• Clinical science

Elevated intracranial pressure and brain herniation


Intracranial pressure (ICP) is the pressure that exists within the skull and all of its compartments (e.g., the subarachnoid space and the ventricles). ICP varies with the relative position of the head towards the rest of the body and is periodically influenced by normal physiological factors (e.g., cardiac contractions). Adults in supine position have a physiological ICP of 15 mm Hg or less while a pressure of 20 mm Hg or more indicates pathological intracranial hypertension.

Elevation of ICP may occur in a variety of conditions (e.g., intracranial tumors) and can result in a decrease in cerebral perfusion pressure (CPP) and/or herniation of cerebral structures. Symptoms of raised ICP are generally nonspecific (e.g., impaired consciousness, headache, vomiting). However, more specific symptoms may be present depending on the affected structures (e.g., Cushing triad if the brainstem is compressed). Brain imaging (e.g., showing a midline shift) and physical examination (e.g., papilledema) can detect ICP elevation, but not necessarily rule it out. Therefore, ICP monitoring and quantification is vital in at-risk patients. Management usually involves osmotic diuretics such as mannitol or hypertonic saline. Further therapeutic options include controlled hyperventilation, removal of CSF, and decompressive craniectomy.





  • Physiological ICP is ≤ 15 mm Hg in adults (in supine position), children generally have a lower ICP
  • ICP varies with the relative position of the head towards the rest of the body and is influenced by certain physiological processes (e.g., cardiac contractions, sneezing, coughing, Valsalva maneuver).
  • Expansion of either blood, CSF, or tissue within the skull → limited capacity for the intracranial volume to increase within the rigid skull → increase in intracranial pressure

Consequences of elevated ICP


Clinical features


Subtypes and variants

Cerebral herniation syndromes




Clinical examination and imaging may indicate elevated ICP, but cannot rule it out! Additionally, these tests do not allow quantification of intracranial pressure, which is necessary to determine CPP!

Invasive ICP monitoring

  • Indications
    • Patients at risk of elevated ICP
    • Closed head trauma
    • Patients that have a non-surgical intracranial hemorrhage and undergo or have undergone major nonneurological surgery and can not be properly evaluated.
    • Patients suffering from moderate head injury.
  • Placement of monitors
    • Intraventricular (gold standard)
      • Technique: implantation of monitoring device directly into the ventricles
      • Advantages: highest accuracy, allows for treatment of elevated ICP and/or diagnostic collection of CSF samples via drainage system
  • Analysis: > 20 mmHg indicates elevated intracranial pressure that requires treatment
    • ICP is not static but influenced by cardiac action and other factors. → ICP changes in a complex cyclic manner. → represented as distinct waveforms (normal, A wave, B wave, C wave)



Acute stabilization and treatment

ICP management

  • General approach
    • Goal of ICP management is generally to keep ICP < 20 mm Hg.
    • Positioning : e.g., head elevation (about 30 degrees), avoiding neck flexion/rotation or circumstances that may provoke Valsalva responses
    • Fluid management: patients should be euvolemic, blood hypoosmolarity should be avoided
    • Hyperventilation: up to a pCO2 of 26–30 mm Hg
    • Hypothermia
    • Causal treatment (e.g., removal of brain tumor) if possible
  • Medical therapy
    • Osmotic diuretics
      • IV mannitol: can generally be administered every 6–8 hours, effects last for up to 24 hours
      • IV hypertonic saline: particularly for short-term treatment
  • Removal of CSF via an intraventricular monitor with drainage system (e.g., external ventricular drain or lumbar drain) or a cerebral shunt (e.g., in hydrocephalus patients)
  • Decompressive craniectomy: removal of part of the skull, allowing the brain to expand and reduces ICP.



Irreversible loss of brain function (brain death)

  • Definition: irreversible, complete loss of function of the entire brain (including the brainstem), even if cardiopulmonary functions can be upheld by artificial life support.
  • Practical steps for determination of brain death: The American Academy of Neurology has published a practical guide that consists of four steps. It cites specific measures and interpretations (e.g., limits of body temperature) that can be used to determine brain death, although not all of them are evidence-based
  • Management

Requirements for the diagnosis of brain death

If spontaneous breathing is present, the medulla is intact! If the corneal reflex is present, the pons is intact! If the pupillary light reflex is present, the midbrain is intact!

Cerebral edema


We list the most important complications. The selection is not exhaustive.

