Download coma

coma
Zhang Yinglan MD, Associate chief physician
Emergency Department
Longhua Hospital Affiliated Shanghai University of TCM
Definition
 the most serious disturbance of consciousness
 no response to the various external stimuli and
cannot be awakened
 aimless spontaneous activities
A clear consciousness
 an awareness of oneself and surroundings
a quick and accurate response to the pain、
touch、seeing、hearing and language
The important structure to maintain
consciousness
 reticular activating system in the middle-upper
part of the pons
 the lesion of the lower part of the pons or medulla
will not lead to unawareness
 a complete cerebral cortex
Lesion area
 focal brainstem lesions or bilateral hemisphere
with diffuse lesion
 rapidly progressive lesion in one hemisphere
cause the midline shift、 extruding the
ascending reticular activating system of the
brainstem
focal lesions of one hemisphere will not lead to unconsciousness
excessive lesions of bilateral hemisphere but slow progress will
not lead to unconsciousness（like Alzheimer‘s Disease）
mechanism
reflex arc
General receptor
Specific receptor
Specific ascending
projection system
Nonspecific ascending
reticular activiting system
muscle 、
skeleton
Bilateral cerebral
cortex
Pyramidal tracts
Pathogenesis
 Intracephalic diseases：the primary lesion
of cerebral cortex、 interbrain 、 midbrain
and the head-end of the pons
 Systemic diseases（secondary brain
injury）： poisoning、 infection、
metabolic or endocrine disorders
How systemic diseases cause the coma？
 Obstruction of supply or utilization of oxygen and
the substrate
 The change of neuronal excitability
 The change of cranial capacity
 craniocerebral trauma
is the most common reason
to cause coma
 internal medicine diseases
• cerebrovascular disease 50%
• hypoxic-ischemic encephalopathy 20%
• the rest are metabolic disease toxic encephalopathy
The judgement of coma
disturbance of consciousness include
 degree of awakening declined
 conscious content changed
confusion、 delirium
The severity of coma
 light coma
 Moderate coma
 deep coma
 brain death
 Confusion：loss of concentration、
disorientation、 indifference、 inconsistent language
 Delirium：it is an acute advanced nervous disorder
and can be seen in hyperpyrexia、 poisoning or
metabolic disorders.
Special type
 vegetative state VS：in the vegetative state
patients can open their eyelids occasionally and
demonstrate sleep-wake cycles, but completely
lack cognitive function.
 minimally conscious state MCS：it is defined as
a condition of severely altered consciousness in
which minimal but definite behavioral evidence of
self or environmental awareness is demonstrated.
Diagnostic criteria of VS
 loss of cognitive function， unconscious activities，
disable instruction
 unable to understand or express language
 demonstrate sleep-wake cycles
 open the eyes automatically or with stimulus
 aimless eyes tracking movement
 spontaneous breath or blood pressure
 functions of the
hypothalamus and brainstem are basically preserved
Classification of VS
 Persistent vegetative state(PVS)>1 month
 Permanent vegetative state
• brain traumatic>1 year
• non-traumatic>3 months
 transient vegetative state<1 month
Special type
 Decorticate
syndrome: extensive lesions in
bilateral cerebral cortex
 Akinetic mutism: damage of brain specific
or nonspecific activating system but a
complete cortex and efferent pathway
Brain death
 in 1968 Harvard Medical School published the
first criteria of brain death
 in 1981 the United States passed the uniform
standards of brain death diagnosis
 in 2003 Ministry of Public Health of China worked
out a criteria of brain death
Diagnostic criteria of brain death
 Brain death is the complete and irreversible loss
of brain function (including involuntary activity
necessary to sustain life)
 Clinical criteria
• deep coma
• brainstem reflexes disappeared
• no spontaneous breathing
 Comfirmation test
• electrical silence of ECG
• non-perfusion of transcranial color doppler
（TCD）
• short latency somatosensory evoked
potentials（SLSEP) disappeared
Glasgow Coma Scale
 The Glasgow Coma Scale provides a score
in the range 3-15; patients with scores of 38 are usually said to be in a coma.
