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Background: Hypokalemia and acute kidney injury (AKI) occur in patients administered liposomal amphotericin B (L-AMB), a wide-spectrum anti-fungicidal drug. However, the association between potassium supplementation and the occurrence of AKI in patients with hypokalemia who were administered L-AMB is not well understood., Methods: Using nationwide claims data and laboratory data, the occurrence of AKI during L-AMB treatment was retrospectively compared between patients with hypokalemia who were or were not supplemented with potassium and between those adequately or inadequately supplemented with potassium (serum potassium levels corrected to ≥3.5 mEq/L or remained < 3.5 mEq/L, respectively) before or after L-AMB treatment initiation., Results: We identified 118 patients who developed hypokalemia before L-AMB treatment initiation (43 received potassium supplementation [25 adequate and 18 inadequate supplementation] and 75 did not receive potassium supplementation), and 117 patients who developed hypokalemia after L-AMB initiation (79 received potassium supplementation [including 23 adequate and 15 inadequate supplementation] and 38 did not receive potassium supplementation). The occurrence of any stage of AKI was similar between patients with hypokalemia, regardless of potassium supplementation (i.e., before L-AMB treatment initiation [supplementation, 51%; non-supplementation, 45%; P = 0.570] or after L-AMB initiation [supplementation, 28%; non-supplementation, 32%; P = 0.671]). After adjusting for confounding factors, we found that the occurrence of any stage of AKI was not associated with potassium supplementation before L-AMB initiation (odds ratio [OR]: 1.291, 95% confidence interval [CI]: 0.584-2.852, P = 0.528) or after L-AMB initiation (OR: 0.954, 95% CI: 0.400-2.275, P = 0.915). The occurrence of any stage of AKI tended to decline in patients with hypokalemia who were adequately supplemented with potassium (44%) before, but not after, L-AMB initiation relative to that in patients inadequately supplemented with potassium (61%), however this result was not significant (P = 0.358)., Conclusion: Potassium supplementation was not associated with any stage of AKI in patients with hypokalemia who were administered L-AMB.

Background Hyperkalemia can be harmful, but the effect of correcting hyperkalemia is sparsely studied. We used nationwide data to examine hyperkalemia follow-up in patients with hypertension. Methods and Results We identified 7620 patients with hypertension, who had the first plasma potassium measurement ≥4.7 mmol/L (hyperkalemia) within 100 days of combination antihypertensive therapy initiation. A second potassium was measured 6 to 100 days after the episode of hyperkalemia. All-cause mortality within 90 days of the second potassium measurement was assessed using Cox regression. Mortality was examined for 8 predefined potassium intervals derived from the second measurement: 2.2 to 2.9 mmol/L (n=37), 3.0 to 3.4 mmol/L (n=184), 3.5 to 3.7 mmol/L (n=325), 3.8 to 4.0 mmol/L (n=791), 4.1 to 4.6 mmol/L (n=3533, reference), 4.7 to 5.0 mmol/L (n=1786), 5.1 to 5.5 mmol/L (n=720), and 5.6 to 7.8 mmol/L (n=244). Ninety-day mortality in the 8 strata was 37.8%, 21.2%, 14.5%, 9.6%, 6.3%, 6.2%, 10.0%, and 16.4%, respectively. The multivariable analysis showed that patients with concentrations >5.5 mmol/L after an episode of hyperkalemia had increased mortality risk compared with the reference (hazard ratio [HR], 2.27; 95% CI, 1.60-3.20; P <0.001). Potassium intervals 3.5 to 3.7 mmol/L and 3.8 to 4.0 mmol/L were also associated with increased risk of death (HR, 1.71; 95% CI, 1.23-2.37; P <0.001; HR, 1.36; 95% CI, 1.04-1.76; P <0.001, respectively) compared with the reference group. We observed a trend toward increased risk of death within the interval 5.1 to 5.5 mmol/L (HR, 1.29; 95% CI, 0.98-1.69). Potassium concentrations <4.1 mmol/L and >5.0 mmol/L were associated with increased risk of cardiovascular death. Conclusions Overcorrection of hyperkalemia to levels <4.1 mmol/L was frequent and associated with increased all-cause and cardiovascular mortality. Potassium concentrations >5.5 mmol/L were also associated with an increased all-cause and cardiovascular mortality.

Hyperkalemia is a frequent finding in patients with chronic kidney disease (CKD). This increase in serum potassium levels is associated with decreased renal ion excretion, as well as the use of medications to reduce the progression of CKD or to control associated diseases such as diabetes mellitus and heart failure. Hyperkalemia increases the risk of cardiac arrhythmia episodes and sudden death. Thus, the control of potassium elevation is essential for reducing the mortality rate in this population. Initially, the management of hyperkalemia includes orientation of low potassium diets and monitoring of patients' adherence to this procedure. It is also important to know the medications in use and the presence of comorbidities to guide dose reduction or even temporary withdrawal of any of the potassium retention-related drugs. And finally, the use of potassium binders is indicated in both acute episodes and chronic hyperkalemia.

