SESSION TYPE: Neuro Critical Care
PRESENTED ON: Tuesday, October 23, 2012 at 04:30 PM - 05:45 PM
PURPOSE: Hyponatremia is frequently seen in patients with spontaneous subarachnoid hemorrhage (SAH) especially among those who develop cerebrovascular spasm (CVS). The hyponatremia has been thought to be either due to syndrome of inappropriate antidiuretic hormone secretion (SIADH) or to cerebral salt wasting. The latter is probably mediated by increased levels of brain (BNP) and atrial natriuretic peptide (ANP) which are a consequence of hypothalamic injury induced by the CVS. We conducted a retrospective study to determine if there is an association between hyponatremia and CVS.
METHODS: Retrospective chart review of all patients with non-traumatic aneurysmal SAH admitted to Westchester Medical Center, a tertiary-care university hospital from December 2010 to December 2011. Serum sodium levels were recorded daily during their ICU stay.Hyponatremia was defined as serum sodium level <135 meq/l and a fall in sodium level of >4 meq/l from the admission sodium level. The presence of cerebral vasospasm was determined by cerebral angiogram, CT angiogram or MR angiogram performed as a part of the standard of care practiced in the Neurosciences ICU. Patients were assigned to one of four groups based on the presence or absence of CVS and hyponatremia. Student's t-test was used for comparison of means.
RESULTS: 80% (78/98) of the patients developed hyponatremia and 60% (59/98) developed CVS. Among the 78 with hyponatremia, 49 (63%) had evidence of CVS, whereas among the 20 patients without hyponatremia, 10 (50%) had evidence of CVS (p=0.10). More than half of those with hyponatremia and CVS (29/49) developed hyponatremia on the same day or before CVS was diagnosed.
CONCLUSIONS: In patients with SAH, hyponatremia is associated with a greater risk of developing CVS and may precede the detection of CVS.
CLINICAL IMPLICATIONS: The reasonably high sensitivity (83%) of hyponatremia in identifying patients with CVS should make clinicians attuned to the possibility of such a diagnosis whenever a fall in noted in patients with SAH. However the wide variety of other factors that can also have an impact on serum sodium makes such an association very non-specific.
DISCLOSURE: The following authors have nothing to disclose: Vidya Ramachandraiah, Dipak Chandy
No Product/Research Disclosure InformationNew York Medical College, Valhalla, NY