Aspects of phosphate biochemistry pertinent to therapy, the distribution of phosphorus in body compartments, therapeutic phosphorus preparations, prevention of hypophosphatemia, therapeutic guidelines, and side-effects of phosphorus therapy are reviewed. Severe hypophosphatemia (less than mmol/litre or less than 1 mg/dl) can occur with normal or depleted body stores. Because a large amount of phosphorus may shift rapidly between the extracellular and intracellular or bone compartments, the size of a possible total body deficit cannot be estimated from the serum phosphorus level. Similar shifts may occur unpredictably during repair of hypophosphatemia. Therefore, correction of hypophosphatemia in any patient must be empiric and the response of serum levels to therapy should be followed closely. We discuss a method likely to correct hypophosphatemia while minimizing side-effects.
A patient who is gaining weight on 1,200 calories per day in the hospital may require 2,400 calories per day after two weeks and 3,000 calories per day after six weeks (Adams, 1999). Once the metabolic rate increases, so do caloric needs. This is quite shocking to patients who don’t understand why they need so much food to continue to gain weight. The adjustment is difficult and patients often respond by shaving calories. This is why a weekly weigh-in is vitally important. It is the only way to tell if your patient is eating everything required by the dietitian.