Case Presentation
A
25-year old female presents to the ED after having had a witnessed
tonic clonic seizure 30 minutes prior to presentation.
She was sitting on a couch when the event occurred and she
was incontinent of urine.
She recalls feeling “strange” seconds prior to the event which
lasted 3 minutes. She
denies head trauma, alcohol or other drug use, similar past events,
or preceding infections. On
physical exam her vital signs are blood pressure 120/80, pulse 68,
respiratory rate 14, temperature 98, pulse oximetry 98% saturated.
She is alert, oriented to person, place, and time; she can
recite the months of the year forward and backwards, has 3 object
recall after 5 minutes. Cranial
nerves II, III, IV, and VI are intact including a normal appearing
fundus with venous pulsations.
There is no facial asymmetry, speech is fluent, swallowing
is normal. She has no upper or lower extremity weakness and her gait is
normal. Her deep tendon
reflexes are +4 symmetrically in both the upper and lower extremities;
her extensor planter reflexes (Babinski’s) are upgoing bilaterally.
Key Clinical Questions
-
What
are the key components of the history and physical in a patient
with a first time seizure?
-
What
laboratory tests are indicated in this patient in the ED?
-
Does
this patient need a neuroimaging study in the ED?
-
Which
patients with new onset seizures should be started on AEDs in the
ED?
-
Which
patients with new onset seizures need to be admitted to the hospital?
-
What
are the key components to the history and physical in a patient
with a new onset seizure?
-
Patients
with a first time seizure with no co-morbidities should have a serum
glucose, electrolytes; women of child bearing age should have a
pregnancy test. Patients
with co-morbidities should be considered for more extensive metabolic
profiling. (Class II
and Class III evidence)
-
Patients
with a first time seizure should have a noncontrast head CT in the
emergency department. (Class II evidence; no outcome data to support
recommendation)
-
Patients
with a first time seizure with HIV should have a lumbar puncture
either in the ED or after admission to the hospital. (Class II data)
-
Patients
with a first time seizure who have a normal head CT, glucose and
electrolytes, and normal neurologic examination can be safely discharged
from the ED on no AED therapy. (Class III data)
- AED
therapy has potential complications and risk of recurrence is multifactorial;
initiation of AED therapy is best reserved for the physician who will
assume primary care of the patient. (Class III data)
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Evaluation
of the ED Patient with a First Time Seizure
Introduction
The
history begins with a careful description of the event and its surrounding
circumstances with documentation of the preliminary symptoms, progression
of the clinical pattern, duration of the event including the post-ictal
period, presence of incontinence or biting of the tongue.
Every effort must be made to obtain a clear description of
the event(s) from witnesses. Seizures may be exacerbated by a number
of stressors, such as fatigue, pregnancy, or systemic infection. Identification
of the stressors may explain an event and become the focus of management.
An
accurate set of vital signs including a rectal temperature and pulse
oximetry should be obtained. Assess the mental status, skin color,
pupil position and reactivity.
If the patient is actively convulsing, describe the motor activity.
Look for "automatisms" which are repetitive actions such
as lip smacking, swallowing, chewing, or fumbling. Automatisms are
frequently seen in complex partial seizures and may be the only indicator
that there is ongoing seizure activity.
Seizures
resulting from drug overdose may be suggested by the presence of a
toxidrome as seen in anticholinergic, sympathomimetic, or tricyclic
ingestions. Hypertension
with bradycardia may indicate an intracranial catastrophe, while fever
may be the manifestation of a CNS infection (though seizures may independently
result in elevated temperatures from muscular hyperactivity or central
deregulation). Irregular heart rate or carotid bruits may indicate
a stroke, which is a common cause of new onset seizures in the elderly.
Perform
a complete neurological examination identifying focal deficits which
may represent an old lesion, new intracranial pathology, or reversible
postictal neurologic compromise (Todd's paralysis). In cases of a
new Todd's paralysis, the physician must rule out a new structural
lesion. Other physical findings suggestive that a patient has had
a seizure include hyperreflexia and extensor plantar responses both
of which should resolve during the immediate post-ictal period.
Document the patient's mental status recruiting the assistance
of persons familiar with the patient. Post-ictal confusion usually
resolves over several hours and failure for gradual improvement must
prompt a search for other causes.
What laboratory tests are indicated in a patient with a first time
seizure?
The
laboratory tests indicated in the ED for patients presenting after
having had a first time seizure who are alert, oriented, and have
no clinical findings include a serum glucose level, electrolytes,
and women of child bearing age require a pregnancy test.
A drug of abuse screen should be considered.