  • 1. Nelson SL. Hydrocephalus. In: Chawla J. Hydrocephalus. New York, NY: WebMD. http://emedicine.medscape.com/article/1135286-overview#a1. Updated April 13, 2016. Accessed December 14, 2016.
  • 2. Lo BM. Brain Neoplasms. In: Brain Neoplasms. New York, NY: WebMD. http://emedicine.medscape.com/article/779664-overview. Updated November 9, 2015. Accessed February 19, 2017.
  • 3. Gupta G. Intracranial Pressure Monitoring. In: Intracranial Pressure Monitoring. New York, NY: WebMD. http://emedicine.medscape.com/article/1829950-overview. Updated September 17, 2015. Accessed February 19, 2017.
  • 4. Gans MS. Idiopathic Intracranial Hypertension. In: Idiopathic Intracranial Hypertension. New York, NY: WebMD. http://emedicine.medscape.com/article/1214410-overview. Updated January 28, 2016. Accessed March 1, 2017.
  • 5. Montgomery K. Meningitis. http://www.pathophys.org/meningitis/. Updated October 22, 2012. Accessed March 1, 2017.
  • 6. Liebeskind DS. Intracranial Hemorrhage. In: Intracranial Hemorrhage. New York, NY: WebMD. http://emedicine.medscape.com/article/1163977-overview. Updated May 10, 2016. Accessed March 1, 2017.
  • 7. Shah AK, Fuerst D, Sood S et al. Seizures Lead to Elevation of Intracranial Pressure in Children Undergoing Invasive EEG Monitoring. Epilepsia. 2017; 48(6): pp. 1097–1103. doi: 10.1111/j.1528-1167.2006.00975.x.
  • 8. Smith ER. Evaluation and management of elevated intracranial pressure in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/evaluation-and-management-of-elevated-intracranial-pressure-in-adults?source=machineLearning&search=intracranial%20pressure&selectedTitle=1~150&anchor=H2§ionRank=1#H9. Last updated July 10, 2013. Accessed February 19, 2017.
  • 9. Hackett JG, Abboud FM, Mark AL, Schmid PG, Heistad DD. Coronary vascular responses to stimulation of chemoreceptors and baroreceptors: evidence for reflex activation of vagal cholinergic innervation. Circ Res. 1972; 31(1): pp. 8–17. pmid: 4402639.
  • 10. Tasker RC. Elevated intracranial pressure (ICP) in children: Clinical manifestations and diagnosis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/elevated-intracranial-pressure-icp-in-children-clinical-manifestations-and-diagnosis. Last updated February 2, 2017. Accessed March 1, 2017.
  • 11. Shetty A, Gaillard F et al. Sunset eye sign. https://radiopaedia.org/articles/sunset-eye-sign. Updated March 1, 2017. Accessed March 1, 2017.
  • 12. Agamanolis DP. Traumatic Brain Injury and Increased Intracranial Pressure. http://neuropathology-web.org/chapter4/chapter4cHerniations.html. Updated March 1, 2017. Accessed March 1, 2017.
  • 13. Goetz CG. Textbook of Clinical Neurology. Elsevier; 2007.
  • 14. Skalski M, Dawes L. Cerebral herniation. https://radiopaedia.org/articles/cerebral-herniation. Updated March 1, 2017. Accessed March 1, 2017.
  • 15. Case Western Reserve University. Herniation Syndromes. http://casemed.case.edu/clerkships/neurology/NeurLrngObjectives/Herniation%20syndromes.htm. Updated July 17, 2006. Accessed March 1, 2017.
  • 16. Gupta P. Pericallosal artery occlusion. https://radiopaedia.org/cases/pericallosal-artery-occlusion. Updated March 1, 2017. Accessed March 1, 2017.
  • 17. Hacking C, Gaillard F. Subfalcine Herniation. https://radiopaedia.org/articles/subfalcine-herniation. Accessed April 17, 2018.
  • 18. Kasper DL, Fauci AS, Hauser SL, Longo DL, Lameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. New York, NY: McGraw-Hill Education; 2015.
  • 19. Marmarou A. A review of progress in understanding the pathophysiology and treatment of brain edema. Neurosurg Focus. 2007; 22(5): p. E1. pmid: 17613227.
  • 20. Wijdicks EF, Varelas PN, Gronseth GS, Greer DM, American Academy of Neurology. Evidence-based guideline update: determining brain death in adults: report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2010; 74(23): pp. 1911–1918. doi: 10.1212/WNL.0b013e3181e242a8.
