Head Trauma Flashcards
The basics of head trauma
- 500,000 Americans require hospital admission each year for head trauma
- roughly 15% will die eventually, while many more are left with devastating and disabling injuries. - 3x > men than in women
Increasingly found in the elderly, who are surviving with multiple medical problems, and are often on antiplatelet drugs or anticoagulant drugs at the time of head trauma
Much of the damage to the brain occurs immediately, and cannot be reversed, so the goal of medical care is to determine how much damage has occurred, and to prevent subsequent or delayed damage, including death
- costly, cause of serious disability in young people
- common in vehicle accidents, falls, criminal behavior, athletics recreational activities and with industrial work
If there is a loss of consciousness the trauma is more likely to be damaging, and the damage is somewhat proportional to the duration of unconsciousness
The presence of any bleeding inside the brain correlates with severity of trauma, much more than the presence of skull fracture
How serious is the head trauma?
For centuries, physicians used two levels:
A. Serious or Major if a prolonged loss of consciousness, loss of some brain function upon recovery, and the presence of a skull fracture or bleeding
B. Not Serious or Minor if none of these applied, or there was no loss of consciousness at all
Minor head trauma, even if recurrent, was never considered a major medical condition until the 21st century! Now we know just how devastating recurrent “minor” head trauma can be
Clinicians are now very reluctant to use the terms “mild” or “minor” head trauma at any time, especially in pediatrics
Concussion: a definition
The definition has changed from a reversible loss of consciousness from head trauma to the definition by the American Academy of Neurosurgeons:
“a clinical syndrome characterized by immediate and transient alteration in brain function….Even mild concussions should not be taken lightly.”
The medical profession is now interested in the details of this decline or “alteration,” including the resulting level of consciousness, orientation, attention, language, anterograde memory, the presence of headache, dizziness and seizures
Treating head trauma patients
The guidelines for emergency stabilization always apply to comatose patients, who usually will need a rapid evaluation of airway, breathing and circulation, and likely mechanical intubation
Awake patients need as much medical history as can be obtained, and a partial neurological exam emphasizing the likely symptoms and signs on the previous slide
Always check for other trauma to the upper body including the cervical spine, face and orbits, clavicles, sternum, ribs and lungs
Was the trauma “just an accident,” or is the patient delirious, demented, intoxicated, or a victim of assault?
common signs of skull fractures
raccoon eyes battle sign (bruise behind the ear)
Glascow Coma scale
goes up to 15
EVM 4-5-6
Eyes, Verbal, Motor
measures consciousness level.
Current descriptions of head trauma severity
Physicians are using the Glasgow Coma Scale to distinguish three levels of head trauma:
- Minor (Mild): 13-15 on the GSC
* 2. Moderate: 8 to 12 - Major (Severe): 7 and below (high likelihood of death)
gold standard for head trauma dx
A head CT is the gold standard for diagnosis
CT of the head is actually more sensitive for a brain hemorrhage, and a skull fracture, than is a brain MRI, and is more quickly completed
Brain MRI can be ordered later to look for other injuries to the brain
Which “mild head trauma” patients need a CT scan?
In general, CT is likely to be helpful with trauma causing prolonged periods of unconsciousness, in the very young and elderly, with a persistent neurological deficit, and in patients taking anticoagulants
Two guides to ordering head CTs
Canadian- high risk : GCS under 15 at 2 hrs after injury, suspected skull fracture, vomiting >/= 2 episodes, age over 65
New orleans: Any one of the following:
headache, vomiting, > 60y/o, drug/ alcohol, persistent anterograde amnesia, visible trauma above the clavicle, seizure
comparing the guidelines for CT
Both guidelines are very useful
One comparative study showed that both the Canadian and the New Orleans guidelines were essentially 100% sensitive for finding serious brain injury, although the Canadian scale was a little more specific for brain injury
However, in modern day American clinical practice, virtually all patients with a Glasgow Coma Scale (GCS) of less than 15 receive a head CT, and emergency department doctors tend to use the New Orleans scale for considering a CT scan in patients with a GCS of 15
Concussion treatment
activities should be limited for at least two weeks
A. Most physicians are strongly urging young athletes with two or more concussions to END ALL FUTURE PARTICIPATION IN SPORTS IN WHICH CONCUSSIONS ARE COMMON
If there is a full recovery within a few hours, and imaging is normal, or no imaging is done, most patients can go home with family or close friends, but they must return to the emergency department if symptoms return, especially severe headache, decline in level of consciousness or vomiting
Some will develop a POST CONCUSSIVE SYNDROME of persistent headache, light headedness more than vertigo, depression, poor concentration, and irritability for weeks or months, which may be resistant to all forms of treatment
The chronic headaches of patients with concussions are difficult to treat
A. Even though patients often meet the criteria for migraine headaches, the usual treatments for migraines are seldom very effective for these people
Types of Traumatic hemorrhage
Cerebral contusions: small areas of the cerebral hemisphere bruised and bloody from trauma, usually in the cerebral cortex or a little deeper
Subdural hematoma (occasionally occurs without trauma)
Epidural hematoma
Subarachnoid hemorrhage: most are nontraumatic ruptures of cerebral aneurysms. The traumatic subarachnoid hemorrhages are usually smaller in volume, less severe, and the blood is absorbed within days
CONTUSIONS
relatively small areas of bleeding inside the brain itself, from trauma. They are usually near the surface, but occasionally are deeper. They may swell over a few days and cause deeper problems then for patients
Subdural hematoma
Literally hemorrhage under or inside the dura mater
