A physiology-based approach to a patient with hyperkalemic renal tubular acidosis / Abordagem diagnóstica de um paciente com acidose tubular renal hipercalêmica

ABSTRACT Hyperkalemic renal tubular acidosis is a non-anion gap metabolic acidosis that invariably indicates an abnormality in potassium, ammonium, and hydrogen ion secretion. In clinical practice, it is usually attributed to real or apparent hypoaldosteronism caused by diseases or drug toxicity. We describe a 54-year-old liver transplant patient that was admitted with flaccid muscle weakness associated with plasma potassium level of 9.25 mEq/L. Additional investigation revealed type 4 renal tubular acidosis and marked hypomagnesemia with high fractional excretion of magnesium. Relevant past medical history included a recent diagnosis of Paracoccidioidomycosis, a systemic fungal infection that is endemic in some parts of South America, and his outpatient medications contained trimethoprim-sulfamethoxazole, tacrolimus, and propranolol. In the present acid-base and electrolyte case study, we discuss a clinical approach for the diagnosis of hyperkalemic renal tubular acidosis and review the pathophysiology of this disorder.

RESUMO A acidose tubular renal hipercalêmica é uma acidose metabólica de ânion gap normal que invariavelmente indica anormalidade na secreção de íons potássio, amônio e hidrogênio. Na prática clínica, está geralmente atribuída a um estado de hipoaldosteronismo real ou aparente, causado por doenças ou toxicidade por drogas. Descrevemos um paciente de 54 anos, transplantado hepático, que foi admitido com fraqueza muscular associada à hipercalemia, potássio plasmático de 9,25 mEq/L. A investigação adicional revelou acidose tubular renal tipo 4 e importante hipomagnesemia com elevada fração de excreção de magnésio. A história patológica pregressa incluía um diagnóstico recente de Paracoccidioidomicose - uma infecção sistêmica fúngica endêmica que ocorre em algumas partes da América do Sul -, e as medicações de uso habitual continham sulfametoxazol-trimetoprim, tacrolimus e propranolol. No presente relato de caso, discutiremos uma abordagem clínico-laboratorial para o diagnóstico da acidose tubular renal hipercalêmica, assim como da hipomagnesemia, revisando a fisiopatologia desses transtornos.

Diabetes mellitus and hyperkalemic renal tubular acidosis: case reports and literature review / Diabetes mellitus e acidose tubular renal hipercalêmica: relatos de caso e revisão da literatura

ABSTRACT Hyporeninemic hypoaldosteronism, despite being common, remains an underdiagnosed entity that is more prevalent in patients with diabetes mellitus. It presents with asymptomatic hyperkalemia along with hyperchloraemic metabolic acidosis without significant renal function impairment. The underlying pathophysiological mechanism is not fully understood, but it is postulated that either aldosterone deficiency (hyporeninemic hypoaldosteronism) and/or target organ aldosterone resistance (pseudohypoaldosteronism) may be responsible. Diagnosis is based on laboratory parameters. Treatment strategy varies according to the underlying pathophysiological mechanism and etiology and aims to normalize serum potassium. Two clínical cases are reported and the relevant literature is revisited.

RESUMO Apesar de comum, o hipoaldosteronismo hiporeninêmico continua a ser uma entidade sub-diagnosticada, com maior prevalência em pacientes com diabetes mellitus. A doença cursa com hipercalemia assintomática acompanhada de acidose metabólica hiperclorêmica sem disfunção renal significativa. O mecanismo fisiopatológico subjacente não é entendido em sua totalidade, mas postula-se que a deficiência de aldosterona (hipoaldosteronismo hiporeninêmico) e/ou a resistência à aldosterona no órgão-alvo (pseudo-hipoaldosteronismo) possam ser responsáveis. O diagnóstico é fundamentado em parâmetros laboratoriais. A estratégia terapêutica varia de acordo com o mecanismo fisiopatológico subjacente e a etiologia, mas seu objetivo é normalizar o potássio sérico. O presente artigo relata dois casos e analisa a literatura relevante sobre o assunto.