  • 21. Dixon TD, Malinoski DJ. Devastating brain injuries: assessment and management part I: overview of brain death. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672297/pdf/0100011.pdf. Updated February 1, 2009. Accessed February 19, 2017.
  • 22. Young GB. Diagnosis of brain death. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/diagnosis-of-brain-death?source=machineLearning&search=brain%20death&selectedTitle=1~150§ionRank=1&anchor=H2#H2. Last updated May 27, 2015. Accessed February 19, 2017.
  • 23. Schofield GM, Urch CE, Stebbing J, Giamas G. When does a human being die?. QJM. 2014; 108(8): pp. 605–609. doi: 10.1093/qjmed/hcu239.
  • 24. Scott JB, Gentile MA, Bennett SN, Couture M, MacIntyre NR. Apnea testing during brain death assessment: a review of clinical practice and published literature. Respir Care. 2013; 58(3): pp. 532–538. doi: 10.4187/respcare.01962.
  • 25. Rao JVI, Vengamma B, Naveen T, Naveen V. Lead encephalopathy in adults. J Neurosci Rural Pract. 2014; 5(2): pp. 161–163. doi: 10.4103/0976-3147.131665.
  • Roberts I, Sydenham E. Barbiturates for acute traumatic brain injury. Cochrane Database of Systematic Reviews. 2012: p. CD000033. doi: 10.1002/14651858.cd000033.pub2.
  • Torbey MT, Bösel J, Rhoney DH, et al. Evidence-Based Guidelines for the Management of Large Hemispheric Infarction. Neurocrit Care. 2015; 22(1): pp. 146–164. doi: 10.1007/s12028-014-0085-6.
  • Wagner I, Hauer E-M, Staykov D, et al. Effects of Continuous Hypertonic Saline Infusion on Perihemorrhagic Edema Evolution. Stroke. 2011; 42(6): pp. 1540–1545. doi: 10.1161/strokeaha.110.609479.
  • Wells DL, Swanson JM, Wood GC, et al. The relationship between serum sodium and intracranial pressure when using hypertonic saline to target mild hypernatremia in patients with head trauma. Critical Care. 2012; 16(5): p. R193. doi: 10.1186/cc11678.
  • Ryken TC, McDermott M, Robinson PD, et al. The role of steroids in the management of brain metastases: a systematic review and evidence-based clinical practice guideline. J Neurooncol. 2009; 96(1): pp. 103–114. doi: 10.1007/s11060-009-0057-4.
  • Esquenazi Y, Lo VP, Lee K. Critical Care Management of Cerebral Edema in Brain Tumors. J Intensive Care Med. 2016; 32(1): pp. 15–24. doi: 10.1177/0885066615619618.
  • Karnatovskaia LV, Lee AS, Festic E, Kramer CL, Freeman WD. Effect of Prolonged Therapeutic Hypothermia on Intracranial Pressure, Organ Function, and Hospital Outcomes Among Patients with Aneurysmal Subarachnoid Hemorrhage. Neurocrit Care. 2014; 21(3): pp. 451–461. doi: 10.1007/s12028-014-9989-4.
  • Honeybul S, Ho KM, Gillett G. Outcome Following Decompressive Hemicraniectomy for Malignant Cerebral Infarction. Stroke. 2015; 46(9): pp. 2695–2698. doi: 10.1161/strokeaha.115.010078.
  • Andrews et al. Hypothermia for Intracranial Hypertension after Traumatic Brain Injury. New England Journal of Medicine. 2015; 373(25): pp. 2403–2412. doi: 10.1056/nejmoa1507581.
  • Chen H, Wu F, Yang P, Shao J, Chen Q, Zheng R. A meta-analysis of the effects of therapeutic hypothermia in adult patients with traumatic brain injury. Critical Care. 2019; 23(1): p. 396. doi: 10.1186/s13054-019-2667-3.
  • Changa AR, Czeisler BM, Lord AS. Management of Elevated Intracranial Pressure: a Review. Curr Neurol Neurosci Rep. 2019; 19(12): p. 99. doi: 10.1007/s11910-019-1010-3.
  • Wagner KE et al. Trauma. Oper Neurosurg. 2019; 17(Supplement_1): pp. S45–S75. doi: 10.1093/ons/opz089.
  • Kristiansson H et al. Measuring Elevated Intracranial Pressure through Noninvasive Methods. J Neurosurg Anesthesiol. 2013; 25(4): pp. 372–385. doi: 10.1097/ana.0b013e31829795ce.
