Familial pseudohyperkalemia (FP) is an underrecognized cause of pseudohyperkalemia, caused by the leaking of potassium from red blood cells. This extracellular shift of potassium is temperature-dependent and occurs when blood samples are stored below room temperature or for a long time, manifesting as apparent hyperkalemia. We report a suspicious case of FP, which demonstrated an apparent seasonal trajectory of serum-potassium levels at the local clinic. At first, laboratory test results did not show an increase in the serum-potassium levels in our tertiary hospital. However, by replicating the clinic\'s storage conditions, the patient\'s serum sample showed hyperkalemia only when it was stored at a temperature of 4 °C or 20 °C for 4-8 h. Hyperkalemia was not observed in the patient\'s sample when it was stored at 37 °C, or in the healthy control\'s sample at a temperature of 20 °C or 37 °C. When encountering hyperkalemia without an obvious cause and symptoms, physicians should consider pseudohyperkalemia in the differential diagnosis. In particular, if a seasonal trajectory of serum-potassium levels is observed, FP should be suspected as a potential cause of pseudohyperkalemia. Although a genetic test is needed to properly diagnose FP, confirming it by verifying the sample storage conditions or proving it by replicating the test using different storage conditions is easy and very important, as it can prevent unnecessary treatment.

Bevezetés: A káliumzavarok előfordulása a sürgősségi osztályokon számottevő, ami jelentős morbiditással és mortalitással jár. Célkitűzés: A kutatás célja, hogy bemutassa a dyskalaemiák prevalenciáját hazai sürgősségi betegellátó osztályon, a kialakulás és a kezelés körülményeit, befolyásoló tényezőit. Módszer: Keresztmetszeti, retrospektív vizsgálatot végeztünk, anonim módon. A minta, nem véletlenszerű mintavételi módszert követően, a Jász-Nagykun-Szolnok Megyei Hetényi Géza Kórház-Rendelőintézet Sürgősségi Betegellátó Osztályán 2021. szeptember és december között jelentkező, hypo- (n1 = 130) vagy hyperkalaemiával (n2 = 70) diagnosztizált páciensekből állt (n = 200). A kapott adatokat leíró és matematikai statisztikai számításokkal (khi2-próba, kétmintás t-próba, ANOVA és korrelációanalízis) értékeltük ki, SPSS 22.0 szoftver segítségével (p<0,05). Eredmények: A hypokalaemia hajlamosító tényezői közé tartozott a női nem (p<0,001) és a magasvérnyomás-betegség (p = 0,04). A középsúlyos hypokalaemiás páciensek 60%-a diagnosztizált hypertoniás volt (p = 0,003). A hyperkalaemiás állapotokhoz az emelkedettebb vércukorértékek (p<0,001), a diabetes mellitus (p<0,001) és a krónikus vesebetegség volt köthető (p<0,001). Minél súlyosabb volt a káliumeltérés mértéke, annál nagyobb valószínűséggel voltak jelen kórjelző diagnosztikus EKG-eltérések, melyek hyperkalaemia esetén 48,6%-ban fordultak elő (p<0,001). A prezentációs panaszok tekintetében a fulladással jelentkezők esetében volt a legmagasabb a szérumkáliumszint (p<0,001). Az életmentő beavatkozásra szoruló betegek többsége súlyos hypokalaemiával bírt (p<0,001). A hyperkalaemia, illetve a hypokalaemia gyakran járt kórházi felvétellel, míg ritkábban halálozással. Következtetés: Mindenképpen hasznos lenne a dyskalaemiás állapotok kezelésére egységes irányelvek kidolgozása, amelyek nagymértékben növelhetik a betegbiztonságot, és megkönnyíthetik a klinikus döntési helyzetét kritikus szituációkban. Orv Hetil. 2024; 165(5): 183–191.

