classified as hypovolemic (HH) if the maximum height of the internal jugular pulse (HIJP) was below the sternal angle with the patient reclined at 0-30°, in addition to at least two of the following data suggesting hypoperfusion: thirst, orthostatic symptoms/signs, blood pressure ≤ 90/60 mmHg, heart rate ≥ 90 bpm, decreased eye tone on palpation, distal venous filling of the upper limbs below the diaphragmatic line in a sitting position, a rise in serum creatinine (SC) accompanying the descent in SNa ( 19 , 20 ). When the HIJP was not measured, hypovolemia was determined by the presence of at least three of the other signs/symptoms described above.…”

The Role of Ultrasonographic Inferior Vena Cava Measurement in the Volume‐Based Classification of Patients With Hyponatremia

“…For hypertonic hyponatremia, which was one of the exclusion criteria, it was supposed that every 100 mg/dL increase above the normal serum glucose level of 100 mg/dL decreased the serum sodium value by 1.6 mEq/L. Volume‐based classification of patients with hypotonic hyponatremia was based on the PE findings, as stated in the joint hyponatremia guidelines published in 2014, and labeled as hypovolemic, euvolemic, or hypervolemic 2,11 . Urine sodium, urine osmolarity, and serum osmolarity were ordered for each patient in each group.…”

“…Therefore, attempts have been made to simplify the algorithms presented in these guidelines 8,9 . The paramount importance of adequate assessment of volume status in hyponatremia and the inadequacy of PE findings to determine volume status, particularly extracellular fluid volume, in hyponatremia patients makes hyponatremic patient management guidelines to subject of debate, which was also admitted by European Hyponatremia Guidelines, and as a matter of fact, some 50% of hyponatremia cases are falsely labeled, so indirect measurement of volume determination methods as respiratory collapsibility index (CI) of IVC with ultrasonography (USG) has become a fundamental tool at the bedside in the ED 2,10–12 …”

“…8,9 The paramount importance of adequate assessment of volume status in hyponatremia and the inadequacy of PE findings to determine volume status, particularly extracellular fluid volume, in hyponatremia patients makes hyponatremic patient management guidelines to subject of debate, which was also admitted by European Hyponatremia Guidelines, and as a matter of fact, some 50% of hyponatremia cases are falsely labeled, so indirect measurement of volume determination methods as respiratory collapsibility index (CI) of IVC with ultrasonography (USG) has become a fundamental tool at the bedside in the ED. 2,[10][11][12] Point-of-care ultrasonography (POCUS), which has been introduced in the early 80s, aimed to meet the needs in the emergency setting, greatly accelerates diagnostic processes, and increases their accuracy during the clinical examination in the ED. 13,14 Its diagnostic performance in ruling out or ruling in most emergencies, such as the evaluation of IVC diameter for the assessment of volume status, is comparable with that of comprehensive USG and according to a plethora of trial data, it provides better results than physical examination and standard roentgenograms in a great number of clinical scenarios.…”