TYK315
A 6 year-old child with new-onset headaches is admitted to the ICU after a brain CT reveals an intracranial tumor without signs of intracranial hypertension. Anesthesia is requested for a 1-hour brain MRI. The patient’s serum sodium level is 127 and he is alert and conscious. Anesthetic management should include:
a) Limitation of intravenous fluid replacement to insensible losses plus one half of urine output using 0.9% normal saline
b) Administration of 5 mL/kg of 3% hypertonic saline in repeated doses until serum sodium is above 135
c) Placement of an arterial line and bladder catheter for the scan to measure electrolytes and fluid intake and output
Answer
Answer a. This patient likely has the syndrome of inappropriate antidiuretic hormone (SIADH). His hyponatremia is due to free water intoxication, but he is conscious and not exhibiting seizure or signs of alteration of mental status that would require treatment with hypertonic saline. Fluid restriction to insensible losses (400 mL/m2/day as a continuous infusion) plus replacement of ½ to ¾ of urine output (replaced intermittently) should allow stability or recovery of normal serum sodium over time. For a brief anesthetic procedure, limitation of fluids without invasive access for electrolyte measurement is appropriate, though he will require invasive access and bladder catheterization for his subsequent tumor resection. SIADH may be precipitated by neoplasm, infection, neurotrauma, mechanical ventilation and various medications.
Notes
- This question originally printed in the Pediatric Anesthesiology Review Topics kindle book series, and appears courtesy of Naerthwyn Press, LLC.