Spinal Fluid Lactate Dehydrogenase Level Differentiates between Structural and Metabolic Etiologies of Altered Mental Status in Children

Altered mental status is a common cause of intensive care unit admission in children. Differentiating structural causes of altered mental status from metabolic etiologies is of utmost importance in diagnostic approach and management of the patients. Among many biomarkers proposed to help stratifying patients with altered mental status, spinal fluid lactate dehydrogenase appears to be the most promising biomarker to predict cellular necrosis. In this cross sectional study we measured spinal fluid level of lactate dehydrogenase in children 2 months to 12 years of age admitted to a single center intensive care unit over one year. Spinal fluid level of lactate dehydrogenase in 40 pediatric cases of febrile seizure was also determined as the control group. The study group included 35 boys (58.3%) and 25 girls (41.7%). Their mean age was 2.7+/-3 years and their mean spinal fluid lactate dehydrogenase level was 613.8+/-190.4 units/liter. The control group included 24 boys (55.8%) and 19 girls (44.2%). Their mean age was 1.3+/-1.2 years and their mean spinal fluid lactate dehydrogenase level was 18.9+/-7.5 units/liter. The mean spinal fluid lactate dehydrogenase level in children with abnormal head CT scan was 246.3+/-351.5 units/liter compared to 164.5+/-705.7 in those with normal CT scan of the head (p=0.001). Spinal fluid lactate dehydrogenase level is useful in differentiating structural and metabolic causes of altered mental status in children.