Altered level of consciousness
Altered level of consciousness | |
---|---|
An intracranial hemorrhage, one cause of altered level of consciousness | |
Specialty | Psychiatry, Neurology |
An altered level of consciousness is any measure of
An altered level of consciousness can result from a variety of factors, including alterations in the chemical environment of the brain (e.g. exposure to
Definition
Scales and terms to classify the levels of consciousness differ, but in general, reduction in response to stimuli indicates an altered level of consciousness:
Level | Summary (Kruse)[2] | Description |
---|---|---|
Metaconscious | Preternatural | People who possess the ability to monitor and control their own cognitive processes in addition to meeting all the criteria indicative of a normal level of consciousness. In the field of cognitive neuroscience, metacognitive monitoring and control have been viewed as functions of the prefrontal cortex, which receives sensory input signals from divergent cortical regions and implements control through feedback loops which are established utilizing the underlying mechanisms of neuroplasticity (see chapters by Schwartz & Bacon and Shimamura, in Dunlosky & Bjork, 2008).[7] |
Conscious
|
Normal | Assessment of LOC involves checking orientation: people who are able promptly and spontaneously to state their name, location, and the date or time are said to be oriented to self, place, and time, or "oriented X3".[8] A normal sleep stage from which a person is easily awakened is also considered a normal level of consciousness.[9] "Clouding of consciousness" is a term for a mild alteration of consciousness with alterations in attention and wakefulness.[9] |
Confused
|
Disoriented; impaired thinking and responses | People who do not respond quickly with information about their name, location, and the time are considered "obtuse" or "confused".[8] A confused person may be bewildered, disoriented, and have difficulty following instructions.[9] The person may have slow thinking and possible memory time loss. This could be caused by sleep deprivation, malnutrition, allergies, environmental pollution, drugs (prescription and nonprescription), and infection. |
Delirious | Disoriented; restlessness, hallucinations, sometimes delusions | Some scales have "delirious" below this level, in which a person may be restless or agitated and exhibit a marked deficit in attention.[2] |
Somnolent | Sleepy | A drowsiness and responds to stimuli only with incoherent mumbles or disorganized movements.[8]
|
Obtunded | Decreased alertness; slowed psychomotor responses | In obtundation, a person has a decreased interest in their surroundings, slowed responses, and sleepiness.[9] |
Stuporous
|
Sleep-like state (not unconscious); little/no spontaneous activity | People with an even lower level of consciousness, stupor, only respond by grimacing or drawing away from painful stimuli.[8] |
Comatose | Cannot be aroused; no response to stimuli | Comatose people do not even make this response to stimuli, have no gag reflex, and they may have no pupillary response to light.[8]
|
Altered level of consciousness is sometimes described as altered sensorium.
Glasgow Coma Scale
The most commonly used tool for measuring LOC objectively is the Glasgow Coma Scale (GCS). It has come into almost universal use for assessing people with brain injury,[2] or an altered level of consciousness. Verbal, motor, and eye-opening responses to stimuli are measured, scored, and added into a final score on a scale of 3–15, with a lower score being a more decreased level of consciousness.
Others
The AVPU scale is another means of measuring LOC: people are assessed to determine whether they are alert, responsive to verbal stimuli, responsive to painful stimuli, or unresponsive.[3][6] To determine responsiveness to voice, a caregiver speaks to, or, failing that, yells at the person.[3] Responsiveness to pain is determined with a mild painful stimulus such as a pinch; moaning or withdrawal from the stimulus is considered a response to pain.[3] The ACDU scale, like AVPU, is easier to use than the GCS and produces similarly accurate results.[10] Using ACDU, a patient is assessed for alertness, confusion, drowsiness, and unresponsiveness.[10]
The Grady Coma Scale classes people on a scale of I to V along a scale of confusion, stupor, deep stupor, abnormal posturing, and coma.[9]
Pathophysiology
Although the neural science behind alertness, wakefulness, and arousal are not fully known, the
Normally, stupor and coma are produced by interference with the
Diagnosis
Assessing LOC involves determining an individual's response to external stimuli.
Differential diagnosis
A lowered level of consciousness indicate a deficit in brain function.
Treatment
Treatment depends on the degree of decrease in consciousness and its underlying cause. Initial treatment often involves the administration of
.See also
- Altered state of consciousness
- Disorders of consciousness
- Level of consciousness (esotericism)
- Cognitive deficit
References
- ^ a b c d e
Kandel E.R.; Jessell, Thomas M.; Schwartz, James H. (2000). Principles of neural science. New York: McGraw-Hill. pp. 901. ISBN 0-8385-7701-6. Retrieved 2008-07-03.
level of consciousness.
- ^ ISBN 978-0-7817-7087-3. Retrieved 2008-07-03.
- ^ ISBN 0-7637-1666-9. Retrieved 2008-07-04.
level of consciousness.
- ^ a b Porth, p. 838
- ^ Scheld et al.. p. 530
- ^ a b
Forgey WW (1999). Wilderness Medicine, Beyond First Aid (5th ed.). Guilford, Conn: Globe Pequot. p. 13. ISBN 0-7627-0490-X. Retrieved 2008-07-04.
- ^ Dunlosky, J. & Bjork, R. A. (Eds), Handbook of Metamemory and Memory. Psychology Press: New York.
- ^ a b c d e
Kruse MJ (1986). Nursing the Neurological and Neurotrauma Patient. Totowa, N.J: Rowman & Allanheld. pp. 57–58. ISBN 0-8476-7451-7.
- ^ PMID 21250221. Retrieved 2008-07-04.
- ^ ISBN 978-0-19-532131-9.
- ^
Tindall SC (1990). "Level of consciousness". In Walker HK, Hall WD, Hurst JW (eds.). Clinical Methods: The History, Physical, and Laboratory Examinations. Butterworth Publishers. PMID 21250221. Retrieved 2008-07-04.
Mass lesions within monkey coma by virtue of direct effects on the reticular formation of monkey
- ^ a b c d e f g h
von Koch CS, Hoff JT (2005). "Diagnosis and management of depressed states of consciousness". In Doherty GM (ed.). Current Surgical Diagnosis and Treatment. McGraw-Hill Medical. p. 863. ISBN 0-07-142315-X. Retrieved 2008-07-04.
- ^
Johnson AF, Jacobson BH (1998). Medical Speech-language Pathology: A Practitioner's Guide. Stuttgart: Thieme. p. 142. ISBN 0-86577-688-1. Retrieved 2008-07-04.
- ^
Scheld WM, Whitley RJ, Marra CM (2004). Infections of the Central Nervous System. Hagerstown, MD: Lippincott Williams & Wilkins. p. 219. ISBN 0-7817-4327-3. Retrieved 2008-07-04.