Masking of syndrome of inappropriate antidiuretic hormone secretion: the isonatremic syndrome.

Abstract

OBJECTIVE:

To determine whether the administration of isotonic saline in patients undergoing spinal fusion surgery prevents the development of hyponatremia, thus masking the detection of syndrome of inappropriate antidiuretic hormone secretion (SIADH).

STUDY DESIGN:

Prospective observational cohort study conducted in pediatric patients undergoing spinal fusion surgery. Using established criteria for diagnosing SIADH with the exception of serum sodium as a criterion, we separated patients into those with and without masked SIADH. Random cortisol levels were measured in the perioperative period to test for adrenal insufficiency to exclude it as a cause for natriuresis and hyponatremia.

RESULTS:

Of the 40 patients included in the study, 13 (32%; 95% CI, 19%-49%) met study criteria for masked SIADH. The serum sodium levels between the 2 groups were not different throughout the postoperative period. The antidiuretic hormone levels were increased at 24-48 hours after surgery (20.4 pg/mL in masked SIADH group vs 6.6 pg/mL in no masked SIADH group, P = .04). Subjects with masked SIADH demonstrated a tendency for weight gain (3.9 kg vs 2.5 kg, P = .058), which was maximal on postoperative day 2. Cortisol levels were similar between the groups.

CONCLUSION:

Masked SIADH (SIADH-like state without hyponatremia) commonly occurs in the postoperative period in children and young adults undergoing spinal fusion surgery. Early postoperative evaluation and recognition may result in appropriate management of patient's fluid balance.

• Authors: Irfan Khan, Bridget Zimmerman, Patrick Brophy, Sameer Kamath
• Journal: The Journal of pediatrics (J Pediatr) Vol. 165 Issue 4 Pg. 722-6 (Oct 2014) ISSN: 1097-6833 [Electronic] United States
• PMID: 24996987 (Publication Type: Journal Article, Observational Study, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.

Chemical References

• Hemoglobins
• Sodium Chloride
• Hydrocortisone

Topics

• Adolescent
• Child
• Female
• Hemoglobins (biosynthesis)
• Humans
• Hydrocortisone (blood)
• Hyponatremia (prevention & control)
• Inappropriate ADH Syndrome (diagnosis, therapy)
• Linear Models
• Male
• Perioperative Period
• Prospective Studies
• Sodium Chloride (chemistry)
• Spinal Fusion (methods)
• Time Factors
• Young Adult