It's a Bit Crowded in Here: Examining Pressure Reactivity in Craniocerebral Disproportion

Introduction: Pressure reactivity index (PRx) is a measure used to gain insights into cerebrovascular reactivity. It is generally used in acute settings such as traumatic brain injury and subarachnoid hemorrhage, however there is limited data on its utility in cases of slow compensatory changes in intracranial pressure such as craniocerebral disproportion. Here we illustrate a case of how PRx can provide valuable information in such settings. Case presentation: PRx was measured in a 10-year-old boy who presented with multiple cranioneuropathies, found to have craniocerebral disproportion and secondary compression of posterior fossa structures. He was taken to surgery for decompressive craniotomy and cranial expansion procedure. He had an acute worsening in PRx, with a slow stabilization over the following days. Conclusion: This case highlights the importance of monitoring individualized PRx curves, and that autoregulatory curves are not constant between individuals or within same individuals over time. Acute iatrogenic interventions could lead to poor neurological consequences, due to interruption of a chronically compensated state.