Coma

By Shireen Gupta

DefinitionConsciousness

State of awareness of self and the environment

ComaSleep-like state of unresponsiveness.No awareness of self or the environment

Alterations in Sensorium(seat of sensation)“Clouding of Consciousness”

reduced wakefulness alternating with irritability; Defect in attention

Delirium(acute confusional state)disorientation, fear, irritabilityaltered perceptions of sensory stimulirapid onset duration 5-7 days

Obtundation(less than full mental capacity)mild to moderate reduction in alertnessmental blunting

Stuporasleep or behaviorally unresponsiveAroused by repeated vigorous stimulation

Comatose stateA person in a coma cannot be:awakened, fails to respond normally to pain, light or

sounddoes not have sleep-wake cycles, and does not take voluntary actions.

Etiologyintoxication metabolic abnormalities, Pyschogenic/CNS diseasesIatrogenicStructural lesionMedications

Anatomy of ComaAscending Reticular Activating System

(ARAS)

Diencephalon

Cerebral Cortex

ARAS

Underlying cause:Damage to the Reticular formation of

the hindbrain which is important in regulating sleep.

Diencephalon (Thalamus)Input from the ARASOutput to the cerebral cortexBilateral injury required to produce coma

Cerebral CortexMaintains awarenessBilateral diffuse cortical dysfunction can

result in comaFocal lesion with mass effectVegetative state

A llergiesM edicationsP ast medical historyL ast mealE vent

Ask GP, family and check medical records for this information

HISTORY

Coma ExaminationExamination of the comatose patient is an

examination of the brainstemIn the initial assessment of coma, it is common

to gauge the level of consciousness by response to

vocal stimuli ("Can you hear me?")painful stimuli; this is known as the AVPU

(alert, vocal stimuli, painful stimuli, unconscious) scale.

 Glasgow coma scale quantify individual reactions such as eye opening, movement and verbal response on a scale.

The Glasgow coma scaleNeurological scale - a reliable, objective way of

recording the conscious state of a person, for initial as well as continuing assessment.

A patient is assessed against the criteria of the scale, and the resulting points give a patient score between 3 (indicating deep unconsciousness) and

Generally, brain injury is classified as: Severe, with GCS ≤ 8 Moderate, GCS 9 - 12 Minor, GCS ≥ 13

Glascow Coma ScoreEye openingspontaneous 4voice 3pain 2nil 1

Best verbaloriented 5confused 4 inappropriate 3 incomprehens. 2nil 1

Best Motorobeys 6 localizes 5nl flexion 4decorticate 3decerebrate 2nil 1

FOUR Score4 components

•Brainstem reflexes B4•Brainstem reflexes B4

•Motor responses M4•Motor responses M4

•Respiration R4•Respiration R4

•Eye responses E4•Eye responses E4

CP1199945-54

Four ScoreEye Response.

Motor Response

Brainstem Response

Respiration

LaboratoryElectrolytesCalcium & magnesiumCBCToxicology/drug screen

Ancillary StudiesHead imagingCXRECGEEG

Emergent TherapiesABC’sD50

NarcanThiamineFlumazenil

ReferencesSnells Neuroanatomyhttp://en.wikipedia.org