The Neurotransmitters: Clinical Neurology Education

IM Board Prep #2: TBI and ICH

January 24, 2024 Michael Kentris Season 1 Episode 32
The Neurotransmitters: Clinical Neurology Education
IM Board Prep #2: TBI and ICH
Show Notes Transcript Chapter Markers

Hello and welcome to our mini series designed to help prepare internal medicine residents get ready for the neurology section of their board exams! 

While it is aimed at IM residents, it is a good review for anyone feeling a little rusty on traumatic brain injury (TBI) and intracranial hemorrhage (ICH). 

In this session, we talk about the classification and management of mild, moderate and severe TBI. We also discuss epidural and subdural hemorrhages or hematomas and their management. 

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The views expressed do not necessarily represent those of any associated organizations. The information in this podcast is for educational and informational purposes only and does not represent specific medical/health advice. Please consult with an appropriate health care professional for any medical/health advice.

Dr. Michael Kentris:

Hello and welcome back to The Neurotransmitters, your podcast for everything about clinical neurology. I'm Dr Michael Kentris and thank you so much for joining me today. In this recording we're going to be continuing our internal medicine board review series and we are talking about traumatic brain injury, or TBI, and intracranial hemorrhage or ICH, specifically epidural hemorrhage or hematoma, and subdural hemorrhage. So let's talk about traumatic brain injury or TBI. So TBI, as the name implies, occurs after a traumatic injury to the head. Traditionally, this is divided into three different categories mild, moderate and severe and this is based off of a grading scale called the Glasgow Coma Scale, or GCS, as well as the clinical context of what happened after the TBI. So let's start with the GCS. So the GCS is a scale that is in three categories looking at eye opening, best verbal response and best motor response and the scale goes from three to 15 points right. So each category goes from one to four, five or six points. So the score can never be lower than three and normal is 15. So let's go through each one of these categories Eye opening, so normal. A four is spontaneous eye opening. Three is when someone opens their eyes in response to a verbal command. Two, they open their eyes in response to pain, and one no eye opening is noted. Moving on to best verbal response, normal five is oriented. Four is confused. Three is when they give you inappropriate words. Two is incomprehensible sounds right, so vocalizations, but not verbalizations, if you will and one no verbal response.

Dr. Michael Kentris:

Best motor response this starts at six. So six normal obeys commands. Five they localize in response to pain. Four they withdraw in response to pain. Three you see a flexion response to pain. Two, an extension response to pain and one no motor response. So let's dive a little bit more into these motor responses. Specifically, I want to look at numbers three and two, which are flexion to pain and extension to pain. Right, and we're usually talking about posturing. The implication here is that flexor posturing is slightly better than extensor posturing or, to use the other names, decorticate versus decerebrate. The implication is whether the injury is above or below the red nucleus in the midbrain. So just to reinforce the scoring system a little bit, here we have eye opening, best verbal response, best motor response and the best score for eye opening. For verbal response, five, motor response, six, giving you a total of 15 for the best GCS score.

Dr. Michael Kentris:

Now let's move on to our traumatic brain injury, or TBI, gradations mild, moderate and severe. Starting with mild, this is defined as a GCS of 13 to 15, with no loss of consciousness or only a brief loss of consciousness. You'll often see the term concussion used interchangeably with this, both in literature as well as colloquially. So very often when you see these questions in a test, you're going to get a clinical vignette of someone who had a minor accident, maybe in the workplace, or a sports-related accident, maybe some sort of concussion on the football field, soccer field, etc. You also see this very often in people who are in military service, which has a little bit different flavor to it that we'll talk about towards the end of this recording.

Dr. Michael Kentris:

In terms of the mechanism, the symptoms that occur after a mild TBI or concussion can actually be quite varied, but I think we can group them into a few different categories. So we kind of have our physical or somatic category, cognitive difficulties, psychological problems and sleep-related issues. Starting with the physical category, one of the most common things we see is headache. Nausea and vomiting can also occur, as well as dizziness and vertigo. People may also report difficulty walking. You can also get some migranous type things with photophobia and phonophobia, dysarthria and then occasionally seizures. So a quick note about seizures is that we would consider these typically to be an acute symptomatic seizure if they are occurring within the first week, and a lot of times you won't have them on long-term anti-seizure medication unless you find something else in the workup that would put them at high risk going forward for recurrent seizures. But we'll talk about that in a later recording. Also, some common cognitive symptoms that can occur after a mild TBI include difficulty with concentration, a self-reported brain fog, memory difficulties, difficulty learning we see this particularly in younger athletes or students and slowed reaction times. This is described a little bit in the literature when they're looking at athletes who had pre-injury testing and post-injury testing, and it's sometimes used as a marker of returning to play, though this is not necessarily standardized. Our last major category are sleep-related issues after mild TBI and this includes things like daytime fatigue or drowsiness. You can get insomnia as well as hypersomnia. Vivid dreams can also be reported and this may tie into a PTSD constellation of symptoms in some people.

