Elevated lactate as an early marker of brain injury in inflicted traumatic brain injury.
BACKGROUND
Traumatic brain injury is a major cause of disability and death in the pediatric population. The metabolic and neurochemical abnormalities that underlie traumatic brain injury remain poorly understood, but hypoxia-ischemic injury might play an important role.


OBJECTIVE
This study evaluated children with inflicted traumatic brain injury using magnetic resonance spectroscopy (MRS). We postulated that children with hypoxic-ischemic injury indicated by elevated lactate in the acute phase of injury will have worse early neurological status and short-term clinical outcomes than those without lactate upon MRS.


METHODS
This prospective study employed proton MRS to sample bilaterally the frontal lobes and the parasagittal cortex within the parietal and occipital lobes of 11 patients with inflicted traumatic brain injury who were undergoing a clinical MRI examination. Patients' measured clinical course while hospitalized included initial neurological evaluation, presence of seizure activity, need for admission to the pediatric intensive care unit (PICU), number of days hospitalized, presence of retinal hemorrhages and presence of bone fractures. Measurement of outcome was determined using the Pediatric Overall Performance Category Scale (POPCS; 1=good performance; 6=death).


RESULTS
Four children demonstrated elevated lactate and diminished N-acetyl aspartate (a neuronal marker) within several regions, indicating global ischemic injury (lactate-positive global group). These four children all had seizure activity and abnormal initial neurological examinations and required admission to the PICU. The mean POPCS for this group was 3.25. In four other children, lactate was detected within at least one region, indicating a focal ischemic injury (lactate-positive focal group); two of these children had seizure activity, and two had an abnormal initial neurological examination. The mean POPCS score was 1.5 for this group. The remaining three children had no evidence of lactate upon MRS (lactate-negative group). These children did not have seizure activity, did not require admission to the PICU, nor did they have initial abnormal neurological examinations. The mean POPCS score was 1.3 for this group.


CONCLUSIONS
Patients with inflicted traumatic brain injury and evidence of hypoxic-ischemic injury as indicated by elevated lactate on MRS tend to have worse early neurological status and early outcome scores. Lactate levels as sampled by MRS might predict early clinical outcome in inflicted traumatic brain injury.
Makoroff
Kathi L
KL
Department of Pediatrics, Mayerson Center for Safe and Healthy Children, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA. Kathi.Makoroff@cchmc.org
Cecil
Kim M
KM
Care
Marguerite
M
Ball
William S
WS
D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001923:Brain Chemistry; D001930:Brain Injuries / Q000150:complications*; D003422:Critical Care; D005260:Female; D050723:Fractures, Bone / Q000150:complications; D005625:Frontal Lobe / Q000737:chemistry; D023261:Glasgow Outcome Scale; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000209:etiology; D007223:Infant; D007231:Infant, Newborn; D019344:Lactic Acid / Q000032:analysis*; D007902:Length of Stay; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009460:Neurologic Examination; D009778:Occipital Lobe / Q000737:chemistry; D010296:Parietal Lobe / Q000737:chemistry; D011446:Prospective Studies; D012166:Retinal Hemorrhage / Q000150:complications; D012640:Seizures / Q000209:etiology
D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate