Traumatic brain injury is (TBI) is defined as “an alteration in brain function, or other evidence of brain pathology, caused by an external force.” In children, a pediatric TBI disrupts the normal stages of growth required for full maturation of the developing brain. This is further complicated by different stages of growth and development throughout a child’s life. This chapter highlights features of pediatric TBI that distinguish it from that of adult TBI.
Epidemiology
Epidemiological features of pediatric TBI include age, gender, premorbid developmental and environmental history, and mechanisms of injury.
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TBI is leading cause of death and disability in pediatric trauma.
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Under age 10, 50% of TBIs are from transport-related accidents, falls, and assaults.
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In older children, the most common cause is from motor vehicle crashes.
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The largest affected pediatric groups are infants and adolescents. The most common cause of TBI under age 4 is falls.
Morbidity and mortality
Morbidity and mortality rates often reflect the severity of injury, presence of additional injuries, and the age of the child. There is greater morbidity with the presence of serious concomitant injuries—longer hospitalization, increased infections, fewer ventilator-free days, and higher level of care required on discharge from the hospital.
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Morbidity in survivor rates are 75% to 95% with good recovery, 10% with moderate disability, 1% to 3% severe disability.
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“Abusive head trauma is most common TBI-related cause of death under 4 years of age.”
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Children younger than age 2 have a mortality rate of 50% and worse outcomes compared with older children.
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In severe TBI, mortality rates vary from 12% to 62%, in moderate TBI 4%, in mild TBI (mTBI) less than 1%.
Age and gender
Age and gender-related factors play a role in the location, mechanism, and severity of injury.
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Relative risk for TBI is equal between both genders before age 2.
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Cognitive and academic outcomes are worse in the younger age group.
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By age 10, 16% will sustain at least one head injury necessitating medical care.
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TBI mortality increased between 2013-2017 due to increase in suicide mortality despite decrease in motor vehicle crashes in previous years.
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Boys, rural children, and children ages 15-19 had higher mortality rates between 1999-2017 than girls, urban, and younger children
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The majority of sports-recreation related concussions occur in children under 18 years of age.
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Male:female ratio in school-aged children is 2:1.
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In adolescence, this mortality risk increases to a ratio of 4:1.
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Anatomical and physiological factors include head and neck strength differences; with women having less head–neck mass and neck girth to absorb impact and acceleration forces.
Preinjury history can serve as a risk factor for injury. This can include home settings and premorbid conditions.
In very young victims, these can be homes with poor coping skills, limited financial means, psychiatric/psychological difficulties, fewer family resources, and a single-parent household. In older children, hyperactivity and attention deficit may be a risk factor. There has been an association with Hispanic ethnicity and mTBI. Mild TBI can be associated with 50% rate of premorbid learning disabilities or poor academic performance, and 17% of children with persistent deficits after mTBI had previous head injury; hyperactivity; learning, behavioral, psychiatric/neurological conditions; and family difficulties.
As with adults, injury characteristics were predictive of outcomes. In pediatric TBI, additional predictive value was seen in neuroimaging findings that showed bilateral brain edema, multiple and/or diffuse brain lesions, decreased brain volumes, and increased ventricular size. ,
Measurement, pathophysiology, and classification of traumatic brain injury
The classification of pediatric TBI severity involves the integration of acute injury measurement scales and understanding the pathophysiology and mechanisms of injury. Pediatric versions of widely used assessment scales are used to help address limitations in testing. These are because of the differences in the developmental level of the pediatric population being tested. These can be used to classify injury severity, which in turn can predict outcomes. Description of these scales will focus on the differences when used in children.
Measurement scales
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For children 3-15 years of age, the Children’s Orientation and Amnesia Test (COAT). This test incorporates the developmental level when assessing patients
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Glasgow Coma Scale (GCS): Used frequently; appears best for ages 5 years and above; therefore age-appropriate cognitive–linguistic pediatric coma scales are used
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Loss of Consciousness (LOC): As in adults, describes the time frame of consciousness/coma
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Post-Traumatic Amnesia (PTA) can be assessed via the Children’s Orientation and Amnesia Test (COAT). Duration used to predict short and long term outcome after pediatric TBI.
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As in adults, the classification system for grading TBI severity often incorporates GCS, LOC and PLA
Pathophysiological differences
Complex, multifactorial contributions to brain injury can result from pathophysiological differences. These include developmental responses postinjury that distinguish pediatric from adult TBI.
