A.7 - Classification of unconscious conditions

Question 1

Definition of clear consciousness

Answer 1

• The ability to react (Arousal or
  alertness)
• the adequate use of contents of memory and to think (Awareness).
• Allows the Adaptation of the individual to the environment and is the basis of cognition.

Question 2

what is ARAS?

Answer 2

ascending reticular activating system

Question 3

What is The anatomical basis of arousal?

Answer 3

the intact functioning of the
ascending reticular activating system (ARAS)

Question 4

what are the components of ARAS?

Answer 4

• the pontomesencephalic reticular formation
• the monoaminergic networks of the diencephalon
• the intralaminar and medial nuclei of the thalamus

Question 5

what are the main disorders of consciousness?

Answer 5

Disorder of arousal

Disorder of awareness

Question 6

what is the definition of the disorder of arousal?

Question 7

what is the definition of the disorder of awareness?

Answer 7

• Inadequate thinking and behavior.
• Global CNS function is impaired.
• Signs of focal cognitive deficit (e.g. alexia, acalculia) are not part of this.

(Arousal is normal, but content of memory is disturbed, inaccessible or used inappropriately)

Question 7

what are the 3 main disorders of Arousal?

Answer 7

● Somnolence

● Stupor

● Coma

Question 8

what is somnolence?

Answer 8

Mildest form. Awakens with verbal stimuli, but is asleep without stimuli.

Question 10

what is stupor?

Answer 10

• Patient may open eyes to painful stimuli (verbal is not enough)
• Slow and inappropriate reaction to stimuli

Question 11

what is coma?

Answer 11

• Cannot be awakened
• Abnormal posture (decorticate or decerebrate).

i. Coma I - Preserved brainstem reflexes
ii. Coma II - Lost brainstem reflexes

Question 12

what are the 4 disorders of awareness?

Answer 12

Persistent vegetative state

Akinetic mutism

Confusion

Delirium

Question 13

what is the persistent vegetative state?

Answer 13

(decorticate state, apallic synd)

• Rostral brainstem
  remains intact:
  → Thermoregulation (hypothalamus) is intact
  → sleep-wake cycle is intact
  → endocrine system is intact
  → cardiorespiratory and other visceral functions are intact.

Question 14

when vegetative state is considered permanent?

Answer 14

> 30 days

Question 15

what do you see on patients in vegetative state?

Answer 15

Patients seem to be awake with open eyes and elicitable eye movement reflexes (e.g. vestibulo-ocular reflex)

Question 16

when does Decortication position occurs in vegetative state?

Answer 16

After days/weeks

Question 17

what reflexes can be elicited in vegetative state?

Answer 17

Signs of corticospinal tract lesion (e.g. Babinski reflex) and primitive reflexes (suction reflex, Bulldog reflex) can be elicited

Question 18

how does a patient in vegetative state reacts after painful stim.?

Answer 18

Increased decortication and may see autonomic response (sweating, Tachycardia, hyperventilation)

Question 19

what is the etiology behind vegetative state?

Answer 19

• Extensive functional or structural impairment of cerebral cortex
• Extensive white matter damage
• Bilateral damage to the thalamus

Question 20

what can cause Extensive functional or structural impairment of cerebral cortex?

Answer 20

• global cerebral ischemia
• hypoglycemia
• renal/hepatic failure
• post-convulsive state
• Wernicke’s encephalopathy
• final stages of cortical dementias

Question 21

what can cause Extensive white matter damage?

Answer 21

diffuse axonal injury after head trauma

Question 22

what is Akinetic mutism?

Answer 22

the patient is Awake, but mute and does not move.

Not caused by aphasia, can see signs of comprehension

Frequently not recognized

Question 23

how can you exclude paralysis in akinetic mutism?

Answer 23

normal withdrawal reactions to painful stimuli.

Question 24

what signs are present in akinetic mutism?

Answer 24

Usually frontal release signs are present: sucking reflex, bulldog reflex, palmar grasp reflex

Question 25

what causes akinetic mutism?

Answer 25

bilateral interruption of connections between:
the supplementary motor area, cingulate cortex and midline nuclei of the thalamus

Question 26

what is the etiology behind akinetic mutism?

Answer 26

○ Jet bleeding (rupture of anterior communicating artery aneurysm)

○ Frontobasal contusion

○ Bilateral ischemia in the anterior cerebral artery territory (Willis-circle variants)

○ Subfalcial herniation

○ Occlusive hydrocephalus

○ Butterfly tumors growing across the corpus callosum into the prefrontal lobes

○ Tumors of third ventricle

Question 27

what is the definition of confusion?

Answer 27

• Impaired thinking and attention.
• Slow and vague. Incoherent thinking.
• No signs suggestive of delusions. E.g. after epileptic seizure (post-convulsive state or tenebrosity)

Question 28

what is delirium?

Answer 28

• Disorder of attention and awareness (old definition: also disorder of perception. Can use this to differentiate from confusion).
• Cannot focus, change or fix attention.
• Disoriented and incoherent thinking.

Question 29

how fast does delirium evolves?

Answer 29

Evolves quickly (hours-24h)

Question 30

what are the features of delirium?

Answer 30

• Characteristic diurnal fluctuation of intensity
• symptoms deteriorate at night or in an environment lacking stimuli
• Typical inversion of sleep/wake cycle
• Autonomic instability (excitatory): sweating, tachycardia, unstable BP

Question 31

delirium can be a complication of what?

Answer 31

right hemispheric lesions

metabolic disorders

drug or alcohol