Síndrome de Gitelman / Gitelman syndrome

El síndrome de Gitelman forma parte de las denominadas tubulopatías perdedoras de sal. El bloqueo parcial de la reabsorción de sodio en el túbulo contorneado distal determina la aparición de hipokalemia e hipomagnesemia. Se realizó un estudio descriptivo de una serie de cinco casos de síndrome de Gitelman (4 mujeres, de 28 a 85 años de edad) atendidos en nuestra institución entre los años 2004 y 2015. La forma de diagnóstico más frecuente en nuestra serie fue por hallazgo de laboratorio. El único síntoma clínico manifestado en forma espontánea fue astenia. En cuanto a los valores de laboratorio, la potasemia fue 2.5 ± 0.5 mmol/l, con un valor mínimo de 2.1. Adicionalmente, el valor de magnesio en sangre fue 1.3 ± 0.3 mg/dl. Como conclusión, observamos que las formas de presentación consisten en alteraciones bioquímicas con o sin manifestaciones inespecíficas, lo que representa actualmente la mayor dificultad diagnóstica y refuerza la importancia de lograr un diagnóstico oportuno, en especial en pacientes jóvenes y con valores críticos de potasio sérico.

Gitelman syndrome is one of the salt losing tubulopathies. Hypokalemia and hypomagnesemia appear in the setting of the partial blockade of salt absorption in the distal tubule. We conducted a descriptive study of a case series of five patients with Gitelman syndrome (4 women, from 28 to 85 years) in our institution, between the years 2004 and 2015. The most frequent form of diagnosis in our series was by laboratory finding. The only acknowledged clinical symptom was malaise. Regarding laboratory findings, the mean potassemia was of 2.5 ± 0.5 mmol/l, with a minimum value of 2.1 mmol/l. Additionally, the serum magnesium value was of 1.3 ± 0.3 mg/dl. In conclusion, we observed that the forms of presentation consist of biochemical alterations with or without nonspecific manifestations, which currently represents the greatest diagnostic difficulty and reinforces the importance to achieve a timely diagnosis, especially in young patients with critical serum potassium values.

Persistent severe hypokalemia: Gitelman syndrome and differential diagnosis / Hipocalemia grave persistente: Síndrome de Gitelman e diagnósticos diferenciais

Abstract The main causes of hypokalemia are usually evident in the clinical history of patients, with previous episodes of vomiting, diarrhea or diuretic use. However, in some patients the cause of hypokalemia can become a challenge. In such cases, two major components of the investigation must be performed: assessment of urinary excretion potassium and the acid-base status. This article presents a case report of a patient with severe persistent hypokalemia, complementary laboratory tests indicated that's it was hypomagnesaemia and hypocalciuria associated with metabolic alkalosis, and increase of thyroid hormones. Thyrotoxic periodic paralysis was included in the differential diagnosis, but evolved into euthyroid state, persisting with severe hypokalemia, which led to be diagnosed as Gitelman syndrome.

Resumo As principais causas de hipocalemia normalmente são evidentes na história clínica dos pacientes em investigação etiológica, com episódios prévios de vômitos, diarréia ou uso de diuréticos. Entretanto, em alguns pacientes, a causa da hipocalemia pode se tornar um desafio. Em tais casos, dois principais componentes da investigação devem ser realizados: avaliação da excreção do potássio urinário e do "status" ácido-básico. Este artigo traz um relato de caso de uma paciente portadora de hipocalemia grave persistente, com investigação laboratorial complementar caracterizada por hipomagnesemia e hipocalciúria, associada à alcalose metabólica e elevação dos hormômios tireoideanos. A apresen- tação inicial do quadro incluiu paralisia periódica tireotóxica como um dos principais diagnósticos diferenciais, porém, a paciente evoluiu para um es- tado eutireoideo e persistiu com grave hipocalemia, sendo, por fim, realizado diagnóstico clínico de Síndrome de Gitelman.

