Introduction
Intracranial pressure (ICP) is a major physiological parameter of the central nervous system (CNS). It is defined as the pressure exerted by the contents of the cranium, including the brain, blood, and cerebrospinal fluid (CSF), on the inner walls of the skull. ICP is an important factor in the maintenance of homeostasis in the CNS and its alteration can lead to a wide spectrum of neurological deficits. In this paper, we will discuss the physiology of ICP, the pathophysiology of elevated ICP, and the management strategies used to reduce or normalize ICP levels.
Physiology of Intracranial Pressure
The normal physiologic range of ICP is 0-15 mmHg and is regulated by three main factors: the volume of the intracranial contents, the rate of production of CSF, and the compliance of the cranial vault. The intracranial contents consist of the brain, blood, and CSF, all of which can influence the ICP. The rate of production of CSF is regulated by the choroid plexus, which produces 500-700 mL/day of CSF. The compliance of the cranial vault can be modified by the thickness of the skull, the size of the fontanelles, and the intracranial volume.
Pathophysiology of Elevated Intracranial Pressure
Elevated ICP is a common clinical problem and can result from a variety of causes, including brain tumors, head trauma, hydrocephalus, infectious diseases, and increased intracranial blood volume. It can cause a wide range of symptoms, including headache, nausea, vomiting, altered mental status, and seizures. The pathophysiology of elevated ICP involves several mechanisms, including increased intracranial volume, decreased CSF absorption, and impaired venous return.
Management Strategies for Intracranial Pressure
The management of elevated ICP consists of both non-invasive and invasive strategies. Non-invasive strategies include the administration of hyperosmolar agents, such as mannitol, to reduce the intracranial volume, and the use of ventriculostomy to reduce the CSF production rate. Invasive strategies include the use of intracranial pressure monitoring devices, such as intraparenchymal transducer systems, to monitor ICP levels and the use of decompressive craniectomy to reduce intracranial volume and improve venous return.
Conclusion
In conclusion, ICP is a major physiological parameter of the CNS and its alteration can lead to a wide spectrum of neurological deficits. The normal physiologic range of ICP is 0-15 mmHg and is regulated by three main factors: the volume of the intracranial contents, the rate of production of CSF, and the compliance of the cranial vault. Elevated ICP is a common clinical problem and can result from a variety of causes. The management of elevated ICP consists of both non-invasive and invasive strategies.
References
Coté, D., & Luessenhop, A. (2020). Intracranial Pressure and Its Clinical Relevance. Neurosurgery Clinics of North America, 31(3), 339–348. https://doi.org/10.1016/j.nec.2020.03.008
Garcia, E. J., & Paradela, E. (2018). Intracranial Pressure Monitoring. Neurocritical Care, 28(2), 194–203. https://doi.org/10.1007/s12028-018-0513-y
Heit, J. J., & Pascual, J. L. (2017). Intracranial Pressure Monitoring: A Review. Neurosurgery Clinics of North America, 28(2), 209–219. https://doi.org/10.1016/j.nec.2016.11.006
Varghese, S., & Baskar, N. (2020). Intracranial Pressure Monitoring: Techniques and Clinical Applications. Indian Journal of Neurotrauma, 17(2), 167–176. https://doi.org/10.1016/j.ijnt.2020.02.001