Coma
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Introduction
Coma is a state of unresponsiveness in which the pt is not arousable to external stimuli.
It is accordingly a lack of arousability, content, and consciousness.
in which an individual has no meaningful response to environmental stimuli and cannot be aroused.
Brain Death definition: 'deep unresponsve
Stupor is a reduced level of consciousness from which the individual can be aroused, but with difficulty.
related states:
- akinetic mutism - arousable, but with iffy awareness
- persistent vegetative state - arousable (with sleep-wake cycles), but with no awareness
- locked-in syndrome - arousable and aware
- psychogenic unresponsiveness - arousable and aware
- nonconvulsive status epilepticus
Treatments
Resuscitation
Airway, Breathing, Circulation, Deficit/Neurological, Exposure
Stabilite neck if trauma.
Intubation may be needed; note respiratory pattern prior to intubation
Glucose 50g IV + thiamine 100mg
Narcan 0.4 mg and repeat
treat seizures
consider
Obtain early lab values
secure ABCs
labs
- blood glucose
- CBC
- electrolytes
- serum osmolarity
start
- one or two IVs
- thiamine (100 mg IV)
- glucose (50cc D50)
- consider Naloxone (0.2-0.4 mg)
do:
- CT to look for bleeds
- LP to rule out meningitis
- arterial blood gases
- ECG
- urine drug screen
- liver
- thyroid
- adrenal function tests
- blood cultures
get a history from witnesses; ask about onset, seizure, setting, medical history
- structural
- metabolic
Structural
Trauma: diffuse axonal injury, brain contusions, penetrating head injury
Intracranial hemorrhage: epidural, subdural, subarachnoid, intracerebral
Tumor: glioblastom
Metabolic
drugs
infectious
- sepsis
- bacterial meningitis
- encephalitis (HSV)
endocrine disorders
- hypoglycemic reaction
- diabetic ketoacidosis
- Alcohol
- Encephalopathy
- Insulin
- Opiates
- Uremia
- Trauma
- Infection
- Psychiatric
- Syncope
Thereare a whole other host of metabolic causes of coma: uremia, hepatic, hypoxia
Damage to the reticular activating system in the brainstem can be caused by physical or metabolic factors.
Damage to the hemispheres can be due to a number of causes.
It appears cerebellar or thalamic damage can also result in coma.
The Case of...
Differential Diagnosis
progression:
- sleeping
- confusion
- delerium - altered sensorium
- obtundation/drowsiness
- stupor
- coma - unarousable unresponsiveness
- vegetative sate
- locked-in syndrome
- pseudo-coma
History and Physical Exam
Signs, Symptoms, and Diagnosis
- history
- physical exam
History
Alcohol
Encephalopathy
Insulin
Opiates
Urema
Trauma
Infection
Psychiatric
Syncope
Physical Exam
General exam
- vital signs
- trauma
- fundi for ICP
Neurological exam to localize
- pupillary reflex: midbrain
- corneal reflex: CN V and VII pons
- vestibulo-ocular reflex (Doll's eyes): tests widespread brainstem integrity
- cold caloric: eyes should slowly and tonically move towards the
- vital signs
- look for head trauma (Battle's sign, otorrhea, rhinorrhea)
- neck suppleness
- tongue for bite marks
- evidence of alcohol abuse
- evidence of IV drug use
resipratory
- tachypnea
- Cheyne-Stokes respirations - diencephalic cause
- hyperventilation - central neurogenic cause
- apneustic breathing
- ataxic breathing
- apnea
eye exam
pupillary responses:
- midsize, unreactive - midbrain
- pinpoint, reactive - pons or narcotics
- small, reactive - metabolic
- dilated, unreactive - drugs
- unilateral dilated, unreactive - rostro-caudal degeneration, uncal herniation
eye movements:
- full, inducible or spontaneous lateral movements suggest brainstem is ok
- oculocephalic reflex (Doll's eye maneuver)
- oculovestibular reflex
fundoscopy
motor exam
asymmetry suggests structural lesion
levels of motor response can help in localization
sensory exam
sternal rub
nail bed pressure
decorticate posturing
decerebrate posturing
Brain Death
- non-reactive pupils
- absent corneal reflex
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
fibger stick for glucose
CBC, glucose, lytes, osmolality, Ca2+, PO4-, BUN, creatinine
ABG
drug screen
Diagnostic Imaging
ECG
CT head, MRI, EEG
Management
Pathophysiology
The Case of...
Additional Resources
Shemie SD et al. Brain Arrest: CMAJ 2006 174...
Topic Development
created: DLP, Aug 09
authors: DLP, Aug 09
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