All other tests are of very low yield in this group of patients
and there are no prospective studies at this time in adults or children
to support more in depth testing in the ED such as phosphate, calcium,
or magnesium levels. However,
patients who are on dialysis, malnourished, taking diuretics, or who
have underlying significant medical disorders need comprehensive testing
including CBC, blood urea nitrogen (BUN), creatinine, calcium, phosphate,
magnesium, and an urinalysis.
Rhabdomyolysis, which is a rare consequence of a seizure, may
be diagnosed if the urine tests positive for blood in the absence
of red blood cells on the microscopic exam. A serum creatinine phosphokinase
(CPK) level is indicated in these cases. Serum CPK levels have not
been found useful in differentiating seizures from other causes of
loss of consciousness. Cardiac monitoring for dysrhythmias is an important
part of every resuscitation
for patients who have had a seizure of undermined etiology. An ECG
may reveal evidence of drug toxicity.
Lumbar
puncture:
A lumbar puncture is considered in those patients with an unresolving
post-ictal state, fever, headache, meningeal signs, a positive HIV
history or who are otherwise immunocompromised. There are no prospective
studies that support performing a lumbar puncture as part of the diagnostic
evaluation in the ED on patients who are alert, oriented, asymptomatic,
and not immunocompromised even if the seizure was a first time event.
Which
ED patients with a first time seizure need a neuroimaging study in
the ED?
Three
per cent to 41% of patients with a first time seizure have an abnormal
head CT. In one retrospective
review, 22% of patients with a first time seizure who had a normal
neurologic exam had an abnormal head CT.
The question remains whether identifying the abnormality in
patients with nonfocal neurologic examinations who are evaluated in
the ED has an impact on outcome.
This, of course, depends on the outcome measure used; clearly,
identifying a lesion may direct disposition and possibly argues in
favor of ED neuroimaging. A
head CT should be strongly considered in the ED whenever an acute
intracranial process is suspected, in patients with a history of acute
head trauma, history of malignancy, immunocompromise, fever, persistent
headache, history of anticoagulation, or a new focal neurologic examination.
Which patients with a first time seizure need to be
started on an AED and / or admitted to the hospital?
The
decision to initiate anticonvulsant therapy in the ED should be made
in conjunction with the patient's primary care provider or neurologist.
The decision for therapy is based on the underlying cause of the seizure,
the results of a neuroimaging study, and an EEG. All of these data
are rarely available prior to ED discharge, consequently the decision
to initiate therapy must be based on the predicted risk for seizure
recurrence. The chances
of a patient having a recurrent event after one unprovoked seizure
varies depending on the patient's age and the seizure's underlying
etiology. Seizure etiology combined with EEG findings are the best
predictors of recurrence; when no etiology is identified and the EEG
is normal the recurrence rate is 24% at two years .
Patients who have structural lesions on CT or patients with
focal seizures that secondarily generalize have a risk of recurrence
of up to 65% and are the group of patients that probably benefit from
initiating anticonvulsant therapy in the ED.
There
is limited literature to help the clinician decide which patient with
a new onset seizure needs to be admitted to the hospital.
Clearly, those patients with new focal neurologic deficits,
new CNS lesions on neuroimaging, or underlying medical problems need
to be admitted. More
problematic is the patient with no underlying medical problems and
a normal examination. Fundamental to this decision is the risk of a seizure recurrence.
There is only one study that specifically investigated the
incidence of seizure recurrence within 24 hours of ED presentation.
The study suffers from its retrospective design and it is unclear
to what extent selection bias impacts its findings.
The
authors reported a 19% seizure recurrence rate within 24 hours of
presentation, decreasing to 9% if those patients with alcohol related
events or focal lesions on CT were excluded.
Unfortunately, those patients with recurrent seizures are not
well described and it is not possible to assess from the data provided
if a recurrence could have been predicted based on vital signs and
co-morbid factors.
Areas in need of future research
·
A
well designed prospective study of patients with new onset seizures
and results of laboratory testing and patient outcome.
·
A
well designed prospective study of patients with new onset seizures
and the impact of neuroimaging on clinical decision making in the
emergency department.
·
Outcome
data of seizure recurrance rate within 72 hours of patients with new
onset seizure and no etiology identified in the the emergency department.
·
Impact
of emergent neuroimaging and EEG on clinical decision making in the
emergency department.
Recommendations
1. Perform
a lumbar puncture either in the emergency department or after admission
in patients with a first time seizure with HIV disease following a
head CT.
2. Determine a serum glucose and electrolytes on patients with first
time seizure with no co-morbidities who have returned to their baseline.
3. Obtain a pregnancy test if a woman is of child bearing age.
4. Perform a Neuroimaging of the brain in the emergency department
on patients with a first time seizure. If Neuroimaging of the brain
is not available in the emergency department, discuss the risk of
recurrence with the patient and the patient's primary physician and
either admit the patient to the hospital or make arrangement for an
outpatient evaluation.
