Coma Lecture Powerpoint Flashcards
Consciousness definition
State of awareness of self and environment, condition for which a person is capable of perceiving stimuli from the environment and respond appropriately, components include arousal (being awake mediated by reticular activating system) and awareness to sensations, emotions, and thoughts around us
System of consciousness has 2 principle functions
1) maintenance of waking state (arousal)
2) content of experience (awareness)
Components of “normal” waking consciousness (8)
- level of awareness
- content limitations
- attention
- controlled and automatic processes
- Perceptual and cognitive distortions
- emotional awareness
- self control
- time orientation
Clouding of consciousness
Very mild form of altered mental status in which patient has inattention and reduced wakefulness
Confusional state
More profound consciousness deficit that includes disorientation, bewilderment, and difficulty following commands
Delirium
An acute confusional state characterized by alternation of consciousness with reduced ability to focus, sustain, or shift attention
Drowsiness
State of consciousness where a person can be aroused by moderate stimuli but then drifts back to sleep
Lethargy
A state of consciousness of severe drowsiness in which a patient can be aroused by moderate stimuli with drowsiness between sleep states and then drifts back to sleep
Obtundation
A state of consciousness similar to lethargy where patient has lessened interest in environment*** and slowed response to stimulation, tending to sleep more than normal with drowsiness between sleep states
Stupor
State of consciousness where only vigorous and intense stimuli will arouse and individual, but when left undisturbed immediately relapse into unresponsive state
Coma
State of unarousable unresponsiveness
Minimially conscious state and an example
State related to coma with minimal but definite behavioral evidence of self or environmental awareness, with partial preservation of consciousness ex) following commands such as looking up or down
Vegetative state and example
State relating to coma where patient is able to be aroused but not aware** ex) Terri Schiavo case
Brain death
State related to coma considered death by neurological criteria, absence of brain stem reflexes, EEG showing no electrocerebral activity, may be kept alive by medical needs but even involuntary actions need to be performed by external influence
Ascending reticular activating system (ARAS)
Basic network of neurons originating in upper pons and midbrain integral to introducing and maintaining arousal, neurons project to diencephalon (thalamus and hypothalamus) and then to the cerebral cortex integral to awareness
5 causes of coma
- herniation syndrome and various trauma
- structural or brainstem lesions
- metabolic causes
- toxic syndromes (drug overdose)
- infection
Decorticate posturing, what its glasgow coma scale is, and what it indicates (3)
Presentation of stiff bent arms towards body and clenched fists with fingers bend and held on the chest with legs straight out (glasgow coma scale 3 in motor), indicating damage to cerebral hemispheres, midbrain, or thalamus
Decerebrate posturing what its glasgow coma scale is, and what it indicates (4)
Presentation of arms and legs held out straight, toes pointed downward, head and neck arched backwards, muscles tightened and held in rigidity (Glasgow coma scale 2 in motor), indicating brain stem damage, lesions or compression of midbrain, or lesions of cerebellum
Decerebrate posturing is often seen in ___ strokes
pontine
Common causes of metabolic induced coma and what is the most common? (11 of em, just list a few for christ sake)
- Hypoxia (most common)
- hypoglycemia
- hyperglycemia
- hypothyroidism
- CNS infection
- drugs
- hyperkalemia
- hyponatremia
- uremia
- hypocalcemia
- anemia
Asterixis
Tremor of the hand when the wrist is extended, sometimes said to resemble a bird flapping its wings, characterized by an inability to maintain a position upon manipulation by practitioner in already extended state (wave goodbye sign)
myoclonus and what is multifocal myoclonus suggestive of?
