A client with a closed head injury demonstrates signs of syndrome of inappropriate antidiuretic hormone (SIADH). Which additional finding should the nurse expect to obtain?

Choice A reason: This is incorrect because hepatorenal failure is a condition that involves both liver and kidney dysfunction, usually as a complication of cirrhosis or portal hypertension. The symptoms of hepatorenal failure may include jaundice, ascites, edema, oliguria, or encephalopathy. However, these are not consistent with the client's presentation of fever, abdominal pain, vomiting, and elevated amylase and lipase levels.

Choice B reason: This is correct because acute pancreatitis is an inflammation of the pancreas that can be caused by gallstones, alcohol abuse, trauma, infection, or drugs. The symptoms of acute pancreatitis may include fever, upper abdominal pain that radiates to the back, nausea, vomiting, and elevated amylase and lipase levels. These are consistent with the client's presentation and suggest that the cholecystectomy may have triggered an attack of acute pancreatitis.

Choice C reason: This is incorrect because surgical site infection is an infection that occurs at or near the incision site after surgery. The symptoms of surgical site infection may include redness, swelling, warmth, pus drainage, or pain at the wound site. However, these are not consistent with the client's presentation of fever, abdominal pain radiating to the back, vomiting, and elevated amylase and lipase levels.

Choice D reason: This is incorrect because biliary duct obstruction is a blockage of the bile ducts that carry bile from the liver and gallbladder to the intestine. The causes of biliary duct obstruction may include gallstones, tumors, inflammation, or scarring. The symptoms of biliary duct obstruction may include jaundice, dark urine, pale stools, itching, or abdominal pain. However, these are not consistent with the client's presentation of fever, abdominal pain radiating to the back, vomiting, and elevated amylase and lipase levels.

Choice A reason: Potassium 4.7 mEq/L (4.70 mmol/L) is within the normal reference range of 3.5 to 5 mEq/L (3.5 to 5 mmol/L). Potassium is an electrolyte that helps regulate the balance of fluids and acids in the body, as well as the function of nerves and muscles. A high potassium level (hyperkalemia) can cause muscle weakness, irregular heartbeat, and cardiac arrest. A low potassium level (hypokalemia) can cause muscle cramps, fatigue, and arrhythmias.

Choice B reason: Magnesium 2.1 mEq/L (0.86 mmol/L) is within the normal reference range of 1.3 to 2.1 mEq/L (0.65 to 1.05 mmol/L). Magnesium is an electrolyte that helps regulate the activity of enzymes, muscles, and nerves, as well as the balance of calcium and potassium in the body. A high magnesium level (hypermagnesemia) can cause nausea, vomiting, flushing, muscle weakness, and respiratory depression. A low magnesium level (hypomagnesemia) can cause muscle twitching, tremors, seizures, and cardiac arrhythmias.

Choice C reason: Calcium 6.5 mg/dL (1.63 mmol/L) is below the normal reference range of 9 to 10.5 mg/dL (2.3 to 2.6 mmol/L). Calcium is an electrolyte that helps regulate the function of muscles, nerves, bones, and blood clotting. A high calcium level (hypercalcemia) can cause nausea, vomiting, constipation, confusion, kidney stones, and bone pain. A low calcium level (hypocalcemia) can cause muscle spasms, cramps, tingling, numbness, and stridor (a high-pitched sound when breathing). **This is a critical value that should be immediately reported to the healthcare provider**, as it can indicate a serious condition such as acute pancreatitis, sepsis, or massive blood transfusion.

Choice D reason: Sodium 135 mEq/L (135 mmol/L) is slightly below the normal reference range of 136 to 145 mEq/L (136 to 145 mmol/L). Sodium is an electrolyte that helps regulate the balance of fluids and acids in the body, as well as the function of nerves and muscles. A high sodium level (hypernatremia) can cause thirst, dry mouth, confusion, seizures, and coma. A low sodium level (hyponatremia) can cause headache, nausea, vomiting, fatigue, muscle weakness, and confusion.