Unveiling the Patterns of Water Diuresis in Profound Hyponatremia Management in Intensive Care Unit Settings.

BACKGROUND: Hyponatremia treatment guidelines recommend avoiding excessive increases in serum sodium concentration (s[Na]) to prevent osmotic demyelination syndrome. Although an unexpected rise in s[Na] has been attributed to water diuresis during the treatment of hyponatremia, clinical courses of water diuresis are unclear. We conducted this study to investigate the clinical characteristics of water diuresis during profound hyponatremia management. METHODS: In this retrospective observational study, we examined patients with profound hyponatremia (s[Na] ≤120 mEq/L) admitted to the intensive care unit of a Japanese hospital. The manifestation of water diuresis was defined as a urine volume ≥2 ml/kg/h and a urinary sodium plus potassium concentration (u[Na+K]) ≤50 mEq/L. We analyzed changes in urine volume and u[Na+K] over time for patients experiencing water diuresis. This analysis employed a mixed-effects model with spline terms for time, and the results are graphically presented. RESULTS: Among 47 eligible patients, 30 (64%) met the criteria for water diuresis. The etiologies of hyponatremia were drug-related hyponatremia (n=10; 33%), primary polydipsia (n=8; 27%), hypovolemic hyponatremia (n=7; 23%), syndrome of inappropriate secretion of antidiuresis (n=7; 23%), and acute heart failure (n=1; 3%). Among patients with water diuresis, 27 (90%) experienced the manifestation of water diuresis within 24 hours after the start of correction. The increased urine volume and decreased u[Na+K] levels began several hours before the peak manifestation of water diuresis. Within 6 hours after the manifestation of water diuresis, 29 patients (97%) received electrolyte-free infusions and 14 (47%) received desmopressin. One patient (3%) with water diuresis experienced overcorrection. CONCLUSIONS: Water diuresis is common during the treatment for profound hyponatremia and typically occurs within the first 24 hours, preceded by changes in urinary characteristics. Early detection and prompt response to water diuresis through urine monitoring during the early periods of hyponatremia treatment may be effective for managing water diuresis.

Renal Immune-related Adverse Event of Pembrolizumab Masked by Pemetrexed.

A Japanese woman in her 60s developed a kidney injury 9 weeks after treatment with pemetrexed, carboplatin, and pembrolizumab for stage IV lung adenocarcinoma. A renal biopsy showed chronic tubulointerstitial damage with minimal focal interstitial inflammation, consistent with pemetrexed-induced nephropathy; thus, pemetrexed was withdrawn. However, the kidney injury continued to worsen. A repeated biopsy showed severe acute tubulointerstitial nephritis, suggestive of a pembrolizumab-induced immune-related adverse event (irAE). The worsening after pemetrexed discontinuation suggested that the irAE had already begun, as the first biopsy showed focal inflammation. This case suggests thatcombining immune checkpoints and chemotherapy requires considering concurrent drug-induced nephrotoxicity.

Predictive correction of serum sodium concentration with formulas derived from the Edelman equation in patients with severe hyponatremia.

Severe hyponatremia can cause life-threatening cerebral edema. Treatment comprises rapid elevation of serum sodium concentration; however, overcorrection can result in osmotic demyelination. This study investigated potential factors, including predictive correction based on the Edelman equation, associated with appropriate correction in 221 patients with a serum sodium concentration ≤ 120 mEq/L who were admitted to a hospital in Nagoya, Japan. Appropriate correction was defined as an elevation in serum sodium concentration in the range of 4-10 mEq/L in the first 24 h and within 18 mEq/L in the first 48 h after the start of the correction. Appropriate corrections were made in 132 (59.7%) of the 221 patients. Multivariate analysis revealed that predictive correction with an infusate and fluid loss formula derived from the Edelman equation was associated with appropriate correction of serum sodium concentration (adjusted odds ratio, 7.84; 95% confidence interval, 2.97-20.64). Relative without its use, the predictive equation results in a lower proportion of undercorrection (14.3% vs. 48.0%, respectively) and overcorrection (1.0% vs. 12.2%, respectively). These results suggest that predictive correction of serum sodium concentrations using the formula derived from the Edelman equation can play an essential role in the appropriate management of patients with severe hyponatremia.