II. Definition

  1. Coma
    1. Spectrum of dysfunction of awareness and arousal

III. Pathophysiology

  1. Bilateral cortical disease
    1. Unilateral disease does not cause coma
    2. Metabolic and toxic derangements most common
    3. Focal Neurologic signs absent except in Hypoglycemia
  2. Suppression of Reticular Activating System (RAS)
    1. Supratentorial pressure
      1. Subdural Hematoma
      2. Epidural Hematoma
      3. Intracranial Abscess
      4. Subarachnoid Hemorrhage
      5. Brain Tumor
    2. Infratentorial pressure
      1. Cerebellar Hemorrhage
      2. Posterior fossa tumor
    3. Intrinsic Brainstem lesion
      1. Traumatic pontine Hemorrhage
      2. Hypertensive pontine Hemorrhage
      3. Neurologic degenerative diseases
      4. Brainstem tumor
    4. Torque on Brainstem from sudden head blow

IV. Exam

  1. See Coma Exam

V. Differential Diagnosis

  1. See ALOC Causes
  2. See Delirium
  3. Psychogenic Coma
    1. Electroencephalogram (EEG)
    2. Amytal interview

VI. Evaluation

  1. See Altered Level of Consciousness
  2. Step 0: Review History, Exam, Labs
    1. Physiologic Coma with Nonfocal exam may suggest metabolic cause
  3. Step 1: Obtain CT Head and If Abnormal:
    1. Ischemic CVA: Supportive care
    2. Hemorrhagic CVA, Tumor or Brain Abscess
      1. Herniation
        1. Neurosurgical Consultation stat
        2. Decadron
        3. Mannitol
        4. Hyperventilation
      2. No Herniation
        1. Supportive care
        2. Neurosurgical Consultation
  4. Step 2: Obtain Lumbar Puncture and If Abnormal
    1. Meningitis
      1. Antibiotics
    2. Subarachnoid Hemorrhage
      1. Neurosurgical Consultation
  5. Step 3: Unclear etiology (above testing normal)
    1. Etiologies
      1. Brain Stem infarct
      2. Drug Overdose
      3. Complex partial Status Epilepticus
    2. Evaluation
      1. Electroencephalogram (EEG)
      2. MRI Head
    3. Management
      1. Supportive Care

VIII. Prognosis

  1. Nontraumatic coma
    1. Persistent coma for 2 months(n=596)
      1. Mortality: 69% mortality
      2. With severe Disability: 20%
      3. Without severe Disability: 8%
    2. Mortality correlated with:
      1. Abnormal Brain Stem response
      2. Absent verbal response
      3. Absent withdrawal response to pain
      4. Creatinine > 1.5 mg/dl
      5. Age > 70 years
    3. Interpretation
      1. Four or more of above criteria: 96% mortality
  2. References
    1. Hamel (1995) JAMA 273:1842-8 [PubMed]

IX. References

  1. Orman and Chang in Herbert (2017) EM:Rap 17(4): 8-9

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Related Studies

Ontology: Comatose (C0009421)

Definition (MEDLINEPLUS)

A coma is a deep state of unconsciousness. An individual in a coma is alive but unable to move or respond to his or her environment. Coma may occur as a complication of an underlying illness, or as a result of injuries, such as brain injury.

A coma rarely lasts more than 2 to 4 weeks. The outcome for coma depends on the cause, severity, and site of the damage. People may come out of a coma with physical, intellectual, and psychological problems. Some people may remain in a coma for years or even decades. For those people, the most common cause of death is infection, such as pneumonia.

NIH: National Institute of Neurological Disorders and Stroke

Definition (NCI) A state of profound unconsciousness associated with markedly depressed cerebral activity. Causes include central nervous system damage, intoxication, and metabolic abnormalities.
Definition (NCI_NCI-GLOSS) A condition in which a patient is in a state of deep sleep and cannot be awakened. A coma may be caused by many things, including trauma, drugs, toxins, or certain diseases.
Definition (MSH) A profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused. Coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem RETICULAR FORMATION.
Definition (CSP) profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused; coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem.
Concepts Disease or Syndrome (T047)
MSH D003128
ICD9 780.01
ICD10 R40.2 , R40.20
SnomedCT 307760008, 50061006, 158120008, 206715000, 206710005, 371632003
LNC MTHU020645
English Coma, Comas, [D]Coma, Coma, unspecified, [D]Coma (context-dependent category), Coma [D], comatose, exanimation, coma, coma (symptom), Coma (NOS), Coma NOS, Unspecified coma, Coma [Disease/Finding], Comatose, comatose state was observed, comatose state was observed (physical finding), [D]Coma (situation), Coma (finding), Coma (situation), nervous system disorder coma, coma (diagnosis), COMATOSE, COMA, Coma (disorder), Exanimation, Coma, NOS
French COMA, Coma SAI, Comateux/euse, Coma
Portuguese COMA, Coma NE, Coma, Comatoso
Spanish COMA, Coma NEOM, Coma (NEOM), [D]coma (categoría dependiente del contexto), coma (hallazgo), [D]coma, [D]coma (situación), exanimación, Pseudocoma, coma (trastorno), coma, Coma, Comatoso
German KOMA, Koma NNB, komatoes, Koma (NNB), Koma, nicht naeher bezeichnet, Coma, Koma, komatös
Dutch coma (NAO), comateus, coma NAO, Coma, niet gespecificeerd, coma, Coma, Comateus
Italian Coma NAS, Coma (NAS), Comatoso, Stato comatoso, Coma
Japanese 昏睡NOS, 昏睡状態, 昏睡(NOS), コンスイジョウタイ, コンスイ, コンスイNOS, 昏睡, 植物状態
Swedish Koma
Czech kóma, Kóma, Kóma (NOS), Kóma NOS, Komatózní, koma
Finnish Kooma
Korean 상세불명의 혼수
Croatian KOMA
Polish Śpiączka
Hungarian Comatosus, Coma (k.m.n.), Coma k.m.n., Coma
Norwegian Koma