Hypokalemia prolongs the QRS and QT intervals, deteriorates intercellular coupling, and increases the risk for arrhythmia. Melatonin preserves gap junctions and shortens action potential as potential antiarrhythmic mechanisms, but its properties under hypokalemia remain unknown. We hypothesized that melatonin protects against low potassium-induced arrhythmias through the activation of its receptors, resulting in action potential shortening and connexin-43 preservation. After stabilization in Krebs-Henseleit solution (4.5 mEq/L K + ), isolated hearts from Wistar rats underwent perfusion with low-potassium (1 mEq/L) solution and melatonin (100 μmol/L), a melatonin receptor blocker (luzindole, 5 μmol/L), melatonin + luzindole or vehicle. The primary endpoint of the study was the prevention of ventricular fibrillation. Electrocardiography was used, and epicardial action potentials and heart function were measured and analyzed. The ventricular expression, dephosphorylation, and distribution of connexin-43 were examined. Melatonin reduced the incidence of low potassium-induced ventricular fibrillation from 100% to 59%, delayed the occurrence of ventricular fibrillation and induced a faster recovery of sinus rhythm during potassium restitution. Melatonin prevented QRS widening, action potential activation delay, and the prolongation of action potential duration at 50% of repolarization. Other ECG and action potential parameters, the left ventricular developed pressure, and nonsustained ventricular arrhythmias did not differ among groups. Melatonin prevented connexin-43 dephosphorylation and its abnormal topology (lateralization). Luzindole abrogated the protective effects of melatonin on electrophysiological properties and connexin-43 misdistribution. Our results indicate that melatonin receptor activation protects against low potassium-induced ventricular fibrillation, shortens action potential duration, preserves ventricular electrical activation, and prevents acute changes in connexin-43 distribution. All of these properties make melatonin a remarkable antifibrillatory agent., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background/aims: Dietary potassium (K+) has beneficial effects on blood pressure and cardiovascular (CV) outcomes. Recently, several epidemiological studies have revealed an association between urinary K+ excretion (as proxy for dietary intake) and better renal outcomes in subjects with chronic kidney disease (CKD). To address causality, we designed the "K+ in CKD" study., Methods: The K+ in CKD study is a multicenter, randomized, double blind, placebo-controlled clinical trial aiming to include 399 patients with hypertension, CKD stage 3b or 4 (estimated glomerular filtration rate [eGFR] 15-44 mL/min/1.73 m2), and an average eGFR decline > 2 mL/min/1.73 m2/year. As safety measure, all included subjects will start with a 2-week open-label phase of 40 mmol potassium chloride daily. Patients who do not subsequently develop hyperkalemia (defined as serum K+ >5.5 mmol/L) will be randomized to receive potassium chloride, potassium citrate (both K+ 40 mmol/day), or placebo for 2 years. The primary end point is the difference in eGFR after 2 years of treatment. Secondary end points include other renal outcomes (> 30% decrease in eGFR, doubling of serum creatinine, end-stage renal disease, albuminuria), ambulatory blood pressure, CV events, all-cause mortality, and incidence of hyperkalemia. Several measurements will be performed to analyze the effects of potassium supplementation, including body composition monitoring, pulse wave velocity, plasma renin and aldosterone concentrations, urinary ammonium, and intracellular K+ concentrations., Conclusion: The K+ in CKD study will demonstrate if K+ sup-plementation has a renoprotective effect in progressive CKD, and whether alkali therapy has additional beneficial effects., (© 2018 S. Karger AG, Basel.)

Intradialytic hypotensive episodes are deleterious for hemodialysis (HD) patients. Acetate-free biofiltration with profiled potassium (AFBK) dialysate concentration may improve their cardiovascular stability. The aim of the present crossover study was to compare intradialytic hemodynamic tolerance and biological parameters between online hemodiafiltration (olHDF) and AFBK. Ten frail HD patients (8 males) with a mean age of 66.71- ± 12.31 years were studied for three months on olHDF and AFBK. There was a significant reduction of the hypotensive episodes during the AFBK period compared to the olHDF period. Mean intradialytic systolic and diastolic blood pressures were significantly higher during the AFBK period. There was a significant postdialytic increase in serum sodium concentration with the AFBK compared to olHDF. The dry weight and ultrafiltration indices were significantly higher, and the Kt/V was significantly lower during the AFBK period. Serum albumin concentration significantly increased during the AFBK period. AFBK leads to a significantly improved intradialytic tolerance in hemodynamically instable HD patients.

Background: Gitelman syndrome (GS) is a rare autosomal recessive disease caused by loss-of-function mutations in the SLC12A3 gene, and is characterized by hypokalemia and metabolic alkalosis. In this study, we aimed to study the genotype, phenotype, and treatment in 42 GS patients, the largest sample size so far in mainland China., Method: We retrospectively studied the clinical data and genetic characteristics of 42 patients diagnosed with GS in Peking Union Medical College Hospital from 2012 to 2015. Therapeutic efficacy of spironolactone and potassium supplements was also studied retrospectively., Results: Eighty-one mutation alleles were found in 42 patients, and total of 52 distinctly different mutation alleles were identified, of which 15 were new mutation alleles. p.Asp486Asn was a hotspot in our series, with the allele frequency being 19.7 % (16/81), and was found in 13 patients (31.0 %). Treatment with spironolactone or potassium supplements alone significantly increased serum potassium concentration by 0.36 ± 0.37 and 0.45 ± 0.35 mmol/l, respectively (both P < 0.05), and combined therapy with spironolactone and potassium increased serum potassium concentration by 0.69 ± 0.64 mmol/l (P < 0.05)., Conclusions: 18.5 % (15/81) mutation sites identified in 42 Chinese GS patients are novel. p.Asp486Asn mutation is a hotspot, which is different from the reports from other countries. Spironolactone could moderately elevate serum potassium level, and spironolactone in combination with potassium supplements tended to be more effective.

Background and Aims: Increasing the intake of potassium has been shown to lower blood pressure, but whether it also affects heart rate (HR) is largely unknown. We therefore assessed the effect of potassium supplementation on HR in a meta-analysis of randomized controlled trials., Methods and Results: We searched PubMed (1966-October 2014) for randomized, placebo-controlled trials in healthy adults with a minimum duration of two weeks in which the effect of increased potassium intake on HR was assessed. In addition, reference lists from meta-analysis papers on potassium and blood pressure were hand-searched for publications. Two investigators independently extracted the data. We performed random effects meta-analyses, subgroup and meta-regression analyses for characteristics of the study (e.g. design, intervention duration, potassium dose and salt type, change in potassium excretion, sodium excretion during intervention) and study population (e.g. gender, age, hypertensive status, pre-study HR, pre-study potassium excretion). A total of 22 trials (1086 subjects), with a median potassium dose of 2.5 g/day (range: 0.9-4.7 g/day), and median intervention duration of 4 weeks (range: 2-24 weeks) were included. The meta-analysis showed no overall effect of increased potassium intake on HR (0.19 bpm, 95% CI: -0.44, 0.82). Stratified analyses yielded no significant effects of potassium intake on HR in subgroups, and there was no evidence for a dose-response relationship in meta-regression analyses., Conclusion: A chronic increase in potassium intake with supplemental doses of 2-3 g/day is unlikely to affect HR in apparently healthy adults., (Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Dyskalemia is known to cause cardiac arrhythmias and cardiac arrest. In persons undergoing hemodialysis, potassium dialysate composition has been identified as a contributingfactor in addition to co-morbidities, medications, dietary potassium intake, and stage of kidney disease. Current evidence recommends a thorough evaluation of all factors affecting potassium balance, and lower potassium concentration should be used cautiously in patients who are likely to develop cardiac arrhythmias. Nephrology nurses play a key role inpatient assessment and edu- cation related to potassium balance.

A 52-year old man developed hyperkalaemia on the 11th postoperative day following an extensive open retroperitoneal liposarcoma resection that included splenectomy. Despite thorough investigations, no aetiology for the hyperkalaemia was identified and standard empirical treatment was ineffective. On reconsideration, in view of the patient's concurrent thrombocytosis, a pseudofactual or artefactual hyperkalaemia was suspected. This was confirmed by contemporaneous testing of serum and plasma potassium levels, with the latter value lying within the normal range. Treatment for hyperkalaemia was discontinued, thus averting an iatrogenic and potentially dangerous hypokalaemia. This case highlights pseudohyperkalaemia as an often-neglected cause of elevated serum potassium levels and discusses its association with thrombocytosis following splenectomy., (2015 BMJ Publishing Group Ltd.)