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

Changes in the clinical manifestations of primary aldosteronism

BACKGROUND/AIMS: Primary aldosteronism (PA) is now widely recognized to have a higher prevalence than was once thought. In view of its increasing prevalence, we compared chronological changes in clinical manifestations of PA according to different times of diagnosis. METHODS: In total, 85 patients diagnosed with PA from January 1986 through March 2012 were reviewed retrospectively, based on their medical records. During two periods-1986 to 2005 and 2006 to 2012-41 and 44 patients, respectively, were diagnosed with PA. We compared the clinical and biological characteristics of PA between these periods. RESULTS: The results demonstrate an increasing trend in the prevalence of idiopathic hyperaldosteronism (IHA; p = 0.19). In the 2006 to 2012 period, patients with PA presented with higher serum potassium levels at the time of diagnosis than in the 1986 to 2005 period (p < 0.0002). Adrenal vein sampling (AVS) was performed mostly in the latter period (82.3%) and the diagnostic accuracy of adrenal computed tomography, compared with AVS, was only 56.2%. About 78.0% versus 86.3% of patients had at least one target organ damage (TOD) in the 1986 to 2005 and 2006 to 2012 periods, respectively (p = 0.39). However, patients with TOD were older and had longer durations of hypertension than patients without, in both periods. CONCLUSIONS: PA is becoming more prevalent. There was an increasing tendency for IHA, and more PA patients presented with normokalemia than in the earlier period. Early and accurate diagnosis of PA with AVS and proper treatment should have substantial prognostic value.

Evaluating the Utility of Rapid Point-of-Care Potassium Testing for the Early Identification of Hyperkalemia in Patients with Chronic Kidney Disease in the Emergency Department

PURPOSE: Severe hyperkalemia leads to significant morbidity and mortality if it is not immediately recognized and treated. The concentration of potassium (K+) in the serum increases along with deteriorating renal function. The use of point-of-care K+ (POC-K+) in chronic kidney disease (CKD) could reduce the time for an accurate diagnosis and treatment, saving lives. We hypothesized that POC-K+ would accurately report K+ serum level without significant differences compared to reference testing, regardless of the renal function of the patient. MATERIALS AND METHODS: The retrospective study was performed between January 2008 and September 2011 at an urban hospital in Seoul. The screening program using POC was conducted as a critical pathway for rapid evaluation and treatment of hyperkalemia since 2008. When a patient with CKD had at least one warning symptom or sign of hyperkalemia, both POC-K+ and routine laboratory tests were simultaneously ordered. The reliability of the two assays for serum-creatinine was assessed by intra-class correlation coefficient (ICC) analysis using absolute agreement of two-way mixed model. RESULTS: High levels of reliability were found between POC and the laboratory reference tests for K+ (ICC=0.913, 95% CI 0.903-0.922) and between two tests for K+ according to changes in the serum-creatinine levels in CKD patients. CONCLUSION: The results of POC-K+ correlate well with values obtained from reference laboratory tests and coincide with changes in serum-creatinine of patients with CKD.

Hyperkaliemie chez les patients en hemodialyse chronique a Yaounde : prevalence; manifestations cliniques et electrocardiographiques

Introduction : L'hyperkaliemie est frequente chez les patients hemodialyses. Elle expose ces derniers au risque de mort subite. Son dosage ne fait pas partie des examens de routine en hemodialyse au Cameroun. Le but de notre etude etait de determiner sa prevalence et ses manifestations cliniques et electrocardiographiques chez les patients hemodialyses chroniques a l'Hopital General de Yaounde. Patients et methodes : Nous avons mene une etude transversale de novembre 2012 a fevrier 2013. Tous les patients hemodialyses depuis plus de 03 mois ayant accepte de participer a l'etude ont ete inclus. Chez chacun d'entre eux nous avons realise avant le debut de leurs premiere et deuxieme seances hebdomadaires de dialyse; un examen clinique; un dosage sanguin de potassium; de sodium et de calcium ionise et un electrocardiogramme. Resultats :Un total de 88 patients a ete retenu. La prevalence de l'hyperkaliemie etait de 38;7avant le debut de la premiere seance de dialyse et e 17 avant la seconde seance. Une paresie a ete retrouvee dans 03 cas et dans tous ces cas le taux de kaliemie etait au moins de 7;5 mEq/l. Deux cas ont presente un signe electrocardiographique pouvant se rapporter a l'hyperkaliemie; il s'agissait d'une onde T ample. Conclusion : L'hyperkaliemie est bien frequente chez nos patients hemodialyses chroniques; mais ses manifestations cliniques et electrocardiographiques ne sont pas courantes