Potassium disorders are one of the most common electrolyte abnormalities in patients with chronic kidney disease (CKD), contributing to poor clinical outcomes. Maintaining serum potassium levels within the physiologically normal range is critically important in these patients. Dietary potassium restriction has long been considered a core strategy for the management of chronic hyperkalemia in patients with CKD. However, this has been challenged by recent evidence suggesting a paradigm shift toward fostering more liberalized, plant-based dietary patterns. The advent of novel potassium binders and an improved understanding of gastrointestinal processes involved in potassium homeostasis (e.g., gastrointestinal potassium wasting) may facilitate a paradigm shift and incorporation of heart-healthy potassium-enriched food sources. Nevertheless, uncertainty regarding the risk-benefit of plant-based diets in the context of potassium management in CKD remains, requiring well-designed clinical trials to determine the efficacy of dietary potassium manipulation toward improvement of clinical outcomes in patients with CKD.

This study aimed to examine the characteristics and clinical outcomes of Japanese hemodialysis patients with dyskalemia. A retrospective study was conducted using a large Japanese hospital group database. Outpatients undergoing thrice-a-week maintenance hemodialysis were stratified into hyperkalemia, hypokalemia, and normokalemia groups based on their pre-dialysis serum potassium (sK) levels during the three-month baseline period. Baseline characteristics of the three groups were described and compared for the following outcomes during follow-up: all-cause mortality, all-cause hospitalization, major adverse cardiovascular events (MACE), cardiac arrest, fatal arrythmia, and death related to arrhythmia. The study included 2846 eligible patients, of which 67% were men with a mean age of 65.65 (SD: 12.63) years. When compared with the normokalemia group (n = 1624, 57.06%), patients in the hypokalemia group (n = 313, 11.00%) were older and suffered from malnutrition, whereas patients in the hyperkalemia group (n = 909, 31.94%) had longer dialysis vintage. The hazard ratios for all-cause mortality and MACE in the hypokalemia group were 1.47 (95% confidence interval [CI], 1.13-1.92) and 1.48 (95% CI, 1.17-1.86), respectively, whereas that of death related to arrhythmia in the hyperkalemia group was 3.11 (95% CI, 1.03-9.33). Thus, dyskalemia in maintenance hemodialysis patients was associated with adverse outcomes, suggesting the importance of optimized sK levels.

Dyskalemia (hypokalemia and hyperkalemia) is a common comorbidity of heart failure (HF). Although dyskalemia is associated with poor prognosis, different prognostic impacts of hypo- and hyperkalemia remain vastly unclear. This study investigated the association of dyskalemia with prognosis in HF patients, especially the mode of death and left ventricular ejection fraction (LVEF). The multicenter study included 3398 patients hospitalized for HF. Patients were divided into three groups based on serum potassium levels at discharge: hypokalemia (<3.5 mEq/L; n = 115 (3.4%)), normokalemia (3.5−5.0 mEq/L; n = 2960 (87.1%)), and hyperkalemia (≥5.0 mEq/L; n = 323 (9.5%)). Two-year all-cause, cardiac, and non-cardiac mortality was evaluated. Association of serum potassium with two-year mortality demonstrated a U-shaped curve, with a worse prognosis for patients with hypokalemia. All-cause mortality at two-years did not differ among the three groups. Hypokalemia was associated with 2-year cardiac death (adjusted hazard ratio (HR), 2.60; 95% confidence interval (CI), 1.20−5.64) in HF with reduced ejection fraction (HFrEF; LVEF < 40%), but not in non-HFrEF. Regardless of LVEF, hyperkalemia was not independently associated with any mortality. Hypokalemia was independently associated with cardiac death, particularly in HFrEF patients. Such an association was not observed in hyperkalemia regardless of LVEF.

