1.
[Magnesium homeostasis. Etiopathogeny, clinical diagnosis and treatment of hypomagnesaemia. A case study].
González, EP, Santos, F, Coto, E
Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia. 2009;(6):518-24
Abstract
Magnesium is the fourth-most abundant cation in the human body and the second-most abundant intracellular cation after potassium. Magnesium is pivotal in the transfer, storage, and utilization of energy as it regulates and catalyzes more than 300 enzyme systems. Hypomagnesemia may thus result in a variety of metabolic abnormalities and clinical consequences. It results from an imbalance between gastrointestinal absorption and renal excretion of magnesium. The main consequence related directly to hypomagnesemia is cardiovascular arrhythmias secondary to hipokaliemia and if this is not recognized and treated it may be fatal. In this article we review the hypomagnesemic disorders in children with emphasis on the molecular mechanisms responsible for abnormalities in magnesium homeostasis, differential diagnosis and appropriate therapy, and we describe the clinical and biochemical manifestations as well as the genetic defect in a family with Gitelman syndrome.
2.
[Tubolopaties associated to hypokalemia].
Capasso, G
Giornale italiano di nefrologia : organo ufficiale della Societa italiana di nefrologia. 2004;(1):73-83
Abstract
We have described two clinical cases of two young men affected by hypkalemia associated with metabolic alkalosis. The first patient also presented hypercalciucia, normal magnesemia, defect in renal concentrating ability and increased renin activity; in addition he was affected by congenital sensorineural deafness. The diagnosis of Bartter's syndrome was made and it was confirmed by the gene analysis, which revealed a mutation for the beta-subunit of the ClC chloride channels known as barttin. The second case was characterized by hypocalciuria and hypomagnesemia, polyuria and nicturia. The genetic analysis revealed a mutation for the gene encoding the Na+-Cl(-) cotransporter and the diagnosis of Gitelman's syndrome was formulated. We present experimental and clinical evidence to explain, at the molecular level, the differences in calcium and magnesium homeostatis in the two cases. Moreover, we propose different causes to justify the pathogenesis of hypokalemia and the related metabolic alkalosis.