Coma Flashcards
What is Coma?
Medical Emergency
What does coma imply?
Diffcuse insult to the cerebral hemispheres bilaterally or focal damage to the core of the brainstem known as the Reticular Activating System (RAS)
What is the MCC of coma in large city hospitals?
Toxi-metabolic
(non-structural brain injury)
What is the 2nd MCC of coma?
Structural brain damage
What is the duration of coma?
- Acute w/ trauma, stroke or bacterial meningitis
- Subacute or gradual in abscess or neoplasm
What is the 1st step in all medical emergencies?
Evaluate ABC’s
What are the #1 priorities until secure & stable?
Pulse, airway secure & breathing
What do unstable pts often need?
Endotracheal intubation & resp assistance
What should always be established in a coma pt?
IV access & indwelling Foley catheter
How should you speak to the pt during the exam?
Speak loudly to the pt & call their name directly into their ear
What should you ALWAYS do to check for Locked-in-synd?
Ask pt to try to move their eyes or blink
What should be done bilaterally when examing the pt?
Check for withdrawal movement to painful or noxious stim (pressure on supraorbital ridge, pinching nipple, strong pressure to nail bed)
If there is suspicion of trauma what should be performed before doing maneuvers that require the neck to move?
Cross table lateral AP X-ray of the cervical spine
What will pt have w/ brainstem injury when putting limbs through ROM?
Symmetrical or asymmetrical spasticity
What will pts w/ brainstem lesions have when checking DTRs?
Symmetrical or asymmetrical inc DTRs
What will pts w/ brainstem lesions have when checking pathological reflexes?
Unilateral or bilateral + Babinski’s, Hoffmans or Tromner’s
What will pt w/ brainstem lesions have when checking the pupillary light reflex?
Pupillary ABN
What other signs are often ABN ina brainstem injury?
- Doll’s eyes
- Ice water caloric stim
- Corneal reflexes
- Gag reflexes (if not intubated)
What is the best imaging for the brainstem?
MRI
What is the quickest & easiest to obtain in a comatose pt?
CT
What will bedside EEG rule out?
Subclinical seizures & determine if cortical activity present
What is the tx of coma?
- Support ABC’s
- Trial of IV Narcan (narcotic antagonist) in comas of unkown etiology
How can Focal structural hemispheric damage cause coma?
Do not lead to coma unless the lesions are numerous & widespread
What do focal lesions cause?
Herniation of hemispheres leading to secondary compression of RAS in brainstem
Who usually gets coma d/t drug intoxication?
Young adults or adolescents
(all age groups represented)
What is the hx of coma d/t drug intoxication?
- Freq psychiatric hx
- Record of prior events
- Rx meds at scene
What is the most resistant reflex to metabolic or toxic suppresion?
Pupillary light reflex
What will toxicology studies show in coma d/t drug intoxication?
- Causative substance
- Narcotics
- Barbituates
- Tricyclic compounds
- Benzodiazepines
How does drug intoxication cause coma?
Depreses the cerebral cortex diffusely & effect will last until the durg is metabolized
What does death usually result from in drug intoxication?
- Apnea
- Hyopxemia
- Hemodynamic collapse
- Arrythmias
Which metabolic disordes can lead to coma?
- Diabetic Ketoacidosis
- Hyperthyroid Myxedmea
- Liver failure
How do metabolic disorders lead to coma & death?
Creating a metabolic milieu that cannot sustain diffuse brain function
What is most vulnerable to metabolic insults?
Cerebral cortex> brain stem
What are the tech features of metabolic disorders causing coma?
- DKA, inc TSH, inc serum ammonium, ABN hepatic function studies
- Brain imaging not dx
- EEG is ABN in non-specific fashion
What factors can cause coma d/t cerebral perfusion or hypoxemia?
- Mi
- Cardiac arrhythmia
- Strangulation
- Drowning
- Air way occlusion
- Resp failure
What is the hx of coma d/t decreased cerebral perfusion of hypoxemia?
- Hx of near-drowning
- Strangulation
- Suffocation
- Airway occlusion
- Cardiac arrest or lethal arrhythmia
What are the PE findings of coma d/t dec cerebral perfusion or hypoxemia?
No ABN focal neuro fidnigs or abundant focal finding d/ multiple cerebral infarctions
What are the brain MRI findings of dec cerebral perfusion or hypoxemia?
Cerebral hypoxemia or ishcmeia but may take time to evolve
What are the EEG changes of dec cerebral perfusion or ischemia?
Non-specific but sensitive
What will EKG or Chest X-ray show in dec cerebral perfusion or ischemia?
Underlying cardiac or pulmonary causes
What features distinguish brain death from coma?
- Absent pupillary light or corneal reflex
- No withdrawal from painful stimuli
- Apnea even following removal of ventilator support while maintaining adequate oxygenation
What are the tech features of Brain death?
Absencent EEG activity or cerebral perfusion on imaging studies
What does Obtunded mean?
Less than full mental capacity
What is lethargy?
Subjective feeling of tiredness or fatigue
What is Stupor?
Lack of crtical congnitive function & consciousness
What is comatose?
State of unconsciousness >6 hours where a pt can’t be awakened or aroused
