trinka causes of se epilepsia 2012
DESCRIPTION
epilepsyTRANSCRIPT
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Causes of status epilepticusEugen Trinka, Julia Hofler, and Alexander Zerbs
Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Salzburg, Austria
SUMMARY
Status epilepticus (SE) is the most extreme form
of epilepsy. It describes a prolonged seizure that
may occur in patients with previous epilepsy or in
acute disorders of the central nervous system. It is
one of the most common neurologic emergencies,
with an incidence of up to 41 per 100,000 per year
and an estimated mortality is 20%. The three
major determinants of prognosis are the duration
of SE, patient age, and the underlying cause. Com-
mon and easily recognized causes of SE include
cerebrovascular disorders, brain trauma, infec-
tions, and low antiepileptic drug levels in patients
with epilepsy. Less common causes present a clini-
cal and diagnostic challenge, but are major deter-
minants of prognosis. Among them, inflammatory
causes and inborn errors of metabolism have
gained wide interest; recent insights into these
causes have contributed to a better understanding
of the pathophysiology of SE and its appropriate
treatment. This review focuses on the different
etiologies of SE and emphasizes the importance of
prompt recognition and treatment of the underly-
ing causes.
KEY WORDS: Status epilepticus etiology, Treat-
ment, Prognosis.
Status epilepticus (SE) is a term used to describe a pro-longed and self-sustaining seizure that may have overt,subtle, or almost no behavioral manifestations. It may beregarded as the most extreme form of epilepsy, or as anexpression of an acute and often life-threatening brain dis-order, such as stroke, encephalitis, or trauma. Mortalityassociatedwith SE is up to 20% (Shorvon, 1994; Logroscinoet al., 1997, 2005). Less than 50% of people in SE havehad previous seizures or epilepsy (DeLorenzo et al., 1996;Hesdorffer et al., 1998; Coeytaux et al., 2000; Knakeet al., 2001; Vignatelli et al., 2003). SE is one of the mostcommon neurologic emergency, with an overall annualincidence of 1041 per 100,000 (DeLorenzo et al., 1996;Hesdorffer et al., 1998; Coeytaux et al., 2000; Knakeet al., 2001; Vignatelli et al., 2003). Up to 287,000 patientsper year are affected in Europe. Not all forms of status arelife-threatening and, given the variety of its clinical pre-sentations, the management must be tailored according tothe type of SE and the underlying cause. Three majorfactors determine an increased risk of mortality and mor-bidity associated with SE: (1) certain etiologies, (2) age
>60 years, and (3) long duration of SE (Towne et al.,1994; DeLorenzo et al., 1996; Wu et al., 2002; Rossettiet al., 2006). This review focuses on the various causes ofSE, since etiology is increasingly recognized as one of themost important factors for prognosis and outcome. There-fore, identifying and treating the underlying cause of SE isat least as important as prompt and effective treatmentwith early termination of seizures.
Definition and Classificationof Status Epilepticus
Status epilepticus (SE) has been recognized for centu-ries (Shorvon, 1994; Wolf et al., 2009). Henri Gastaut(1970) recognized SE as a prolonged seizure with as manyforms as there were types of epileptic seizures. Therefore,SE classification mirrored exactly the seizure classifica-tion. In the International League against Epilepsy (ILAE)1981 Classification, SE was defined as a seizure that per-sists for a sufficient length of time, or repeated frequentlyenough that recovery between attacks do [does] notoccur (Commission on Classification, ILAE, 1981).Generalized tonicclonic seizures usually do not lastlonger than 23 min (Theodore et al., 1994); the risk of aseizure becoming self-sustaining increases as the durationreaches 5 min or more (Lowenstein et al., 1999). For thepurpose of this review, we use a clinical classification
Address correspondence to Eugen Trinka, Department of Neurology,Christian Doppler Klinik, Paracelsus Medical University, Ignaz HarrerStrae 79, 5020 Salzburg, Austria. E-mail: [email protected]
Wiley Periodicals, Inc. 2012 International League Against Epilepsy
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SEIZURES IN SPECIAL AND SEVERE SITUATIONS
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along two taxonomic criteria: the presence (or absence) ofmotor symptoms and the impairment (or retention) of con-sciousness. Therefore, one can distinguish (A) SE typeswith prominent motor symptoms, such as convulsive SE,and (B) SE types without prominent motor symptoms,summarized as nonconvulsive SE (NCSE). NCSE canoccur with or without coma; this has important etiologicimplications and determines its treatment. A third cate-gory (C) comprises the boundary syndromes, includingepileptic encephalopathies and acute forms of coma withstatus-like electroencephalography (EEG) patterns.Table 1 briefly outlines this tentative classification. For amore detailed discussion of SE classification, refer to:(Shorvon, 1994; Walker et al., 2005; Bauer & Trinka,2006, 2009; Berg et al., 2010). However, the definitionsand classifications are in flux and an ILAE Task force iscurrently developing a new draft classification of SE, fol-lowing the concepts of the ILAEs new classification pro-posal of seizures and syndromes (Berg et al., 2010).
