The Clinical Biology of Sodium
The Physiology and Pathophysiology of Sodium in Mammals
- A.R. Michell, The Royal Veterinary College, University of London, North Mymms AL9 7TA, UK
A book for clinicians and basic scientists
The pathophysiology of sodium is central to the management of a wide range of clinical conditions, notably liver disease, renal disease, cardiac failure, hypertension (including hypertension in pregnancy), oedema, diarrhoea, hypovolaemia, shock, the behavioural effects of hyper- or hyponatraemia and various endocrine disorders. Intensive care and fluid therapy depend crucially on sound management of sodium balance. No single clinical discovery has saved more lives at less cost than the fact that the fundamental impact of diarrhoea rests on disturbances of enteric sodium balance: the ability to restore net uptake by oral rehydration has converted cholera from a killer to a home-nursing disease. Yet if we look at animals, as well as humans, we realise that the gut is not just a source of sodium disturbances but, perhaps, a major regulator of sodium balance. We also realise that unless humans have some defect in their renal function, their routine exposure to salt is not only exorbitant but beyond their control and, arguably, pathological. The classic model animal for hypertension is the dog yet evidence suggests that the real interest in dogs lies less in their ability to model hypertension than their inherent resistance to it. This book emphasises the limitations and pitfalls, as well as the benefits of across-species extrapolation. In addition, a growing range of diseases, hitherto seeming to be unrelated, are linked by the underlying involvement of abnormalities of sodium handling: these include such disparate conditions as osteoporosis, cystic fibrosis, urolithiasis and gastric cancer. The book also discusses drugs intended to alter sodium balance, drugs whose mode of action depends on sodium transport and the interactions with electrolyte physiology which underlie the effects of these and many other drugs. It should enable clinicians better to understand the rationale behind their clinical routines and, perhaps more importantly7, provide the flexibility to recognise the need for change.
For clinicians and veterinarians involved in renal, enteric or cardiovascular medicine.
- Published: September 1995
- Imprint: PERGAMON
- ISBN: 978-0-08-040842-2
Every now and again there appears a monograph on the physiological and clinical aspect of sodium. This is the best that I have come across.
Professor H.E. de Wardener, Journal of the Royal College of Physicians
Table of Contents
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 CSF. Functions of Sodium. Sodium Transport: Na–K ATPase. Isoforms. Factors affecting activity. Na–H exchange? Renal Sodium Regulation. Introduction. Segmental Distribution of Sodium Reabsorption. Effects of hypovolaemia. Endocrine Aspects of Renal Sodium Regulation. Glomerular Filtration. Ultra-filtration. Proximal Reabsorption. Loop of Henlé. Ascending thick limb. Regulation of ADH release. Distal Nephron. Immaturity of Renal Function. Conclusion. 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. 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. Neural Aspects. Taste. Hepatic chemoreceptors. Other brain mechanisms. Humoral Aspects. Adrenal hormones and angiotensin. Reproductive hormones. Other hormones. Salt Appetite and Hypertension. Biological Role of Salt Appetite. Na, K and the Sodium Transport Hypothesis of Salt Appetite. Conclusion. 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. 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 Hyptertension. Conclusion: Salt and Hypertension — Whose Decision? Endocrine Effects on Normal and Abnormal Sodium Excretion. Introduction. Adrenal Steroids. Aldosterone: regulation and effects. Renin–Angiotensin System (RAS). ANP. MSH. Kallikrein–Kinin System. Haemodynamic changes. Water balance. Hormonal changes. 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. Volume Excess. Oedema. Nephrotic oedema. Hepatic oedema. Cardiac Oedema. Chronic Obstructive Pulmonary Disease. Sodium Concentration. Hypernatraemia and Hyponatraemia. Hypernatraemia. Hyponatraemia. Volume Depletion. Anaesthesia and surgery. Hypovolaemia and shock. Crystalloid vs colloid? Blood. Corticosteroids. Hypertonic saline. Adrenal insufficiency, (Addisons disease). Heat and exertion. Renal Dysfunction. Chronic renal failure. Acute renal failure (ARF). Interactions Between Sodium, Potassium, Calcium and Magnesium. Introduction. Cellular Interactions. Renal Interactions. Physiological and Clinical Implications. Conclusion. 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. 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. Concluding Synthesis. Index.