Usually the result of a tearing of bridging veins, but occasionally the tearing of a small artery
More common than epidural hematomas, and usually the result of less severe trauma
More common in elderly patients who may have atrophy of the brain and more room between the brain and the skull, allowing more movement with relatively light trauma
Again, may occur without known trauma at any time
Can also be bilateral
acute vs chronic subdural hematoma
Considered “acute” if patients are seen within 72 hours of the suspected onset
Considered “chronic” if at patients are seen at least 21 days from suspected onset
Commonly found in patients who fall or are struck by objects in the head, and automobile accidents
Symptoms include headache, confusion, hemiparesis but rarely total hemiplegia, seizures, and cranial nerve III palsies if large
CT or MRI shows a “crescent” shape
Surgery for any mass effect or continuing CNS deficit
Epidural hematoma
Fortunately much less common than subdural hematomas
The result of severe, life threatening trauma, with more than 75 % of patients also having a skull fracture
- Usually due to a tear of the MIDDLE MENINGEAL ARTERY, and only occasionally a large vein
Compress the brain more quickly and over a smaller area than subdural hematomas- Under arterial pressure
- There are dural attachments to the inner skull which limit the lateral spread of epidural bleeds
Epidural hematoma- prognosis
Patients have suffered a serious injury and typically lose consciousness immediately, or after a matter of a few hours
They are often the result of life threatening motor vehicle accidents, including motorcycles, and bicycle accidents
Some patients never lose consciousness at all
Only a small per cent of patients will immediately lose consciousness, wake up for a few hours, and then lose consciousness a second time, but this time BETWEEN the two periods of unconsciousness is known as the LUCID INTERVAL
1. However, a lucid interval is NOT specific for epidurals, and can apply to subdural hematoma and any head injury
Head CT shows a LENS (convex) shaped area of fresh blood
Epidural hematoma treatment
Surgical drainage is always required, since the mortality approaches 100% without intervention
Surgeons will drill one or more burr holes near the site of bleeding, which can usually be suspected by the area of clinical course or a skull fracture even before a head CT is done
Occasionally emergency department doctors or family doctors in rural areas will simply have to drill holes themselves!
Ideally surgery should occur well before there are signs of a CN III palsy or a deep coma
Chronic Traumatic Encephalopathy
A disease of the 21st century, with roots in the 20th century
Essentially, an irreversible brain disease cause by multiple “minor” head injuries including concussions
The patients are nearly all former athletes, especially professional football and hockey players, and boxers, or military veterans
Originally described in 1928 in boxers, who were called “punch drunk” due to dysarthria, mental slowness, poor memory, and difficulty walking, but at first not apparently demented, until the term “Dementia pugilistica” was used in boxers (also called pugilists)
They develop a worsening syndrome at various times after retirement, usually a decade or more
The severity of chronic traumatic encephalopathy appears proportional to the number of head injuries, and the duration of the athletic career
CTE in football players
Dr. Bennet Amalu, a neuropathologist in Pittsburgh, wanted to understand why a retired Hall of Fame National Football League player could develop severe dementia and depression in his 40s.
The deceased patient had essentially negative head CT scans and brain MRIs, and nothing was visible on gross inspection during autopsy, except for atrophy
Knowing that patients with Alzheimer’s Disease and other dementias have high levels of phosphorylated tau, a protein associated with microtubules, he stained brain sections for tau in this patient, and published his remarkable findings in 2002
He eventually demonstrated CTE in three retired NFL players
Dr. Bennet Amalu
He refused to bow to pressure from other physicians, and later the National Football League, in determining how three middle aged football players developed such severe depression and dementia, with early deaths. He is a role model for all of us who want to do “everything” for our patients. There are still many diseases left to be discovered!
The NFL’s Response to Dr. Bennet Amalu
The league and its hired neurologists and neurosurgeons flatly denied any suggestion that head injuries during football could cause CTE. It gave some money for research, and offered a nearly $1 billion legal settlement. No official of the NFL had ever admitted that there was any link until March, 2016!
McKee’s pathology studies in CTE
She and her colleagues have studied approximately 150 football players, some of them who died in their teenage years.
More than 95% show pathological evidence of Chronic Traumatic Encephalopathy
Grossly visible atrophy of the cerebral hemispheres
The septum pellucidum between the two lateral ventricles is often damaged, as is the corpus callosum
At a microscopic level, there are enormous collections of phosphorylated TAU, especially in the frontal and temporal lobes
A. This is often found at the bottom of sulci
C. CTE patients do NOT have amyloid plaques, however, unless they are also in the early stages of Alzheimer’s
A. Phosphorylated tau may undergo a conformational change and become toxic to neurons, leading to biochemical cascades and apoptosis
Levels of Chronic Traumatic Encephalopathy
Early symptoms include irritability, easy anger, aggression, impulsivity, sometimes violent behavior, memory loss and SEVERE DEPRESSION OFTEN WITH SUICIDAL IDEATION
Ultimately a severe dementing illness, with poor judgement, lack of insight, inability to manage ones affairs, loss of language skills
The dementia is not typical for Alzheimer’s Disease, but is somewhat like frontotemporal dementia
Some patients with CTE look as if they could have Parkinson’s Disease, and they may develop amyotrophic lateral sclerosis
Other patients may look like they have motor neuron disease (amyotrophic lateral sclerosis), and have spinal cord atrophy
Treatment is of limited value for CTE, and is certainly best avoided!