Objective: Urinary excretion of angiotensinogen [urine angiotensinogen (UAGT)] has been proposed as a biomarker of intrarenal renin-angiotensin system activity. We investigated the association between UAGT and salt-sensitivity and potassium-sensitivity of blood pressure (BP) among Genetic Epidemiology Network of Salt Sensitivity study participants., Methods: The intervention consisted of a 7-day low-sodium diet (51.3  mmol sodium/day), 7-day high-sodium diet (307.8  mmol sodium/day), and 7-day high-sodium diet with potassium supplementation (307.8  mmol sodium/day and 60  mmol potassium/day). Twenty-four-hour UAGT was estimated at baseline and at the end of each intervention for 100 randomly selected participants., Results: Median UAGT (μg/24  h) and UAGT-to-creatinine ratio (UAGT/Cr, μg/g) were significantly reduced during the low-sodium and potassium-supplementation interventions and increased during the high-sodium intervention (both P = 0.01). Baseline log-transformed UAGT and UAGT/Cr ratio were significantly positively associated with BP at baseline and at the end of each intervention. For example, one standard deviation higher log-UAGT/Cr ratio (1.2  μg/g) was associated with a 5.0-mmHg (95% confidence interval 2.3-7.8) higher SBP at the end of the high-sodium intervention, after adjusting for multiple covariates (P = 0.003). In addition, one standard deviation higher log-UAGT/Cr ratio was associated with a 1.6-mmHg increase in age-adjusted and sex-adjusted SBP from the low-sodium intervention to the high-sodium intervention (95% confidence interval 0.1-3.1, P = 0.04). This association was no longer statistically significant after multivariable adjustment., Conclusion: These data indicate that elevated UAGT are associated with BP sodium sensitivity. Augmentation of intrarenal renin-angiotensin system activity may play an important role in developing salt-sensitive hypertension.

Introduction: Serum concentrations of potassium (K) and calcium (Ca) influence ionic currents and play an important role in the duration of ventricular action potential. Further, the influence of alkalosis in reducing ionized calcium has been well known for a long time. The aim of this study was to assess the effects of different dialysate electrolytes and bicarbonate concentrations on changes of QTc interval in patients on chronic hemodialysis., Methods: The study hemodialysis sessions were performed in 22 patients, with different electrolyte and bicarbonate concentrations in dialysate. Tested dialysate concentrations were K of 2 and 3 mmol/L; Ca 1.25, 1.5 and 1.75 mmol/L; and bicarbonate 30 and 34 mmol/L. An electrocardiogram (ECG) was recorded 1 hour before, at the end and every hour for 4 hours after each study dialysis session. QTc interval was measured from the beginning of the QRS complex to the end of a T wave on a 12-lead ECG. Blood was collected and K, total Ca, ionic Ca and pH evaluated., Results: At the end of the study hemodialysis session with dialysate containing low K (2 mmol/L), low Ca (1.25 mmol/L) and high bicarbonate concentration (34 mmol), mean QTc interval was significantly prolonged compared with that recorded with dialysate containing high K (3 mmol/L), high Ca (1.75 mmol/L) and bicarbonate (30 mmol) (40 ± 10 milliseconds vs. 2 ± 2 milliseconds; p<0.01). Dialysate with low concentration of low Ca, K and high concentration of bicarbonate was an independent predictor of QTc; the combination of low Ca and K and high bicarbonate strongly increased the risk of prolonged QTc interval., Conclusion: The present pilot study shows that changes in QTc interval during hemodialysis depend on both electrolyte and bicarbonate concentrations in dialysate.

Background: A daily single capsule (polycap) of 3 blood pressure (BP) lowering drugs (hydrochlorthiazide, 12.5 mg; atenolol, 50 mg; ramipril, 5 mg) at low doses, simvastatin (20 mg), and aspirin (100 mg) has been demonstrated to be well tolerated and to reduce BP and low-density lipoprotein cholesterol. We examined the incremental effects of 2 (full dose) plus K(+) supplementation versus single polycap (low dose) on risk factors and tolerability., Methods and Results: After a run-in period, 518 individuals with previous vascular disease or diabetes mellitus from 27 centers in India were randomly assigned to a single-dose polycap or to 2 capsules of the polycap plus K(+) supplementation for 8 weeks. The effects on BP, heart rate (HR), serum lipids, serum and urinary K(+), and tolerability were assessed using an intention-to-treat analysis. The full-dose polycap (plus K(+) supplementation) reduced BP by a further 2.8 mm Hg systolic and 1.7 mm Hg diastolic, compared with that observed with the low-dose polycap (P=0.003; P=0.001), but there were no differences in HR (0.1 bpm). The differences in total and low-density lipoprotein cholesterol between the full-dose and low-dose polycap was 7.2 mg/dL (P=0.014) and 6.6 mg/dL (P=0.006), respectively, but there were no differences in high-density lipoprotein cholesterol or triglycerides. The rates of discontinuation of the study drug after randomization were similar in the 2 groups (6.9% low dose versus 7.8% full dose)., Conclusions: The full-dose polycap (plus K(+) supplementation) reduces BP and low-density lipoprotein cholesterol to a greater extent compared with the low dose, with similar tolerability. Therefore, the full-dose polycap should potentially lead to larger benefits. Clinical Trial Registration- URL: http://www.ctri.nic.in. Unique identifier: CTRI/2010/091/000054.

In the ischemic myocardium, extracellular potassium ([K(+)](o)) increases to ≥20 mmol/l. To determine how lethal arrhythmias occur during ischemia, we investigated whether the increased spatial pattern of [K(+)](o), i.e., a regional or a global increase, affects the incidence of arrhythmias. Force, sarcomere length, membrane potential, and nonuniform intracellular Ca(2+) ([Ca(2+)](i)) were measured in rat ventricular trabeculae. A "regional" or "global" increase in [K(+)](o) was produced by exposing a restricted region of muscle to a jet of 30 mmol/l KCl or by superfusing trabeculae with a solution containing 30 mmol/l KCl, respectively. The increase in [Ca(2+)](i) (Ca(CW)) during Ca(2+) waves was measured (24°C, 3.0 mmol/l [Ca(2+)](o)). A regional increase in [K(+)](o) caused nonuniform [Ca(2+)](i) and contraction. In the presence of isoproterenol, the regional increase in [K(+)](o) induced sustained arrhythmias in 10 of 14 trabeculae, whereas the global increase did not induce such arrhythmias. During sustained arrhythmias, Ca(2+) surged within the jet-exposed region. In the absence of isoproterenol, the regional increase in [K(+)](o) increased Ca(CW), whereas the global increase decreased it. This increase in Ca(CW) with the regional increase in [K(+)](o) was not suppressed by 100 μmol/l streptomycin, whereas it was suppressed by 1) a combination of 10 μmol/l cilnidipine and 3 μmol/l SEA0400; 2) 20 mmol/l 2,3-butanedione monoxime; and 3) 10 μmol/l blebbistatin. A regional but not a global increase in [K(+)](o) induces sustained arrhythmias, probably due to nonuniform excitation-contraction coupling. The same mechanism may underlie arrhythmias during ischemia.

