TCE Flashcards
what is the classic sign of uncal herniation
ipsilateral pupillary dilation associated with contralateral hemiparesis
whats the normal intracranial pressure
10mmHg
pressured >20mmHg, particularly if sustained and refractory to tx, are associate w/ poor outcomes
whats the Monro-Kellie doctrine
the total volume of the intracranial contents must remain constant, because the cranium is a rigid, nonexpansible container. Venous blood and CSF may be compressed out of the container, providing a degree of pressure buffering. Thus, very early after injury, a mass such as a blood clot may enlarge while the ICP remains normal. However, once the limit of displacement of CSF and intravascular blood had been reacher, ICP rapidly increases
in a clinical setting, how is the cerebral perfusion pressure definer
MAP - ICP
what are the clinical signs of basilar skull fracture
periorbital ecchymosis (racoon eyes)
retroauricular ecchymosis (Battle’s sign)
CSF leakege from nose or rear
7th and 8th nerve dysfx (facial paralysis and hearing loss)
classification of brain injury according to morphology
skull fractures:
- vault: linear vs stellat, depressed/nondepressed, open/closed
- basilar: w/ or w/o CSF leak. w/ or w/o 7th nerve palsy
intracranial lesions:
- focal: epidural, subdural, intracerebral
- diffuse: concussion, multiple contusions, hypoxic/ischemic injury, axonal injury
characteristics of diffuse brain injuries
range from mild concussions to severe hypoxic ischemic injuries
CT scan can seem normal, or the brain may appear diffusely swollen, with loss of the normal gray-white distinction
another diffuse pattern, often seen in high-velocity impact or deceleration injuries, may produce multiple punctate hemorrhages throughout the cerebral hemispheres
what kind of brain injuries are epidural hematomas, subdural hematomas, contusions, and intracerebral hematomas
focal brain injuries
characteristics of epidural hematomas
uncommon
typically become biconvex or lenticular in shape as they push the adherent dura away from the inner table of the skull
they are most often located in the temporal or temporoparietal region and often result from a tear of the middle meningeal artery are the result of fracture
a lucid interval between time of injury and neurologic deterioration is the classic presentation of an epidural hematoma
characteristics of subdural hematomas
more common than epidural hematomas
often develop from the shearing of small surface of bridging blood vessels of the cerebral cortez
more often appear to conform to the contours of the brain
brain damage underlying an acute subdural hematoma is typically much more sever than that associated with epidural hematomas due to the presence of concomitant parenchymal injury
characteristics of contusions
fairly common
the majority occure in the frontal and temporal lobes
may evolve to form an intracerebral hematoma or a coalescent contusion with enough mass effect to require immediate surgical evacuation
pt with contusions generally undergo repeat CT scanning to evaluate for changes in the pattern of injury within 24 hrs of the initial scan
how is a minor traumatic brain injury defined
by a history of disorientation, amneasia, or transient loss of consciousness in a pt who is conscious and walking
GCS 13 - 15
characteristics of a moderate brain injury
pt able to follow simple commands, but usually are confused or somnolent and can have focal neurologic deficits such as hemipareseis
GCS 9 - 12
management of a moderate brain injury
CT scan and a follow up CT scan within 24 hrs is recommened if the initial CT scan ir abnormal or if there is deterioration of pts neurologic status
observation and frequent neurologic reassessment for at least the first 12 - 24 hrs
characteristics of severe brain injury
pt unable to follow simple commands, even after cardiopulmonary stabilization
GCS 3 - 8
management of a severe brain injury
ABCDE's primary survey and resuscitation secondary survey and AMPLE history frecuent neurological reevaluation admit to a facility capable of definitive neurosurgical care CT scan
What’s an early sign of temporal lobe (uncal) herniation
dilation of the pupil and loss of the pupillary response to light
recommended IV solutions when pt has a traumatic brain injury
Ringer’s lactate or normal saline
recommended ventilation in a pt that has suffered TBI
hyperventilation should only be used in moderation and for as limited as a period as possible
it is preferable to keep the PaCO2 at approx. 35mmHg
brief periods of hyperventilation (PaCO2 of 25 - 30mmHg) may be necessary for acute neurologic deterioration while other tx are initiated
hyperventilation will lower ICP in a deteriorating pt with expanding intracranial hematoma until emergent craniotomy can be performed
recommendations in using mannitol in a pt with a traumatic brain injury
mannitol is used to reduce elevated ICP
preparation most commonly used is 20% solution (20g mannitol / 100ml solution)
should be given to pt with hypotension (b/c it doesn’t lover ICP in hypovolemia and is a potent osmotic diuretic which can further exacerbate hypotension and cerebral ischemia)
strong indicators to admin mannitol in a euvolemic pt:
- acute neurologic deterioration
- development of dilated pupil
- hemiparesis
loss of consciousness
^^^ in this setting a bolus of mannitul (1g/kg) should be given rapidly (over 5 mins) and the pt transported immediately to the CT scanner or directly to the OR
preferable solution to use in pt with hypotension in a pt with a traumatic brain injury
hypertonic saline (concentrations of 3% -23.4%) doesn't act as a diuretic
what are the tree main factors linked to a high incidence of late epilepsy
seizures occurring within the 1st week
intracranial hematoma
depressed skull fracture
how are seizures treated in an pt with traumatic brain injury
pehytoin and fosphenytoin are the agents generally used in the acute phate
adults: loading dose is 1g of phenytoin given IV at a rate no faster than 50mg/min
usual maintenance dose: 100mg/8hrs, with dose titrated to achieve therapeutic serum levels
diazeoam or lorazepam is frequently used in addition to phenytoin until the seizure stops
control of continious seizured may require general anesthesia
anticonvulsants may also inhibit brain recovery, so they should be used only when absolutely necessary
what are the criteria for the dx of brain death
GCS = 3
Nonreactive pupils
Absent brainstem reflexes (oculocephalic, corneal, Doll’s eyes, no gag reflex)
No spontaneous ventilatory effort on formal apnea testing
ancillary studies that may be used to confirm the dx of brain death include:
- ECG: no activity at high gain
- CBF studies: no CBF
- cerebral angiography