1. Patients
with a first time seizure who have a normal neuroimaging of the brain,
normal serum glucose and sodium, and normal neurologic examination
can be discharged from the ED with outpatient follow-up.
2. Patients with a first time seizure who have a normal neurologic
exam, normal neuroimaging of the brain, normal serum glucose and sodium,
and no co-morbidities do not need to be started on an antiepileptic
drug (AED) in the ED.
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Evaluation
of the ED Patient with a First Time Seizure
Annotated Bibliography
1.) DeLorenzo R, Hauser
W, Towne A, et al. A prospective, population-based epidemiologic study
of status epilepticus in Richmond, Virginia. Neurology 1996; 46:1029-1035.
This
is an important prospective study that used a strict definition of status
epilepticus involving 204 events.
The authors report a projected annual incidence of status epilepticus
of 50 per 100,000 population, with an overall mortality of 22%; 3% for
children and 26% for adults. According
to the study, over one half of patients presenting to the ED in status
epilepticus had no prior seizure history. Mortality in patients with
status epilepticus is linked to the duration of the seizures and the
underlying etiology
2.)
American College of Emergency Physicians. Clinical policy for
the initial approach to patients presenting with a chief complaint
of seizure who are not in status epilepticus. Ann Emerg Med 1997;
29:706-724.
This clinical policy is currently under revision.
In essence, it is a formal consensus document that provides general
guidelines for approaching the patient who has had a seizure. The policy
recommends that patients with a first time seizure have, at a minimum,
a set of electrolytes, a glucose level, and a pregnancy test if a female
of child-bearing age. Therapeutics
are not addressed.
3.)
Turnbull T, Hoek T, Howes D, Eisner D. Utility of laboratory
studies in the emergency department patient with a new onset seizure.
Ann Emerg Med 1990; 19:373-377.
This
is a prospective study of 136 patients with new onset seizures seen
over a four-year period; it is not clear if these were consecutive
patients (though doubtful thus introducing selection bias into the
study). All patients had an evaluation of electrolytes, BUN, Cr, CBC,
glucose, calcium, and magnesium.
11 cases of laboratory abnormalities were discovered, only
two of which (patients with hypoglycemia) were not suspected.
The authors conclude that, with the exception of serum glucose,
serum analyses are of low yield in patients with new onset seizures
who have normal physical exams and no co-morbidities.
4.)
Pesola G, Westfal R. New onset generalized seizures in patients
with AIDS presenting to an emergency department. Acad Emerg Med. 1998;
5:905-911.
This
is a retrospective review of 26 AIDS patients with new onset seizures
which were compared to 120 non-HIV patients.
Four of the HIV patients were found to have treatable lesions
that were not suggested by clinical findings.
This study supports the need for a CT and a LP in HIV patients
with new onset seizures.
5.)
Tardy B, Lafond P, Convers P. Adult first generalized seizure:
etiology, biological tests, EEG, CT scan, in an ED. Amer J Emerg Med.
1995; 13:1-5.
This
is the only study that specifically looks at seizure recurrence within
24 hours of presentation. It
suffers from its retrospective design with probable selection bias.
Of 247 patients, alcohol and acute stroke were the most common etiologies
identified. 5 patients
were hypoglycemic, 4 were hyponatremic, 3 had calcium or sodium abnormalities.
85 patients had a focul lesion on head CT; 32% had an EEG with a focal
abnormality. Seizure
recurrence was 19% in the first 24 hours; when alcohol and focal lesions
were excluded, the rate dropped to 9%.
Unfortunately, a complete data set is not provided to allow
for an of predictors that might enable the clinican to risk stratify
patients.
6.)
Henneman P, DeRoos F, Lewis R. Determining the need for admission
in patients with new-onset seizures. Ann Emerg Med 1994; 24:1108-1114.
This
is a retrospective review of 333 adult patients with new onset seizures.
The authors conclude that patients needing admission can be
predicted by a standardized medical evaluation in the ED though unfortunately
the retrospective study design did not allow for a standardized evaluation
to have been performed. A complete data set on patients is not provided making
it difficult to support some of the conclusions made by the authors.
7.)
American College of Emergency Physicians, American Academy of
Neurology, American Association of Neurological Surgeons, American Society
of Neuroradiology. Practice Parameter: Neuroimaging in the emergency
patient presenting with seizure (Summary Statement). Ann Emerg Med 1996;
27:114-118.
This
is an important practice guideline that all emergency physicians should
be familiar with. The
guideline was a joint collaboration between ACEP and the AAN and the
AANR. An evidence-based
approach was taken to formulate recommendations.
The three societies jointly recommended that a neuroimaging
study could be obtained as an outpatient if the patient the neurologic
exam was normal and no predisposing co-morbidites, eg malignancy,
are identified.
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