To study the pattern of magnesium levels among traumatic (TBI)and non traumatic brain injury (CVA) critically ill patients.
Patients admitted to ICU from january 2004 to january 2005 were included .Inclusion criteria were the presence of traumatic brain injury (TBI), thrombotic or hemorrhagic non traumatic strokes (CVA).Data was abstracted from a prospectively collected ICU database .Magnesium levels were collected retrospectively for the first seven days of admission .Patients were classified into three groups (Contusion, Hemmorhage and Thrombosis) based on their radiographic findings .
90 patients were included (46 TBI and 44 CVA). CVA patients were older (60.84±16.4 vs. 28.21±14.9 p<0.001) had higher APACHE scores (23.8±7.1 vs. 20.16 ±4.6 p=0.01)and higher Glascow coma scores GCS (8.9±4 vs. 5.5±2.6 p=0.006) .On the other hand TBI patients had lower magnesium on admission (0.75±0.13 vs. 0.89±0.2 p=0.019) and for the most part of the first week (see figure).There was no difference in ICU mortality between the two groups . 25% of patients in the TBI group had hypomagnesemia on admission versus 16% of the CVA group .27.2% of CVA patients had hemorrhage versus 56.5% among TBI group (P<0.001).Serum magnesium levels were compared among several groups of brain injury (hemorrhage versus thrombosis versus contusion ) based on the radiologic findings and were not statistically different.There was no correlation between admission serum magnesium and Glascow coma score GCS (R=0.03, P=0.8).
Serum magnesium levels seems to be lower among traumatic brain injury than non traumatic brain injury patients .Radiographic findings such as hemorrhage or thrombosis do not appear to influence serum magnesium .
Magnesium levels on admission and during ICU stay are not influenced by the radiographic findings of brain injury .TBI seems to be associated with lower magnesium levels than CVA. Whether this is specific to TBI or attached to other reasons is not known.Other factors such as comorbid conditions and possibly hormonal or metabolic disturbances may be potential reasons .Further larger studies are necessary to clarfiy these findings.
Ousama Dabbagh, None.