Hyperkalemia in chronic kidney disease

SUMMARY 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.

RESUMO A hiperpotassemia é um achado frequente em pacientes com doença renal crônica (DRC). Esta elevação do nível sérico de potássio está associada à diminuição da excreção renal do íon, assim como ao uso de medicações para retardar a progressão da DRC ou para controlar doenças associadas, como diabetes mellitus e insuficiência cardíaca. A hiperpotassemia aumenta o risco de episódios de arritmia cardíaca e morte súbita. Assim, o controle da elevação de potássio é essencial para a diminuição da taxa de mortalidade nessa população. O manejo da hiperpotassemia inclui, inicialmente, orientação de dietas com baixo teor de potássio e acompanhamento da aderência dos pacientes a esse procedimento. Também é importante conhecer as medicações em uso e a presença de comorbidades, a fim de orientar a redução de doses ou até mesmo a suspensão temporária de alguma das drogas relacionadas à retenção de potássio. E, finalmente, o uso de quelantes de potássio é indicado tanto em episódios agudos como nos casos de hiperpotassemia crônica.

Pseudohipoaldosteronismo y aparente exceso de mineralocorticoides: cara y ceca en dos pacientes pediátricos / Pseudohypoaldosteronism and apparent mineralocorticoid excess: two faces, two pediatric patients

Los síndromes endocrinológicos con hipofunción o hiperfunción con niveles paradójicos de dosajes hormonales han sido bien caracterizados en los últimos años del siglo XX, a partir del desarrollo de técnicas genéticas y moleculares. Presentamos dos pacientes con pseudohipoaldosteronismo y aparente exceso de mineralocorticoides como síndromes en espejo, con la intención de alertar al médico clínico respecto de su consideración como entidad diagnóstica en niños con alteraciones hidroelectrolíticas. (AU)

Endocrinological syndromes with underactive or overactive hormonal levels with paradoxical dosages have been well characterized over the years of the twentieth century, from the development of genetic and molecular techniques. We present two patients with pseudohypoaldosteronism and apparent mineralocorticoid excess as mirror syndromes, with the aim to alert the clinician regarding their consideration as a diagnostic entity in children with fluid and electrolyte disturbances. (AU)

Pseudohiperkalemia por trombocitosis esencial: una entidad pobremente reconocida / Pseudohyperkalaemia in essential thrombocytosis: a poorly recognized

INTRODUCCIÓN: La hiperkalemia representa una emergencia médica frecuentemente manejada en servicios de urgencia. Identificar una pseudohiperkalemia en pacientes que presentan recuentos plaquetarios elevados permite evitar terapias innecesarias e iatrogenia que pueden tener consecuencias potencialmente fatales. PRESENTACIÓN DEL CASO: Mujer de 73 años, con enfermedad renal crónica (ERC) etapa-3a (etiología no precisada). En consulta neurológica por crisis isquémica transitoria (abril 2011), se demostró hiperkalemia de 6,0 mEq/L (suero), tasa de filtración glomerular(TFG) de 51 mL/min y trombocitosis de 1.113.000 plaquetas/mm3. Se trata la hiperkalemia con furosemida y dieta pobre en potasio. Inició hidroxiurea indicada por hematología. En control nefrológico (diciembre 2012) presenta hiperkalemia de 7,5 mEq/L (suero), TFG de 37 ml/min y trombocitosis de 1.052.000 plaquetas/mm3. Electrocardiograma (ECG), sin signos de cardiotoxicidad acordes al nivel de kalemia. Se sospechó pseudohiperkalemia secundaria a trombocitosis esencial (PSTE), se suspendió atenolol, furosemida y se continuó hidroxiurea. En febrero de 2013 presentó kalemia de 6,1 mEq/L (suero), trombocitosis de 713.000 plaquetas/mm3 y TFG de 31 mL/min. En mayo de 2014 la kalemia en suero fue de 5,5 mEq/L y en plasma de 5,2 mEq/L; trombocitosis de 503.000plaquetas/mm3 y TFG de 23 ml/min, confirmándose la PSTE. DISCUSIÓN: Hiperkalemia asociada a trombocitosis exige descartar PSTE. La regresión de la kalemia junto con la trombocitosis y ECG sin alteraciones en hiperkalemia, apoyan este diagnóstico. Su confirmación exige demostrar una hiperpotasemia mayor en suero que en plasma (0,36 +/-0,18 meq/L). Tratar una pseudohiperkalemia, puede generar iatrogenia (hipokalemia y/o hemoconcentración que aumenta riesgo de trombosis). Se descarta hiperkalemia secundaria a ERC con TFG>15ml/min

INTRODUCTION: Hyperkalemia is a medical emergency often managed in emergency services. Identifying a pseudohiperkalemia in patients with high platelet counts will avoid unnecessary iatrogenic therapies, which can have potentially fatal consequences. CASE REPORT: 73 year old woman, with chronic kidney disease (CKD) stage-3a (unknown etiology). In neurological consultation by transient ischemic attack (april 2011) it was evidenced a hyperkalemia of 6.0 mEq/L (serum), glomerular filtration rate (GFR) of 51 mL/min and thrombocytosis of 1,113,000 platelets/mm3. Hyperkalemia is treated with furosemide and potassium poor diet. Started on hydroxyurea indicated by hematology. Nephrology consultant (december 2012) realized hyperkalemia of 7.5 mEq/L (serum), GFR of 37mL/min and thrombocytosis of 1,052,000 platelets/mm3. EKG with no sign of cardiotoxicity was found in relation to potassium serum level. A pseudohyperkalemia secondary to essential thrombocytosis (PSET) was suspected. Atenolol and furosemide were discontinued and hidroxiurea was continued. In February 2013 potassium serum level was 6.1 mEq/L, platelet count: 713,000/ mm3 and GFR: 31 mL/min. In may 2014 serum potassium was 5.5 mEq/L and plasma potassium was 5.2 mEq/L; platelet count: 503,000//mm3 and GFR: 23 mL/min, confirming PSET. DISCUSSION: Hiperkalemia associated with thrombocytosis requires to rule out PSET. Regression of serum potassium with platelet count and the abscense of EKG changes with simultaneous hyperkalemia, support this diagnosis. Confirmation of PSTE diagnosis needs to demonstrate a potassium serum level greater than in plasma (0.36 +/- 0.18 mEq/L). Treating a pseudohiperkalemia can generate iatrogenia (hypokalemia and/or hemoconcentration, increasing the risk of thrombosis). A hyperkalemia secondary to CKD is ruled out with GFR >15mL/min

