Diet



A source of protein is required in patients with ATN, since the underlying disease process as well as the presence of renal insufficiency re­sults in increased catabolism and decreased anabolism of protein. On the other hand, protein contributes to the generation of urea nitrogen and perhaps other products thought to be involved in the genesis of the “uremic syndrome.” In a patient who is not severely catabolic and not requiring dialysis, protein intake should be limited to 40 grams/day and protein should contain a high con­tent of essential amino acids (high biological value protein). Carbohydrates should be admin­istered to provide sufficient calories. If the patient is severely catabolic, as evidenced by a rise in the urea nitrogen concentration of over 20 mg/dl/day, higher intakes of protein are often required to maintain nitrogen balance. In this circumstance, dialysis is almost always indicated.

Adjustment in Drug-Dosing Regimens. Drug-induced renal failure is a common clinical prob­lem.. In addition, renal failure is associated with abnormalities in the metabolism of a number of commonly used drugs. The relationship between drugs and renal disease is discussed more fully in Chapter 35. It is critical, however, to carefully re­view the indications for and the dose of all drugs administered to patients with ATN. A question that often arises relates to the .administration of potentially nephrotoxic drugs to a patient with ATN due to some other cause. For example, a pa­tient with ATN may require an aminoglycoside antibiotic for life-threatening sepsis. In this clin­ical circumstance, the following points need to be considered. If there is an equally effective drug that has less or no renal toxicity, it should be em­ployed. If no alternative is available, the drug should be administered in amounts required to achieve the desired therapeutic effect. The amount of drug to be administered and the dosing intervals, however, need to be carefully consid­ered. For drugs that are removed by dialysis, the pharmacokinetics of the drug are even more com­plex. Monitoring of blood concentrations is an im­portant adjunct to effective treatment. The critical point is that potentially life-saving but nephro­toxic drugs should not be withheld in a patient with ATN. The same general considerations apply to the requirement for radiographic studies in­volving potentially nephrotoxic radiocontrast dyes. If indicated for the effective management of a patient with ATN, the tests should be per­formed. Dialysis is effective in removing the water-soluble x-ray contrast agents.