12. Depressed consciousness and coma Flashcards
Coma defn
state of depressed consciousness in which pt not aware, not awake, no response to vigorous stim
Disruption of what flow of sensory input and ability to process information may lead to depressed consciousness
visual
aud
olfactory
gustatory
visceral
somatosensory
Consciousness two domains
arousal
awareness
Consciousness: arousal defn
fully awake to arousable with verbal/tactile stim, to not rousable
Consciousness: arousal maintained by?
subcortical structures - brainstem nuclei, thalamus, basal forebran, hypothalamus and ascending reticular activating system
Awareness defn
content of consciousness, ranging from self-aware and coherent to confused, inattentive, or perhaps delu- sional.
Awareness brain structures involved
bilateral cerebral cortices
controlling processing and understanding of sensory input
What CN sit in the medullopontin junction level?
CN VIII, 9, 5
What “seemingly minor” things may effect consciousness of elderly?
accidental overdose, drug-drug interactions, and adverse drug reac- tions. Seemingly minor infections such as a urinary tract infection, upper respiratory infection, or viral gastroenteritis with dehydration may cause depressed consciousness or com
Special populations to consider in coma?
OA
immunocompromised
List 10 ddx causes of coma
hypoglycemia/hyperglycemia
adrenal crisis
pituitary apoplexy
sepsis
Wernicke
Hyponatremia
hyperammonemia
hypercalcemia
uremia
hepatic encephalopathy
thyrotoxic crisis
myxedema coma
heat stroke
high altitiude cerebral edema
hypoglycemic agents
opioids
simple asphyxiants
co
histotoxic hypoxia (cyanide/car fire)
methemoglobinemia
sedatives
toxic etoh
inhalants
psych meds
antivonculsants
anticholinergics
clonidine
beta blockers
salicyclates
NMS
serotonin syndrome
ICH
cortical infarct
cerebellar infarct
basilar a occlusion
List 4 main categories to consider in coma
metabolic
structural
drugs/toxins
infection
Name 8 drugs/categories/environment that can cause coma
hypoglycemic agents
opioids
simple asphyxiants
co
histotoxic hypoxia (cyanide/car fire)
methemoglobinemia
sedatives
toxic etoh
inhalants
psych meds
antivonculsants
anticholinergics
clonidine
beta blockers
salicyclates
Name 8 metabolic causes for coma
hypoglycemia/hyperglycemia
adrenal crisis
pituitary apoplexy
sepsis
Wernicke
Hyponatremia
hyperammonemia
hypercalcemia
uremia
hepatic encephalopathy
thyrotoxic crisis
myxedema coma
heat stroke
high altitiude cerebral edema
What sx of basilar a occlusion may occur?
Hemiparesis or quadriparesis, abnormal spontaneous movements, facial weak- ness, dysarthria, dysphagia
–> locked in syndrome: voluntary loss of all except eyes
Sx and signs of NMS
Hyperpyrexia, muscular rigidity, delirium, autonomic instability, elevated CPK
Tx NMS
Cooling, isotonic fluid; benzodiazepines, bromocriptine
Serotonin syndromeL signs and symptoms
Multiple serotonergic agents, hypertension, tachycardia, hyperreflexia, muscular rigid- ity, tremor, nausea, diarrhea, clonus
Serotonin syndrome tx
Isotonic fluid; check CPK; benzodiazepines; cooling, hydration, cyproheptadine
Salicyclate sx and signs
Nausea, vomiting, tinnitus, delirium, hyperpnea, anion gap metabolic acidosis with mixed respiratory alkalosis
Salicyclate tx
Isotonic fluids; urinary alkalinization with sodium bicarbonate; correct hypokale- mia; consider hemodialysis
Signs and sx clonidine od
Bradycardia, hypotension, somnolence
Clonidine tx
isotonic fluid
vasopresors
Beta blocker sx
Bradycardia, hypotension, hypoglycemia, seizure
Beta blocker tx
Isotonic fluid; glucagon IV (5 mg); atro- pine IV (0.5 mg); vasopressors IV; high dose insulin infusion; transcutaneous or transvenous pacing
Antiocholingeric sx OD
Hyperpyrexia, pupillary dilation, urinary retention, visual hallucinations
Anticholinergic tx
Physostigmine; benzodiazepines may help in severe agitation
toxic etoh od signs
Nausea, vomiting, intoxication, vision changes, early osmolar gap then anion gap acidosis, renal failure
toxic etoh tx
Fomepizole 15 mg/kg IV load; correct electrolyte abnormalities; isotonic fluid 500 mL/h
Cyanide toxicity sx
Confusion, seizure, collapse, hydrogen sulfide smells like rotten eggs, cyanide (bitter almond smell) may result from combustion of plastics
Cyanide toxicity tx
100% oxygen; hydroxocobalamin 70 mg/kg (or 5 g) IV for cyanide
CO poisoning tx
100% oxygen; hyperbaric oxygen per toxicology
methemoglobinemia signs/sx
Use of medications, such as topical anesthetics or dapsone, cyanosis, pulse oximeter 85%
methemolglobinemia tx
100% oxygen; methylene blue 1–2 mg/ kg IV
Myxedema coma signs
Sluggishness, weight gain, edema, depres- sion, hair loss, constipation
Myxedema coma tx
Levothyroxine or liothyronine; hydrocorti- sone 100 mg IV (variable)
Thyrotoxic crisis sx
Fever, tachycardia, diaphoresis, diarrhea
Thyrotoxicosis tx
Isotonic fluid; propranolol 1 mg IV, PO; propylthiouracil 600 mg PO starting dose (variable)
Hyperammonia secondary to VPA toxcity -tx?
levocarnitine for valproic acid toxicity
kussmaul breathing defn
deep labored
cheyne stokes breathing:
isodes of gradually increasing and then decreasing respirations are separated by brief apneic periods and is associated with stroke and heart failure.
