Renal Tubular Acidosis in Children : New Insights in Diagnosis and Treatment

This book is a compilation of scientific knowledge regarding the clinical entity known as “Renal Tubular Acidosis in Children” (RTA). It contains the information needed to comprehend the intricate mechanisms of acid-base metabolism, electrolyte imbalance, and complications related to renal tubular acidosis in the pediatric age group, since the acid-base physiology and the clinical disorders associated with it in children are quite different from the adult counterpart. The chapters, written by authors, experts in the field, describe systemic and renal physiology, electrolyte alterations, as well as the pathogenesis and chromosomal mutations leading to the development of RTA. The reader will find the latest information on diagnostic tools and learn how to approach diagnosis, avoiding improper treatment, rickets, nephrocalcinosis, and renal failure. In addition, new insights on classification, the clinical presentation of each type of RTA, molecular biology, and transmembrane protein transporters are covered. This work is primarily directed at pediatric nephrologists and pediatricians. Nevertheless, general practitioners, medical students, residents and fellows at different medical training programs, and other health care professionals of nutrition, growth and development, gastroenterology and endocrinology may surely benefit from it. Foreword Preface Contents Contributors Abbreviations Chapter 1: Systemic Regulation of Acid-Base Metabolism Introduction: Evolutionary Aspects of Acid-Base Metabolism Physical and Chemical Principles of Acid-Base Metabolism Buffer Mechanisms, pH, and pK Concepts CO2 Production and Excretion Acid Production and Hydrogen Balance Acid-Base Balance Hemoglobin and Erythrocyte Physiology Clinical Aspects of Alterations in Acid-Base Metabolism Metabolic Acidosis Metabolic Alkalosis Respiratory Acidosis Respiratory Alkalosis Mixed Acid-Base Alterations References Chapter 2: Renal Regulation of Acid-Base Metabolism Introduction Hydrogen Excretion and Bicarbonate Reabsorption in the Proximal Tubule Ammonia Synthesis and Excretion in the Proximal Tubule Hydrogen Excretion and Bicarbonate Reabsorption in the Loop of Henle Metabolism of Ammonia in the Loop of Henle Hydrogen and Ammonium Excretion in the Distal and Connector Tubules Hydrogen Excretion in the Collecting Tubule Excretion of Ammonia in the Collecting Tubule The Physiological Impact of Urinary Buffers in the Excretion of Hydrogen References Chapter 3: Physiology of Renal Potassium Handling Introduction Potassium Balance Renal Handling of Potassium Factors that Regulate the Secretion of Potassium Relationship Between Renal Potassium Metabolism and Acid-Base Balance References Chapter 4: Genetic Origin of Renal Tubular Acidosis Introduction Autosomal Recessive Proximal RTA Autosomal Dominant Proximal RTA Fanconi Syndrome with Proximal RTA Distal RTA Autosomal Dominant Distal RTA Autosomal Recessive Distal RTA Is Heterogeneous Autosomal Recessive Distal RTA Has Been Documented in Several Racial Groups FOXI1 Transcription Factor Autosomal Dominant Distal RTA Autosomal Recessive Distal RTA Due to SLC4A1 WDR72 Mixed Renal Tubular Acidosis (Type III) Hyperkalemic RTA (Type IV) References Chapter 5: History of Renal Tubular Acidosis Distal Renal Tubular Acidosis Transient Tubular Acidosis Proximal Tubular Acidosis (PRTA) The Other Forms of Renal Tubular Acidosis References Chapter 6: Classification of Renal Tubular Acidosis Proximal Renal Tubular Acidosis (Type 2) Distal Renal Tubular Acidosis (Type 1) Type 3 Renal Tubular Acidosis Type 4 Renal Tubular Acidosis References Chapter 7: Laboratory Diagnosis of Renal Tubular Acidosis. Acidification Tests Simple Determinations Blood Urine Tests in Which H+ Secretion Is Stimulated by an Acid Overload Acidification Test with Ammonium Chloride (ClNH4) Tests Performed with Another Source of Hydrogen Production Tests in Which the Secretion of Hydrogen Ions Is Stimulated by an Increase in Tubular Electronegativity Acidification Test with Furosemide (Stimulus to Acidify in Acidic Urine) Determination of Maximum Urinary pCO2 (Stimulus to Acidify in Alkaline Urine) Other Tests to Assess Urine Acidification by Increasing Tubular Electronegativity Study of Proximal Tubular Reabsorption of Bicarbonate (HCO3−) Determination of the Renal Threshold of Bicarbonate Reabsorption Bicarbonate Fractional Excretion (FEHCO3−) References Chapter 8: Proximal Renal Tubular Acidosis (Type II) Introduction Etiology and Pathophysiology Clinical Aspects References Chapter 9: Distal Renal Tubular Acidosis (Type I DRTA) Introduction Pathophysiology of Hereditary DRTA Chromosomal and Physiological Alterations of the AE1 Antiporter Chromosomal and Physiological Alterations of the H+ATPase Transporter Protein Chromosomal and Physiological Alterations of the Carbonic Metalloenzyme Anhydrase II (AC II) Pathophysiology of the Most Frequent Complications of RTA Type I Diagnosis and Treatment of DRTA in Pediatric Patients References Chapter 10: Hyperkalemic Renal Tubular Acidosis (RTA Type IV) Introduction Physiological Mechanisms and Renal Pathophysiology in RTA with Hyperkalemia Clinical Alterations Related to the Production and Renal Tubular Activity of Aldosterone Differential Diagnosis of Hypoaldosteronism and Pseudo-Hypoaldosteronism Management and Treatment of ATR IV Prognosis References Chapter 11: Renal Tubular Acidosis Due to Miscellaneous Etiology Introduction RTA Secondary to Nephrotoxic Drugs Acting in the Distal Tubule (DRTA) RTA Secondary to Nephrotoxic Drugs Acting in the Proximal Tubule (PRTA) RTA Secondary to Nephrotoxic Drugs Acting in the “Distal Aldosterone-sensitive Nephron” (ASDN) RTA Type IV in the Full-term Baby and the Premature Newborn RTA Secondary to Severe Caloric-Protein Malnutrition References Correction to: Physiology of Renal Potassium Handling Correction to: Chapter 3 in: R. Muñoz (eds.), Renal Tubular Acidosis in Children, https://doi.org/10.1007/978-3-030-91940-5_3 Index