Jamie Rice
In individuals under 45 years of age traumatic injuries are the leading cause of death,
approximately fifty percent of which are head injuries (Unden, 43). The leading cause of death
in children worldwide is traumatic brain injury. In the United States alone, children (individuals
aged younger than 18 years old) account for approximately 7400 deaths, 60000
hospitalizations, and 600000 emergency room visits every year (Identification of Children at Very
Low Risk of Clinacally-important Brain Injuries After Head Trauma: a Prospective Cohort Study). This
makes the ability to diagnose the injury quickly a necessity. Computed tomography (CT) scans
and magnetic resonance imaging (MRI) are used to determine the presence and severity of a
traumatic brain injury as well as skull fractures and other severe injuries that could in the
instance of head impact. It is argued, however, that these tests expose children to (in many
cases) unnecessary radiation, which had the potential to cause malignancies. It is also argued
that these two types of imaging are not sensitive enough for some brain injuries to be seen on
the images produced. There is a need for an alternative method for quick diagnosis and a way
to determine whether it is necessary for a child to undergo some form of neuroimaging. The
following research explores the question: Is there a way to determine whether a pediatric
patient needs a neurological scan and is there a method of diagnosing head trauma without
scanning the brains of children? Biomarkers are the most researched alternative and aid for
diagnosis of head injuries in children.
This topic is important because head trauma in children can have many life threatening
consequences. Children cannot be treated the same adults because they “have a more
susceptible cranial vault due to thinner bones, large head-to-torso ratio, late development of
air sinuses and differences in the immune system and in their capability of maintaining body
temperature”(Alexiou, 403). In order to determine the severity of head traumas in pediatric
patients many factors should be taken into account. A detailed history of the patient, loss of
consciousness, seizures, and amnesia, should be recorded and a physical examination should be
performed that involve assessment of patient’s airway, breathing and circulation, Glasgow
coma scale scores (Glasgow coma scale is a 15 point test based on eye opening response, verbal
response, and motor response(Rowlett)), the size or their pupils, the head and spine, and ears.
Such extensive evaluations need to be done because there are many possible injuries that can
result from head trauma. Skull fractures can be found in anywhere between two and twenty
percent of children that experience head trauma. These fractures can be linear, depressed,
diastatic, and of skull base. Children with head trauma can also have epidural hematoma, a
collection of blood between the inner skull and dura mater, subdural hematoma, which results
because of injury to the bridging cortical veins, intracerebral hematoma, and penetrating head
trauma. (Alexiou)
Physical examination, Glasgow Coma Scale scores, and computed tomography (CT) scan
of the cranium are considered the current gold standards for diagnosing traumatic brain injury
in children, even though these “standards” have a number of limitations in their ability to
predict the neurological outcome and have a low sensitivity for detecting mild traumatic brain
injury. This study is focusing on the use of the biochemical marker S-100B, a large number of
studies have explored the S-100B as an analytical and predictive index of head trauma. S-100B
is a calcium-binding protein produced by astrological cells that exerts extracellular functions so
it is actively secreted. S-100B stimulates neuronal growth and enhances the survival of neurons
during development and after injury. Piazza measured the range of S-100B concentration in
children that experienced traumatic brain injury and the possible roles of the protein. “S-100B
is a small diametric calcium-binding protein that is found in astroglial within the central nervous
system.” Piazza’s studied fifteen children between the ages of one and fifteen years of age with
head injury that were admitted to the emergency department within 12 hours of injury. The
severity of their head injuries was determined by Glasgow coma scores. Nine patients had mild
traumatic brain injury (TBI), two patients had moderate TBIs, and four patients had severe TBIs.
The patients’ characteristics were recorded, as well as the time and cause of injury. Cerebral CT
scans were performed at admission to the emergency department and after 48 hours. Blood
samples were also obtained at the same time intervals, these samples were used to analyze the
S-100B measurement in the patients’ bodies. The lower detection level was .02 µg/l. Six of the
fifteen children analyzed had heightened levels (greater than .3µg/l) of S-100B in their systems.
In three out of the four cases the concentration of the protein remained elevated for at least 48
hours. The result of this study showed a trend towards increasing levels of the protein with
increased severity of the head injury. The serum concentrations of S-100B was higher in
children with a score of eight or less in Glasgow coma scale test, the lower the score the more
severe the head injury. Although the results of this investigation showed that there is a
correlation between the severity of head injuries and the levels of the S-100B protein, the
conductors of this research conclude that the role of S-100B is not yet cleared and it is not a
reliable prognostic index. (Piazza, 258-260, 262)
Undén performed a similar study with a fourteen-year-old male and a seventeen-yearold male. In the case of the 14-year-old he was sent home after visiting a primary care center
with no substantial symptoms and was sent home. The next morning he could not be waken
and he was rushed to the hospital. At the hospital the child underwent a CT scan which showed
“a skull fracture with a massive epidural hematoma with signs of a cerebral herniation” (Undén,
44). His S-100B levels were measured at .2µg/l. The 17-year-old suffered a massive epidural
hematoma after a blunt head injury. The hematoma was rather large and resulted in possible
cerebral herniation. S-100B levels were .14µg/l three and a half hours after the initial injury and
.10µg/l six hours after the injury. Undén suggests that S-100B is the most promising biomarker
to date. This protein has a high negative predictive value, which means there are minimal
numbers of false negatives produced when measurements of S-100B are used to determine.
