EVIDENCE FROM PROTON MAGNETIC-RESONANCE SPECTROSCOPY FOR A METABOLIC CASCADE OF NEURONAL DAMAGE IN SHAKEN BABY SYNDROME

Objective. The purpose of this study was to use proton magnetic resona nce spectroscopy (MRS) as a metabolic assay to describe biochemical ch anges during the evolution of neuronal injury in infants after shaken baby syndrome (SBS), that explain the disparity between apparent physi cal injury and the neurological deficit after SBS. Methodology. Three infants [6 months (A), 5 weeks (B), 7 months (C)] with SBS were examin ed repeatedly using localized quantitative proton MRS. Examinations we re performed on days 7 and 13 (A), on days 1, 3, 5,and 12 (B), and on days 7 and 19 (C) posttrauma. Long-term follow-up examinations were pe rformed 5 months posttrauma (A) and 4.6 months posttrauma (B). Data we re compared to control data from 52 neurologically normal infants pres ented in a previous study. Results. Spectra from parietal white matter obtained at approximately the same time after injury (5 to 7 days) sh owed markedly different patterns of abnormality. Infant A shows near n ormal levels of the neuronal marker N-acetyl aspartate, creatine, and phosphocreatine, although infant C shows absent N-acetyl aspartate, al most absent creatine and phosphocreatine, and a great excess of lactat e/lipid and lipid. Analysis of the time course in infant B appears to connect these variations as markers of the severity of head injury suf fered in the abuse, indicating a progression of biochemical abnormalit y. The principal cerebral metabolites detected by MRS that remain norm al up to 24 hours fall precipitately to similar to 40% of normal withi n 5 to 12 days, with lactate/lipid and lipid levels more than doubling concentration between days 5 and 12. Conclusions. A strong impression is gained of MRS as a prognostic marker because infant A recovered al though infants B and C remained in a state consistent with compromised neurological capacity. Loss of integrity of the proton MR spectrum ap pears to signal irreversible neurological damage and occurs at a time when clinical and neurological status gives no indication of long-term outcome. These results suggest the value of sequential MRS in the man agement of SBS.