  • Clark J, Ellens N, Figueroa B. The use of barbiturate-induced coma during cerebrovascular neurosurgery procedures: A review of the literature. Brain Circulation. 2015; 1(2): p. 140. doi: 10.4103/2394-8108.172887.
  • Carney N, Totten AM, O’Reilly C, et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. Neurosurgery. 2016; 80(1): pp. 6–15. doi: 10.1227/neu.0000000000001432.
  • Burgess S, Abu-Laban RB, Slavik RS, Vu EN, Zed PJ. A Systematic Review of Randomized Controlled Trials Comparing Hypertonic Sodium Solutions and Mannitol for Traumatic Brain Injury. Ann Pharmacother. 2016; 50(4): pp. 291–300. doi: 10.1177/1060028016628893.
  • Boone M, Oren-Grinberg A, Robinson T, Chen C, Kasper E. Mannitol or hypertonic saline in the setting of traumatic brain injury: What have we learned?. Surgical Neurology International. 2015; 6(1): p. 177. doi: 10.4103/2152-7806.170248.
  • Mangat HS. Hypertonic saline infusion for treating intracranial hypertension after severe traumatic brain injury. Critical Care. 2018; 22(1): p. 37. doi: 10.1186/s13054-018-1963-7.
  • Rowland MJ, Veenith T, Hutchinson PJ, Perkins GD. Osmotherapy in traumatic brain injury. The Lancet Neurology. 2020; 19(3): p. 208. doi: 10.1016/s1474-4422(20)30003-x.
  • Winn HR. Youmans and Winn Neurological Surgery. Philadelphia, PA: Elsevier; 2016.
  • Hutchinson PJ, Kolias AG, Timofeev IS, et al. Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension. N Engl J Med. 2016; 375(12): pp. 1119–1130. doi: 10.1056/nejmoa1605215.
  • Fried HI, Nathan BR, Rowe AS, et al. The Insertion and Management of External Ventricular Drains: An Evidence-Based Consensus Statement. Neurocrit Care. 2016; 24(1): pp. 61–81. doi: 10.1007/s12028-015-0224-8.
  • Le Roux P, Menon DK, Citerio G, et al. Consensus Summary Statement of the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care. Neurocrit Care. 2014; 21(S2): pp. 1–26. doi: 10.1007/s12028-014-0041-5.
  • Watson HI, Shepherd AA, Rhodes JKJ, Andrews PJD. Revisited: A Systematic Review of Therapeutic Hypothermia for Adult Patients Following Traumatic Brain Injury. Crit Care Med. 2018; 46(6): pp. 972–979. doi: 10.1097/ccm.0000000000003125.
  • Andrews PJ, Sinclair HL, Rodríguez A, et al. Therapeutic hypothermia to reduce intracranial pressure after traumatic brain injury: the Eurotherm3235 RCT. Health Technol Assess (Rockv). 2018; 22(45): pp. 1–134. doi: 10.3310/hta22450.
  • Crompton EM, Lubomirova I, Cotlarciuc I, Han TS, Sharma SD, Sharma P. Meta-Analysis of Therapeutic Hypothermia for Traumatic Brain Injury in Adult and Pediatric Patients. Crit Care Med. 2017; 45(4): pp. 575–583. doi: 10.1097/ccm.0000000000002205.
  • Bullock MR, Chesnut R, Ghajar J, et al. Guidelines for the Surgical Management of Traumatic Brain Injury Author Group. Neurosurgery. 2006; 58(3): pp. S2–vi–S2–vi. doi: 10.1093/neurosurgery/58.3.vi.
  • Godoy DA, Seifi A, Garza D, Lubillo-Montenegro S, Murillo-Cabezas F. Hyperventilation Therapy for Control of Posttraumatic Intracranial Hypertension. Frontiers in Neurology. 2017; 8: p. 250. doi: 10.3389/fneur.2017.00250.
  • Walls R, Hockberger R, Gausche-Hill M. Rosen's Emergency Medicine. Philadelphia, PA: Elsevier Health Sciences; 2018.
  • Carey E, Krucik G. Increased Intracranial Pressure. http://www.healthline.com/health/increased-intracranial-pressure#Overview1. Updated October 22, 2015. Accessed March 1, 2017.
  • Dimitriou J et al. Comparison of Complications in Patients Receiving Different Types of Intracranial Pressure Monitoring: A Retrospective Study in a Single Center in Switzerland. World Neurosurg. 2016; 89: pp. 641–646. doi: 10.1016/j.wneu.2015.11.037.
last updated 11/19/2020
{{uncollapseSections(['qgcCwb0', '7gc49b0', 'IgcY9b0', 'HgcK9b0', 'sgct9b0', '8gcOCb0', 'Egc8Cb0', '-gcDBb0'])}}