Traumatic Brain Injury: Diagnosis

00:01 What's the mechanism of a traumatic brain injury where we can see closed head injuries where the head has been struck by something, the head strikes something that is fixed.

00:12 This can result in an acceleration-decelerate deceleration injury or injury as a result of rotational mechanisms.

00:19 And each of these mechanisms can contribute to a traumatic brain injury.

00:24 We can also see traumatic brain injuries from penetrating trauma or blast trauma.

00:30 One of the important things to think about is how the brain is injured.

00:34 And an acceleration-deceleration mechanisms, we can see two injuries to the brain.

00:40 Both a coup injury that occurs at the site of the direct impact of the brain on surrounding structures, including the skull.

00:49 And a secondary contrecoup injury which occurs at the area of the brain opposite the site of impact.

00:57 And this contrecoup injury can actually often result in more severe injuries to the brain.

01:02 And so we may see frontal and occipital injuries, we may see bitemporal and parietal injuries as a result of this coup and contrecoup injury.

01:14 We grade and scale traumatic brain injuries based on the severity of the patient's symptoms.

01:20 And we can categorize TBI as mild, moderate or severe.

01:24 And there are a number of things that I want you to think about as you're evaluating whether a patient may have suffered a mild, moderate or severe traumatic brain injury.

01:32 First we use the Glasgow Coma Scale.

01:35 Mild TBI is defined as a GCS of 13 to 15.

01:39 Moderate TBI is 9 to 12 and severe TBI as less than 8.

01:45 We also think about loss of consciousness.

01:47 With mild TBI, there is often a brief period of loss of consciousness or none at all.

01:52 The patient may maintain consciousness throughout the entirety of the traumatic event.

01:58 With moderate TBI there is frequently loss of consciousness in the range of 30 minutes with impaired a consciousness, sometimes extending out to several days.

02:09 And then with more severe TBI, patients can remain in a coma for a prolonged period of time requiring hospitalization during that.

02:17 Post-traumatic amnesia is a differentiating factor.

02:21 Amnesia after the traumatic event is typically very short or not at all.

02:24 With a mild TBI, it can last 1 to 7 days.

02:28 With moderate TBI, it may last for a prolonged period of time with severe TBI.

02:34 And we can often see some other key factors that help differentiate these three categories.

02:39 Non-severe mechanisms may be in place for mild TBI, such as a fall or an injury during practice in a sporting event.

02:47 With moderate TBI, patients may have headache, severe vomiting that may be refractory to medication interventions or alterations in their mental status at the time of the injury.

02:57 And then severe long term and even persistent neurologic deficits can result from severe TBI.

03:04 What about diagnosis? How do we diagnose a TBI or traumatic brain injury? Well, first the Glasgow Coma Scale is critical.

03:12 We often perform a pupillary examination looking for unequal pupils or anisocoria.

03:18 Anisocoria is a concerning finding and should prompt immediate workup for cause of of that abnormal pupil exam.

03:26 In particular, we think about herniation, either transtentorial herniation, uncal herniation or brainstem herniation, which could be compressing the third cranial nerves or other important structures.

03:39 In addition, in patients with neck injury, your injury to the carotid artery can result in a Horner syndrome which may lead to abnormal pupil exam, ptosis, meiosis and anhidrosis which requires imaging evaluation for possible dissection.

03:58 In addition to the physical exam, imaging is critical in patients presenting with TBI particularly moderate to severe TBI.

04:05 A CT of the head without contrast is the first line modality of choice.

04:09 We're looking for skull fractures, intracranial hemorrhage or cerebral edema.

04:12 And here we see a noncontrast head CT demonstrating an open skull fracture with underlying cerebral edema.

04:19 MRI has better diagnostic sensitivity for underlying brain pathology.

04:24 And here we see an associated MRI demonstrating a significant area of broad temporal contusion.