Radionuclide content of food and water in high mountainous regions of Georgia - Adjara (Keda, Shuakhevi, Khulo) has been studied, internal and total irradiation doses for the population have been defined and preventive measures for its reduction have been proposed. Internal irradiation dose for the population caused by K-40 was identified as 0,63 mSv/y, total irradiation dose - 1,73 mSv/y, that slightly exceeds acceptable levels, due to this it seems desirable to provide some measures with aim to reduce the radiation dose of the population and conduct further observation of the radiation situation. Measures intended to reduce irradiation doses includes: provision of population with less radioactive water sources, the regulation of medical radiation procedures (mostly - X-ray diagnostic procedures), the rational use of fertilizers with 40K content, construction of buildings on the territories with the lowest values of gamma radiation and radon release from soil, use of materials with low content of natural radionuclides for building construction, provision of premises with effective ventilation and radiation monitoring of buildings at any stages of construction, reconstruction or repair.

Background: External biphasic electrical cardioversion (CV) is a standard treatment option for patients suffering from acute symptoms of atrial fibrillation (AF). Nevertheless, CV is not always successful, and thus strategies to increase the success rate are desirable., Objective: The purpose of this study was to evaluate the effect of intravenously administered K/Mg solution on the biphasic CV energy threshold and success rate to restore sinus rhythm (SR) in patients with AF., Methods: The study consisted of 170 patients with persistent AF. The patients were randomly assigned to undergo biphasic CV either with (n = 84) or without (n = 86) pretreatment with K/Mg solution. An energy step-up protocol of 75, 100, and 150 W (J) was used., Results: Biphasic CV of AF was effective in 81 (96.4%) patients in the pretreatment and 74 (86.0%) patients in the control group (P = 0.005). The effective energy level required to achieve SR was significantly lower in the pretreated group (140.8 ± 26.9 J vs 182.5 ± 52.2 J, P = 0.02). No K/Mg-solution-associated side effects such as hypotension or bradycardia were observed., Conclusion: Administration of K/Mg solution positively influences the success rate of CV in patients with persistent AF. Furthermore, significantly less energy is required to successfully restore SR and therefore K/Mg pretreatment may facilitate SR restoration in patients undergoing CV for AF., (© 2011 Wiley Periodicals, Inc.)

Case Description: 12 European shorthair cats (6 males and 6 females; age range, 2 months to 3 years) from 1 household were evaluated for clinical signs of recurrent and progressive muscle spasticity. Genetic relationships among the cats were suspected but were not known., Clinical Findings: Physical examination of all cats revealed a thin to mildly emaciated body condition and signs of suppurative rhinitis. Results of neurologic evaluations revealed no abnormalities in any cats at rest, but exercise- and stress-induced episodes of muscle spasticity were observed. Results of hematologic (7/12 cats) and CSF (4) analysis, diagnostic imaging (including radiography [7] and magnetic resonance imaging [4]), electromyography (4), motor nerve conduction tests (4), screening for metabolic storage diseases (4), provocation tests via exercise in a cold (4°C [39.2°F]) environment (7), and gross pathological and histologic examination (5) revealed no abnormalities that could potentially explain the clinical signs. However, consumption of a potassium-enriched diet resulted in severe aggravation of clinical signs in 7 of 7 cats, leading to a diagnosis of potassium-aggravated muscle stiffness., Treatment and Outcome: 5 cats were euthanized after initial examination because of poor physical condition and severe clinical signs. Spasticity in the 7 remaining cats was improved during a 6-week follow-up period as they reduced their own activity. Further investigation and treatment were declined., Clinical Relevance: Channelopathies are rarely recognized diseases in domestic animals. In addition to conventional diagnostic evaluation methods, provocation tests in a clinical environment can be used in the assessment of channelopathies.

The main aim was to investigate the effects of raised [K+](o) on contraction of isolated non-fatigued skeletal muscle at 37°C and 25°C to assess the physiological significance of K+ in fatigue. Mouse soleus muscles equilibrated at 25°C had good mechanical stability when temperature was elevated to 37°C. The main findings at 37°C vis-à-vis 25°C were as follows. When [K+](o) was raised from 4 to 7 mM, there was greater twitch potentiation, but no significant difference in peak tetanic force. At 10 mM [K+](o) there was (1) a faster time course for the decline of peak tetanic force, (2) a greater steady-state depression of twitches and tetani, (3) an increase of peak force over 50-200 Hz (whereas it decreased at 25°C), (4) significant tetanus restoration when stimulus pulse duration increased from 0.1 to 0.25 ms and (5) greater depolarisation of layer-2 fibres, with no repolarisation of surface fibres. These combined data strengthen the proposal that a large run-down of the K+ gradient contributes to severe fatigue at physiological temperatures via depolarisation and impaired sarcolemmal excitability. Moreover, terbutaline, a β(2)-adrenergic agonist, induced a slightly greater and more rapid, but transient, restoration of peak tetanic force at 10 mM [K+](o) at 37°C vis-à-vis 25°C. A right shift of the twitch force-stimulation strength relationship at 10 mM [K+](o) was partially reversed with terbutaline to confer the protective effect. Thus, catecholamines are likely to stimulate the Na+ -K+ pump more powerfully at 37°C to restore excitability and attenuate, but not prevent, the detrimental effects of K+.

