Critical Care Medicine-Renal, Electrolyte and Acid Base Disorders>>>>>Sodium
Question 7#

• A 24-year-old woman is brought to the emergency department by her boyfriend for worsening lethargy. He reports that she has no known medical history and was doing well until 2 days ago after they returned home from a hiking trip on the Appalachian trail. She started experiencing diarrhea after drinking from the fresh springs. Vital signs are as follows:
• temperature is 37.8°C
• blood pressure is 97/64 mm Hg
• pulse rate is 112 beats/min
• respiratory rate is 14 breaths/min

On physical examination, abdominal examination reveals tenderness in the left lower quadrant and weak radial pulses.

Lab. results:

• Sodium 144 mEq/L (mmol/L)
• Potassium 3.9 mEq/L (mmol/L)
• Chloride 110 (mmol/L)
• Bicarbonate 18 (mmol/L)
• BUN 42 mg/dL
• Creatinine 1.2 mg/dL
• Glucose 123 mg/dL
• Urine sodium 24 mEq/L

What is the next BEST step in management of this patient’s condition?

 

A. Normal saline with 20 KCl mEq/L
B. Ringer lactate
C. ½ normal saline
D. ½ normal saline with D5W
E. Normal saline with D5W

Correct Answer is B

Comment:

Correct Answer: B

In patients who cannot tolerate oral rehydration therapy (ORT), the usage of isotonic fluids such as lactated Ringers (LR) is the most appropriate. The lactate found in LR is converted to bicarbonate in the liver and replaces the bicarbonate that is lost with diarrhea (which contains high level of sodium, bicarbonate and potassium). Thus, persistent diarrhea will lead to a hypokalemic, hyperchloremic metabolic acidosis in most patients which should be replaced by isotonic fluids, such as LR. However, close monitoring of potassium should be performed as the correction of the metabolic acidosis will lead to an intracellular shift of potassium leading to hypokalemia.

Reference:

1. Pandya S. Practical Guidelines on Fluid Therapy. 2nd ed. Bhalani Medical Book House; 2012.