Brain development
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Increased cerebral water content and blood volume
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Larger head:body ratio
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Immature nerve cell myelination
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Weaker neck musculature and ligamentous connections
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Increased blood-brain permeability
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Decreased skull absorption of mechanical forces
Post–brain injury development
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Brain atrophy
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Impaired brain autoregulation
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Increased diffusion of excitotoxic neurotransmitters
Classification of pediatric traumatic brain injury
The mechanical properties of pediatric brain tissue and the immature skull play an important role in defining the underlying injury. Infant brain tissue is mostly composed of axons. Increased myelination of astrocytes and oligodendrocytes decrease the “stiffness” of the brain tissue. Age-dependent variances in skull thickness and infant cranial suture fusions should also be considered. Because of this, most pediatric brain injuries result in generalized brain injury.
The developing brains of the pediatric group respond differently to trauma than adults, with more susceptibility to hypoxic–ischemic insults, hypotension, posttraumatic swelling, and diffuse injuries. Despite the similarities in brain injury mechanisms reviewed, individual differences with varying complex patterns of neuromuscular and neuropsychological impairments are evident in all patients with TBI.
Abusive head trauma
AHT, also known as shaken baby syndrome , is a unique feature of pediatric TBI. Child abuse is the major cause of AHT in the youngest subgroups. Pathological mechanisms of inertial forces alone are associated with an increased likelihood of diffuse injury, traumatic axonal injury, and subdural hematoma. Anatomical factors include open fontanelles, softer skulls with poorer impact absorption, and weaker neck musculature with relatively large heads. These factors making infants likely to sustain a diffuse TBI.
Concussion and mild traumatic brain injury
A distinct subset of pediatric TBI involves concussion, considered a form of mTBI. Concussion is defined as “a traumatically induced transient disturbance of brain function.” Although concussion and mTBI are not unique to pediatric TBI and the topic is reviewed elsewhere in this textbook, it is worth noting certain aspects of concussion in children:
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From 2001 – 2012, 70% of ED visits for sports related concussions were among children.
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In males, higher rates in contact sports—American Football, Basketball, Soccer and Baseball
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In females—Soccer, Basketball and Hockey
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Second-impact syndrome is a controversial and rare but serious complication seen with children who have reinjury during the initial postinjury period.
| Penetrating Head Injury (PHI) | Closed Head Injury (CHI) |
|---|---|
|
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| Primary Injury | Secondary Injury |
|---|---|
|
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* Acceleration–deceleration forces: combination of translational and rotational acceleration is the most damaging mechanism of inertial forces; correlated more with subdural hematoma and DAI (the latter correlated with long-term functional disabilities)
| Risk factors | Male gender, young mother (under 21 years of age), and multiparity |
| Presenting symptoms | Nonspecific (i.e., altered state of consciousness, seizures, vomiting, breathing difficulty, apnea, increasing head circumference, failure to thrive, and delayed development), and the traumatic event is not easily disclosed |
| Unique features of abusive head trauma | Subdural hematoma (diffuse, interhemispheric, or posterior fossa locations) and retinal hemorrhage (most common findings) with multiple fractures of varying ages, irritability, poor feeding, vomiting, observed periods of apnea, and skin lesions |
Total rest is no longer recommended. Current guidelines recommend symptom-limited cognitive and physical rest in the immediate postinjury period (up to 48 hours), followed by a gradual or graded increase in physical activity. In children, there is also a gradual return to learn protocol to allow the transition back to academic activity. This should precede the return to sport protocol, with resolution of concussion-related symptoms before a return to play.
Rehabilitation strategies in pediatric traumatic brain injury
Sections after this address common issues pertaining to the treatment of pediatric brain injury in the rehabilitation setting. These include pharmacological management for cognition and arousal, dysautonomia, and spasticity. This is followed by selected medical complications in children with TBI.
Medications for cognition, arousal, and dysautonomia
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Amantadine: N-methyl-D-aspartate receptor antagonist used to improve arousal and attention in children
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Melatonin: Postulated to help reset the sleep–wake cycle with possible neuroprotective role in TBI ; children may secrete more, not less, melatonin in the acute stages of brain injury
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Bromocriptine: Dopamine D2 agonist cited in multiple case reports for treatment-resistant central hyperthermia
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Morphine: Centrally acting opioid analgesic used in children with autonomic instability ,
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Beta-adrenergic receptor antagonists: Used in autonomic instability; slows cerebral metabolism and catecholamine-induced catabolic state
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Clonidine: Used for sympathetic hyperactivity in combination with beta blockers
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Gabapentin: Effective for dysautonomia in which standard treatments were ineffective
Medications for spasticity
Treatment goals for spasticity in the child with a brain injury not only include goals for improving gross and fine motor function but also seek to improve positioning, comfort, ease of care, and decreased need for surgical intervention in a growing child. Unlike in adults, spasticity management in pediatric patients must also incorporate future physical and developmental stages.
