Flashcards in Coma Deck (74)
What is consciousness?
Awareness of self and environment
What are the 2 types of alterations in consciousness?
-Cognitive and affective mental functioning
What is lethargy?
Tired/sleepy, but easily aroused
What is stupor?
Unresponsiveness from which the patient can be aroused only be vigorous, often noxious stimuli
What are the two mechanisms of coma?
Hit both hemispheres or brainstem
What are the two major structural locations for a coma?
Where does arousability begin in the brain?
Pontine reticular activating system (reticular formation)
Where do the fibers from the RF go?
Decussate, and ascend into the thalamus, where they then project diffusely in the cortices
Where does the reticular activating system reside?
Tumors in what location (generally) coma?
Pons (hitting the pontine reticular activating system)
True or false: stroke patients typically do not cause a LOC
Why are carotid artery doppler not useful for patient who lose consciousness?
Need to affect the pons to cause LOC, and carotids go to the cerebrum.
What does the anterior pons contain?
Motor neurons from the motor cortices
Locked-in syndrome is caused by a lesion where?
What, generally, causes diffuse cortical involvement?
Toxins or diffuse problems
What are battle signs?
Postauricular ecchymosis 2/2 basilar skull fracture
What are Racoon eyes?
Periorbital ecchymoses 2/2 basilar skull fracture
Why is temp important with CNS s/sx?
Which is more likely to cause a LOC: toxic or metabolic/infx problem or localized lesion
What two parts of the neuro exam cannot be performed on a comatose pt?
Coordination and gait (obviously)
True or false: cerebral hemispheres are always unavailable with the neuro exam in comatose patients
What is the neuro exam focused on with a comatose patient?
What is the max score on a Glasgow coma scale? What is the lowest?
What are the three categories of the glasgow coma scale?
What parts of the brain control breathing?
Brainstem and forebrain
What are Cheyne-Stokes breathing?
Slow oscillation between hyper and hypoventilation
What is the one breathing pattern that does not result from a brainstem problem? What causes it?
What is a central neurogenic respiration?
rapid, continuous hyperventilation are more than 25
What, generally, causes Cheyne-stokes breathing pattern?
What is apneustic breathing?
Prolonged inspiratory gasp with pause at full respiration
What happens to breathing patterns with lesions that are progressively inferior in the brainstem?
Become more chaotic
What is cluster breathing?
Periodic-respiration of variable amplitude and frequency with variable pauses between clusters
What is ataxic breathing?
Breathing that is completely irregular in rate and rhythm
What is the main question being asked with comatose patients?
"Does the brainstem work?"
What are the four things that are assessed with brainstem exam?
What are thalamic pupils?
Small, but reactive
What are midbrain pupils?
Midposition and fixed
What are pontine pupils?
Pinpoint but reactive
What are uncal pupils?
Dilated, asymmetric and fixed (bad news)
What can uncal ("blown") pupils indicate?
Brain is herniating (impending death)
What are in the outer parts of CN III?
PNS fibers--thus motor is lost before pupillary response
What are usually the last thing to reveal an abnormality with a coma: respirations, Pupils, EOMs, or motor problems? What can alter this pattern?
Toxic or other diffuse effects can cause pupil dysfunction
Normal eye motility implies integrity in what structure?
Brainstem vestibular nuclei at the postomedulary junction
Normal conjugate gaze in an alert patient may be disconjugate when?
Sleep or slight alteration in consciousness d/t unmasking of strabismus
Conjugate ocular motility comes from where?
Frontal eye field
Eyes that deviate downward spontaneously = lesion where?
Dysconjugate motility of the eyes = ?
Damage to the frontal eye fields
Upward deviating eyes in a comatose patient = ?
Skewed eyes in a comatose patient = ?
Brainstem or cerebellar problem
What is the oculocephalic reflex, and what does it indicate in a comatose patient if intact?
Doll's eye reflex
Indicates that CN VIII is intact, and thus the brainstem is at least somewhat intact
What is the vestibulo-oculogyric reflex?
Caloric testing--cold water injected into the ear, to cause eyes to deviate toward the cold water, and away from warm water
What causes the Doll's eye reflex?
When Supranuclear influences on oculomotor nerves are removed, eye maintain fixation on a point in the distance when the head it turned, providing brainstem integrity
What is the COWS mnemonic, and when does it apply? Why?
Applies only to awake pts, because the fast component of nystagmus is controlled by the hemispheres
How is nystagmus named?
What controls the fast beat of nystagmus?
There is not fast component of nystagmus when?
In the comatose patient
Does the COWS mnemonic apply to the comatose patient?
NO-It is OPPOSITE
What is decorticate posturing? What does this indicate?
Bilateral flexion at the elbows and wrists with extension of the lower extremities
Lesion is above the brainstem
What is decerebrate posturing? What does this indicate?
Bilateral extension of the elbows with extension of the lower extremities
Usually bilateral or midbrain pontine
What is myoclonic jerking?
Non-rhythmic movement d/t metabolic causes
What is rhythmic myoclonus?
True or false: the plantar reflex may be extensor in coma for any reason
True or false:Most patients with absent cortical or brainstem function will have some form of spinal reflex
Which generally has a rapid, and which a slow onset: structural / metabolic causes of a coma?
Structural = rapid
Metabolic = slow
What are the respirations like with metabolic problems?
What are the three major non-structural causes of coma?
What are the PE signs of head trauma?
-Rhinorrhea or otorrhea (with CSF)
Where is the major breathing center in the brain?
Medulla and Pons
What are the pupil characteristics of opioid use?
What is the role of the vestibulo-oculogyric reflex testing?
Confirm or refute a negative Doll's eye maneuver
In the comatose patient, putting cold water in the right ear will cause the eyes to deviate what direction?
There is no fast nystagmus phase in the comatose patient, but the slow phase remains intact. Thus the COWS mnemonic is reversed, and the eye deviates TOWARD
Asymmetry with eye movements indicates a metabolic or structural problem?
What is the reversal agent for opioids?