Decreased intake – poor dietary intake, chronic disease
Excess losses – Skin (sweating, burns), GI (diarrhoea, vomiting, laxatives), Renal (diuretics, tubular disorders)
Endocrine - Mineralocorticoid excess (Cushing’s disease, Conn’s syndrome)
Transcellular shift – Beta agonists, Insulin therapy, Alkalosis, Refeeding syndrome