eMedicine Specialties > Radiology > Brain/Spine

Brain, Herniation: Follow-up

Author: Margaret Loh, MD, Staff Physician, Department of Radiology, Santa Clara Valley Medical Center
Coauthor(s): Mahesh R Patel, MD, Chief of MRI, Department of Radiology, Santa Clara Valley Medical Center
Contributor Information and Disclosures

Updated: Sep 28, 2007

Intervention

The following treatments are used to decrease intracranial pressure, which can prevent or decrease brain herniation: hyperventilation, mannitol therapy, steroid treatment, barbiturate coma, hypothermia, and surgical intervention. In patients with obstructing hydrocephalus, ventriculostomy is appropriate for relieving some symptoms

Hyperventilation
The presence of carbon dioxide in the intracranial vasculature causes vasodilation. Hyperventilation of an intubated patient to normocapnia (PaCO2 of 4.0 kPa/30 mm Hg) is the goal for controlling the intracranial pressure. The use of hyperventilation is controversial and has not been shown to improve patient outcomes. Consequently, hyperventilation is reserved for short-term use to gain immediate control when necessary of the intracranial pressure.1

Drug therapy
Mannitol is an osmotic diuretic.2,3 When given as a bolus, it causes an osmotic gradient, drawing water from neuronal cells. After prolonged use, its osmotic effect decreases because the mannitol molecule itself eventually crosses into the cerebral interstitium, decreasing the beneficial gradient.

Steroid treatment has been known to decrease cerebral swelling by decreasing the cell metabolism in the brain, allowing for healing.4 Dexamethasone 12-20 mg/d is given intravenously or orally, depending on the patient's condition.

The mechanism of action of barbiturates reflects their ability to depress metabolic function; by decreasing cerebral blood flow, they bring about a reduction of intracranial pressure. As the induction of a barbiturate coma may result in systemic hypotension, it should not be routinely administered to patients in unstable condition.

Hypothermia

 Hypothermia has been shown to decrease the rate of cerebral metabolism, decreasing cerebral blood flow and intracranial pressure. Hypothermia can reduce the cerebral metabolism rate of oxygen by 5% per degree reduction in core body temperature. Use of this technique is limited, as it increases risk of infection, cardiac arrhythmia, and coagulopathy.

Surgery
Surgical intervention for increased intracranial pressure is dependent on cause. Neoplasms causing brain herniation may be resected or partially resected, if possible, to reduce mass effect. Patients with a large parenchymal and extra-axial hemorrhage may benefit from a standard craniotomy or craniectomy with duraplasty, followed by clot evacuation.

In cases of descending transtentorial herniation of the brain caused by a large subdural hematoma, emergency surgical decompression is required to prevent irreversible and catastrophic injury to the brainstem, as well as to other areas of the brain.

 


More on Brain, Herniation

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Imaging: Brain, Herniation
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Multimedia: Brain, Herniation
References
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References

  1. Muizelaar JP, Marmarou A, Ward JD, et al. Adverse effects of prolonged hyperventilation in patients with severe head injury: a randomized clinical trial. J Neurosurg. Nov 1991;75(5):731-9. [Medline].

  2. Kaufmann AM, Cardoso ER. Aggravation of vasogenic cerebral edema by multiple-dose mannitol. J Neurosurg. Oct 1992;77(4):584-9. [Medline].

  3. Mendelow AD, Teasdale GM, Russell T, et al. Effect of mannitol on cerebral blood flow and cerebral perfusion pressure in human head injury. J Neurosurg. Jul 1985;63(1):43-8. [Medline].

  4. Gutin PH. Corticosteroid therapy in patients with brain tumors. Natl Cancer Inst Monogr. Dec 1977;46:151-6. [Medline].

  5. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 1999:61-2.

  6. Kan P, Amini A, Hansen K, et al. Outcomes after decompressive craniectomy for severe traumatic brain injury in children. J Neurosurg. Nov 2006;105(5 Suppl):337-42. [Medline].

  7. Meadows J, Kraut M, Guarnieri M, et al. Asymptomatic Chiari type I malformations identified on magnetic resonance imaging. J Neurosurg. Jun 2000;92(6):920-6. [Medline].

  8. Osborn AG. Diagnostic Neuroradiology. St Louis, Mo: Mosby-Year Book; 1994:222-9, 456.

  9. Procaccio F, Stocchetti N, Citerio G, et al. Guidelines for the treatment of adults with severe head trauma (part I). Initial assessment; evaluation and pre-hospital treatment; current criteria for hospital admission; systemic and cerebral monitoring. J Neurosurg Sci. Mar 2000;44(1):1-10. [Medline].

  10. Schedler P, Geary S. Kernohan's notch phenomenon: a case study. J Neurosci Nurs. Jun 2002;34(3):158-9. [Medline].

  11. Takeuchi K, Yokoyama T, Ito J, et al. Tonsillar herniation and the cervical spine: a morphometric study of 172 patients. J Orthop Sci. Jan 2007;12(1):55-60. [Medline].

  12. Tse V. Neurological monitoring and management of intracranial hypertension. Semin Neurosurg. 2003;14:89-98.

  13. Wijdicks EF. Uncal herniation in acute subdural hematoma: point of no return. Arch Neurol. Feb 2002;59(2):305. [Medline].

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Further Reading

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Keywords

brain displacement, mass effect, transtentorial herniation, subfalcine/cingulate herniation, subfalcial herniation, foramen magnum/tonsillar herniation, sphenoid/alar herniation, extracranial herniation, uncal herniation

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Contributor Information and Disclosures

Author

Margaret Loh, MD, Staff Physician, Department of Radiology, Santa Clara Valley Medical Center
Margaret Loh, MD is a member of the following medical societies: Radiological Society of North America
Disclosure: Nothing to disclose.

Coauthor(s)

Mahesh R Patel, MD, Chief of MRI, Department of Radiology, Santa Clara Valley Medical Center
Mahesh R Patel, MD is a member of the following medical societies: Radiological Society of North America
Disclosure: Nothing to disclose.

Medical Editor

Chi-Shing Zee, MD, Chief of Neuroradiology, Professor, Departments of Radiology and Neurosurgery, University of Southern California School of Medicine
Chi-Shing Zee, MD is a member of the following medical societies: American Society of Neuroradiology
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

Robert L DeLaPaz, MD, Director, Professor, Department of Radiology, Division of Neuroradiology, Columbia University
Robert L DeLaPaz, MD is a member of the following medical societies: American Society of Neuroradiology, Association of University Radiologists, and Radiological Society of North America
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

L Gill Naul, MD, Professor and Head, Department of Radiology, Texas A&M University College of Medicine; Chair, Department of Radiology, Chief, Section of Magnetic Resonance Imaging, Scott and White Memorial Hospital and Clinic
L Gill Naul, MD is a member of the following medical societies: American College of Radiology, American Medical Association, American Roentgen Ray Society, Radiological Society of North America, and Texas Medical Association
Disclosure: Nothing to disclose.

 
 
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