A Conceptual Overview of Axonopathy in Infants and Children with Allegedly Inflicted Head Trauma.

Fatal, allegedly inflicted pediatric head trauma remains a controversial topic in forensic pathology. Recommendations for systematic neuropathologic evaluation of the brains of supposedly injured infants and children usually include the assessment of long white matter tracts in search of axonopathy - specifically, diffuse axonal injury. The ability to recognize, document, and interpret injuries to axons has significant academic and medicolegal implications. For example, more than two decades of inconsistent nosology have resulted in confusion about the definition of diffuse axonal injury between various medical disciplines including radiology, neurosurgery, pediatrics, neuropathology, and forensic pathology. Furthermore, in the pediatric setting, acceptance that "pure" shaking can cause axonal shearing in infants and young children is not widespread. Additionally, controversy abounds whether or not axonal trauma can be identified within regions of white matter ischemia - a debate with very significant implications. Immunohistochemistry is often used not only to document axonal injury, but also to estimate the time since injury. As a result, the estimated post-injury interval may then be used by law enforcement officers and prosecutors to narrow "exclusive opportunity" and thus, identify potential suspects. Fundamental to these highly complicated and controversial topics is a philosophical understanding of the diffuse axonal injury spectrum disorders.