JB is a 52-year-old cachectic white male with a history of peripheral vascular disease and hepatitis C; he was recently hospitalized for an infected sacral decubitus ulcer. During that hospitalization, his examination revealed diffuse lymphadenopathy suggestive of malignancy. He then presented to the emergency department (ED) after a 2-week history of decreased oral intake, altered mental status, and syncope. In the ED, the patient was hypotensive, with an initial systolic blood pressure of 60 mm Hg, and had tachycardia, with a heart rate of 100 beats per minute. He had leukocytosis (white blood cell count 27.4), lactic acidosis, and was in acute renal failure with a creatinine level of 2.1 mg/dL (previous admission creatinine was 0.9). At that time, 2 sets of blood cultures were drawn, and antibiotic therapy was initiated with vancomycin, ciprofloxacin, and a piperacillin and tazobactum injection (Zosyn). He received a 2-L normal saline bolus, and his systolic blood pressure improved to 90 mm Hg.
The patient was admitted to the intensive care unit (ICU) with the following vital signs, laboratory values, and measurements:Temperature 95.2°F; pulse 82 beats per minute; respirations 18 breaths per minute; blood pressure 95/63 mm Hg;
Electrolyte panel: Sodium 133 mEq/L, potassium 4.8 mEq/L, chloride 92 mEq/L, bicarbonate 24 mEq/L, blood urea nitrogen (BUN) 57, creatinine 2.1 mg/dL, glucose 168 mg/dL;
Arterial blood gas: pH 7.34, pCO2 39, pO2 179;
Anion gap 17, lactic acid elevated at 7.6; and
Height 68 inches, weight 98.9 pounds.
The patient remained in the ICU for 2 days and was treated for hypovolemia and sepsis with IV fluid hydration and broad-spectrum antibiotics. He had aggressive volume expansion with a 1-L 0.9% normal saline bolus, followed by normal saline at 250 cc/hour. His blood pressure improved appropriately, with the systolic blood pressure increasing to 120 mm Hg. His laboratory values also showed improvement, with his lactic acidosis and acute renal failure resolving. On the second hospital day, his IV fluid rate was decreased to150 cc/hour.
Once he was hemodynamically stable, the patient was transferred to the medicine floor on the third day of his hospitalization. He was treated with maintenance IV fluids (0.9% normal saline at 125 cc/hour) and kept for continued monitoring.
As the patient awaited a lymph node biopsy (for further evaluation of his lymphadenopathy), he continued to receive 0.9% normal saline at 125 cc/hour for 3 days, which was then decreased to 100 cc/hour. On the seventh hospital day, the patient complained of some mild shortness of breath at rest and had increasing oxygen requirements. At that time, the following laboratory values were recorded: sodium ,145 mEq/L; potassium, 3.1 mEq/L; chloride, 117 mEq/L; bicarbonate, 15 mEq/L; BUN, 35; creatinine, 1.0 mg/dL; and glucose, 168 mg/dL
Identify the acid-base disturbance and formulate a differential diagnosis.
What other laboratory tests would you order?
Discussion to follow....!!