This technique proposes a new approach to correlate intra- and extracellular variations of the ionic concentrations in vivo by means of tapered optical waveguides coupled to standard electrophysiological electrodes to monitor in vivo simultaneously the intracellular and extracellular K(+) concentration as well as the neighboring field potential. The optical fibers were tapered to a final diameter of approximately 10 μm and were used to guide the excitation light deep into the tissue and to collect the fluorescence emanating from the intracellular milieu. This fiber was coupled to a double barrel ion-sensitive electrode forming a micro-optrode with a final diameter around 15 μm. The method was successfully used to record the intracellular K(+) evolution with the fluorescent indicator PBFI during three states: normal sleep-like patterns, paroxysmal seizures, and coma. While we could not disclose any phasic fluctuations of the intracellular K(+) during normal sleep patterns, they were clearly present during seizures and coma. In the majority of cases (58%), paroxysmal discharges were associated with positive variations of the intracellular fluorescence of 62±5% corresponding to extracellular K(+) increases of 2.04±0.4 mM. In the remaining cases (42%) intracellular K(+) dropped by 44.4±12% for an extracellular K(+) increase of 2.62±0.47 mM. We suggest that this differential behavior might reflect different cellular populations (glia vs. neurons, respectively). Comatose states were accompanied by an extracellular drop of K(+) of 1.31±0.13 mM, which was reflected, in all cases, by an intracellular K(+) increase of 39±4%., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Background: Few data guide the prescription of dialysate potassium (dK) in hemodialysis, which is usually prescribed empirically on the basis of predialysis serum potassium levels., Methods: This was a retrospective cohort study of prospectively collected data. We studied all patients initiating chronic hemodialysis in the Northern Alberta Renal Program (NARP) between January 2001 and December 2006. Data on demographic, clinical and treatment characteristics as well as the dates of death or transplant were extracted from the NARP database. We aimed to examine the relation between dialysate potassium level and all-cause death., Results: During the study, 515/1,267 of patients (41%) died. The frequency of dK of 0 or 1 mEq/L, 2, 3 and 4 mEq/L was 6%, 40%, 51% and 3%, respectively. In our base model, which considered dK as a categorical exposure, the hazard ratios associated with 0 or 1 mEq/L, 2, 3 and 4 mEq/L were 1.13 (95% confidence interval [95% CI], 0.78-1.63), 1 (referent), 1.29 (95% CI, 1.07-1.56) and 1.74 (95% CI, 1.09-2.77), respectively. When markers of inflammation or malnutrition were adjusted for separately, the association between dK and mortality was attenuated but remained significant. After simultaneous adjustment for markers of inflammation and malnutrition, the risk of death associated with the higher dK categories was attenuated, and the overall trend was eliminated. Analyses using dK as a time-varying covariate found similar results., Conclusions: Although unadjusted and partially adjusted models suggested a graded association between higher dK and the risk of all-cause death, this association was apparently due to confounding by factors suggesting malnutrition and inflammation. The relative paucity of data on the association between dK and clinical outcomes despite the biological importance of potassium suggest that further studies are needed.

Background: No data exist regarding the safety and effectiveness of a potassium replacement protocol for hospitalized patients when potassium replacement dosing regimens (KRDRs) are adjusted to Modification of Diet in Renal Disease estimation of glomerular filtration rate (MDRD GFR)., Objective: To evaluate the effectiveness and safety of a potassium replacement protocol in which KRDRs are prescribed based on MDRD GFR and serum potassium deficiency (Kdef)., Methods: Patients prescribed the potassium replacement order set were identified in a retrospective fashion. Serum potassium, prescriber-defined goal serum potassium, and MDRD GFR data were collected for patients who received protocol KRDRs. The KRDR to be administered is selected based on Kdef (goal serum potassium minus measured serum potassium) of 0.1-0.2, 0.3-0.5, or more than 0.5 mEq/L and the patients' MDRD GFR of greater than 70, 40-70, or less than 40 mL/min/1.73 m(2) (any patient undergoing dialysis is included in the <40 mL/min/1.73 m(2) group). Efficacy was evaluated by determining the change in serum potassium level (Delta K) following potassium replacement, the number of KRDRs needed to achieve goal serum potassium, and the milliequivalents of potassium needed to achieve goal serum potassium levels. Safety was assessed by the incidence of serum potassium values greater than 5.0 mEq/L following replacement., Results: One hundred forty-nine patients were evaluated. There were 184 protocol initiations and 257 KRDRs administered to achieve goal serum potassium levels. The DeltaK was 0.50 +/- 0.40 mEq/L (mean +/- SD) following KRDR. The Delta K was similar between MDRD GFR groups. One hundred thirty six (73.9%) protocol initiations required 1 KRDR, and 168 (91.3%) protocol initiations required 1 or 2 KRDRs to achieve goal serum potassium. Patients whose MDRD GFR was 40-70 mL/min/1.73 m(2) were less likely to achieve goal serum potassium value after 1 KRDR (58.2% vs 79.6% >70 group and 84.6% <40 group). This was true regardless of the patient's goal serum potassium. One (0.54%) serum potassium greater than 5.0 mEq/L occurred following a KRDR., Conclusions: Our potassium replacement protocol based on MDRD GFR and Kdef effectively corrects hypokalemia. Fewer protocol initiations achieved goal serum potassium levels in the group with MDRD GFR 40-70 mL/min/1.73 m(2). Hyperkalemia rarely occurred following KRDR.

Objective: We sought to determine analytically the potassium content of different varieties of raw potatoes, and to estimate the amount of potassium that can be extracted or leached from raw potatoes by cooking., Design and Methods: Six different varieties of fresh potatoes were obtained from the Whole Foods Market in Manhasset, New York. Two different cooking methods (normal cooking [NC] and double cooking [DC]) were applied to each potato. Potassium was extracted from the ash of dried samples. The potassium content of aqueous extractions was ascertained by atomic absorption spectrophotometry., Results: Mean potassium content was highest in the purple Viking potato (448.1 +/- 60.5 mg [11.5 +/- 1.6 mEq]/100 g [values are mean +/- SD unless otherwise noted]), and lowest in the Idaho potato (295 +/- 15.7 mg [7.6 +/- 0.4 mEq]/100 g). All raw potatoes had a mean potassium content of about 300 mg (7.7 mEq)/100 g or greater. The DC method resulted in a greater reduction in potassium from raw potatoes than the NC method. All potatoes retained a mean potassium content greater than 200 mg (5.1 mEq)/100 g, using the NC versus the DC method., Conclusion: The potassium content of the raw potatoes studied varied considerably, with most tubers retaining a moderate amount of potassium after leaching. This study showed that the DC method appears to be more effective than the NC method in leaching potassium from the potatoes studied. Our findings provide useful information for dietitians involved in menu planning for people on potassium-restricted diets.

The kidney is the major regulator of potassium homeostasis. In addition to the ROMK channels, large conductance Ca(2+)-activated K(+) (BK) channels are expressed in the apical membrane of the aldosterone sensitive distal nephron where they could contribute to renal K(+) secretion. We studied flow-induced K(+) secretion in BK channel alpha-subunit knockout (BK(-/-)) mice by acute pharmacologic blockade of vasopressin V(2) receptors, which caused similar diuresis in wild-type and knockout mice. However, wild-type mice, unlike the BK(-/-), had a concomitant increase in urinary K(+) excretion and a significant correlation between urinary flow rate and K(+) excretion. Both genotypes excreted similar urinary amounts of K(+) irrespective of K(+) diet. This was associated, however, with higher plasma aldosterone and stronger expression of ROMK in the apical membrane of the aldosterone-sensitive portions of the distal nephron in the knockout than in the wild-type under control diet and even more so with the high-K(+) diet. High-K(+) intake significantly increased the renal expression of the BK channel in the wild-type mouse. Finally, despite the higher plasma K(+) and aldosterone levels, BK(-/-) mice restrict urinary K(+) excretion when placed on a low-K(+) diet to the same extent as the wild-type. These studies suggest a role of the BK channel alpha-subunit in flow-induced K(+) secretion and in K(+) homeostasis. Higher aldosterone and an upregulation of ROMK may compensate for the absence of functional BK channels.