Dr. Michael Kentris:

So we've got a patient coming into the ED after some sort of blow to the head. They've had a mild TBI. Who needs to get a CAT scan of their head? Who doesn't. So there are some criteria for those who should, so typically, anyone over the age of 60 years old. If they have vomiting or headache. If they had a post-traumatic seizure. If there is any suspicion or evidence of drug or alcohol intoxication. If they have persistent drowsiness or any short-term memory difficulties after the injury. If they had a high-risk mechanism of their injury, they should also receive a CT of the head. This includes falls from a height of over 3 feet or if they've fallen down more than 5 steps. If they were ejected from a motor vehicle. If they were struck by a vehicle as a pedestrian or other similar, more high-velocity, high-impact types of injuries.

Dr. Michael Kentris:

Other reasons to get a CT head on initial presentation to the emergency department include people with a GCS of less than 15. If their GCS is not pristine, get that CT head. If there are any focal neurologic deficits on your examination, get the imaging. If there is any evidence on your physical examination of significant trauma to the head or neck any bruising, bleeding, weird bumps that shouldn't be there, get the pictures. And lastly, anyone with any coagulopathy. So obviously we think about oral anticoagulation with things like warfarin or some of our newer anticoagulant agents, but this also includes anyone, even on something as innocuous as a low-dose aspirin. So these patients also require CT of the head on presentation, even if their exam is initially fairly unremarkable.

Dr. Michael Kentris:

So what's the prognosis look like for these people? Well, overall it's actually quite good. Most patients will have the majority of their symptoms resolved in about 7 to 10 days. Now, that being said, there is some conflicting literature about things such as post-concussion syndrome, and we suggest a range of 10 to 15%, others as high as 30 to 80 plus percent. So persistent post concussion syndrome is generally considered to be longer than three months, with some constellation of the symptoms we described earlier, and the treatment really revolves around what kind of persistent symptoms they have, whether that's headache, disequilibrium, dizziness, etc. So you do have to tailor the treatment to what kind of persistent symptoms may be there. Out of these, headache is the most common and the injury may cause new headaches that are persistent. Or if someone has a pre-existing headache disorder, it may worsen and be more difficult to control symptoms following the injury. So you do have to tailor the treatment to the headache phenotype. Look back at our previous episode on headaches for a little more discussion about this. But just like we talked about in that episode.

Dr. Michael Kentris:

You do want to avoid opioids and you do want to avoid barbiturates, in particular things containing butylpatol, like fioriset, for patients who are having difficulty with resolution of their symptoms. You will also work very closely with different types of physical and occupational therapists, in particular focused on vestibular rehabilitation, visual and sometimes cognitive therapies, as appropriate to the symptoms the patient is having. A lot of times in the olden days we would talk about complete bedrest. You'd be sitting in a quiet, dark room, this kind of quote-unquote brain rest. However, that is not really recommended. We're really looking more at a graded return to activity. So we want people to be as active as tolerated without worsening or exacerbating their symptoms, and you do want to do that in a gradual fashion. So in that recovery period there may be a need for temporary modifications of school and or work environments, again, depending on what kind of activity is the person is normally engaged in in their day-to-day activity. So it does require a lot of asking about like, what is that job and tell, what kind of work are you expected to do? Does that worsen your symptoms? And there is a lot of trial and error and working alongside your therapy colleagues to determine what is this person capable of doing, and how quickly can we get them back to normal function safely?

Dr. Michael Kentris:

Moving on to moderate TBI this is defined as a GCS of 9 to 12 and or an initial loss of consciousness of 30 minutes up to 24 hours. And we're going to move right along to severe traumatic brain injuries. This is defined as a GCS of 3 to 8 and or an initial loss of consciousness of more than 24 hours. Mechanisms may be a little bit different than with mild to moderate, including more severe blunt force versus penetrating trauma. We also have to think about the risk factors as far as the imaging indications that we mentioned earlier Though, as we mentioned earlier, everyone with a GCS less than 15 is getting imaging we just have to keep these risk factors in mind in terms of potential complications going forward.

