Common mistakes in managing metabolic disorders.

Three mistakes are commonly made in managing metabolic disorders. 1. Oral fluids may be pushed to treat simple volume depletion. However, almost all fluids used for this purpose are sodium-poor and do not restore salt and water balance. 2. The physician may not be aware of common causes of hypophosphatemia, such as hyperventilation, sepsis, stress, use of antacids or diuretics, and alcoholism. If the patient is not monitored adequately, severe hypophosphatemia may develop with serious consequences. 3. Low serum bicarbonate levels may be attributed to metabolic acidosis only, when in actuality metabolic acidosis may coexist with respiratory alkalosis. Arterial blood gas studies differentiate the conditions and direct attention to the cause of respiratory alkalosis when present.

Potassium imbalance: causes and prevention.

The amount of potassium normally found in the serum is less than 2% of the total body amount. Thus, the serum potassium level is not the ideal indicator of potassium activity in the body. Potassium homeostasis or imbalance is a function of changes in input, changes in output, and shifts of potassium between the serum and the intracellular fluid. Most significant hyperkalemia is associated with renal impairment, either glomerular or tubular; hypokalemia in many instances is causally related to increased renal potassium losses. Such losses can be sequentially measured and the information used to prevent potassium depletion. The key to understanding and treating potassium imbalance is to know which patients are at risk, what the physiologic consequences of hypokalemia and hyperkalemia are, and how to use urinary potassium measurements and the ECG for prevention rather than relying on the serum potassium level only.