Approach to Coma

Question 1

Lethargy?

Answer 1

Sleepy but easily aroused

Question 2

Hypersomnia?

Answer 2

Excessively sleepy but normal congition when awakened

Question 3

Obtundation?

Answer 3

Mental blunting, decreased alertness

Question 4

Stupor?

Answer 4

Eyes open only briefly after vigorous stimulation before returning to deep sleep. Cognition impaired

Question 5

Coma?

Answer 5

Eyes remain closed after vigorous stimulation

Question 6

Delirium?

Answer 6

Disoriented, misperception of sensory stimuli, hallucinations. Vacillates between quiet, sleepy periods and hyper-vigilance/agitation

Question 7

When do pts in comas develop eye opening and sleep wake cycles?

Answer 7

2-4 weeks

Question 8

Abulia?

Answer 8

Awake but apathetic, no spontaneity. With vigourous stimulation, cognitive function may be normal. (bilateral frontal lobe disease, lobotomized)

Question 9

Akinetic mutism?

Answer 9

Silent, alert-appearing immobility. No mental activity with vigorous stimulation (disease of frontal lobes and hypothalamus)

Question 10

Minimally conscious state?

Answer 10

Fragments of awareness

Question 11

Vegetative state?

Answer 11

Awake, no awareness or meaningful interaction with the enviroment

Question 12

Patients in MCS may do what?

Answer 12

Reach for objects, grunt, or gesture in response to a command, Visually fixate and track

Question 13

Components of consciousness?

Answer 13

Arousal, Content

Question 14

How is arousal achieved?

Answer 14

Neural circuits that mediate sleep-wake cycles and involves a specific area of the upper brainstem referred to as the reticular activating system or ascending arousal system of the rostral brainstem

Question 15

Disruption of the arousal system leads to?

Answer 15

Stupor and coma

Question 16

What does the content system refer to?

Answer 16

Cerebral activity for self-awareness, cognition, and purposeful interactions with the environment

Question 17

Are the content system behaviors premeditative or reflexive in nature?

Answer 17

Premeditative

Question 18

Lesion in encephalitis lethargica?

Answer 18

Rostral periaqueductal grey matter and posterior 3rd ventricle

Question 19

Cataplexy?

Answer 19

sudden involuntary loss of muscle tone during emotional excitement

Question 20

Neuropathological patterns associated with coma?

Answer 20

A. Extensive, acute bihemispheric disease
B. Lesions of the diencephalon (thalamus and hypothalamus)
C. Lesions of midbrain peri-aqueductal grey matter
D-E. Involvement of upper one third of pontine tegmentum

Question 21

Reticular grey formation?

Answer 21

Mediates arousal

Question 22

Route of the reticular grey formation?

Answer 22

Upper third of the pons through the midbrain tegmentum, the floor of the third ventricle and into the thalami

Question 23

Injuries to what will cause coma?

Answer 23

Reticular grey formation

Question 24

Nuclei responsible for arousal are located where?

Answer 24

Ascending arousal system

Question 25

What makes up the ascending arousal system?

Answer 25

Two Cholinergic nuclei | Monoaminergic System nuclei

Question 26

What do the cholinergic nuclei of the AAS do?

Answer 26

Inhibit thalamic firing that increases wakefulness. This puts the thalamus in transmission mode for filtering and relaying sensory info to the cortex.

Question 27

What happens if you did not have the cholinergic projections to the thalamus?

Answer 27

Thalamus would continue their periodic electrical "bursting" and with their widespread connections to the cortex, induce sleep through synchronizing cortical electrical activity.

Question 28

Role of the monaminergic system in the AAS?

Answer 28

It has widespread connections to the cortex, both direct and indirect. Improves signal to noise ratio for messages from the thalamus and thereby prevents any misperception of incoming sensory stimuli

Question 29

What is the sleep promoting center?

Answer 29

The ventro-lateral preoptic nucleus (VLPO)

Question 30

What NT does VLPO use?

Answer 30

GABA

Question 31

Role of VLPO?

Answer 31

Inhibits the many nuclear centers that promote wakefulness and comprise the ascending arousal system.

Question 32

The AAS receives feedback from many sources including?

Answer 32

Thalamus, the Limbic System, the frontal and association cortex

Question 33

Causes of coma?

Answer 33

Structural, Metabolic, Psychogenic (rare)

Question 34

What do you always rule out first in a comatose patient?

Answer 34

Psychogenic coma

Question 35

Structural comas?

Answer 35

Supratentorial mass lesion Acute obstructive hydrocephalus Infratentorial mass lesion

Question 36

Metabolic comas?

Answer 36

``` Reversible injury (sedative OD) Irreversible injury (hypoxia in cardiac arrest) ```

Question 37

What does transtentorial (Uncal) herniation lead to?

Answer 37

Occulomotor entrapment as well as sometimes PCA entrapment.

Question 38

Common cause of transtentorial (Uncal) herniation?

Answer 38

Epidural hematoma from the laceration of middle meningeal artery

Question 39

What does a falcine herniation trap?

Answer 39

One of both ACAs

Question 40

How does a falcine herniation occur?

Answer 40

When mass effect pushes the brain under the falx cerebri

Question 41

How does central herniation present?

Answer 41

Rostral-Caudal deterioration - Diencephalon --> midbrain failure - Reduced conciousness - Small reactive pupils - Decorticate posturing - Cheyne - Stokes respirations - Midbrain failure follows (FIxed mid-position pupils, decerebration)

Question 42

Intrinsic brainstem lesions?

Answer 42

Top of the Basilar Artery ischemic stroke | Pontine hemorrhage

Question 43

Extrinsic brainstem lesions?

Answer 43

Compress and distort the brainstem - Cerebellar hemorrhage - Cerebellar infarction - Cerebellar brain tumor

Question 44

Primary brainstem lesions?

Answer 44

Segmental cranial nerve deficits Ascending (spinothalamic) tract dysfunction Descending (corticospinal, central sympathetic) tract dysfunction Early cerebellar signs

Question 45

Pontine hemorrhage presentation?

Answer 45

``` Abrupt coma Pinpoint pupils Decerebrate rigidity or flaccid quadriplegia Horizontal gaze paresis Ocular bobbing ```

Question 46

Metabolic insult to the brain is?

Answer 46

Global, diffuse, symmetric

Question 47

Neuro-exam shows in pts with metabolic insult?

Answer 47

Does not show any focal or lateralizing deficits

Question 48

What does head CT show in pts with metabolic insult?

Answer 48

Normal

Question 49

What is the state of the pupils in metabolic insult?

Answer 49

Reactive