Dr. Michael Kentris:

What is more or less likely Signs and symptoms to watch out for? Seizures, obviously, are going to be more common in this population. Focal neurologic deficits, especially if we're running into things like cerebral contusions, periorbital or mastoid bruising, hemo-tympanum that is, blood behind the eardrum basilar skull, fractures on the CT head All of these things are going to put them at risk for other complications over the course of a potentially prolonged hospitalization. So what kind of treatments are we providing to people with severe TBI, so generally a GCS less than 8? We are looking at intubation for the majority of these people.

Dr. Michael Kentris:

A lot of our goals are focused around maintaining good brain homeostasis and perfusion. So we want to avoid low blood pressure, so hypotension is a no-no. We want that systolic greater than 90 millimeters of mercury. We also want to avoid hypoxia surprise with a goal PO2 of greater than 60 millimeters of mercury. We also really want to avoid elevated temperatures. So using acetaminophen as needed to control that temperature is also very important.

Dr. Michael Kentris:

One issue that can frequently come up in these patients is elevated intracranial pressure, or ICPs. Depending on the severity of injury, you may go ahead and put in different monitoring devices in order to watch for trends that may be suspicious of impending elevation of that ICP. Two of the more common devices one is a bolt, which is a little more focal in terms of its measurements, and the other is an external ventricular drain, or EVD, which goes usually into the lateral ventricles. That one is a little more global theoretically and it also can be helpful because it can drain spinal fluid out. So if the pressures do go up we can sometimes divert one of the compartments right. We've got brain blood and spinal fluid in the skull, so you only have so much volume there. So if the brain is swelling, it is taking up more space in the skull and we have two options either divert some spinal fluid or increase the space surgically.

Dr. Michael Kentris:

But let's talk about our medical management first. So simple things elevating the head of the bed right let's make gravity work for us. If anyone has ever hung upside down as a child, they know that you can start feeling that blood really start pulling in your head and we don't want that in these particular cases. Other medical options include the use of IV-manital or hypertonic saline. The goals in terms of serum sodium and serum osmolality are really beyond the scope of our podcast today, as well as the reasons for different ones, but there are lots of good resources out there. They both have their pluses and minuses in terms of the whole medical picture, so they're sometimes used together. Sometimes one is favored over another, but it really depends on the clinical context. You can also sometimes hyperventilate these patients blow off a little CO2. That is usually a temporizing measure as you're getting these patients prepped for some sort of neurosurgical procedure.

Dr. Michael Kentris:

We also need to touch on the role of steroids in the management of increased ICP in traumatic brain injury, which is to say it essentially does not have one. The crash study showed an increased number of deaths in patients given steroids compared to those who did not receive them, so the routine use of steroids in traumatic brain injury is not recommended. This is not meant to be an exhaustive discussion of surgical considerations, but patients who are more likely to have neurosurgery include those who have underwent penetrating trauma to the brain, as well as those who have depressed skull fractures or other types of intracranial hemorrhage. Two entities that we'll often travel along with TBI are epidural and subdural hematomas. Subarachnoid hemorrhages can also be quite common in these patient populations. However, we're going to talk about subarachnoids when we get to stroke in a later podcast.

Dr. Michael Kentris:

Epidural hematomas are a collection of blood between the dura mater and skull, forming a lentiform or lens-shaped appearance on the CT of the head. Very often, and dare I say always, when we talk about test questions, this will be due to an injury of the middle meningial artery, often associated with a temporal bone fracture. While in real life this may not be as clear cut, these mechanisms of injury are still important to consider in these patients. Very often you'll have a clinical history of an initial injury where the patient may have a brief loss of consciousness but then wakes up and is relatively asymptomatic the quote-unquote lucid interval and then they start having progressive decline and the symptoms that are most common include headache, vomiting, worsening mental status to the point of developing stupor or coma. Sometimes this depressed level of consciousness may be associated with an ipsilateral, third nerve palsy and contralateral hemiparesis, suggesting an uncle herniation. Obviously, this can be a surgical emergency in some situations. Subdural evacuation is generally recommended for those with a GCS less than 9, those with anisocorrhea or pupillary asymmetry suggestive of, as mentioned above, the uncle herniation although it may not rise to that level of severity, but any pupillary abnormality is a potential warning sign and those who have a hematoma volume greater than 30 cc.

Dr. Michael Kentris:

Next up we have subdural hematomas. This is a collection of blood between the dura mater and the brain, as opposed to the dura mater and the skull with ipsidurals. Subdural hemorrhages or hematomas can be acute, subacute, chronic or even acute. On chronic, subdurals usually occur secondary to rupture of bridging veins. So as the brain atrophies as people get older, these veins become under more and more tension and sometimes relatively innocuous trauma can lead to bleeding and this can sometimes be quite slow.