 3’ → poor prognosis
 15’ → better prognosis
Differential diagnosis
 hysterical lethargy
 syncope
 affective stupor
 shock
 narcolepsy
 locked-in syndrome
Diagnostic program
 medical history
 physical
examination
observation
 assistant examination
and
vital
signs
Key points of inquiry
 initial symptoms，the speed of onset？
 medication history， drinking history and
toxic exposure？
 brain trauma history？
 HBP、DM or a history of heart、lung、
brain、liver、kidney？
 fever ？
How to estimate extracephalic or
intracephalic disease
intracephalic disease
systemic disease
initial symptoms
headache，convulsion，
mental disorder，
paralysis
primary disease's perform
ance
intracranial hypertention
obvious
not obvious
location sign of central
nervous system
yes
no
radiography
abnormal
normal
cerebral spinal fluid
maybe abnormal
normal
intracranial
disease
types of onset
acute
angiopathy
trauma
infection
subacute chronic
infection tumor
subdural
or
epidural
hematoma
location sign
focal signs
angiopathy
trauma
tumor
meningeal irritation
subarachnoid
hemorrhage
meningitis
sinus thrombosis
Localization diagnosis from
special type of breath
type of breath
diseased region
apnea after overventilation
bilateral frontal lobe
Cheyne-Stokes breathing
hemisphere
conditioned central neurogenic hyperpnea midbrain
apneusis
upper part of the pons
cluster breathing
lower part of the pons
irregular breathing
medulla oblongata
Odors in the breath
 ammonia smell → uremia
 apple smell → diabetic ketoacidosis
 garlic smell → organophosphorus pesticide poisoning
 fetor hepaticus → hepatic encephalopathy
 alcohol smell→ alcoholism
Involuntary movement
 muscle twitch： uremia、 pulmonary encephalopathy
：
hepatic
encephalopathy 、
pulmonary encephalopathy
 paroxysmal twitch： carbon monoxide intoxication、
atropine intoxication or some drug poisoning
 epilepsy
：
hypertensive encephalopathy、 cerebral hemorrhage、
craniocerebral injury
 choreic movement： rheumatic encephalopathy
 asterixis
Brainstem reflexes
reflexes
location
ciliospinal reflex
interbrain
frontalis-obicular muscle reflex
midbrain-interbrain
oculocephalogyric reflex
pupil light reflex
midbrain
corneal reflex 、 jaw reflex
upper part of pons
horizontal oculovestibular reflex
lower part of pons
oculocardiac reflex
medulla
corneomandibular reflex
inerbrain or midbrain
Systemic disease
 toxic disease
 metabolic disease：five visceral organ，
five pathogenic factors
 endocrine disease：five glands
 infectious diseases
Toxic disease
 characteristics
• acute onset， toxic exposure
• group onset
• frequently nausea、vomiting、 diarrhea、
excessive sweating、 convulsion
• multiple system damaged
• special clinical signs：change in skin color、
body odour、temperature、pupils
 clinical manifestations
• carbon monoxide intoxication → cherry-red lips
organophosphorus pesticide poisoning → breath
that smells of garlic
• sedative intoxication → low temperature 、low
blood pressure
• contracted pupil → organophosphorus pesticide
、sedative
• dilated pupil → atropine poisoning
•
Five visceral organs
 cardiogenic coma ：severe heart failure、arrhythmia 、




cardiac shock
pulmonary coma ：chronic bronchitis 、 emphysema 、
pulmonary heart disease
hepatic coma ：jaundice 、 cirrhosis、 hepatic dysfunction
renal coma ：oliguria 、 anuria 、anemia、HBP、renal
dysfunction
brain-derived coma ：no systemic disease、 focal signs of
CNS
Five glands
 pituitary crisis： severe bleeding after birth、
postpartumamenorrhea or agalactia
 hypothyroidism crisis： myxoedema、obvious
low temperature
 Addison disease： mucosa pigmentation of the
skin、fatigue、 hyponatremia
 hyperparathyroidism or hypoparathyroidism crisis：
significantly increased or decreased of
serum calcium
 pancreatic encephalopathy：abdominal pain、
blood amylase ↑、urine amylase↑
Five pathogenic factors
 glucose： hypoglycemia or hyperglycemia coma
 saline：hyponatremia、 hypernatremia
 acid：metabolic acidosis、 respiratory acidosis
 toxin：exogenous intoxication
 blood pressure：hypertensive encephalopathy、
hypotension and shock
Conclusion of diagnostic
thinking
differentiate intracranial diseases 、
systemic disease （ initial symptom 、
intracranial hypertension 、 focal signs ）
intracranial diseases ： type of onset （acute、subacute、
chronic）
location sign （ focal lesion 、 meningeal irritation sign ）
systemic disease： toxication
metabolism ：five visceral organs 、five pathogenic
factors
endocrine disease ：five glands
infection