Clinical Approach to Stupor and Coma (Hon) Flashcards
What generally causes coma?
Bilateral hemispheric dysfunction
Brainstem dysfunction
or
Both
What are the requirements of consciousness?
1) Arousal
2) Awareness
Consciousness depends on arousal of cerebral cortex by?
The brainstem ascending reticular activating system
Coma and stupor are caused by?
Impaired consciousness
1) Diffuse or bilateral impairment of cerebral hemispheres
2) Failure of brainstem ARAS
3) Both the above
What are broad categories of lesions that produce coma?
1) Large, pressure producing Supratentorial mass lesions that involve ARAS
2) Infratentorial mass lesions that involve the brainstem
3) Diffuse or multifocal brain disease
What are broad categories of lesions that produce coma?
1) Large, pressure producing Supratentorial mass lesions
2) Infratentorial mass lesions that involve the brainstem
3) Diffuse or multifocal brain disease
What are some examples of supratentorial causes of stupor and coma that affect the unilateral hemisphere (mass effect)?
1) Intracerebral hemorrhage
2) Large MCA infarct
3) Subdural hematoma
4) Epidural hematoma
What are some examples of supratentorial causes of stupor and coma that affect bilateral hemisphere?
1) Subarachnoid hemorrhage
2) Cerebral edema
3) Acute hydrocephalus
What are some examples of subtentorial causes of stupor and coma?
1) Pontine hemorrhage
2) Basilar artery occlusion
3) Central pontine myelinolysis
What causes the pupil to be enlarged on one side?
Parasympathetic dysfunction (usually CN III)
What causes pinpoint pupils?
1) Pontine lesions
2) Opiates
3) Pilocarpine
What extraocular movement is common to see in comatose patients?
Roving eye movements
If the roving eye movements are moving together (conjugate) this implies?
If they are dysconjugate this implies?
1) Brainstem intact
2) Brainstem lesion
Which direction do the eyes move with a destructive hemispheric lesion?
With an irritative hemispheric lesion?
With a destructive brainstem lesion?
1) Toward lesion
2) Away from lesion
3) Away from lesion
Oculocephalic maneuver (Doll’s Eyes) is used to assess which CNs?
III, IV, and VI
When performing the Oculocephalic maneuver, what direction do the eyes move with passive horizontal head rotation?
what direction do the eyes move with passive vertical head rotation?
1) Horizontally opposite
2) Vertically opposite
When performing a caloric (oculovestibular) reflex what to you first want to make sure of?
Canal is clear and TM intact
Unilateral cold water irrigation with intact brainstem causes the eyes to deviate to which side?
Bilateral irrigation?
1) Toward irrigated side
2) Downward
A patient in the decorticate position points to the issue located where? What does this look like?
If they are in the decerebrate position?
1) Hemispheric; arms flexed, legs extended
2) Brainstem; all extremities extended
The initial signs of supratentorial mass lesions are usually?
The progression of signs are?
Motor signs are often?
1) Focal
2) Rostral to caudal
3) Asymmetric
Herniation Syndromes are caused by?
Expanding supratentorial mass lesions
The effect of herniation syndrome is to?
Displace brain tissue into adjacent intracranial compartments
Uncal transtentorial herniations causes what do be compressed?
What does this cause initially?
What progressive sign is seen next?
1) CN III
2) Ipsilateral dilated pupil
3) Ipsilateral hemiparesis
What are usually present with subtentorial mass lesions?
Cranial nerve palsies
With diffuse/metabolic causes coma, what usually precedes motor signs?
Motor signs are usually?
1) Confusion and stupor
2) Symmetrical
What are some general causes of diffuse/metabolic coma?
1) Hepatic/renal failure
2) Hyper/hypoglycemia
3) Hyper/hyponatremia
4) Endocrine disorders
What occurs whenever blood flow is inadequate to meet the metabolic requirements of the brain, as in cardiac or pulmonary arrest?
Global Cerebral Ischemia
Global Cerebral Ischemia usually lasts for how long?
≤ about 6 minutes
What is brain death by definition?
1) Irreversibility
2) Complete cessation of brain function (including respiration but not heartbeat)
3) Persistence
In order to determine cessation of all brain function, what is the gold standard to confirm this?
(She emphasized this)
Apnea test
What is the apnea test?
She emphasized this
Respiratory responses are absent at 8 to 10 minutes
after the patient’s pC02 is allowed to rise to 60mmHg, while oxygenation is maintained with 100% O2
If a comatose patient is febrile and a source cannot be determined and the CT is normal, what should be the next step?
(She emphasized this)
Lumbar puncture