Objectives: Evaluate potassium and phosphorus repletion in hospitalized patients. Assess the potential role for use of various methods, including healthcare information technology, to improve prescribing and patient safety., Research Design and Methods: Inpatient medication profiles were screened to identify orders for potassium and phosphorus replacement products. Electronic laboratory and medical records were used to evaluate efficacy and safety. Eligibility for oral therapy was defined by the presence of other scheduled oral medications on the medication profile. Appropriateness of prescribing was based on adherence to the hospital guidelines for repletion., Results: Overall, 134 orders for potassium in 92 patients and 36 orders for phosphorus in 27 patients were evaluated over a 3-week data collection period. Intravenous (IV) potassium was prescribed in 73% of replacement episodes (46% as single doses and 54% within large volume IV fluids), with 85% for normokalemia or mild-to-moderate cases of hypokalemia. Phosphorus orders involved single doses of IV potassium phosphate (mean 13.1 mmol) in 75% of cases. Approximately 85% of doses were for mild or moderate hypophosphatemia. Eligibility for oral therapy was evident in 74% of normokalemic or mild hypokalemic cases receiving IV potassium products and in 33% of cases receiving IV phosphorus replacement. Six cases of mild hyperkalemia were observed. No hyperphosphatemia was documented. Study limitations include use of a retrospective design, inability to discern whether some electrolyte doses were given with a preventative intent, potential overestimation of the number of patients eligible for oral repletion, and lack of data on the accessibility of the laboratory serum concentrations or the awareness of serum values to the prescribers., Conclusions: Intravenous potassium and phosphate products are commonly prescribed for mild or moderate cases of hypokalemia or hypophosphatemia. Many patients met eligibility for oral therapy. Efforts to enhance prescriber education and implement computerized prescribing and decision support systems have the potential to improve prescribing and reduce possibilities of adverse drug events and medication errors related to potassium and phosphate administration.

Background: Several clinical trials have suggested that a metabolic cocktail of glucose-insulin-potassium (GIK) decreases mortality rates in patients with acute myocardial infarction (AMI). It has also been reported that Fas-mediated apoptosis plays an important role in ischaemic/reperfusion injury in the rat model. This study was designed to evaluate the interaction of ischaemic/reperfusion and reperfusion therapy coadministered with high-dose GIK treatment on soluble Fas/APO-1 (sFas) and Fas ligand (sFasL) plasma concentration in patients with AMI., Materials and Methods: Seventy-four patients presenting with AMI who underwent reperfusion therapy were randomized into a GIK group (n = 35) receiving high-dose GIK for 24 h or a vehicle group (n = 39). Thirty-four control subjects were also enrolled in the present study. Strepavidin-biotin ELISA was used to determine the soluble sFas and sFasL plasma concentration at baseline, 24 h (h), 3 day (d), 7 d and 14 d., Results: Soluble Fas and sFas-L serum concentrations ([sFas] and [sFas-L]) of patients with AMI were significantly elevated at baseline as compared with normal controls (NCs; P < 0.01 vs. NC). The sFas in the GIK and vehicle groups markedly decreased 24 h after the GIK infusion (10.7-->5.9 ng mL(-1) and 9.7-->6.5 ng mL(-1); P < 0.01 vs. baseline) and then increased during the 3-7-d period (5.9-->12.1 ng mL(-1) and 6.5-->11.1 ng mL(-1); P < 0.01 vs. 24 h). The GIK group demonstrated reduced sFas (12.1-->5.9 ng mL(-1)) at 14 d (P < 0.01 vs. 7 d), with no concomitant changes in the vehicle group. The sFas-L in the GIK and vehicle groups was not significant different during the 14-d period., Conclusions: These results indicate that the sFas and sFasL in patients with AMI increased significantly compared with NC. Owing to the cardioprotective effects reported here and by others, a high-dose GIK infusion co-administered with the timely re-establishment of nutritive perfusion should be strongly considered as a treatment of choice for AMI. Additionally, sFas may be a valuable marker of the physiological response to ischaemic/reperfusion injury and reperfusion associated with high-dose GIK treatment.

Background: In ST-elevation myocardial infarction (STEMI) there is conflicting evidence that mortality, morbidity and infarct size is reduced by therapies influencing myocardial metabolism, such as infusion of glucose-insulin-potassium (GIK). Several clinical trials with GIK have already provided insight into the magnitude of this effect. The aim of this article was to review randomized trials on adjunctive GIK infusion in STEMI., Methods: Randomized trials comparing GIK with placebo or untreated controls in patients with STEMI were identified by electronic and manual searches. A systematic analysis of all data was performed, with regard to inclusion criteria, dose of GIK and additional use of reperfusion therapy. Thirteen trials, involving 4992 patients, were included., Results: Overall, hospital mortality was 10.8% after GIK compared to 12.9% in controls (p = 0.02). GIK infusions were in particular effective when a high dose was used and if given as an adjunct to reperfusion therapy. In patients with heart failure on admission, GIK may have worse effects. In all analyzed trials, GIK infusion caused only mild adverse effects, although fluid overload may be a problem in certain patients., Conclusions: GIK may reduce mortality in patients with STEMI, particularly if a high dose is used and when GIK is administered as an adjunct to reperfusion therapy. However, all studies had a relative small sample size and additional large randomized trials are certainly needed before a definite conclusion can be made. The limited evidence currently available does not warrant GIK therapy to be applied in patients at the present time.