Causes of Convulsive StatusEpilepticus in Adults
Most population-based studies have used a traditional30-min duration of SE, and so the numbers given are thelowest estimates. Using the 5-min definition, determiningthe time from onset to starting emergency treatment, theincidence in clinical practice is much higher than in theepidemiologic studies. Convulsive SE comprises 3770%of all forms of status, and its annual incidence is up to 40per 100,000 (Waterhouse, 2008). In adults with preexist-ing epilepsy, the most common etiologies are low antiepi-leptic drug (AED) levels (accounting for at least onefourth of SE [Fig. 1]), remote symptomatic etiologies, and
stroke (DeLorenzo et al., 1995, 1996). This subgroup withepilepsy and low AED levels has a good prognosis, with alowmortality of 4.08.6% (Towne et al., 1994; DeLorenzoet al., 1995). Overall, acute symptomatic causes are themost common etiology, accounting for 4863% of all SEcases (Hesdorffer et al., 1998; Coeytaux et al., 2000;Knake et al., 2001). Stroke is the leading cause among theacute symptomatic cases, accounting for 1422% of SE inadults (DeLorenzo et al., 1995; Knake et al., 2001). Inolder adults, remote stroke is a major cause. Knake et al.(2001) found that remote stroke caused 36% of SE inpatients older than 56 years. In the Richmond VirginiaStatus Epilepticus Study, 41% of adults and 61% of theelderly had acute or remote ischemic and hemorrhagicstrokes as cause of status (DeLorenzo et al., 1995).In the context of epilepsy, SE may develop in those with
a previous diagnosis of epilepsy or de novo, as its initialmanifestation. Approximately 15% of patients with epi-lepsy have had at least one episode of status during theirlifetime. Most often, the SE is due to the epilepsy itself,triggered by medication nonadherence, resulting in sub-therapeutic AED levels (Aminoff & Simon, 1980) or byinappropriate drug treatment (Thomas et al., 2006a,b).The clinical features of SE in these patients depend on theunderlying epilepsy syndrome. In the context of idiopathicgeneralized epilepsy, status is most often nonconvulsive(Shorvon & Walker, 2005); in the context of juvenilemyoclonic epilepsy it may be myoclonic (Thomas et al.,2006a,b; Larch et al., 2009). Myoclonic status may alsodevelop in progressive myoclonic epilepsy, Lennox-Gastaut syndrome, or epilepsy with myoclonic absences.
Table 1. Proposed classification of seizure
types according to their semiology, along two
taxonomic criteria: motor symptoms and
impairment of consciousness
With prominent motor symptoms
Convulsive SE (syn.: tonicclonic SE)
Myoclonic SE (prominent epileptic myoclonic jerks)
Focal motor (including EPC)
Tonic SE
Hyperkinetic SE
Without prominent motor symptoms (i.e., NCSE)
NCSE with coma
NCSE without coma
Generalized
Focal
Boundary syndromes
Epileptic encephalopathy
Acute forms of coma with status-like EEG pattern
Epileptic behavioral disturbance and psychosis
Confusional states, or delirium with epileptiform EEG changes
Figure 1.