FOUR score: what is this?
like gcs but brainstem reflex and breathing patterns, greater predictive value than GCS in intubated pt
FOUR score: Eye response and score
Eyelids open or opened, tracking, or blinking to command
4
Eyelids open but not tracking
3
Eyelids closed but open to loud voice
2
Eyelids closed but open to pain
1
Eyelids remain closed with pain
0
FOUR score: motor response and score
Thumbs-up, fist, or peace sign
4
Localizing to pain
3
Flexion response to pain
2
Extension response to pain
1
No response to pain or generalized myoclonus status
0
FOUR score: brainstem reflexes
Pupil and corneal reflexes present
4
One pupil wide and fixed
3
Pupil or corneal reflexes absent
2
Pupil and corneal reflexes absent
1
Absent pupil, corneal, and cough reflex
0
FOUR score: respiration criteria and points
Not intubated, regular breathing pattern
4
Not intubated, Cheyne-Stokes breathing pattern
3
Not intubated, irregular breathing
2
Breathes above ventilator rate
1
Breathes at ventilator rate or apnea
0
Deviation of eyes: what is consistent with stroke?
forced devi- ation of the eyes, usually in the horizontal plane, may indicate an ipsi- lateral hemispheric or contralateral pontine lesion
Deviation of eyes: what is consistent with seizure?
deviation away from epileptiform activity region
DDX 8 of nystagmus in an unresponsive pt?
NCSE), brainstem dysfunction, drug overdose (e.g., anti- convulsants, lithium, ketamine, ethanol, phencyclidine), or envenom- ation (scorpion sting)
Name 4 brainstem function reflexes
oculocephalic reflex (doll’s eyes), oculovestibular reflex (cold caloric testing), corneal reflex, and gag reflex
How to perform oculocephalic reflex?
no airway issues or suspicion for cervical spine injury, the oculocephalic reflex is tested by rotating the head from side to side in the horizontal plane. In a patient with a normally functioning brain- stem, the eyes will move in a direction opposite the head movement and appear to maintain visual fixation on a single point in space. Brain- stem dysfunction should be suspected if the eyes remain in midposi- tion with respect to the bony orbits and move in unison with the head. Conscious patients can usually suppress the oculocephalic reflex.
How to test the oculovestibular reflex?
After cerumen impaction and tympanic membrane perforation have been excluded, the patient’s head is elevated to 30 degrees up from the horizontal and ice water is infused into the external auditory canal. In a comatose patient with an intact brainstem, the stimulus results in sustained conjugate devia- tion of the eyes toward the ear being irrigated. Absence of a response to the irrigation should raise suspicion for brainstem dysfunction.
Oculovestibular reflex: what indicates wakefullness and psychogenic unresponsiveness?
In response to cold water caloric testing, conscious patients experience not only tonic deviation of the eyes toward the stimulated ear but also nystagmus (with the fast phase away from the side of irrigation), ver- tigo, nausea, and vomiting. The presence of nystagmus is suggestive of wakefulness and psychogenic unresponsiveness.
Testing for coma
vitals
cbc
chem10
vbg
urinalysis
cxr
salicylate, acetaminophen, etoh
+/- ct/cta
+/-eeg
Approach to pt with depressed consciousness:
ABC
IV, o2 monitors
ECG, CXR, PO labs
+/- dextrose, naloxone, thiamine
PE/neuro
if not improving and no brainstem signs–> secure airway
ct
DDX no structural cause on CT for coma?
toxic
seizuree
pres
infection
nutrition
endocrine
Name 5 ways to provide neuroprotective resus
- Elevate head of bed to 30 degrees if there is no suspicion for thoracic spine injury.
- Avoid constricting ties or collars around neck.
- Avoid hypoxia and hyperoxia.
- Maintain end-tidal CO2 at 35 cm H2O.
- Avoidhypotension.
- Avoidhyperthermia.
- Prevent and treat seizure activity.
In infants, what is the most common cause of a depressed level of consciousness?
a. Accidental toxic ingestion
b. Inborn error of metabolism
c. Infection
d. Physical abuse
c
What Glasgow Coma Scale (GCS) score would be given to an adult
patient who opens the eyes to painful stimuli, speaks in an incom- prehensible manner, and withdraws from pain?
2+ 2+4= 8
What Glasgow Coma Scale (GCS) score would be given to a pediat-
ric patient who opens the eyes and flexes the extremities to painful stimuli and who is irritable and continually cries?
2+3+4 = 9
Awareness of one’s self and surroundings defines which of the fol-
lowing?
a. Cognition
b. Consciousness c. Judgment
d. Orientation
b
In the evaluation of a comatose patient, which of the following responses most clearly indicates brainstem dysfunction?
a. A drop of saline on the cornea of one eye causes both eyes to
blink
b. Infusion of cold water into the right ear causes rightward devia-
tion of the eyes
c. Stimulation of the posterior pharynx has no effect on the soft
palate of pharyngeal muscles
d. When the head is rotated from side to side in the horizontal
plane, the eyes remain in midposition and move in unison with
the head.
d ??
