Examination Of COmatos Px Flashcards
What is the state of full awareness of self and one’s relationship to the environment?
Consciousness
What are the 2 components of consciousness?
Content & arousal
What are the ways consciousness can be damaged?
- If there is damage to the cortical networks + diffused -> level of consciousness is affected
- Small lesions -> selective or fractional loss of consciousness
- Injury to the brain stem or diencephalic pathways -> overall consciousness may be decreased
What is the state of sustained pathologic unsconsiousness?
Coma
What happens if there is pain in coma px?
Still retain some form of responsiveness in the form of reflex
What are the acute disorders of consciousness?
Confusion
Delirium
Obtundation
Stupor
Coma
What is an inappropriate repsponse to the environemnt?
Confusion
What is the misperception of sensory stimuli & vivid hallucinations, agitation, and tremulousness?
Delirium
What is the mild to moderate reducction in alertness accompanied by lesser interest in the environment??
Obtundation
What is the state where px are arousable only by vigorous stimulation?
Stupor
What is the main neuroanatomic basis for consciousness?
Ascedning reticular activating system
-> network of neurons originating in the tegmentum of the upper pons and midbrain
What are the 2 acetylcholine grps in ARAS?
Peduncopontine tegmental nucleus & Lateral dorsal tegmental (LDT) nucleus -> major input
WHat is the pathway of ARAS from LDT & PPT?
Inhibition of reticular nucleus -> activation of thalamic relay nucleus -> transmission mode of relaying sensory information
What are the series of direct inputs in ARAS?
Monoaminergic
Peptidergic
Cholinergic
Gabaergic inputs
What happens if ther eis unilateral and bilateral cerebral lesion?
Unilateral cerebral lesion = does not abolish consciousness
Bilateral cerebral lesion = consciouness is affect
How do you do hx taking in px with decreaed sensorium?
- Obtain hx from key witnesses
- Temporal profile or time over which coma devleops
- Onset: acute vs gradual
- Symptoms prior to onset of coma
- Recent complaints
- Previous medical illnesses
- Previous psychiatric hx
- Access to frugs and other medications
If u observe rapid progression of hemiparesis, hemisensory deficit or aphasia to coma from mins to hrs, what do u suspect is the cause?
Intracerebral hemorrhage
What do u suspect if px presents with delirium, agitation, changes in behavior without lateralizing signs & symptoms, associated w/ fever?
Infection (meningitis or encephalitis(
What is indicated if there is acute confusional state prior to the coma?
Metabolic derangement
what are done in Gen PE in px with decreased sensorium?
- Vital signs
- Evidence of trauma
- evidence of acute/chronic systemic illness
- evidence of durg ingestions
- nuchal rigiditiy =assume that cervical trauma has been excluded then exam for potential CNS infection
what are indications of extreme hypertension?
- posterior reversible encephalopathy syndrome
- HTN encephalopathy
- HTN intracerebral hemorrhage
what are the causes of Hypotension in px with DEC sensorium?
sepsis
hypovolemia
cardiac failure
what are the causes of Hyperthermia in px with DEC sensorium?
infection
antiocholinergic intoxication
what are the causes of hypothermia in px with DEC sensorium?
hypothyroidism
sepsis
alcohol intoxication
what are the causes of hypothermia in px with DEC sensorium?
hypothyroidism
sepsis
alcohol intoxication
what are the possible causes of Ecchymosis, Petechial-purpuric rash, Icterus & cherry-red skin?
Ecchymosis = trauma, corticosteroid use, abnormal coag from liver dis or Anticoagulants
Petechial purpuric rash = meningococcemia, gonococcemia, staphylococcemia, etc
Icterus = hepatic dysfunction or hemolytic anemia
Cherry-red skin = CO poisoning
How do you assess the levels of consciousness?
- verbal stimulation or sound stimulation
- tactile stimulation
- painful stimulation = compression of nail bed, supraorbital ridge or temporomandibular joint
what are the GCS interpretation?
