PURPOSE: Cerebral vasospasm (CVS) is a common complication of spontaneous subarachnoid hemorrhage (SAH). Hyponatremia, which develops in about a third of patients with SAH, is thought to be due to hypothalamic injury induced by the CVS. Hyponatremia has often been noted to precede the onset of CVS, although this relationship is not well established. In this study, we sought to determine if the hyponatremia, when present, predates the clinical detection of CVS.
METHODS: We conducted a retrospective study of all adult patients with spontaneous SAH admitted to Westchester Medical Center between 1/00 and 5/02. A total of 177 charts were reviewed of which 106 met our eligibility criteria, which included the absence of any serious concomitant medical illness and a requirement that the patient should have received aggressive medical care at our institution for at least 10 days. Hyponatremia was defined as both an absolute value of <135 meq/l occurring at any point during the first 14 days of hospitalization and a decrease from the admission serum sodium level of > 4 meq/l. CVS was determined by transcranial doppler or cerebral angiography.
RESULTS: 42% (44/106) of the patients developed CVS while 39% (41/106) developed hyponatremia. 50% (22/44) of the patients with CVS developed hyponatremia. Among these, hyponatremia occurred at least one day before CVS was detected in 59 % (13/22) of patients while in only 18% (4/22) of patients did it occur after the detection of CVS (Fig. 1).
CONCLUSION: When present concomitantly, most cases of hyponatremia occur before the detection of CVS.
CLINICAL IMPLICATIONS: Hyponatremia could be used as an additional early marker of CVS in conjunction with the other independent predictors of CVS that have been identified in the literature.
DISCLOSURE: Dipak Chandy, None.