Ch 2 - TBI: Medical Management Flashcards
When is CT head mandatory (GCS level)?
Early head CT is mandatory in GCS < 13
When can MRI brain be useful in TBI?
Define non-hemorrhagic lesions of the brain (cortical contusions, subcortical gray matter
injury, and brainstem lesions)
What sedating medications can delay neurologic recovery in TBI?
Benzodiazepines
What can barbiturates be used for in TBI?
Induce coma and dec metabolic requirements of the brain
Control ICP
What is an advantage for using propofol for sedation?
Rapid return to consciousness after discontinuation to allow for frequent neuro exams
What is a normal ICP in an adult?
Head and trunk elevated to 45° normal ICP is 2-5 mmHg.
What is considered elevated ICP?
ICP > 20 mmHg for >5 minutes
What can unchecked inc ICP lead to?
Death from deformation of tissue, brain shift, herniation and cerebal ischemia
What happens with ICP >40 mmHg?
Neurological dysfunction and impairment of the brain’s electrical activity
What happens with ICP >60 mmHg?
Fatal
What can worsen cerebral edema and inc ICP?
Fever
Hyperglycemia
Hyponatremia
Seizures
How is cerebral perfusion pressure (CPP) measured?
CPP=MAP-ICP
What should cerebral perfusion pressure (CPP) be to ensure cerebral blood flow?
> 60 mmHg
What happens to cerebral perfusion pressure (CPP) with increased ICP?
Reduced CPP
What are indications for monitoring ICP and for ventilation (GCS levels)?
- GSC <8 and CT findings w/ inc ICP
- GSC <6 w/o hematoma
- GSC <12 w/ severe chest and facial injuries
- GSC <8 prior to IC hematoma evacuation
What are methods to monitor ICP?
Papilledema
CT head
LP if no papilledema
Intraventricular ICP monitoring
What are methods to decrease ICP?
Elevated HOB to 30 deg Intraventricular ICP monitoring Neurosurgical decompression Hypothermia Dec PaCO2 through hyperventilation
What are surgical options for epidural hematoma or SDH?
Emergency craniotomy
Emergency burr hold
What does uncal herniation of the medial temporal lobe produce?
- CN3: ipsi pupil dilation, ptosis, ophthalmoplegia
- Ipsi hemiparesis from corticospinal tract on contralateral crus cerebri
- Contra hemiparesis from precentral motor cortex or internal capsule
- AMS
What is a post traumatic seizure?
Single recurrent seizure after TBI
What are types of post traumatic seizures (PTS)?
Partial (majority of PTS)
Generalized
What is the time frame for immediate post traumatic seizures (PTS)?
1st 24 hr post injury
What is the time frame for early post traumatic seizures (PTS)?
24hr to 7 days post injury
What is the time frame for late post traumatic seizures (PTS)?
After 1st week post injury
What are risk factors for Late post traumatic seizures (PTS)?
Penetrating head injury Intracranial hematoma Early PTS Depressed skull fx Age Alcohol abuse Use of TCAs Dural tearing Focal signs (aphasia, hemiplegia)
When is the greatest risk for post traumatic seizures (PTS)?
1st 2 years post injury
What lab finding can indicate posttraumatic epilepsy?
Increase prolactin level confirms true seizure activity but normal level does not rule out
seizure activity
What time frame is AED for seizure ppx effective?
Phenytoin and valproic acid have been proven effective only during the first week post-injury
Which AED’s are considered drug of choice for treatment of post traumatic seizures (PTS)?
Carbamazepine (partial seziures) and valproic acid (generalized seizures)
Keppra commonly used 1st line
When are therapeutic anticonvulsant medications are usually started?
Once late seizures occur
What is the probability of recurrent late seizures after the first late seizure?
Recurrent late PTS is up to 86% within 2 years
Which AEDs should be avoided in TBI post traumatic seizures (PTS)?
Phenobarbital: cognitive impairment
Phenytoin: cognitive effects and impede brain recovery
What does carbamazepine do to haloperidol?
Reduces concentration and effectiveness of haloperidol
What does lamotrigine used with carbamazepine cause?
Increase levels of 10,11-epoxide (an active metabolic of carbamazepine)
Which drug does lamotrogine reduce concentration of when used concurrently?
Valproic acid
What happens when phenytoin and theophylline are taken concurrently?
Phenytoin levels may be lowered and theophylline metabolized more rapidly
What does phenytoin decrease effectiveness of?
Decreases effectiveness to contraceptives