Frailty is a state of increased vulnerability to poor resolution of homeostasis after a stressor. We hypothesized that frail older adults would tend to have electrolyte imbalances because they should have many stressors together with fragile physiological systems. In this study, we aimed to determine whether older adults with higher Frailty Index scores have electrolyte imbalances and to establish which domains of the Frailty Index are correlated with electrolyte imbalances.
A cross-sectional study.
A total of 4204 older adults aged 70 years or over who visited the Japanese National Center for Geriatrics and Gerontology.
We calculated the 50-item Frailty Index with the following domains: comorbidities, cognitive function and mood, basic and instrumental activities of daily living, physical function, nutrition, and fall risks from physical weakness and comorbidities. Participants were categorized into four groups: a non-frail group (Frailty Index ≤0.2), mildly frail group (0.20 < Frailty Index ≤0.3), moderately frail group (0.3 < Frailty Index ≤0.4), and severely frail group (0.4 < Frailty Index). Their serum sodium, potassium, calcium, and phosphorus concentrations were measured. A multiple regression model was used to explore the relationship of electrolyte imbalances with the Frailty Index and to determine which frailty domains are correlated with electrolyte imbalances.
Compared with the non-frail group, the mildly and moderately frail groups tended to have hypernatremia and hypophosphatemia, whereas the severely frail group tended to have dysnatremia, hypokalemia, and hypophosphatemia. The estimated odds ratios increased by 15%-52% for each electrolyte imbalance as the Frailty Index increased by 0.1. The Frailty Index domains of cognitive function, activities of daily living, and nutrition were correlated with more than three kinds of electrolyte imbalances, the domains of physical function and fall risks from physical weakness were correlated with three kinds of electrolyte imbalances, and the domains of comorbidities and fall risks from comorbidities were correlated with two kinds of electrolyte imbalances.
Older adults with higher Frailty Index scores tend to have electrolyte imbalances.

BACKGROUND: Available information about prognostic implications of potassium levels alteration in the setting of acute heart failure (AHF) is scarce.
OBJECTIVE: We aim to describe the prevalence of dyskalemia (hypo or hyperkalemia), its dynamic changes during AHF-hospitalization, and its long-term clinical impact after hospitalization.
METHODS: We analyzed 1779 patients hospitalized with AHF who were included in the REDINSCOR II registry. Patients were classified in three groups, according to potassium levels both on admission and discharge: hypokalemia (potassium < 3.5 mEq/L), normokalemia (potassium = 3.5-5.0 mEq/L and, hyperkalemia (potassium > 5 mEq/L).
RESULTS: The prevalence of hypokalemia and hyperkalemia on admission was 8.2 and 4.6%, respectively, and 6.4 and 2.7% at discharge. Hyperkalemia on admission was associated with higher in-hospital mortality (OR = 2.32 [95% CI: 1.04-5.21] p = 0.045). Among patients with hypokalemia on admission, 79% had normalized potassium levels at discharge. In the case of patients with hyperkalemia on admission, 89% normalized kalemia before discharge. In multivariate Cox regression, dyskalemia was associated with higher 12-month mortality, (HR = 1.48 [95% CI, 1.12-1.96], p = 0.005). Among all patterns of dyskalemia persistent hypokalemia (HR = 3.17 [95% CI: 1.71-5.88]; p < 0.001), and transient hyperkalemia (HR = 1.75 [95% CI: 1.07-2.86]; p = 0.023) were related to reduced 12-month survival.
CONCLUSIONS: Potassium levels alterations are frequent and show a dynamic behavior during AHF admission. Hyperkalemia on admission is an independent predictor of higher in-hospital mortality. Furthermore, persistent hypokalemia and transient hyperkalemia on admission are independent predictors of 12-month mortality.

