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Disease Categories > Neurologic Disease

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Postanoxic Coma - Anoxia

Coma is a common occurrence in intensive care units.

Epidemiology

Prevalence
- Approximately 20% of patients receiving mechanical ventilation
- 80% of survivors of cardiac arrest are comatose following resuscitation

Pathophysiology

Brain oxygen is depleted within 20 seconds
Central nervous system neurons have sufficient glucose stores to support 5 minutes of brain activity
Prolonged resuscitation or anoxia does not provide adequate circulation to the brain
Brain becomes ischemic
Ischemia produces cytoxic cascade with activation of damaging processes to the brain
Further damage may ensue and result in neuronal death
These processes may result in permanent brain damage
In patients who remain comatose >48-72 hours after an anoxic event (eg, trauma, cardiac arrest), outcome assessment is difficult, yet necessary. Predictive test indicators may be helpful in this assessment process.

Clinical Presentation

Patient remains unconscious and minimally responsive or unresponsive to stimulation
Absent brain stem reflexes (pupil, cornea, gag/cough responses); absent motor responses; absent vestibular reflexes (oculomotor – doll’s eyes and cold calorics)
Seizures

Diagnosis

Indications for testing: coma >72 hours after anoxic event without evident metabolic or structural etiology
Laboratory testing
- Recent reports suggest combining somatosensory evoke potentials (SSEP) with specific serum neurobiochemical markers
  - Neuron specific enolase (NSE)
    - Enolase isoenzyme is a specific neurobiochemical marker for damage to neuronal brain tissue
      - Elevated in traumatic brain injury
      - Elevated in anoxic brain injury
  - S-100B protein
    - Released into peripheral circulation immediately following primary brain trauma
    - Predictive power of elevated serum S-100B is higher than that of traditional clinical indicators
Poor outcome prediction is highly likely when (N20) SSEP is absent and NSE >33 μg/L at 72º post event

Test Name and Number	Recommended Use	Limitations	Follow Up
Neuron Specific Enolase 0098198 Method: Enzyme-Linked Immunosorbent Assay	Aid in the prediction of poor outcome in postanoxic coma	Absolute values not yet established	Should be ordered with SSEP and used in conjunction with clinical findings
S-100B Protein, Serum 0081328 Method: Enzyme-Linked Immunosorbent Assay	Aid in the prediction of poor outcome in postanoxic coma Monitor patients with acquired brain injury for ongoing brain damage	Absolute values not yet established Due to the short half-life and rapid decrease of serum S-100B, knowledge of the time of injury is important for accurate interpretation and outcome prediction S-100B is not specific for brain injury. Increased serum concentrations are found in patients with melanoma, liver and renal injury, inflammation and infection
Immunohistochemistry Stain Offering arup005 Method: Immunohistochemistry	For fixed tissue samples, consultative services as well as immunohistochemical staining for NSE are available

General References

Berger RP, Adelson PD, Pierce MC, Dulani T, Cassidy LD, Kochanek PM. Serum neuron-specific enolase, S100B, and myelin basic protein concentrations after inflicted and noninflicted traumatic brain injury in children. J Neurosurg. 2005;103(1 Suppl):61-68. (Link to PubMed)

Berger RP. The use of serum biomarkers to predict outcome after traumatic brain injury in adults and children. J Head Trauma Rehabil. 2006;21(4):315-333. (Link to PubMed)

Casmiro M, Maitan S, De Pasquale F, Cova V, Scarpa E, Vignatelli L. Cerebrospinal fluid and serum neuron-specific enolase concentrations in a normal population. Eur J Neurol. 2005;12(5):369-374. (Link to PubMed)

Cooper EH. Neuron-specific enolase. Int J Biol Markers. 1994;9(4):205-210. (Link to PubMed)

Darnell RB, Posner JB. Paraneoplastic syndromes involving the nervous system. N Engl J Med. 2003;349(16):1543-1554. (Link to PubMed)

Eriksson B, Oberg K, Stridsberg M. Tumor markers in neuroendocrine tumors. Digestion. 2000;62 Suppl 1:33-38. (Link to PubMed)

Korfias S, Stranjalis G, Boviatsis E, Psachoulia C, Jullien G, Gregson B, Mendelow AD, Sakas DE. Serum S-100B protein monitoring in patients with severe traumatic brain injury. Intensive Care Med. 2007;33(2):255-260. (Link to PubMed)

Meyer NJ, Hall JB. Brain dysfunction in critically ill patients--the intensive care unit and beyond. Crit Care. 2006;10(4):223-. (Link to PubMed)

Puttgen HA, Geocadin R. Predicting neurological outcome following cardiac arrest. J Neurol Sci. 2007;261(1-2):108-117. (Link to PubMed)

Raabe A, Kopetsch O, Woszczyk A, Lang J, Gerlach R, Zimmermann M, Seifert V. Serum S-100B protein as a molecular marker in severe traumatic brain injury. Restor Neurol Neurosci. 2003;21(3-4):159-169. (Link to PubMed)

Selakovic V, Raicevic R, Radenovic L. The increase of neuron-specific enolase in cerebrospinal fluid and plasma as a marker of neuronal damage in patients with acute brain infarction. J Clin Neurosci. 2005;12(5):542-547. (Link to PubMed)

Tanabe T, Suzuki S, Hara K, Shimakawa S, Wakamiya E, Tamai H. Cerebrospinal fluid and serum neuron-specific enolase levels after febrile seizures. Epilepsia. 2001;42(4):504-507. (Link to PubMed)

Townend W, Ingebrigtsen T. Head injury outcome prediction: a role for protein S-100B?. Injury. 2006;37(12):1098-1108. (Link to PubMed)

Wijdicks EF, Hijdra A, Young GB, Bassetti CL, Wiebe S. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006;67(2):203-210. (Link to PubMed)

Zandbergen EG, de Haan RJ, Hijdra A. Systematic review of prediction of poor outcome in anoxic-ischaemic coma with biochemical markers of brain damage. Intensive Care Med. 2001;27(10):1661-1667. (Link to PubMed)

Zandbergen EG, Hijdra A, Koelman JH, Hart AA, Vos PE, Verbeek MM, de Haan RJ. Prediction of poor outcome within the first 3 days of postanoxic coma. Neurology. 2006;66(1):62-68. (Link to PubMed)

Reviewed by

Grenache, David G., Ph.D. Medical Director, Special Chemistry at ARUP Laboratories; Assistant Professor, Clinical Pathology, University of Utah

Comprehensive Review: May 2008
Last Update: May 2008

Postanoxic Coma - Anoxia

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