Undén also stated the faults of using the biomarker in clinical use. S-100B has a very short halflife, so if a patient has samples taken too late there is the possibility of a reading that suggests a
less serious injury. Even in the case if the 17-year-old the concentration of S-100B was not a
good indicator of “the most feared of complications after head injury.” This is extremely
important because a misdiagnosis of epidural hematoma can be harmful consequences. Undén
concludes that he showed that S-100B does not always detect intracranial hematomas, even
when serum is taken shortly after the head impact.
A study was conducted to determine when it is necessary for a child to undergo two CT
scans. The study was conducted on patients aged 0 to 21 years who had initial and subsequent
head imaging studies performed at a participating children’s hospital and their initial scan
documented. Patients were excluded if they had transferred to a participating hospital with a
cranial injury confirmed by a CT scan performed elsewhere, a second image of the brain injury
was not performed, they were treated to manage hypertension before the second CT scan was
performed, and if the patient had a history or diagnosis of a bleeding disorder, neurological
disorder, or bone metabolism disorder. Forty-seven patients were involved in the study, of
these patients, only 5 had to undergo surgical intervention when the results of the second CT
scan were produced. Of the five, four were infants that suffered nonaccidental trauma and had
follow up MRIs performed. The fifth child suffered a closed head injury while sledding which
cause an epidural hematoma without mass effect. The other 42 children remained stable. This
study was concluded by the researcher stating that children that do not require surgery may
not benefit from serial brain imaging, but a larger study would need to be performed in order
to determine who can be exempt from neuroimaging. (Schnellinger)
Tang researches the when to image children and what can actually be found by a CT
scan. CT scans are the “first-line investigation” for head trauma in pediatric patients, even
though MRIs may be more sensitive and effective in finding the full extent of the injuries. In
cases of minimal head trauma, the patient may be discharged and given head injury advice
from the medical professional that saw them. Patients with moderate to severe head trauma,
loss of consciousness for more than five minutes, or focal neurological deficit should be sent for
an urgent CT scan. Ambiguity is caused when there is an in between case, where patients
cannot be considered mild nor severe and are less than moderately injured. There is no clear
consensus on where to draw the line for CT scans. Positive findings are seen in less than ten
percent of patients that are screened and approximately 0.5% require surgical intervention.
The indications for a CT scan in a child younger than 16 years of age with head
trauma include:
1. Witnessed unconsciousness >5 min.
2. Amnesia >5 min.4
3. Abnormal drowsiness
4. Three or more discrete episodes of vomiting
5. Clinical suspicion of nonaccidental injury
6. Posttraumatic seizure in absence of history of epilepsy
7. GCS score <14 in a child or GCS score <15 in infants in the emergency
department
8. Suspicion of open/depressed skull fracture or tense frontanelle
9. Clilical evidence of base of skull fracture
10. Focal neurological deficit
11. Bruise, swelling or laceration >5 cm in infants
12. High impact head trauma
The National Institute for Health and Clinical Excellence guidelines recommends that the
Children’s Head injury Algorithm for the Prediction of Important Clinical Excellence guidelines
shown above be followed. Minor head injuries account for the largest percentage of children
seen for head trauma and the concerns for exposing them to unnecessary radiation has
increased. Although children absorb a lower dose of radiation for a CT scan of the head than
adults do, the effective dose can be up to four times greater in a neonate (a child four weeks
old or younger). If the tube current could be decreased, the dose of radiation could decrease by
up to fifty-eight percent. CT scans are useful for finding very serious brain conditions due to
head traumas hematoma is more commonly due to a dural vein tear, it is imperative to
diagnose an extradural hematoma because it could be due to a middle meningeal artery. (Tang)
Based on the research that I studied, it can be concluded that the biomarker S-100B
cannot be used in clinical practice. The half-life of S-100B is very short, therefore the
concentrations decrease very quickly. If a patient is not taken to the hospital within a few hours
of the injury there may be no information gained from taking samples and the patient would
get a CT scan regardless of whether serum samples were taken. The protein S-100B does has
been shown to make accurate predictions to the severity of head traumas, but in realistic
situations, patients would not be seen by a medical professional in time to be tested for
concentration levels of the protein. S-100B has a very high negative predictive value, yet since it
is not 100% accurate it cannot be cleared for clinical use. Although there specifications for what
a child’s symptoms should be in order to undergo some sort of neuroimaging, many pediatric
patients still experience unnecessary scanning. From the research I conducted, I can conclude
that there are possible ways to reduce the number or neurological scans performed on
children, but methods have not been implemented because they may not be practical for
clinical use and rare cases of overlooked severity of a head injury.
Works Cited
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