Hiperpotassemia na vigência de espironolactona em pacientes com insuficiência cardíaca descompensada / Hyperkalemia during spironolactone use in patients with decompensated heart failure

FUNDAMENTO: A incidência de hiperpotassemia relacionada à espironolactona é baixa na insuficiência cardíaca estável, entretanto não foi estudada durante a descompensação. OBJETIVO: Avaliar a influência da espironolactona na insuficiência cardíaca descompensada sobre o potássio sérico. MÉTODOS: Em um estudo de coorte, selecionamos pacientes hospitalizados por descompensação da insuficiência cardíaca, FEVE < 0,45 e potássio sérico entre 3,5 e 5,5 mEq/l. Os pacientes foram divididos segundo o uso da espironolactona (grupo E) ou não (grupo C). O desfecho foi aumento do potássio (> 6,0 mEq/l) e uso de poliestireno de cálcio. Realizou-se a análise multivariada pela regressão logística, e p < 0,05 foi considerado significante. RESULTADOS: Foram estudados 186 pacientes (grupo E: 56; grupo C: 130), FEVE 0,25, idade 55,5 anos e 65,2 por cento de homens. A incidência de hiperpotassemia foi de 10,7 por cento no grupo E e de 5,4 por cento no grupo C (p = 0,862). A análise multivariada mostrou que a uréia sérica > 60,5 mg/dl, durante a internação, apresenta risco relativo de 9,6 (IC 95 por cento 8,03 - 11,20; p = 0,005) para a ocorrência de hiperpotassemia. CONCLUSÃO: A incidência de hiperpotassemia foi duas vezes maior com espironolactona, mas não estatisticamente significante. Elevação da uréia foi associada à hiperpotassemia. Estudos randomizados são necessários para esclarecer o assunto.

BACKGROUND: The incidence of hyperkalemia related to spironolactone use is low in stable heart failure; however, it has not been studied during decompensation. OBJECTIVE: To evaluate the influence of spironolactone on serum potassium in decompensated heart failure (HF). METHODS: In a cohort study, patients that had been hospitalized due to decompensated HF, with left ventricular ejection fraction (LVEF) < 0.45 and serum potassium between 3.5 and 5.5 mEq/l were selected. The patients were divided according to spironolactone use (Group S) or no use (Group C). The outcome was potassium increase (> 6.0 mEq/l) and the use of calcium polystyrene. A multivariate analysis through logistic regression was carried out and values of p < 0.05 were considered significant. RESULTS: A total of 186 patients (group S: 56; group C: 130) were studied; LVEF of 0.25, aged 55.5 years and 65.2 percent of them males. The incidence of hyperkalemia was 10.7 percent in group S and 5.4 percent in group C (p = 0.862). The multivariate analysis showed that serum urea > 60.5 mg/dl during the hospitalization presents a relative risk of 9.6 (95 percentCI 8.03 - 11.20; p = 0.005) for the occurrence of hyperkalemia. CONCLUSION: The incidence of hyperkalemia was two-fold higher with spironolactone use, but it was not statistically significant. The increase in urea levels was associated to the hyperkalemia. Randomized studies are necessary to clarify this issue.

The clinical implication of sodium-potassium ratios in dogs

Although there have been substantial evidences on the usefulness of electrolytes for the diagnosis of disease, the evidences for a direct link between serum sodium and serum potassium in relation to a specific disease are very limited. This study was performed to investigate an association between diseases and Na:K ratios in dogs. From January 1997 to December 1999, a total of 39 cases with an Na:K ratio less than 27 were retrieved from the medical records of Veterinary Medical Teaching Hospital, Seoul National University. Ten dogs (25.6%) had a renal or urinary disease, and six (15.4%) had a parasitism. Other miscellaneous diseases included deep pyoderma, grade III patellar luxation, bacterial pneumonia, diabetes, pancreatitis, and pyometra. The Na:K ratio was significantly lower in dogs with renal failures than those with parasitic diseases (p=0.0735). With the criterion of the Na:K ratio < 27, twenty seven dogs (69.2%) had hyperkalemia, whereas thirteen dogs (33.3%) had hyponatremia. Of 13 dogs with Na:K ratios between 20 and 24, six were diagnosed as a renal or urinary tract disease, two as diabetes, and two as a parasitism. The Na:K ratios of 9 dogs were < 20, being with the most prevalent with the disease of renal failures (55.6%). The serum Na:K ratios were more closely related to serum potassium concentrations (gamma= -0.8710) than serum sodium concentrations (gamma=0.4703). Two dogs with diabetes had an electrolyte pattern of hyperkalemia with normonatremia. Further studies are needed to determine the usefulness of Na:K ratio for diagnosis of hypoadrenocorticism, and to establish a relationship between patellar luxation and electrolyte unbalance.