Clin: Stupor and Coma Flashcards
What is central transtentorial herniation and the signs/symptoms?
- Herniation into foramen magnum
- Leads to early coma, small pupils, normal EOM’s, posturing and later bilateral fixed pupils
- Respiratory arrest and death
Impaired consciousness means involvement of what 3 things?
- Diffuse or bilateral impairment of both cerebral hemispheres, or
- Failure of brainstem ARAS, or
- BOTH
What is the characteristic signs of someone with diffuse/metabolic injury of the nervous system (i.e., motor signs, consciousness, breathing, and presentation)?
- Confusion and stupor commonly precede motor signs
- Motor signs usually symmetrical
- Pupillary rxns usually preserved
- Asterixis, myoclonus, tremor, seizures common
- Acid-base imbalance with hyper or hypoventilation
- Fluctuating level of consciousness
Rule of thumb for lesion location when pupils are enlarged bilaterally?
Bilateral CN III lesion, post-ictal, or intoxications
Which state of altered consciousness is represented by arousal only to noxious stimuli and not enviornmental, only rudimentary awareness (i.e., purposeful motor response)?
Stupor
The initial signs of a supratentorial mass lesion are usually (global or focal)?
How do the signs progress?
Motor signs are often?
- Initial signs usually focal
- Progression of signs is rostral to caudal (i.e., herniation pushing down)
- Motor signs are often asymmetric
What are the criteria for persistence of brain death?
- 6 hours w/ confirmatory (flat) EEG: performed to tech. standards of AEES
- 12 hours w/o a confirmatory isoelectric EEG
- 24 hours for anoxic brain injury w/o confirmatory isoelectric EEG
What must be known when making the call of brain death?
Cause of the coma should be known, it MUST be adequate to explain the clinical picture, and it MUST be irreversible
Which level of the pons is assessed with the Oculocephalic manuever (Doll’s Eyes) vs. Caloric (oculovestibular) reflex test?
- Oculocephalic = mid pons; assess CN III, IV, and VI
- Caloric = lower pons
What is the location of the lesion if the eyes have a ping-pong nystagmus?
Bihemispheric, midbrain
Which test can be done to clinically document someone as being brain dead?
- Apnea test
- Disconnect ventilator –> Catheter w/ 100% O2 and observe chest wall and abdomen for movement
- No respiratory movements for 8 mins (PCO2 >60mmHg
What are specific interventions that can be done to reduce ICP?
- Elevate head of bed
- Intubate and hyperventilate to PCO2 of 20 mmHg
- Use mannitol for ischemic lesions
- Use decardron for tumor, abscess, and perhaps cerebral hemorrhage
What defines unresponsivness in someone who is truly brain dead?
Absence of?
- Unresponsive to ALL sensory input, including pain and speech
- Absent brainstem reflexes
What is Decorticate vs. Decerebrate posturing and where is the lesion for each?
- Decorticate = arms flexed, legs extended (hemispheric)
- DEcrebrate = all extremities Extended (brainstem)
During a general medical exam of the skin of a patient with impaired consciousness what should be considered with dry skin?
- Hypothyroid
- Drugs (anticholinergics, TCA’s)
Rule of thumb for lesion location when pupils are enlarged on one side?
Parasympathetic division (usually CN III)
Frontal gaze centers deviate eyes where?
Pontine gaze centers deviate eyes where?
- Frontal gaze centers deviate eyes to opposite side (i.e., if right area is dysfunctional, there is no drive to the left, so eyes will be looking right)
- Pontine gaze centers deviate eyes to same side
Consciousness depends on arousal of the cerebral cortex by the ____________
Brainstem Ascending Reticular Activating System (ARAS)
During a general medical exam of the skin of a patient with impaired consciousness what should be considered with acne?
Long-term antiepileptic use
What are the 3 intial steps of managing a comatose patient?
1) A: insure patent airways
2) B: insure breathing and adequate oxygenation
3) C: insure adequate circulation and control any active bleeding
*Stabilize neck, get C-spine films if trauma suspected
What is commonly seen preceding brainstem dysfunction (4 D’s) due to a subtentorial mass lesion?
- Dysequilibrium
- Dysarthria
- Dysphagia
- Diplopia
*Vertigo
What does conjugate vs. dysconjugate gaze imply about the brainstem?
- Conjugate implies brainstem intact
- Dysconjugate implies brainstem lesion
Large, pressure producing supratentorial mass lesions can cause coma how?
- Dysfunction in the upper ARAS
- Downward herniation of the brain to compress the ARAS
What is the characteristic sign of Hepatic dysfunction causing stupor and coma?
- Asterixis!
- Pt extends arms and wrists, the wrists will twitch!
What must be ruled out before making the call that someone is brain dead?
- Sedative intoxication
- Hypothermia (<90F)
- Neuromuscular blockage
- Shock
*All can mimic brain death*
Which state of altered consciousness is represented by disorientation, stimuli misinterpretation, and hallucinations (visual)?
Delirium
Convergence nystagmus or Retractory nystagmus indicates a lesions where?
Mesencephalon
Bobbing nystagmus (rapid down, slow up) indicates a lesion where?
Pons
What are Cheynes-Stokes respirations?
Seen with what disorders?
- Hyperpnia regularly alternating w/ apnea (bilateral hemispheres or diencephalon)
- Many disorders ranging from metabolic to structural
What are the 3 P’s associated with pinpoint pupils?
1) Pontine lesion
2) oPiates
3) Pilocarpine
Rule of thumb for lesion location when pupils are constricted?
Sympathetic division (hypothalamus, carotid)
What are the respiratory patterns of someone with a subtentorial mass lesion?
Bizarre respiratory patterns common
Why do absent or unequal pupillary responses imply a brainstem lesion?
Nuclei/tracts controlling pupils are anatomically adjacent to ARAS
What are the essential elements of the neurological examination for a patient with stupor?
- Pupillary responses
- Corneal reflex
- Extaocular movements
- Cough/gag reflex
- Motor responses
- Respiratory pattern
*Start at highest CN and work your way down
