BACKGROUND: Hyponatremia has been reported in children undergoing cranial remodeling for repair of craniosynostosis (CS), with evidence to suggest it is not uncommon. This hypo-osmotic state may precipitate neurologic sequelae, including confusion, cerebral edema, seizure, and death. Although etiology remains controversial (cerebral salt wasting vs. syndrome of inappropriate antidiuretic hormone), the investigation of hyponatremia remains prudent, and the identification of associated factors may facilitate preventative care.
Our goal is to review the peri-operative care of the surgically treated craniosynostotic population, and determine the incidence of hyponatremia and equate possible risk factors for its development in an effort to devise preventative strategies.
METHODS: The Cleft-Craniofacial Database of a major metropolitan children’s hospital was retrospectively reviewed for patients diagnosed with and surgically treated for CS between 2003-2008. Demographic and peri-operative data were collected and included: age, weight, medical history, pre-operative intracranial pressure (ICP), type and duration of surgery, electrolyte, BUN, Cr, hemoglobin and hematocrit levels, administration of DDAVP, volume of blood loss during surgery, type and volume of intravenous fluids transfused intra- and post-operatively, and finally any complications that developed. Hyponatremia was defined as more than one serum sodium ≤134 mEq/L.
RESULTS:
67 patients met our inclusion criteria, of which 29.9% became hyponatremic (as low as 121 mEq/L). The average age, weight, and duration of surgery was 1.8±2.0 yrs, 10.6±3.7 kg, and 6.8±2.0 hrs, respectively. 12% were diagnosed with syndromic CS. There were no instances of intra-operative hyponatremia. The majority of hyponatremic events occurred on post-operative day (POD) 0 or 1, with an average duration of 1.2 days (range: 0.1-4.0 days). Hospital stay averaged 5.58 days and did not differ significantly between the two groups. The duration of intensive care unit (ICU) stay, however, was significantly longer for hyponatremic patients (2.9 vs. 1.9 days; p<0.001). Furthermore, hyponatremia was associated with elevated pre-operative ICP (p<0.006) and a syndromic diagnosis of CS (p<0.05). The association between hyponatremia and POD 0 or 1, syndromes, and ICU stay remains significant even after controlling for age. The use of hypotonic intravenous fluids was not associated with post-operative hyponatremia. In all instances, hyponatremia was corrected before any neurologic complications developed.
CONCLUSIONS:
Post-operative hyponatremia is an important source of potential morbidity in children who undergo surgical correction of CS. We observe an incidence of 29.9%, and identify significant associations with elevated pre-operative ICP and a syndromic diagnosis. Taken together, the identification of susceptible patients is useful in better anticipating and preventing hyponatremia and its potential complications, as well as reducing ICU stay and associated cost of care.