> 13 = mild brain injury
9-12 = Moderate brain injury
<8 = severe brain injury
in what cases do you see unilateral dilated pupil in comatose px?
posterior communicating artery aneurysm or temporal lobe herniation
what reflex is an example of Spinobulbospinal response where pain stimulus arises from the CN V or spinal dorsal horn?
Ciliospinal reflex = indicates integrity of these circuits form lower brainstem to spinal cord
what are the Oculocephalic response & Vestibulo-ocular response?
Oculocephalic response
= integrity of midbrain & pons
= done if suspected injury is at the CERVICAL SPINE
Vestibulo-ocular response
= check for brainstem dysfunction
what are the response of intact & damage brainstem when indicating Oculocephalic response?
intact brainstem = conjugate movement of the eyes in the direction opposite to the head movement
dysfunctional/damaged brainstem = absent or asymmetric response
how do u elicit the corneal reflex in comatose px?
vigorous stimulation by not touching the cornea with any material
where does the network of neurons responsible for respiratory rhythm located?
Ventrolateral medulla inclusing pre-Botzinger complex
what is the pattern of periodic breahting with phases of hyperpnea alteration regularly with apnea?
Cheyne-stroke respiration
- seen in forebrain or diencephalic function or metabolic encephalopathies
In what cases do u see posthyperventilation apnea?
Diffuse metabolic impairment of forebrain or bilateral structure damage to the frontal lobes
- respiration stops after deep breathing has lowered CO2 content in the blood
in what cases do u see hyperventilation in comatose px?
hepatic coma
sepsis
conditions with chemical stimuli cause hyperpnea
due to metabolic acidosis (diabetic keotacidosis)
what is indicated if there is apneustic breathing?
Apneustic breathing = respiratory pause @ full inspiration
Cause:
- injury to pontine respiratory nuclei
- setting of pontine infarction due to basilar a occlusion
- metabolic encephalopathy (hypoglycemia, anoxia or CNS infection)
- transtentorial herniation as brainstem dysfunction advances
what is the cause of ataxic breathing in comatose px?
Ataxic breathing = irregular gasping respiratory
Cause
- damage to respiratory rhythm generator at pre-Botzinger level of upper medulla
- bialteral rostral medullary lesions
What are the causes of sleep apnea and Ondine’s curse?
Obstructive sleep apnea = cross-section of upper airway is anatomically narrow
Ondine’s curse = central hypoventilation syndrome
how do u detect hemiplegia in unconscious px?
- Inspection = look for unilateral asymmetry of movement, posture, muscle tone, unilateral flaccidity
- Flaccidity of the cheek = sucks in inspiration & puff out with expiration
- Eyelid release test = gently pull both eyelids up with 2 thumbs then release them simultaneously
- Limb drop test =wrist, arm, leg dropping
what is the result of hemiplegia in unconscious px in eyelid release test?
eyelid of hemiplegic side glides down slowly, whereas opposite lid closes rapidly
what are the best motor response to sensory stimulation?
- decorticate posturing = rubrospinal tract
- decerebrate posturing = vestibulospinal tract
what are the diff motor tests done in unconscious px?
motor reflex = cutaneous, prefrontal cutaneous, muscle stretch
rostro-caudal deterioration
central syndrome
what is a positive apnea test?
no respiratory response to a PaCO2 >60mmHg
what are the prerequisites of apnea test?
- core temperature >36C
- SBP >100mmHg
- Eucapnia (PaCO2 35-45mmHg)
- Absence of hypoxia
- Euvolemic status
what are the factors that may mimic brain death?
locked-in syndrome
fulminant Guillan-Barre syndrome
Severe hypothermia
Post-cardiac arrest syndrome
Massive baclofen/anticholinergic overdose
Severe overdose of CNS depressants, valproic acid, tricyclic antidpressants
