The Approach to Coma and Altered Consciousness

Question 1

Simply put, what is a coma?

Answer 1

a state of unarousable unresponsiveness

Question 2

The first steps in coma evaluation are 1) ABCs 2) look for obvious etiology clues and 3) try reversing common reversible etiologies. What are the three “drugs” given for this purpose?

Answer 2

Naloxone
thiamine
dextrose

Question 3

Essentially, what does the mental status exam entail in a coma patient?

Answer 3

level of consciousness – see what they will respond to. Voice command? Loud voice? Sternal rub?

if they do respond to voice, try to assess attention, language, visuospatial function, etc.

Question 4

What part of the neuro exam is most helpful to assess brainstem function in a coma exam?

Answer 4

cranial nerves

Question 5

In an unresponsive patient, how do you test cranial nerves II and III?

Answer 5

pupillary light reflex

Question 6

In an unresponsive patient, how can you test CN III, IV, VI and VIII? (two ways…)

Answer 6

the oculocephalic reflex (doll’s eyes)

calorics if necessary

Question 7

What is a normal result for caloric testing?

Answer 7

inject 50 mL of ice water into each ear and observe for conjugate eye deviation toward the injected ear

Question 8

In an unresponsive patient, how can you test trigeminal V1 and VII?

Answer 8

corneal reflex

Question 9

In an unresponsive patient, how can you test CN IX and X/XI?

Answer 9

gag reflex

Question 10

In an unresponsive patient, how can you test visual fields?

Answer 10

check for blink in response to visual threat

Question 11

In general, what are the two main ways in which consciousness can be depressed?

Answer 11

1. brainstem dysfunction
2. dysfunction in both cerebral hemispheres

(but also large hemispheric lesions that cause pressure on the other side)

Question 12

The absence of a brainstem reflex suggests the dysfunction is higher or lower in the brainstem?

Answer 12

lower

Question 13

What is the typical first-step imaging modality for coma?

Answer 13

head CT (non-contrast is hemorrhage is a possibility)

Question 14

Is it ever ok to do an LP before a CT in a coma patient?

Answer 14

No, even if bacterial meningitis is suspected, you’re better off starting empiric antibiotics and then getting a CT prior to the LP in this situation

Question 15

Elevated ICP can be an emergency if the patient has signs of herniation, but if there are no emergent signs, what are a few strategies to lower ICP?

Answer 15

raise the head of the bed
hyperventilate
osmotic diuretic like mannitol

corticosteroids only with edema from tumors

Question 16

What are the main prognostic factors in coma?

Answer 16

etiology and age

Question 17

How does a persistent vegetative state differ from coma?

Answer 17

they have lost all awareness and cognitive function but may remain with their eyes open, exhibit sleep-wake cycles and maintain respiration

Question 18

How does a locked-in patient differ from a coma patient/

Answer 18

Locked-in patients are awake and may not have any abnormalities of consciousness - they just can’t move anything except their eyes

Question 19

Where is the lesion in locked-in syndrome?

Answer 19

base of the pons

Question 20

What are the typical guidelines for how brain death can be declared?

Answer 20

in general, patient must be comatose, with absent brainstem reflexes, no spontaneous respirations (even when pCO2 is allowed to rise)

no confounding factors of hypothermia or drug OD

EEG with electrocerebral silence or cerebral angiography with absence of blood flow to the brain

Question 21

Acute confusional state (or encephalopathy or delirium depending on who you’re talking to) is primarily an issue with what cognitive process?

Answer 21

attention - they can’t carry out a coherent plan of thought or action