case files neurology
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case files neurology


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venue in which they take place. It has been estimated that at
least one player experiences a concussion in every game of football. Rates of
concussion are also high in soccer, ice hockey, and basketball. While sports and
bicycle accidents are the most common causes of concussion in patients 5 to 14
years of age, falls and motor vehicle accidents are the more common precipi-
tants in adults.
Pathophysiology
Because the ascending reticular-activating system (ARAS) is a key structure
mediating wakefulness, transient interruption of its function can be partly
responsible for temporary loss of consciousness following head injury. The
junction between the thalamus and the midbrain, which contains reticular neu-
rons of the ARAS, seems to be particularly susceptible to the forces produced
by rapid deceleration of the head as it strikes a fixed object. The pathophysi-
ology of other symptoms, such as anterograde and retrograde memory diffi-
culties, is less clear. Certainly more severe traumatic brain injuries can be
associated with diffuse axonal injury as well as cortical contusions leading to
dysfunction.
Classification of Concussion
There are several different schemes available to classify concussions, but the
one most commonly used is that developed by the American Academy of
Neurology. According to this system:
\u2022 A grade 1 concussion involves no loss of consciousness and all symp-
toms resolve within 15 minutes.
\u2022 A grade 2 concussion involves no loss of consciousness but symptoms
last longer than 15 minutes.
\u2022 A grade 3 concussion involves loss of consciousness for any period
of time.
Such a grading system is useful in thinking about management as well as
in considering possible return to play for sports-related concussions. It should
be noted that this scheme is currently undergoing revision.
Initial Management of Concussion
In any patient with a head injury immediate thought must be given to whether
or not there is a concomitant cervical spine injury. If any suspicion exists then
the spine must be immobilized, and the patient transported to an emergency
room for evaluation. If a spinal injury is suspected, taking off the football hel-
met should only be performed by a health care provider experienced in its
CLINICAL CASES 89
removal. Apart from the spine, the possibility of intracranial hemorrhage is the
principal concern in the setting of a concussive injury. This is relatively uncom-
mon, complicating only 10% of such injuries, but must be considered as its
presence will change subsequent management. A noncontrast head CT is more
than sufficiently sensitive to detect clinically significant bleeding. An MRI scan
is not necessary.
An important clinical question is to determine which patients require imag-
ing and which do not. Clearly any patient with focal neurologic findings, per-
sistent mental status changes, or worsening neurologic status requires
imaging. Conversely, patients who experience only very brief transient confu-
sion without any subsequent symptoms (a grade 1 concussion) are very
unlikely to have any significant intracranial pathology. The New Orleans
Criteria recommends a head CT if any of the following are true: (1) persistent
headache, (2) emesis, (3) age: older than 60 years, (4) drug or alcohol intoxi-
cation, (5) persistent anterograde amnesia, (6) evidence of soft-tissue or bony
injury above the clavicles, or (7) a seizure. Imaging is often recommended for
children younger than 16 years of age because clear validated clinical criteria
do not yet exist.
The next issue will be for how long and in what context to observe the
patient. Clearly individuals with hemorrhage or other acute abnormalities on
imaging will require hospitalization and careful monitoring. Relatively small
surface contusions are not uncommon and are very unlikely to portend any sig-
nificant neurologic problem other than headache. Such patients should be
observed overnight in the hospital but can be discharged the next day if their
neurologic examination is normal. Patients with normal head CTs and normal
neurologic examinations who sustained a grade 1 or grade 2 concussion can
safely be discharged home from the emergency room after 2 hours of obser-
vation. The practice of discharging patients with the instruction to wake them
up at intervals to make sure that they can be aroused is not recommended. If
such monitoring is necessary, it would be better performed in a hospital
setting.
Prior to discharge it is important to clarify with the patient and the family
what symptoms are to be expected and what symptoms should prompt a phone
call or return visit. The postconcussive syndrome, discussed below, is quite com-
mon and symptoms such as headache, dizziness, irritability, and difficulty con-
centrating are to be expected. However, worsening cognitive function, new
sensory or motor symptoms, increasing drowsiness, or significant emesis should
prompt a return for further evaluation.
Postconcussion Syndrome
Following a concussion, up to 90% of patients will continue to experience
headaches and dizziness for at least 1 month. Between 30% and 80% of
patients develop a more extensive constellation of symptoms within 4 weeks
of their head injury referred to as the postconcussion syndrome (PCS). These
90 CASE FILES: NEUROLOGY
individuals report other symptoms such as irritability, depression, insomnia,
and subjective intellectual dysfunction. Fatigue, anxiety, and excessive noise
sensitivity can also be seen. Some patients report becoming unusually sensi-
tive to the effects of alcohol. Many patients who develop PCS also become
preoccupied with fears of brain damage. PCS appears to be more likely to
develop in non\u2013sports-related concussions such as those following motor vehi-
cle accidents or falls. The peak of symptom intensity is generally 1 week after
injury, and most patients are symptom free by 3 months. However, approxi-
mately 25% of patients will still be symptomatic after 6 months, and 10%
report symptoms 1 year following injury. Particularly in patients with such
unrelenting symptoms, it remains unclear and somewhat controversial how
much is caused by psychogenic factors and how much is caused by residual
pathophysiologic effects of the initial TBI. Psychiatric consultation would
most certainly be warranted in patients with persistent PCS. More detailed
neuroimaging using an MRI should also be considered in these patients to
fully exclude significant parenchymal injury. Educating patients at the time of
their initial injury regarding common symptoms and the benign self-limited
nature of PCS is likely to be helpful.
Return to Play Guidelines
For sports-related concussions, an important consideration is when the athlete
will be able to return to playing. Guidelines to assist in this decision have been
developed by the American Academy of Neurology (AAN), although they are
currently being revised.
Grade 1 concussion should be removed from the game for at least 15 minutes
and assessed at 5 minute intervals. If there was no loss of consciousness and
the symptoms have resolved completely by 15 minutes (the definition of a
grade 1 concussion) then the athlete can return to play.
Grade 2 concussion (symptoms persisting longer than 15 minutes without
initial loss of consciousness) merits removal from the game for the remainder
of the day. If the athlete\u2019s neurologic examination is normal, he or she may
return to play in 1 week.
Grade 3 concussion (any concussion associated with loss of conscious-
ness) merits transport to an emergency room for evaluation and possible neu-
roimaging. Following this evaluation the patient\u2019s neurologic examination
should be repeated both at rest and after exertion. If the examination is normal
and the initial loss of consciousness was brief then the player can return after
1 week. If the loss of consciousness