The inflammatory cellular constituents of foetal and infant leptomeninges – a survey of hospital-based autopsies without trauma

Introduction: We investigated the possible association of leptomeningeal inflammatory infiltrates and iron deposition in neonates and infants, with the objective of deriving a baseline for reference in forensic cases.

Methods: Leptomeninges derived from non-forensic deaths with atraumatic, natural causes was studied. Because of the vastly dissimilar neuroanatomy between newborn infants and older ones, 33 cases were divided into two groups, according to set age groups. Inflammatory cells and iron levels in these were quantified.

Results: In group 1 there was a correlation between an increased number of inflammatory cells and the presence of subdural or subarachnoid haemorrhages. Inflammatory cells, albeit reduced in number, were also present in a number of cases in the absence of subdural or subarachnoid haemorrhages. Iron was found in the leptomeninges in several cases in similar quantities, even those without recent haemorrhage. Overall and within the two subgroups, ranges and means of the counts were wide and not significantly different.

Conclusion: These findings suggest that inflammatory cells and iron in the leptomeninges can be found in a number of natural and non-traumatic conditions. Further, two cases with no reported neuropathology demonstrated the presence of inflammatory cells and iron. Thus, cautious interpretation of neuropathology found in paediatric forensic cases is recommended.