The nurse is caring for a patient who has been vomiting and has diarrhea for 3 days and now has muscle weakness and paresthesias in his hands and feet, along with an irregular pulse rate and rhythm, and shallow respirations with crackles on auscultation of his lungs bilaterally. The nurse suspects that these symptoms are most likely due to which electrolyte imbalance?

Choice A reason: Sodium. Sodium is not affected by serum phosphate level in chronic kidney disease (CKD) patients. Sodium level is mainly regulated by the renin-angiotensin-aldosterone system and the antidiuretic hormone. Sodium level can be altered by fluid intake, fluid loss, diuretics, or salt restriction, but not by phosphate level.

Choice B reason:

Magnesium. Magnesium is also not affected by serum phosphate level in CKD patients. Magnesium level is mainly influenced by dietary intake, intestinal absorption, renal excretion, and exchange with bone and soft tissues. Magnesium level can be altered by malnutrition, malabsorption, diarrhea, vomiting, diuretics, or alcoholism, but not by phosphate level.

Choice C reason:

Calcium. Calcium is the correct answer because calcium and phosphate have an inverse relationship in the body. When serum phosphate level is elevated, as in CKD patients, serum calcium level tends to decrease. This is because high phosphate level binds to calcium and forms insoluble complexes that are deposited in soft tissues and bones. This reduces the amount of free calcium in the blood and triggers the secretion of parathyroid hormone (PTH), which further lowers the calcium level by increasing its excretion in the urine.

Choice D reason:

Bicarbonate. Bicarbonate is not directly affected by serum phosphate level in CKD patients. Bicarbonate level is mainly determined by the acid-base balance in the body. Bicarbonate level can be altered by metabolic acidosis or alkalosis, respiratory acidosis or alkalosis, renal failure, or diarrhea, but not by phosphate level.

Choice A reason:

Serum glucose 600 mg/dL. This is an expected finding for a client who has diabetic ketoacidosis (DKA) DKA results from a deficiency of insulin, which leads to hyperglycemia and ketosis. The normal range for serum glucose is 70 to 110 mg/dL.

Choice B reason:

Serum bicarbonate 28 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences ketosis, which results in ketones in the urine and blood. The nurse should expect a client who has DKA to have an HCO3- less than 15 mEq/L. This decreased value is due to an increased production of ketones, which results in metabolic acidosis. The normal range for serum bicarbonate is 22 to 26 mEq/L.

Choice C reason:

Serum potassium 2.5 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences osmotic diuresis and subsequent dehydration, which can cause electrolyte imbalances. The nurse should expect a client who has DKA to have elevated serum potassium levels due to the movement of potassium from the intracellular to the extracellular space in response to acidosis. The normal range for serum potassium is 3.5 to 5 mEq/L.

Choice D reason:

Serum sodium 150 mEq/L. This is not an expected finding for a client who has DKA. A client who has DKA experiences osmotic diuresis and subsequent dehydration, which can cause electrolyte imbalances. The nurse should expect a client who has DKA to have decreased serum sodium levels due to the dilutional effect of excess glucose in the blood. The normal range for serum sodium is 136 to 145 mEq/L.