7. Classification of unconcious conditions

Question 1

Define conciousness

Answer 1

The brain’s ability to react (arousal or altertness), adequate use of memories, and to think (awareness).

Question 2

Anatomical bases of arousal

Answer 2

Ascending reticular activating system (ARAS). Composed of pontomesencephalic reticular formation, monoaminergic networks of diencephalon and the intralaminar and medial nuclei of thalamus.

Question 3

Disorder of conciosuness: categorization

Answer 3

1. Disorder of arousal
2. Disorder of awareness

Question 4

Undercategorization of arousal disorders

Answer 4

Disorders of arousal
- Somnolence
- Stupor
- Coma

Question 5

Undercategorization of disorders of awareness

Answer 5

Disorder of awareness
- Peristent vegetative state
- Akinetic mutism
- Confusion
- Deilirium

Question 6

Define somnolence

Answer 6

Wakes with verbal stimuli, but asleep without stimuli

Question 7

Define stupor

Answer 7

May open eyes to painful stimuli. Still asleep when verbal stimuli.

Question 8

Define coma

Answer 8

Cannot be awakened. Abnormal posture (decorticate or decerebrate)

Question 9

Classification of coma

Answer 9

Coma I. preserved brainstem reflexes
Coma II. Lost brainstem reflexes

Question 10

What is a disorder of arousal?

Answer 10

Reduced arousal, sleep-like state, won’t react to awakening stimuli

Question 11

What is a disorder of awareness?

Answer 11

Inadequate thinking and behaviour. Global CNS function impaired. Arousal normal. Content of memory disturbed or used inappropriately.

Question 12

Define perisistent vegetative state

Answer 12

Disorder of consciousness in which patients with severe brain damage are in a state of partial arousal rather than true awareness. Midbrain intact: thermoreg., sleep cycle, endocrine system, other visceral functions intact.

Question 13

Location and function of the midbrain

Answer 13

• The rostral most portion of brainstem. Connects diencephalon and cerebrum with pons.
• Consists of cerebral peduncles, tegmentum and tectum
• Function: arousal, wakefullness, sleep, temp. regulation, vision, hearing and motor control

Question 14

Characteristic/clinical of persistent vegetative state

Answer 14

• Persistent when > 1 month
• Eyes open, eye movement reflexes (e.g. vestiulo-ocular reflex)
• Decortiate position after days/weeks
• Sings of corticospinal tract lesion (e.g. babinski)
• Painful stimulus can increase decortication and may see autonomic respone (sweating, tachycardia, hyperventilation)

Question 15

Decorticate position

Answer 15

Plantar flexion, wrist- and forearm flexion, legs internally rotated and arms adducted

Question 16

Decerebrate position

Answer 16

Plantar flexion, hand flexed, wrist pronated, arm extended and edducted. No flexion at the arm (laying on the chest)

Question 17

Causes of persistent vegative state

Answer 17

Extensive functional or structural impairment of cerebral cortex:
- global cerebral ischemia
- hypoglycemia
- renal/hepatic failure
- Wernicke’s encephalopathy
- Extensive white matter damage
- Bilateral damage to thalamus

Question 18

Definition of akinetic mutism

Answer 18

Awake, but mute and does not move

Question 19

Clinical features akinetic mutism

Answer 19

• Signs of comprehension (so not aphasia)
• Normal withdrawal to pain stimuli (so not paralysis)
• Frontal release signs/primitive reflexes: sucking-, bulldog-, and palmar grasp reflex

Question 20

Etiology akinetic mutism

Answer 20

Bilateral interruption of connections bw. the supplementary motor area, cingular region and midline nuclei of thalamus.

• jet bleeding
• frontobasal contusion
• bilateral ischemia in anterior cerebral artery territory
• subfacial herniation
• occlusive hydrocephalus
• tumors of 3rd ventricle

Question 21

Definition of confusion

Answer 21

Impaired thinking and attention. Slow and vague. Incoherent thinking. No signs suggestive of delusions.

Question 22

Define delirium

Answer 22

Disorder of attention and awereness. Cannot focus, change or fix attention. Disoriented and incoherent thinking.

Question 23

Characteristics of delirium

Answer 23

• Evolves quickly (<24h)
• Fluctation of intensity; sympt. worse at night or in environment lacking stimuli
• Change in sleep/wake cycle
• Autonomic instability: sweating, tachycardia, unstable BP

Question 24

Brainstem reflexes

Answer 24

• Pupillary Light Reflex
• Corneal Reflex
• Oculo-vestibular Reflex
• Pain Stimulus
• Gag Reflex
• Cough Reflex

Question 25

Causes of deilirum

Answer 25

Complication of right hemispheric lesions, metabolic disorders, drugs, alcohol, infection (UTI) in elderly