A novel homozygous mutation in the solute carrier family 12 member 3 gene in a Chinese family with Gitelman syndrome

Loss of function of mutated solute carrier family 12 member 3 (SLC12A3) gene is the most frequent etiology for Gitelman syndrome (GS), which is mainly manifested by hypokalemia, hypomagnesemia and hypocalciuria. We report the genetic characteristics of one suspicious Chinese GS pedigree by gene sequencing. Complete sequencing analysis of the SLC12A3 gene revealed that both the proband and his elder sister had a novel homozygous SLC12A3 mutation: c.2099T>C and p.Leu700Pro. Moreover, the SLC12A3 genes of his mother and daughter encoded the same mutated heterozygote. It was noted that in this pedigree, only the proband complained about recurrent episodes of bilateral lower limb weakness over 8 years, while his elder sister, mother and daughter did not present symptoms. The inconsistent clinical features of this pedigree implied that besides diverse phenotypes possibly originated from the same genotype, gender difference may also dominate the variant GS phenotypes. Further genetic and proteomic research are needed to investigate the precise mechanisms of GS, including the study of specific ethnicities.

Síndrome de Gitelman: do diagnóstico ao acompanhamento na gestação / Gitelman's Syndrome: from diagnosis to follow-up during pregnancy

Resumo A síndrome de Gitelman (SG) é uma forma rara de nefropatia autossômica recessiva perdedora de sal, caracterizada classicamente por hipocalemia, hipomagnesemia, hipocalciúria, alcalose metabólica e pressão arterial baixa. Fadiga, fraqueza muscular e paralisia muscular estão entre seus sintomas mais comuns. Além dos distúrbios eletrolíticos típicos, outros achados laboratoriais incluem a hiperreninemia e o hiperaldosterismo secundário. Nefrocalcinose bilateral pode ocorrer. O tratamento consiste basicamente na reposição de potássio e uso de antagonistas da aldosterona. A melhor abordagem para gestantes portadoras de SG ainda está por ser definida. Entretanto, enfatiza-se a necessidade de suplementação dos íons, o controle do peso como ferramenta clínica de avaliação do balanço hídrico e a monitorização frequente do feto e dos níveis de líquido amniótico. O risco cirúrgico associado à cesariana em paciente com SG não está definido. Apesar dos riscos associados às crises sintomáticas de hipocalemia/hipomagnesemia, a SG apresenta bom prognóstico quando adequadamente tratada. A gravidez impõe a necessidade de controle mais intenso da doença, mas apresenta bom prognóstico para o binômio materno-fetal.

Abstract Gitelman's Syndrome (GS) is a rare autosomal recessive salt-wasting nephropathy, classically characterized by hypokalemia, hypomagnesemia, hypocalciuria, metabolic alkalosis and low blood pressure. Fatigue, muscle weakness and muscle paralysis are common symptoms. Besides the typical electrolyte disturbances, others laboratory findings include hyperreninemia and secondary hyperaldosteronism. Bilateral nephrocalcinosis may occur. The treatment consists of potassium replacement and use of aldosterone antagonists. The best approach to pregnant women with GS is yet to be defined. However, we emphasize the need for ions supplementation, weight control as a clinical tool for assessing the water balance, and frequent monitoring of the fetus and amniotic fluid levels. The surgical risk associated with cesarean section in a patient with GS is not yet defined. Despite the risks related to symptomatic episodes of hypokalemia/hypomagnesemia, GS has a good prognosis when treated properly. Pregnancy imposes the need for more intensive control of the disease, but has a good prognosis for the mother and neonate.

Rabdomiólisis por hipopotasemia severa: Report of six cases / Severe hypokalemic rhabdomyolysis

Rhabdomyolysis results from acute necrosis of skeletal muscle fibers and consequent leakage of muscle constituents into the circulation. It ranges from an asymptomatic state to a severe condition associated with extreme elevations in creatine kinase and acute renal failure. Reported etiologies of rhabdomyolysis include alcohol abuse, drugs, muscle trauma and muscle overexertion. Less common causes include muscle enzyme deficiencies, electrolyte abnormalities, infectious causes, toxins and endocrine disorders. Hypokalemia is a rare cause of rhabdomyolysis. We report six patients aged 31 to 57 years (three women) with a severe hypokalemic rhabdomyolysis, secondary to chronic diarrhea in two patients, treatment with loop diuretics in one and Gitelman syndrome in three. Rhabdomyolysis may be underdiagnosed in the context of hypokalemia, because the neuromuscular symptoms can be attributed solely to the electrolyte disorder.