Electrolytes and acid–base: common fluid and electrolyte disorders

Disturbances of fluid and electrolyte balance are common in clinical practice, especially in a hospital setting, and can be iatrogenic or compounded by inappropriate medical or surgical treatment. Their recognition and appropriate management are not necessarily difficult or complex. Although specific formulae and standard protocols can be helpful 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.