TBI Board Review

Which statement is TRUE about the relative responses of the brain and the spinal cord after concussive trauma?

• The brain is more sensitive to trauma than the spinal cord
• The spinal cord is more sensitive to trauma than the brain.
• The brain and the spinal cord are equally sensitive to trauma
• The brain’s neurologic recovery is less predictable than the spinal cord’s in its response to a given amount of trauma.

Answer explanation

Concussive injuries of the spinal cord are more varied in gradation than injuries to the brain. Seemingly mild spinal concussions, seen most frequently in cervical hyperextension, may lead to complete tetraplegia, even in the absence of penetration of the spinal canal or even vertebral fracture. Mild concussive trauma to the brain results in a more mild brain injury and a more severe concussive trauma to the brain results in a more severe neurologic dysfunction

In patients with a traumatic brain injury, which factor suggests a poor prognosis for emergence from unresponsiveness?

• Decorticate posturing
• Flaccid muscle tone
• Conjugate eye movement
• Reactive pupils

Answer explanation

After a traumatic brain injury, the following factors are associated with a better prognosis: younger age, reactive pupils, conjugate eye movement, decorticate posturing, early spontaneous eye opening, absence of ventilatory support, and higher Disability Rating Score on admission. Factors associated with poor prognosis include decerebrate posturing and flaccid muscle tone. The Disability Rating Score is a 30-poing scale covering the following 8 dimension:
 1. Eye opening
2. Verbalization/communication
3. Motor responsiveness
4. Feeding
5. Toileting
6. Grooming
7. Overall level of functioning/dependence
8. Employability

A 23-year-old woman who is unresponsive after an acute traumatic brain injury can visually track. She periodically pushes the nurse’s hand away when the nurse administers a subcutaneous heparin injection. The patient is exhibiting

• coma state.
• minimally conscious state.
• vegetative state.
• sleep/wake cycle.

Answer explanation

Minimally conscious state is a condition of severely altered consciousness in which minimal but definite behavioral evidence of self, or environmental awareness, is demonstrated by any or all these actions: simple gestures, purposeful behavior, appropriate smile/cry or vocalization to stimulation, reach for object, purposeful visual tracking.
The vegetative state is associated with preserved hypothalamic and brainstem autonomic function and the patient exhibits a sleep/wake cycle, but there is an absence of cortical activity, judged behaviorally. The patient may exhibit visual pursuit but not in relation to meaningful behavior. The term persistent vegetative state is confusing and it is suggested that the term be abandoned, since it combines diagnosis (vegetative) with prognosis (persistent).
Coma is a transient state after a traumatic brain injury (TBI) of being not awake and not aware of surroundings, and is seen in patients with a severe TBI and a Glasgow coma scale (GCS) of 8 or lower.  The defining feature of coma is the complete loss of spontaneous or stimulus-induced arousal.  There is no sleep/wake cycle.  It is self limiting and usually resolved within 2 to 4 weeks.

Which statement is TRUE about Posttraumatic amnesia (PTA)?

• Longer duration is associated with good outcomes
• Severe disability is unlikely when PTA is more than 2 months
• Good recovery is unlikely when PTA is greater than 3 months

Answer explanation

Longer duration is associated with worse outcomes. Severe disability is unlikely when PTA is less than 2 months. Good recovery is unlikely when PTA is greater than 3 months 

Which stroke syndrome has ipsilateral ptosis, external strabismus, a dilated pupil, and contralateral weakness of the lower face, tongue, arm, and leg?

• Weber
• Wallenberg
• Millard-Gubler
• Locked-In

Answer explanation

Weber syndrome includes the symptoms of ipsilateral ptosis, external strabismus, a dilated pupil, and contralateral weakness of the lower face, tongue, arm, and leg

Which of the brain tumors listed is a benign tumor?

• Medulloblastoma
• Astrocytoma
• Glioblastoma
• Craniopharyngioma

Answer explanation

Primary tumors in adults-gliomas comprise approx. 60% of all primary CNS tumors.  Cerebellar astrocytoma in most common primary CNS solid tumor in young adults.  Favorable prognostic features of brain tumors are younger age, high performance rating at diagnosis and favorable histology. Medulloblastoma is most common posterior fossa tumor in childhood and most prevalent brain tumor in children less than 7

Which factor is a risk for heterotopic ossification in traumatic brain injury?

• Late seizures
• Prolonged coma
• Male gender
• Diabetes insipidus

Answer explanation

Significant risk factors for heterotopic ossification in traumatic brain injury include prolonged coma (>1 month), increased muscle tone, limited movement in the involved lower extremity, and associated fractures. Late seizures, gender, and diabetes insipidus are NOT not associated with increased risk of heterotopic ossification.

What is the greatest risk factor for late post-traumatic seizures in patients with a traumatic brain injury?

• Multiple subcortical contusions
• Subdural hematoma with evacuation
• Midline shift greater than 5mm
• Bilateral parietal contusions

Answer explanation

In a 4-site Model System Center observational study, the highest risk factors for late post-traumatic seizures were found to be bilateral parietal contusion (66%), penetration of the dura (62.5%), and multiple intracranial operations (36.5%), multiple subcortical contusions (33.4%), subdural hematoma with evacuation (27.8%), and midline shift greater than 5mm (25.8%).

Which diagnosis is associated with an increased risk of post-traumatic hydrocephalus

• Diffuse axonal injury
• Subdural hematoma
• Epidural hematoma
• Subarachnoid hemorrhage

Answer explanation

Hydrocephalus is a well-recognized complication of subarachnoid hemorrhage. The fundamental abnormality in post-traumatic hydrocephalus is an imbalance in the production and absorption of cerebral spinal fluid (CSF). As the blood in the subarachnoid space obstructs the arachnoid villi it impairs absorption of CSF, thus causing hydrocephalus.

A 53-year-old right-handed male presents with alexia without agraphia following a stroke. Which is most common blood vessel infarcted?

• Left PCA
• Left PICA
• Left ACA
• Left retinal artery

Answer explanation

PCA infarct in the left occipital lobe can result in alexia without agraphia. These patients are not able to read but can write. The infarct includes the left primary visual cortex, causing a right homonymous hemianopsia. It also includes the posterior corpus callosum, which disconnects the right primary visual cortex from the language network. Thus the patient can see words in the left hemispace but cannot transfer visual images to the language centers. Writing is not affected because there is no disconnection between the language network and motor cortex. Patients with this lesion may have some left neglect syndrome as well. Answer b results in lateral medullary syndrome. Answer c result in spinal cord infarction. Answer d result in sudden loss of eyesight in one eye.