Non-Oliguric Hyperkalemia in Extremely Low Birth Weight Infants

PURPOSE: It is to examine clinical manifestations, early biochemical indicators, and risk factors for non-oliguric hyperkalemia (NOHK) in extremely low birth weight infants (ELBWI). MATERIALS AND METHODS: We collected clinical and biochemical data from 75 ELBWI admitted to Ajou University Hospital between Jan. 2008 and Jun. 2011 by reviewing medical records retrospectively. NOHK was defined as serum potassium > or =7 mmol/L during the first 72 hours of life with urine output > or =1 mL/kg/h. RESULTS: NOHK developed in 26.7% (20/75) of ELBWI. Among NOHK developed in ELBWI, 85% (17/20) developed within postnatal (PN) 48 hours, 5% (1/20) experienced cardiac arrhythmia and 20% (4/20) of NOHK infants expired within PN 72 hours. There were statistically significant differences in gestational age, use of antenatal steroid, and serum phosphorous level at PN 24 hours, and serum sodium, calcium, and urea levels at PN 72 hours between NOHK and non-NOHK groups (p-value <0.050). However, there were no statistical differences in the rate of intraventricular hemorrhage, arrhythmia, mortality occurred, methods of fluid therapy, supplementation of amino acid and calcium, frequencies of umbilical artery catheterization and urine output between the two groups. CONCLUSION: NOHK is not a rare complication in ELBWI. It occurs more frequently in ELBWI with younger gestational age and who didn't use antenatal steroid. Furthermore, electrolyte imbalance such as hypernatremia, hypocalcemia and hyperphosphatemia occurred more often in NOHK group within PN 72 hours. Therefore, more use of antenatal steroid and careful control by monitoring electrolyte imbalance should be considered in order to prevent NOHK in ELBWI.

Disorders of potassium homeostasis: pathophysiology and management.

Disorders of potassium homeostasis are common electrolyte abnormalities encountered in hospitalized patients. Hypokalemia and hyperkalemia have been estimated to occur in about 21% and 3% of hospitalized patients, respectively; though the morbidity and mortality associated with the latter is significantly higher. Potassium is a predominantly intracellular ion and the understanding of its dynamics between intra- and extracellular fluid milieus, along with its handling by the kidneys, is important in the diagnosis and treatment of potassium disorders. This article aims to provide a clinically relevant update on management of potassium disorders for internists.

Evaluating mortality rate caused by electrolyte abnormalities in hospitalized patients

Adjustment of composition of body fluids and electrolytes is one of the most important aspects of patients care. Sodium and Potassium are the most important body cations, the improper adjustment of them will cause sever disorders in neuromuscular, gastrointestinal, respiratory and cardiovascular systems. Acute renal failure indicated by increase in creatinine and nitrogen urea, brings an accumulation of fluids, salts and metabolites of nitrogen in body. This study intends to assess the status of electrolyte abnormalities and mortality rates of the patients hospitalized in ICU wards in our country. This is a descriptive and retrospective study on the records of 378 patients hospitalized in ICU. A questionnaire was prepared and the data were entered in SPSS system. They were statistically analyzed by using chi-square and fisher's Exact test methods. Out of 378 patients hospitalized in ICU, over 2/3 of them were male and over half of them were>45 years old. Frequency distribution of electrolyte abnormalities was as follows: Hyponatremia 59% hypernatremia 23% hypokalemia 37% hyperkalemia 28%, 35% and 21% of patients had respectively BUN and creatinine more than the normal range. 26% of patients hospitalized in ICU had nonsurgical problems and 74% of the patients had surgical problems. Average time of hospitalization in ICU was 85 days and mortality rate was 35%. The most common electrolyte abnormality was related to variation in serum sodium levels in the form of hyponatremia. And the highest prevalence electrolyte abnormality in dead patients was hyponatremia. This study proves that the prevalence of electrolyte abnormalities is directly related to mortality and increase in hospitalization period and those having undergone surgical operations during hospitalization in ICU, manifested more abnormalities

Profound hyperkalemia and the electrocardiogram. Lack of correlation: a case report

We report a case of severe hyperkalemia as a result of treatment with potassium sparing diuretics, digoxin and angiotensin receptor antagonist valsartan in the presence of renal insufficiency. Inspite of a maximal serum potassium concentration of 10.3 mmol/l, only non-specific ECG changes were found. The patient survived after an uneventful dialysis. Thus severe hyperkalemia may present without typical ECG changes, and values exceeding 10.3 mmol/l may not necessarily be fatal

Osteopetrosis associated with hyperkalaemia: a case report

Osteopetrosis is a rare disease of childhood. We report a 4-month-old infant with clinical and radiological features of osteopetrosis who had dehydration and hyperkalaemia on admission and, during investigations, was found to have pseudohypoaldosteronism