- Quick involuntary muscle jerk (hyperreflexia) characterized by practitioner pushing back on neutral state wrist or ankle and seeing jerking movement
- multifocal is strongly suggestive of metabolic coma
Pupils and vital signs with the various toxidromes (sympathomimetic, anticholinergic, hallucinogenic, opioid, sedative, cholinergic, serotonin syndrome)
Sympathomimetic - mydriasis and elevations and hyperactive bowel sounds
Anticholinergic - mydriasis and elevations
Hallucinogenic - mydriasis and elevations and hyperactive bowel sounds
Opioid - Miosis and depressions
Sedative - Miosis and depressions
Cholinergic - miosis and depressions but hyperactive bowel
Serotonin syndrome - Mydriasis and elevations
Common causes of infectious coma (4)
- Bacterial meningitis
- viral encephalitis
- syphilis
- malaria
Waterhouse-friderichsen syndrome
Adrenal failure due to bleeding into the adrenal glands most often infectious in origin caused by neisseria meningitidis
How does locked in syndrome differ from coma?
Consciousness is preserved even though patient cannot move muscles they can voluntary blink and move vertical eyes, can still perceive and detect the environment
How does Akinetic mutism differ from coma?
A lack of motor response in awake individual where a patient cannot move or speak
How does Psychogenic unresponsiveness differ from coma?
It is a prolonged motionless dissociative attack with absent or reduced response to external stimuli despite no activity cessation on an EEG, likely in response to trauma
Initial evaluation and history of suspected coma patient (6)
- history from witnesses
- old charts or medical bracelets
- abrupt, gradual, or fluctuating?
- preceding focal signs and symptoms (transient visual symptoms indicate ischemia!)?
- recent illness?
- drug use/abuse?
Cherry red skin in suspected coma patient is associated with…
…carbon monoxide poisoning
Osler’s nodes
Painful purple nodules on palms and soles seen in bacterial endocarditis
Neurologic exam on a suspected coma patient
- Level of consciousness: (Glasgow coma scale)
- Motor responses (muscle tone, reflexes, posturing)
- Brainstem reflexes (pupillary light, corneal reflexes)
Glasgow coma scale does not include ____ in coma assessment while FOUR score does making it slightly better
Brainstem reflexes
Glasgow coma scale definition and ranges
Grades severity of coma according to 3 categories of responsiveness excluding the brainstem, with a score of 3 being worst and 15 being best, 13 or higher indicates mild brain injury, 9-12 indicates moderate, 8 or less is severe
FOUR score definition and ranges
4 component exam to grade severity of coma, including eye, motor, brainstem**, and respiratory, lower the score the greater the severity of coma, has better biostatistical properties than glasgow coma scale in terms of sensitivity, specificity, accuracy, and positive predictive value
FOUR score <6 predicts…
….expected death
Pinpoint pupils is indicative of ____, significant asymmetric pupillary response is indicative of ____ or ___, unreactive midsized pupils indicates ___ or ___
Pontine lesion, brainstem involvement, ruptured aneurysm, drugs, death
Vestibule-ocular reflex
Detects an intact brainstem, if when turning patients head, eyes remain facing forward, they have an intact brainstem, but if eye turns with the head then brainstem is damaged
Caloric reflex test
Intact brainstem reflex test, cold water placed in the ear causes eyes to move toward the same ear in normal response, warm water placed in the ear causes the eyes to move away from the ear in normal response
Things to give in suspected coma patient (4), things to order in suspected coma patient (6)
- Glucose IV
- thiamine
- naloxone (counteract narcotic OD)
- O2
- Non contrast CT
- EKG
- TSH
- CBC
- blood culture
- EEG
Lumbar puncture is indicated if these 2 things are present (suspicion of meningitis)
- elevated or depressed temp
- nuchal rigidity
Status epilepticus abortion drug choices in order of first choice to third
- IV lorazepam
- IV dilantin or valproic acid
- IV phenobarbital
Confirmatory test for brain death
Blood flow perfusion on MR scintigraphy
Cardinal feature of metabolic coma
-symmetrical nature of neurologic deficits, such as symmetric pupils that appear abnormal but constrict with light
Glasgow coma scale criteria
- Eye opening (1-4) (4 is spontaneous)
- Best verbal response (1-5) (5 is oriented)
- Best motor response (1-6) (6 is obeys commands)