Dr. Michael Kentris:

Some potential causes obviously trauma, people who are on anticoagulation, and sometimes these used to occur spontaneously, although if you dig into the history you may find a bit of an unusual mechanism. I remember once I had a patient who had developed a subdural hemorrhage and, after talking with him for a while, found out that a few days prior they had actually been out on Lake Erie in a boat and the water had been quite choppy that day. So they'd been having this kind of up and down shaking kind of movement for several hours while they were out fishing. So in this person's case it was suspected that maybe he had a little bit of like acceleration, deceleration kind of injury, without any actual blow to the head, leading to this kind of slow bleed.

Dr. Michael Kentris:

Now let's talk a little bit about some of the differences in terms of presentation for acute versus chronic subdural hemorrhages. So for acute, very often we're seeing someone who's coming in with some altered mental status and they may or may not have some neurologic compromise. Now that may be focal neurologic deficits or it may be an imaging finding that suggests this person is at risk of impending neurologic deterioration. Generally we're considering surgical evacuation for those with a hematoma thickness greater than 10 millimeters, those who have a GCS less than nine and again those with pupillary asymmetry, as mentioned with epidurals above. For chronic subdurals the presentation might be slightly different. Very often they will present with altered mental status and this can be a kind of subacute to maybe even slightly chronic cognitive decline like a dementia type process, and they may or may not have any focal neurologic deficits, usually like some weakness or numbness on one side versus the other, maybe a little bit of speech difficulty, depending on the areas that are affected. In general, surgical evacuation is again considered for a hematoma thickness greater than 10 millimeters, midline shift of greater than five millimeters or if there is significant neurologic compromise attributable to the hematoma.

Dr. Michael Kentris:

To finish us out on this topic, I wanted to talk a little bit about special populations in TBI as well as subdural hematoma and epidural hematomas. With athletes, if there is suspicion for a mild TBI or concussion during play, they should be removed from the game and, as we mentioned earlier, there should be a stepwise return to play after resolution of symptoms and with this increasing stepwise activity increase. We should not see recurrence of symptoms In those with more persistent cognitive issues. Neuropsychologic testing may be appropriate to see if there are any specific cognitive domains that are more or less affected. Something to consider more, but not exclusively, in professional athletes is chronic traumatic encephalopathy, or, as it was known in the Olden Times, dementia pugilistica, where we have recurrent strikes to the head, either with concussive or even subconcussive forces that can lead to a form of dementia. Another population with some special considerations are military personnel. The mechanism of injury may be slightly different than the average person with a mild to moderate TBI, including things like blast injuries leading to concussive forces not just affecting the brain but other parts of the body, and there may be more elements of PTSD than we see in the general population as well. In the geriatric population, special consideration has to be given to falls, as some people are going to be more predisposed towards recurrent injuries, whether that involves striking the head or just the acceleration deceleration from falling, as well as accidental blows to the head and, of course, motor vehicle collisions.

Dr. Michael Kentris:

Finally, we have people who are on anticoagulation, which we did mention earlier. This applies both to people with severe enough traumatic brain injuries to cause intraparenchymal hemorrhages as well as those with subdural and epidural hematomas, depending on what agent they are on. This will need to be reversed, whether that is warfarin versus one of the direct oral anticoagulants. One of the challenging questions is deciding when to resume anticoagulation after an injury that results in an intracranial hemorrhage. Some guidelines suggest possibly after 72 hours, if they are considered low risk for hematoma expansion and at high risk for a thromboembolic event, such as someone who has a mechanical heart valve, for instance. In practice, this is usually going to be a conversation amongst the different members of the different care teams taking care of a specific patient neurology, neurosurgery, icu, etc. And deciding what is the relative risk of having one of these complications off of anticoagulation versus the risk of resuming the anticoagulation in terms of hematoma expansion.

Dr. Michael Kentris:

Thank you so much for making it to the end with me. This concludes our internal medicine board review session on traumatic brain injury as well as intracranial hemorrhage. There will be more things touching on these around the edges with upcoming sessions. If you want to find me online, you can find me on twitterx, at drkentris, or you can also find me at theneurotransmitterscom, and feel free to email there as well for any future questions or show suggestions. Thanks again and I'll see you next time.

Glasgow Coma Scale (GCS)
Mild TBI
Moderate TBI
Severe TBI
Epidural hematoma
Subdural hematoma
Special populations