Disturbances of fluid and electrolyte balance are common in clinical practice, especially in
hospital settings, and can be iatrogenic or compounded by inappropriate medical or surgical
treatment. Recognition and appropriate management are not necessarily difficult or
complex. Although specific formulae and standard protocols can help at the bedside, there is
no substitute for an understanding and application of some basic principles of renal and
endocrine physiology, which this article sets out. Some knowledge of basic renal physiology …