Intracranial Pressure
Blood, cerebrospinal fluid (CSF) and brain tissue are all constituents of the cranium. The pressure within the cranium is known as intracranial pressure (ICP); it is the same as that found in the brain tissue and CSF. (2) The pressure-volume relationship between ICP, brain tissue, blood, volume of CSF, and cerebral perfusion pressure (CPP) is known as the Monro-Kellie hypothesis.(12) This hypothesis states that the cranial compartment is considered as an enclosed and inelastic container, which has a fixed volume; if an increase of any one of the components occurs, it must be accompanied with a decrease in another in order to maintain a state of equilibrium, if this does not occur it will eventually lead to an increase in ICP. (13)
The normal values for ICP are dependent on the age of the patient, their body posture and clinical conditions. In adults normal range is considered 40mm Hg. (7)
ICP hypertension can be caused by a number of things, these can be: either intracranial (primary) - brain tumour, trauma, non-traumatic intracerebral haemorrhage, ischemic stroke or hydrocephalus. Or it may be extracranial (secondary) - airway obstruction, hypoxia, hypertension, seizures, posture, drug intoxication, or it may be postoperative- mass lesions, increased cerebral volume or disturbances of CSF. (14)
ICP hypertension signs and symptoms vary relying on etiology. Common symptoms that suggest a rise in ICP include headache, nausea, vomiting, ocular palsies, back pain, progressive mental status decline and papilledema. (17)
In regards to the boy in our case study, it is clear that he most probably has elevated ICP due to traumatic brain injury (TBI)- which is a primary cause of elevated ICP; this is evident from the symptoms that he was experiencing. In order to get a definitive diagnosis it is crucial that further tests be carried out.
Sustained elevated levels of ICP will lead to reduced cerebral blood flow and hence brain herniation. Pressure will arise from the
The normal values for ICP are dependent on the age of the patient, their body posture and clinical conditions. In adults normal range is considered 40mm Hg. (7)
ICP hypertension can be caused by a number of things, these can be: either intracranial (primary) - brain tumour, trauma, non-traumatic intracerebral haemorrhage, ischemic stroke or hydrocephalus. Or it may be extracranial (secondary) - airway obstruction, hypoxia, hypertension, seizures, posture, drug intoxication, or it may be postoperative- mass lesions, increased cerebral volume or disturbances of CSF. (14)
ICP hypertension signs and symptoms vary relying on etiology. Common symptoms that suggest a rise in ICP include headache, nausea, vomiting, ocular palsies, back pain, progressive mental status decline and papilledema. (17)
In regards to the boy in our case study, it is clear that he most probably has elevated ICP due to traumatic brain injury (TBI)- which is a primary cause of elevated ICP; this is evident from the symptoms that he was experiencing. In order to get a definitive diagnosis it is crucial that further tests be carried out.
Sustained elevated levels of ICP will lead to reduced cerebral blood flow and hence brain herniation. Pressure will arise from the
References: 6. Figaji AA, Zwane E, Thompson C, et al. Brain tissue oxygen tension monitoring in pediatric severe traumatic brain injury: Part 1:Relationship with outcome. Childs Nervous System. 2009; 25: 1325-1333 7 8. Lavin, P. Management of hypertension in patients with acute stroke. Archives of Internal Medicine, 1986;146: 66. 10. Mayhall, C., Archer, N., & Lamb, V., et. Al. Ventriculostomy-related infections. A prospective epidemiologic study. New England Journal of Medicine, 1984;310:9: 553-559. 11. Miller, J., Bobo, H., & Kapp, J. Inaccurate Pressure Readings From Subarachnoid Bolts.Neurosurgery, 1986;19:2: 253-250. 12. Mokri B, The Monro-Kellie hypothesis: applications in CSF volume depletion. Neurology. 2001;56 12: 1746–8. 14. National Institute of Health. (2000). Intracranial Pressure Monitoring. Warren G. Magnuson Clinical Center. Retrieved 22/10/2011 http://clinicalcenter.nih.gov/ccmd/pdf_doc/Clinical%20Monitoring/04-Intracranial%20Pressure%20Mo.pdf/ 15 19. Zhong, J. (2003). Advances in ICP Monitoring Techniques. Maney Publishing. Retrieved 21/10/2011from http://www.ingentaconnect.com/content/maney/nres/2003/00000025/00000004/art00005[pic][pic][pic]