Which of the following clinical laboratory findings are sometimes associated with serotonin syndrome?

A. Leukopenia.
B. Elevated serum bicarbonate levels.
C. Hemolytic anemia.
D. Hyperkalemia.
E. Increased creatine phosphokinase (CK) levels.
 

• Answer E is correct.

• Increased CK levels occur in about 15% of patients with serotonin syndrome and may correspond with increased neuromuscular activity (e.g., rigidity, muscular contractions, and shivering).

• Leukocytosis may occur in approximately 11% of patients.

• Decreased serum bicarbonate levels may occur with metabolic acidosis.  Metabolic acidosis is a complication of serotonin syndrome that occurs in about 9% of patients.

• Hemolytic anemia is not associated with serotonin syndrome.

• Hyperkalemia is not associated with serotonin syndrome.  Hypokalemia may accompany metabolic acidosis.

• Additionally, elevated liver transaminase levels occur in about 8% of patients and are probably due to hyperthermia.

References: 1, 2, and 3

Back to Module IX