Background: GIK-201Tl imaging reportedly improves the detection of viable myocardium, so the present study evaluated whether it can detect myocardial viability after acute myocardial infarction (AMI)., Methods and Results: Resting 201Tl and 99mTc-pyrophosphate (PYP) dual single photon emission computed tomography (SPECT) and 201Tl SPECT after 201Tl with GIK (10% glucose, insulin 5 U, and KCl 10 mmol) infusion (GIK-201Tl) were performed in 25 AMI patients within 10 days of admission. GIK-201Tl SPECT images were obtained immediately and 4 h after infusion. Left ventriculography (LVG) was performed within 3 weeks and at 6 months when follow-up 201Tl SPECT was also performed. From 20 SPECT segments, both the summed defect score (RDS) and the number of defect segments (ES) were calculated. The infarcted area was defined as 99mTc-PYP uptake segments. Wall motion was estimated in 7 LVG segments. The ES of R-201Tl (5.5 +/- 2.8), immediate GIK-201Tl (4.0 +/- 2.3), and 4-h GIK-201Tl (5.6 +/- 2.7) were lower than that of 99mTc-PYP (7.5 +/- 4.1) (p<0.05), and the ES had significantly declined 6 months later on 201Tl (3.5 +/- 2.8) (p<0.05). Although the RDS of R-201Tl (11.3 +/- 7.9) and 4-h GIK-201Tl (11.2 +/- 6.3) were greater than at the 6-month 201Tl (7.1 +/- 6.5), immediate GIK-201Tl (7.4 +/- 6.5) was equivalent to follow-up 201Tl. The sensitivity of immediate GIK-201Tl was highest among the imaging methods., Conclusion: To detect myocardial viability after AMI, early imaging with GIK-201Tl is more useful than resting 201Tl imaging.

The Food and Drug Administration (FDA) is amending the general labeling provisions for over-the-counter (OTC) drug products to require that the labeling of all OTC drug products intended for oral ingestion include: The calcium content per dosage unit when the product contains 20 milligrams (mg) or more per single dose; a warning statement that persons with kidney stones and persons on a calcium-restricted diet should ask a doctor before using when the product contains more than 3.2 grams (g) of calcium in the labeled maximum daily dose; the magnesium content per dosage unit when the product contains 8 mg or more per single dose; a warning statement that persons with kidney disease and persons on a magnesium-restricted diet should ask a doctor before using if the product contains more than 600 mg magnesium in the labeled maximum daily dose; the potassium content per dosage unit when the product contains 5 mg or more per single dose; and a warning statement that persons with kidney disease and persons on a potassium restricted diet should ask a doctor before using if the product contains more than 975 mg potassium in the labeled maximum daily dose. FDA is issuing this final rule in order to provide uniform calcium, magnesium, and potassium content and warning labeling for all OTC drug products intended for oral ingestion whether marketed under an OTC drug monograph, the ongoing OTC drug review, a new drug application (NDA) or abbreviated new drug application (ANDA), or no application.

Thyrotoxic Periodic Paralysis is an uncommon disorder seen primarily in Asian males and caused by excessive thyroid hormones. This is an endocrine emergency that can lead to respiratory failure, dysrhythmia, and death. The mainstay of therapy has been potassium replacement, however, recent evidence suggests propranolol is a more effective therapy. We present a severe case of TPP in a 22-year-old Latino male with rapidly progressive ascending paralysis and hypokalemia severe enough to lead to cardiac arrest.

Results of scientific studies are obtained by analysing of the present knowledge of a current problem and a corresponding new experimental set-up. Under ideal conditions the data of the new study agree with the deduced working hypothesis. This general consideration is true for the well established correlation between K content and growth rates of plants. At low K concentrations (up to 3% of dry matter) K causes a linear increase of growth and finally a saturation. This positive effect of K on growth rates of plants is accompanied by some side effects. There is no doubt that a high intake of K is involved in the pathogenesis of grass tetany and of milk fever. The present publication gives some information about this correlation and discusses the discrepancy between the intention of a scientific study and possible "side effects", which cannot be predicted in many cases.

Background: Cardiac arrhythmia is often present in patients with acute coronary syndrome (ACS) and may be due to the electrolyte imbalance., Aim: To assess the prevalence and clinical significance of electrolyte imbalance in ACS., Methods: Serum potassium and magnesium levels were measured within the first few hours in 204 consecutive patients with ACS admitted to our department over a period of 23 months. Cardiac arrhythmia was documented using continuous ECG monitoring, telemetry or standard ECG., Results: Hypokalemia was observed in 34% of patients, and was significantly associated with the occurrence of life-threatening ventricular arrhythmias (26% of patients with potassium level <4 mmol/l vs 11.9% of patients with normokalemia, p<0.001). No relationship was found between potassium level and supraventricular arrhythmias or in-hospital mortality. Decreased magnesium serum concentration was found in 22% of patients but was not significantly associated with cardiac arrhythmias or mortality., Conclusions: Hypokalemia and hypomagnesemia are often present in patients with ACS. The former is associated with dangerous ventricular arrhythmias. Early assessment of electrolyte serum concentration is needed in order to implement proper supplementation.

Background: Metabolic treatment with insulin or glucose-insulin-potassium (GIK) has received attention in association with myocardial infarction, cardiac surgery and critical care. As a result of insulin resistance during neuroendocrine stress, doses of insulin up to 1 IU kg-1 b.w.*h are required to achieve maximal metabolic effects after cardiac surgery. The clinical experience with regard to safety issues of such a high-dose GIK regime in critically ill patients after cardiac surgery is reported., Methods: Retrospective, observational study involving all patients treated with high-dose GIK after cardiac surgery during one year in a cardiovascular center at a University Hospital., Results: Eighty-nine patients out of 854 adult patients undergoing cardiac surgery were treated with high-dose GIK. Mean age was 69 +/- 1 years, Higgins score 5.3 +/- 0.3. Preoperatively 31.4% had left ventricular function EF< or =0.35 and 32.5% had sustained a myocardial infarct during surgery. Mortality was 5.6% and the average ICU stay was 3.7 +/- 0.5 days. The main indication for GIK was intraoperative heart failure (69.7%). The average glucose infusion rate during the first 6 h was 4.22 +/- 0.15 and 4.91 +/- 0.14 mg kg-1 b.w.*min, respectively, in diabetic and non-diabetic patients (P = 0.023). Blood glucose and s-potassium control was acceptable., Conclusions: The high-dose GIK regime allowed substantial amounts of glucose to be infused both in diabetic and critically ill patients with maintenance of acceptable blood glucose control. Provided careful monitoring, this regime can be safely used in clinical practice and deserves further evaluation for treatment of critically ill patients following cardiac surgery.

Background: hyperkalaemic paralysis is a rare, treatable, and potentially fatal entity presenting with flaccid motor weakness., Case Report: a patient with acute hyperkalaemic paralysis caused by erroneous oral potassium supplementation in the context of chronic renal failure. The clinical picture of quadriplegia was initially interpreted as spinal cord injury due to a pathological cervical fracture., Discussion: the diagnosis of hyperkalaemic paralysis requires a high index of suspicion. Instructions for over-the-counter supplements must be clear and concise to prevent life-threatening medication errors.

