The Clinical Biology of Sodium

Preface

Introduction


1. Body Sodium in Context: Distribution, Functions and Regulation

Introduction: Some Problems in Context

Distribution and Concentration of Sodium

Basic Principles

Simple Disturbances

Oedema

Bone Sodium

Sodium in Brain and Cerebrospinal Fluid

Functions of Sodium

Sodium Transport: Na-K ATPase

Isoforms

Factors Affecting Activity

Na+-H+ Exchange

Conclusion


2. Renal Sodium Regulation

Introduction

Segmental Distribution of Sodium Reabsorption

Effects of Hypovolaemia

Endocrine Aspects of Renal Sodium Regulation

Glomerular Filtration

Ultrafiltration

Proximal Reabsorption

Loop of Henlé

Ascending Thick Limb

Regulation of ADH Release

Distal Nephron

Immaturity of Renal Function

Conclusion


3. Enteric Sodium Uptake

Introduction

Enteric Sodium Transport

Enteric Sodium Regulation

Enteric Responses to Changes in Sodium Balance

Diarrhoea

Oral Rehydration

Principles and Criteria of Efficacy

Amino Acids

Bicarbonate Precursors

Sodium

Sequestration: Third Space'

Iatrogenic Disturbances

Conclusion


4. Behavioural Regulation of Sodium Intake

General Issues

An Assumed Need, or a Real One?

Experimental Approaches

Early Studies of Salt Appetite

Studies in Sodium-Depleted Sheep


1. Neural Aspects

Taste

Hepatic Chemoreceptors

Other Brain Mechanisms


2. Humoral Aspects

Adrenal Hormones and Angiotensin

Reproductive Hormones

Other Hormones


3. Salt Appetite and Hypertension


4. Biological Role of Salt Appetite

Na, K and the Sodium Transport Hypothesis of Salt Appetite

Conclusion


5. Physiological Basis of Nutritional Requirement for Sodium

Introduction

Subjectivity, Science and Sodium Intake

Sodium Requirement and Normality, an Elusive Relationship

Attitudes, Beliefs and Prejudice

Definition of Requirement; Factorial, Empirical—and Pitfalls

Unmeasured Losses

Comparative Aspects of Sodium Requirement

Rats

Cats

Dogs

Ruminants, Horses and Pigs

Conclusion


6. Comparative Aspects of Salt and Hypertension

Introduction

What Matters about Hypertension?

Nutrition and Blood Pressure; Influences other than Sodium

Lipids and Fibre

Magnesium and Potassium

Calcium

Sodium and Possible Mechanisms of Hypertension

The Natriuretic Hormone (ASTI) Hypothesis

Effects of Hypertension on Fluids and Electrolytes

Pregnancy Hypertension

Salt and Human Hypertension

Comparative Aspects of Hypertension

Conclusion: Salt and Hypertension—Whose Decision?


7. Endocrine Effects on Normal and Abnormal Sodium Excretion

Introduction

Adrenal Steroids

Aldosterone: Regulation and Effects

Renin-Angiotensin System (RAS)

ANP

MSH

Kallikrein-Kinin System

Pregnancy

Haemodynamic Changes

Water Balance

Hormonal Changes


8. Clinical Aspects of Extracellular Volume and Sodium Concentration

Introduction

Sodium Depletion, Dehydration and Plasma Sodium

Sodium Excess: Hypertension and Oedema

Other Aspects of Abnormal Sodium Balance

Hypertonic, Hypotonic and Isotonic Dehydration

Isotonic Dehydration

Hypertonic Dehydration

Hypotonic Dehydration


1. Volume Excess

Oedema

Nephrotic Oedema

Hepatic Oedema

Cardiac Oedema

Chronic Obstructive Pulmonary Disease


2. Sodium Concentration: Hypernatraemia and Hyponatraemia

Hypernatraemia

Hyponatraemia


3. Volume Depletion

Anaesthesia and Surgery

Hypovolaemia and Shock

Adrenal Insufficiency (Addison's disease)

Heat and Exertion


4. Renal Dysfunction

Chronic Renal Failure

Acute Renal Failure (ARF)


9. Interactions Between Sodium, Potassium, Calcium and Magnesium

Introduction

Cellular Interactions

Renal Interactions

Physiological and Clinical Implications

Conclusion


10. Clinical Disturbances of Sodium Transport

Introduction

Cystic Fibrosis

Disorders of Muscle Excitation

Down's Syndrome: Alzheimer's Disease

Papillary Necrosis

Polycystic Kidney Disease

Gastric Cancer

Renal Tubular Acidosis (and Fanconi Syndrome)

Haemolytic Anaemia

Bartter's Syndrome


11. Drugs Affecting Sodium Transport and Sodium Balance

Diuretics

Osmotic Diuretics

Thiazides

Potassium-Sparing Diuretics

Loop Diuretics

Other Side Effects

Other Diuretics

Cardiac Glycosides

NSAIs

Other Drugs


12. Concluding Synthesis

References

Abbreviations

Index