BACKGROUND: Potassium abnormalities are frequent in intensive care but their incidence in the emergency department is unknown.
OBJECTIVE: We describe the spectrum of potassium abnormalities in our tertiary-level pediatric emergency department.
METHODS: Retrospective case-control study of all the patients admitted to a single-center tertiary emergency department over a 2.5-year period. We compared patients with hypokalemia (<3.0mEq/L) and patients with hyperkalemia (>6.0mEq/L) against a normal randomized population recruited on a 3:1 ratio with potassium levels between 3.5 and 5mEq/L.
RESULTS: Between January 1, 2013 and August 31, 2016 we admitted 108,209 patients to our emergency department. A total of 9342 blood samples were tested and the following potassium measurements were found: 60 cases of hypokalemia (2.8±0.2mEq/L) and 55 cases of hyperkalemia (6.4±0.6mEq/L). In total, 200 patients with normokalemia were recruited (4.1±0.3mEq/L). The main causes of the disorders were non-specific: lower respiratory tract infection (23%) and fracture (15%) for hypokalemia, lower respiratory tract (21.8%) and ear-nose-throat infections (20.0%) for hyperkalemia. Patients with hyperkalemia had an elevated creatinine level (0.72±1.6 vs. 0.40±0.16mg/dL, P<0.0001) with lower bicarbonate (19.4±3.8 vs. 21.8±2.8mmol/L, P=0.0001) and higher phosphorus levels (1.95±0.6 vs. 1.42±0.27mg/dL, P=0.0001). Patients with hypokalemia had an elevated creatinine level (0.66±0.71 vs. 0.40±0.16mg/dL, P<0.0001) and a lower phosphorus level (1.12±0.31 vs. 1.42±0.27mg/dL, P=0.0001). We did not observe significant differences in pH, PCO2, base excess and lactate, or in the mean duration of hospitalization in general wards and pediatric intensive care units according to the PIM and PRISM scores.
CONCLUSIONS: Dyskalemia is rare in emergency department patients: 0.64% for hypokalemia and 0.58% for hyperkalemia. This condition could be explained by a degree of renal failure due to transient volume disturbance. The main mechanism is dehydration due to digestive losses, polypnea in young patients, and poor intake. In the case of hypokalemia, poor intake and digestive losses could be the main explanation. These disorders resolve easily with feeding or perfusion and do not impair development.
CONCLUSIONS: Dyskalemia is rare in emergency department patients and is easily resolved with feeding or perfusion. A plausible etiological mechanism is a transient volume disturbance. Dyskalemia is not predictive of poor development in the emergency pediatric population.

OBJECTIVE: To determine the severity, concurrent clinical signs, and disease processes associated with potassium abnormalities in dogs and cats presenting to a veterinary emergency department and associated mortality.
METHODS: Retrospective and descriptive study over 20 months.
METHODS: University teaching hospital.
METHODS: 1916 dog and 525 cat visits.
METHODS: None.
RESULTS: Medical records from patients with a potassium concentration measured within 24 hours of admission were identified. Hypokalemia and hyperkalemia were defined as a potassium concentration <3.5 mmol/L [3.5 mEq/L] and >5 mmol/L [5 mEq/L], respectively. Associated disease processes and pathophysiologic risk factors for potassium abnormalities were reviewed for moderate to severe potassium abnormalities (<3 mmol/L or ≥6 mmol/L) [<3 mEq/L or ≥6 mEq/L]. Mortality associated with normokalemia, mild, and moderate to severe dyskalemia were evaluated. Overall prevalence of abnormal potassium concentration was 27% in dogs and 40% in cats. Moderate to severe hypokalemia and hyperkalemia were present in 3% of dogs and 8% of cats, and 2% of dogs and 7% of cats, respectively. Moderate to severe hypokalemia was most commonly associated with gastrointestinal disease (48% of dogs and 44% of cats) while moderate to severe hyperkalemia was most commonly associated with urinary tract disease (60% of dogs and 97% of cats). Dogs with hypokalemia and dogs and cats with hyperkalemia (P < 0.001) had significantly greater mortality than those with normokalemia. Dogs with mild hypokalemia and mild hyperkalemia (P < 0.0001) had higher mortality than dogs with normokalemia, but this was not found in cats.
CONCLUSIONS: Dyskalemia was common in this population and was associated with greater mortality. Moderate to severe potassium abnormalities were uncommon in this population and occurred most frequently in animals with gastrointestinal and urinary tract disease.

Total-body potassium (K+) content and appropriate distribution of K+ across the cell membrane is vitally important for normal cellular function. Total-body K+ content is determined by changes in excretion of K+ by the kidneys in response to intake levels. Under normal conditions, insulin and β-adrenergic tone also make important contributions in maintaining internal distribution of K+. However, despite these homeostatic pathways, disorders of altered K+ homeostasis are common. Appreciating the pathophysiology and regulatory influences that determine the internal distribution and external balance of K+ is critical in designing effective treatments to restore K+ homeostasis. We provide an up-to-date review of the regulatory aspects of normal K+ physiology as a preface to highlighting common disorders in K+ homeostasis and their treatment. This review of K+ homeostasis is designed as a resource for clinicians and a tool for educators who are teaching trainees to understand the pivotal factors involved in K+ balance.