Brain herniation in a patient with apparently normal intracranial pressure: a case report

Abstract

Introduction: Intracranial pressure monitoring is commonly implemented in patients with neurologic injury and at high risk of developing intracranial hypertension, to detect changes in intracranial pressure in a timely manner. This enables early and potentially life-saving treatment of intracranial hypertension.

Case presentation: An intraparenchymal pressure probe was placed in the hemisphere contralateral to a large basal ganglia hemorrhage in a 75-year-old Caucasian man who was mechanically ventilated and sedated because of depressed consciousness. Intracranial pressures were continuously recorded and never exceeded 17 mmHg. After sedation had been stopped, our patient showed clinical signs of transtentorial brain herniation, despite apparently normal intracranial pressures (less than 10 mmHg). Computed tomography revealed that the size of the intracerebral hematoma had increased together with significant unilateral brain edema and transtentorial herniation. The contralateral hemisphere where the intraparenchymal pressure probe was placed appeared normal. Our patient underwent emergency decompressive craniotomy and was tracheotomized early, but did not completely recover.

Conclusions: Intraparenchymal pressure probes placed in the hemisphere contralateral to an intracerebral hematoma may dramatically underestimate intracranial pressure despite apparently normal values, even in the case of transtentorial brain herniation.

Figures

Figure 1

Continuously recorded intracranial pressure readings from the time of insertion of the intraparenchymal pressure probe (black arrow) to the time that clinically evident brain herniation appeared (grey arrow).

Figure 2

CT scan images after clinical signs of brain herniation developed. (A) Basal ganglia hemorrhage with perifocal edema. (B) Left-sided transtentorial herniation of the parahippocampal gyrus. (C) Edema of the left hemisphere with normally appearing right hemisphere.