Oral medications
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Baclofen: Gamma aminobutyric acid (GABA B) receptor agonist at the level of the spinal cord; adverse effects include sedation and fatigue; abrupt discontinuation may cause withdrawal-increased spasticity, seizures, hyperthermia, altered mental status; most severe withdrawal complication is rhabdomyolysis and multiorgan failure ; treatment of withdrawal usually involves reinstitution of oral baclofen
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Tizanidine: Centrally acting alpha-2 adrenergic agonist that increases presynaptic inhibition of motor neurons; adverse effects include sedation, drowsiness, hypotension, dizziness, and dry mouth; contraindicated in patients taking antihypertensives
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Benzodiazepines: Act at spinal cord and supraspinal levels by mediating GABA A receptors; adverse effects include ataxia, urinary retention, constipation, and hypersalivation
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Dantrolene: Inhibits release of calcium at the level of the sarcoplasmic reticulum; adverse effects of weakness, gastrointestinal symptoms, hepatoxicity with features of acute hepatitis ; no cases of hepatotoxicity have been reported in children
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Clonidine: Centrally acting alpha-2 adrenergic agonist that increases presynaptic inhibition of motor neurons; common effects include hypotension, sedation, and dry mouth; contraindicated in patients taking antihypertensives; has additional benefit of use in treatment of sympathetic hyperactivity
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Gabapentin: Inhibits presynaptic glutamate release by modulating calcium channels; has the adverse effects of sedation, dizziness, and ataxia
Interventional medications
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Botulinum toxin: For treatment of focal spasticity; blocks transmission of acetylcholine from the presynaptic nerve terminal at the neuromuscular junction; adverse events include localized pain and excessive weakness; more severe adverse events can include respiratory failure and systemic weakness
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Intrathecal baclofen: GABA B receptor agonist, blocking polysynaptic and monosynaptic afferent neuronal transmission; used for generalized spasticity; contraindications include hypersensitivity to oral baclofen
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Complications include dose-related causes (overdose or withdrawal) and implant malfunction ; symptoms of baclofen withdrawal can include itching, rebound spasticity, hallucinations, seizures, and eventual rhabdomyolysis; treatment of withdrawal can include restarting oral baclofen, administering diazepam, or dantrolene
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For intrathecal baclofen withdrawal can also give cyproheptadine, a serotonin agonist
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Neurolysis with alcohol/phenol: Alcohol and phenol effect neurolysis through the destruction of peripheral nerves; adverse events include injection site pain, dysesthesia, and hypotension
Medical complications in pediatric traumatic brain injury
These are selected medical complications with differences in their frequency, management, and outcomes.
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Heterotopic ossification: Lower frequency compared with adults ; risk factors include severity of injury, autonomic instability, and persistent vegetative state ; concerns over bisphosphonates because of long half-life, unknown teratogenic effect, and impact on growing bone
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Venous thromboembolism Incidence significantly lower than adults ; associated with older age, surgery, transfusion, ventilation, injury severity and lower GCS score
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Epilepsy and prophylaxis: 5% to 21% of children experience posttraumatic seizures; 32% to 40% develop a recurrence ; posttraumatic seizures most associated with younger age, severity of injury, and nonaccidental trauma ; prophylaxis in first week advised but none afterward unless posttraumatic seizures occur
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Attention deficit hyperactivity disorder (ADHD): Commonly seen after TBI; often associated with both premorbid and postinjury ADHD
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Depression: Occurs less frequently in children than in adults ; serotonergic antidepressants, cognitive behavioral interventions show best preliminary evidence for treatment
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Endocrine dysfunction: Most common is growth hormone deficiency (varies from 2%–57% of cases); second most common is gonadotropin-releasing hormone (GnRH) deficiency (4%–37%) ; unique to children; precocious puberty, requiring GnRH agonist therapy ,
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Olfactory dysfunction: May affect children because of role of olfaction in diet, resulting in decreased feeding and ability to thrive
Functional outcomes in pediatric brain injury
Functional domains most sensitive to TBI are intellectual functioning, processing speed, attention, and verbal memory. Most recovery include intellectual functioning and processing speed. On the other hand, children with a significant premorbid history are more likely to have negative lasting impact from their injury.