Objective: Transfusion of packed red blood cells containing high concentrations of potassium have been associated with fetal and neonatal arrhythmia and hyperkalemic cardiac arrest. This study sought to determine the biochemical and associated clinical effects of packed red blood cells transfusion in critically ill children., Design: Prospective case series., Setting: Tertiary multidisciplinary university hospital pediatric intensive care unit., Patients: Consecutive sample of 28 children 2.7-27 kg (1 wk to 12 yrs old) receiving a packed red blood cell transfusion., Interventions: None., Measurements and Main Results: Potassium concentration was prospectively measured from packed red blood cell transfusions. Adverse events were recorded during and for 4 hrs following transfusion including hyperkalemia, therapy for hyperkalemia, arrhythmia, cardiac arrest, and death. There were 54 packed red blood cell transfusions (mean volume of 11.8 +/- 2.8 mL/kg). The measured packed red blood cell potassium concentration was > 25 mmol/L in 16, 15-25 mmol/L in 11, and < 15 mmol/L in 25. The mean patient potassium concentrations before (3.85 +/- 0.55, range 2.7-5.2 mmol/L) and after transfusion (3.94 +/- 0.62, range 2.8-5.7 mmol/L) were not significantly different. There was no therapy required for hyperkalemia, no new arrhythmia, no cardiopulmonary arrest, and no deaths during and up to 4 hrs following transfusion. Of the six children given a bolus of packed red blood cells (> or = 5 mL/kg over < 10 mins), the maximum increase in patient potassium concentration was 0.8 mmol/L, in a child who had an initial potassium concentration of 2.7 mmol/L. No patient's potassium concentration was > 5 mmol/L following rapid transfusion., Conclusions: This prospective study found no significant change in patient potassium concentration and no acute adverse events related to transfusion in critically ill children, including those receiving packed red blood cells by bolus. Larger prospective studies are required to evaluate the acute effects of rapid and central venous transfusion in critically ill children.

People practising regular physical activity usually drink hydrosaline beverages. In this study is reported the case of a young football player suffering from premature ventricular beats. He used to take regularly an hydrosaline supplementation which gave him a daily intake of potassium of about 5 g. A stress test on a cycle ergometer showed many monomorphus premature ventricular beats which disappeared when the heart rate was higher than 110 beats/min. Moreover, 3629 polimorphus premature ventricular beats were recorded during a 24 hr ECG monitoring. At the time of the first examination, the plasma potassium concentration was 7,8 mEq x l(-1). The football player was then suspended from practicing sport and he was asked to stop his intake of potassium. The clinical examination was repeated after 3 and 6 months and no ventricular arrhythmias were observed during the stress test as well as during the 24 hours ECG monitoring. The plasma potassium concentration was normal again. The present case report is an example of how the misuse of saline supplementations could result in hyperkalemia and how this condition may lead to ventricular arrhythmias.

Objective: To review the role of glucose-insulin-potassium (GIK) solution in the management of acute myocardial infarction (AMI)., Data Sources: MEDLINE (1966-October 2001) database, using the search terms glucose, insulin, potassium, and myocardial infarction., Study Selection: Relevant English-language human studies and meta-analyses., Data Synthesis: Most studies that have investigated the use of GIK in AMI have been from the prethrombolytic era. Although most data trended toward favoring GIK in improving mortality and morbidity of AMI, the Polish GIK study was terminated prematurely because of an increase in mortality in patients treated with GIK. Dosage, duration of treatment, and route of administration of GIK varied among studies., Conclusions: Until results from larger-scale studies become available, the routine use of GIK infusion in AMI patients is not recommended.

Background: Hypokalemia is a well-known, consistent finding in thyrotoxic periodic paralysis (TPP). It is less well known that hypophosphatemia and mild hypomagnesemia are often present in TPP and that rebound hyperkalemia can occur as a result of potassium therapy., Objective: To report the prevalence of these electrolyte abnormalities in 24 episodes of TPP in 19 patients admitted to a single university-affiliated public hospital during a 15-year period., Methods: The medical records of all patients admitted to the Santa Clara Valley Medical Center in San Jose, Calif, between August 1, 1982, and June 1, 1997, with any type of hypokalemic periodic paralysis were reviewed. In patients with TPP, serum potassium, phosphorus, and magnesium levels were evaluated during and after episodes of paralysis. The administered dose of potassium chloride, recovery time from hypokalemia, and prevalence of rebound hyperkalemia after recovery were also ascertained. Data are presented as mean +/- SD., Results: Hypokalemia was present in all 24 initial episodes of TPP, with serum potassium levels ranging from 1.1 to 3.4 mmol/L (mean, 1.9+/-0.5 mmol/L). After recovery from hypokalemia, the maximum serum potassium level significantly increased, ranging from 4.0 to 6.6 mmol/L (mean, 4.9+/-0.5 mmol/L; P<.001). In 10 (42%) of 24 episodes, rebound hyperkalemia (serum potassium level >5.0 mmol/L) was present. Recovery time did not correlate with the potassium chloride dose administered (r = 0.17). Initial serum phosphorus levels ranged from 0.36 to 0.97 mmol/L (mean, 0.61+/-0.23 mmol/L) (1.1-3.0 mg/dL [mean, 1.9+/-0.7 mg/dL]), with hypophosphatemia present in 12 (80%) of 15 episodes. Serum phosphorus levels significantly increased (P<.01), to 1.26 to 1.74 mmol/L (mean, 1.48+/-0.16 mmol/L) (3.9-5.4 mg/dL [mean, 4.6+/-0.5 mg/dL]), with or without phosphorus replacement therapy. A slight increase in serum magnesium levels after paralysis resolved was observed in all patients (P<.07). No further episodes of paralysis occurred in any patients after they became euthyroid., Conclusions: Hypokalemia, hypophosphatemia, and mild hypomagnesemia are characteristic features of TPP. Hypokalemia occurred in 100% and hypophosphatemia in 80% of the episodes in our study. Rebound hyperkalemia is a potential hazard of potassium administration and occurred in 42% of 24 episodes.

Nonpharmacologic treatment currently is recognized as an important part in the treatment of hypertension, and the role of dietary potassium intake in blood pressure (BP) control is becoming quite evident. Clinical studies have examined the mechanism by which hypokalemia can increase BP and the benefit of a large potassium intake on BP control. Epidemiologic data suggest that potassium intake and BP are correlated inversely. In normotensive subjects, those who are salt sensitive or who have a family history of hypertension appear to benefit most from the hypotensive effects of potassium supplementation. The greatest hypotensive effect of potassium supplementation occurs in patients with severe hypertension. This effect is pronounced with prolonged potassium supplementation. The antihypertensive effect of increased potassium intake appears to be mediated by several factors, which include enhancing natriuresis, modulating baroreflex sensitivity, direct vasodilation, or lowering cardiovascular reactivity to norepinephrine or angiotensin II. Potassium repletion in patients with diuretic-induced hypokalemia improves BP control. An increase in potassium intake should be included in the nonpharmacologic management of patients with uncomplicated hypertension.