Children with abusive head trauma (AHT) may be at risk for elevated intraocular pressure (IOP), according to a study published in the American Journal of Ophthalmology. The research shows that children who died from AHT have orthograde axonal transport block in the lamina cribrosa (LC).
Investigators at the University of California, Irvine received 36 sets of eyes from pediatric patients with and without AHT from the Los Angeles coroner for a 4-year period. Immunohistochemistry was performed on the eyes, and the axonal transport block was assessed using light microscopy. A subset of eyes from individuals (n=21) with known survival were evaluated for correlations between time since injury and laminar area block.
Accumulation of amyloid precursor protein (APP-A4) reaction product was observed in retinal ganglion cell bodies, nerve fiber layer axons around the ends of Bruch’s membrane, and axons in LC optic nerve axon bundles in the eyes of patients with AHT. These observations indicated that obstruction of axonal transport was likely due to elevated IOP.
Among specimens with known survival of between 1 to 382 days after their injury, most globes (94%) of cases were positive for LC accumulation.
The proportion of laminar area block ranged from 0.77% to 55.51%. The specimen with the highest proportion of APP-A4 LC block was from a child who had survived 4 days and the lowest, for 1 day after their injuries. The specimen from the patient who survived for 382 days had a laminar block of 19.07%. No correlation between accumulation and time since injury was observed.
The variance between left and right eyes was 0.76, indicating a consistency of their measurement technique.
This study may have been limited by the differing time from autopsy to quantification across specimens.
“We found consistent APP-A4 labeling of retinal ganglion cells and accumulations of APPA4 reaction product in the LC of the anterior optic nerve in the majority of suspected AHT specimens in which the nerve head was available for study,” investigators report. “IOP should be included in the clinical evaluation of suspected AHT, and if elevated, monitored and therapy considered.”
Minckler DS, Brown DJ, Nalbandian A, Suh DW. Amyloid precursor protein in abusive head trauma suspects. Am J Ophthalmol. Published online February 16, 2022. doi:10.1016/j.ajo.2022.02.018