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Glasgow Outcome Scale Extended Peds (GOS-E Peds): Designed to predict outcome measures from infancy to adulthood; modeled after the Glasgow Outcome Scale (GOS)
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Children’s Orientation and Amnesia Test (COAT): Derived from the Galveston Orientation and Amnesia Test (GOAT); measures PTA and cognitive functioning in children and adolescents from 3 to 15 years; made up of 16 items that assess general orientation, temporal orientation, and memory
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Time to Follow Commands (TFC): Interval in days from injury until individual followed simple verbal commands twice within 24 hr interval ; TFC and PTA both added statistically significant predictive power above and beyond the GCS
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Functional Independence Measure for Children (WeeFIM): Adaptation of the Functional Independence Measure (FIM) used in adults; for children from 6 months to 7 years without disabilities and older children with developmental disabilities; three domains: self-care (eight items), mobility (five items), and cognition (five items); has been further expanded to include children up to 18 years, allowing interface with the adult FIM
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Pediatric Evaluation of Disability Inventory (PEDI): Assesses self-care (73 items), mobility (59 items), social function (65 items), caregiver assistance (20 items); for children ages 6 months to 7.5 years with physical limitations, combination of physical and cognitive limitations; also used in older children with developmental disabilities
Review questions
- 1.
A 13-year-old boy is tackled during a football game. He does not lose consciousness but was disoriented for 20 seconds and cannot recall his injury. His headache is improving, but during sideline evaluation he is unsteady and has difficulty with single-leg stance during balance testing.
The next best step is
- a.
home rest for 1 week, then graded return to learn/play.
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home monitoring with family, then graded return to learn/play.
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computed tomography (CT) scan, then graded return to learn/play.
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magnetic resonance imaging (MRI), then graded return to learn/play.
- a.
- 2.
You are at a long-term care facility seeing a 7-year-old girl with severe traumatic brain injury (TBI). The child has been noted to have weight gain, onset of menses, and signs of breast development. What is the most likely treatment option?
- a.
Gonadotropin-releasing hormone (GnRH) agonist
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GnRH antagonist
- c.
Estrogen
- d.
Testosterone
- a.
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You are following a child with TBI in the outpatient clinic. His mother notes that the child is “different” since the injury. He has behavioral issues in school. He keeps getting up in the middle of class to wander about, disrupting lessons. Teachers report that he is unable to focus on schoolwork. At home he takes longer to fall asleep. What is the most likely cause of the changes in behavior?
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Depression
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Anxiety
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Attention deficit hyperactivity disorder (ADHD)
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Oppositional defiant disorder
- a.
Answers on page 400.
Access the full list of questions and answers online.
Available on ExpertConsult.com
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You are following a 4-year-old patient in the TBI unit, admitted after a subdural hematoma. She is on phenytoin for posttraumatic seizures. She was making gains over the first 2 months but has plateaued over the last few weeks. She is reportedly more “irritable” and “feeding poorly.” On examination she appears less interactive and has more difficulty maintaining her balance when walking. What is the most likely cause of the change in clinical presentation?
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Infection
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Phenytoin toxicity
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Seizures
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Hydrocephalus
- a.
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A 3-month-old boy is brought into the emergency department (ED) after having a seizure. His mother describes increasing lethargy, then vomiting before the seizure. The mother is 20 years old with two other children. On examination, the child is somnolent with apneic breathing. A noncontrast head CT is ordered.
What is the most likely finding on imaging?
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Diffuse axonal injury
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Isolated skull fracture
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Epidural hematoma
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Subdural hemorrhage
- a.
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Compared with adults, pediatric TBI has a greater risk for
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decreased cerebral water content.
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increased blood flow volume.
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decreased blood-brain permeability.
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decreased diffusion of excitotoxic neurotransmitters.
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decreased seizure risk.
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increased skull absorption of traumatic forces.
- a.
- 7.
In adolescence, what is the mortality of TBI between males and females?
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1:1
- b.
2:1
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3:1
- d.
4:1
- a.
- 8.
A child with history of TBI and an intrathecal baclofen pump presents to the ED. She has no allergies or other medications. One week ago she had her pump refilled; 2 days ago she began to have nausea and vomiting. Eventually there was difficulty with breathing, increased weakness, and somnolence. In the, she was hypotensive, flaccid, and had a brief seizure. What is the most likely treatment?
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Intravenous lorazepam
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Pump aspiration
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Oral baclofen
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Broad spectrum antibiotics
- a.
- 9.
Which group with pediatric TBI has the worst mortality, morbidity, and outcomes compared with the other groups?
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Younger than 2 years of age
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2–8 years of age
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8–14 years of age
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Older than 14 years of age
- a.
- 10.
A 12-year-old with severe TBI has improved in Glasgow Coma Scale scores from 6 to 13 and Rancho Los Amigos score from 5 to 6. There are continued cognitive–linguistic deficits and impaired new-memory formation. What is the most appropriate tool to assess the posttraumatic amnesia?
- a.
WeeFIM
- b.
Galveston Orientation and Amnesia Scale (GOAT)
- c.
Children’s Orientation and Amnesia Scale (COAT)
- d.
Agitation Behavioral Scale
- a.
Reference
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