Etiology of status epilepticus in adults, with associated
mortality for each category. Based on data from
DeLorenzo et al., 1995. AED, antiepileptic drugs; CNS,
central nervous system.
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However, the precise incidence of convulsive status ormyoclonic status in these syndromes is not known.Approximately 12% of patients who eventually develop
epilepsy have presented with SE as their first clinical man-ifestation (Hauser, 1990; Hesdorffer et al., 1998). In thesepatients, SE may be an intrinsic manifestation of disease,sometimes with recurrent episodes, or the epilepsy may bethe consequence of a prolonged SE, with neuronal deathand alteration of networks causing recurrent seizures afterthe initial event. During a 10-year follow-up, epilepsydeveloped in 42% of patients who had acute symptomaticSE and in 14% of patients who had acute symptomaticseizures (Hesdorffer et al., 1998). The development ofsubsequent epilepsy is more likely if the status is refrac-tory to treatment (Holtkamp et al., 2005), supporting thehypothesis that SE contributes to epileptogenesis byenhancing hyperexcitable networks.
Nonconvulsive StatusEpilepticus
NCSE may be defined as an enduring epileptic condi-tion with reduced or altered consciousness, behavioral andvegetative abnormalities, or merely subjective symptomswithout major convulsive movements (Drislane, 2000).This umbrella term includes a wide spectrum of disorders,ranging from benign conditions, such as absence status inidiopathic generalized epilepsy, to severe life-threateningconditions, such as subtle SE or coma with generalizedepileptiform discharges (coma-GEDs). Therefore, it isimportant to subdivide this category according to thedegree of unresponsiveness or to the depth of coma(Fig. 2). Consciousness, which notoriously resists defini-tion, becomes a taxonomic criterion for subdividingNCSE (Bauer & Trinka, 2009). Consciousness itself canbe categorized into quantitative and qualitative conscious-ness. The quantitative element depends upon the patientslevel of consciousness and arousability, which in turndepends upon the integrity of the ponto-mesodiencephalicreticular pathways and the thalamocortical projections.Qualitative consciousness, on the other hand, dependsupon the content of consciousness, experience, emotions,and sensations, known only to patients themselves. Itreflects the inner monologue and it is essential for anymeaningful interaction with the environment. Qualitativeconsciousness is associated with awareness, enabling thepatient either to focus on and interact with the environ-ment or to engage in an inner monologue. Table 2describes the different types of NCSE.The incidence of NCSE, based on epidemiologic stud-
ies, ranges from 40.0 to 66.9% (DeLorenzo et al., 1995;Hesdorffer et al., 1998; Coeytaux et al., 2000; Knakeet al., 2001; Vignatelli et al., 2003). Like convulsive sta-tus, NCSE may occur in acute central nervous system(CNS) disorders or may be a part of certain electroclinical
syndromes. We do not know the precise incidence ofNCSE in the epilepsy population. In our own audit (1975to 2003) at the University Hospital Innsbruck, 220 patientswith epilepsy (140 women, median age 45 years [range 289]) had at least one episode of NCSE either during their
Figure 2.
Relationship between depth and coma (x-axis), prog-
nosis (x-axis), degree of structural brain damage (red y-
axis), and epileptic brain dysfunction (blue y-axis) due
to status epilepticus. Clinical entities depicted in the
upper part of the graph are arranged along the x-axis
without distinct positions, in recognition that large
border zones and overlaps between the conditions
may exist. With permission from Bauer & Trinka, 2009.
AS, absence status epilepticus; EPC, epilepsia partialis
continua; GEDs, generalized epileptiform discharges;
IGE, idiopathic generalized epilepsy; LEDs, lateralized
epileptiform discharges; NCSE, nonconvulsive status
epilepticus.
Epilepsia ILAE
Table 2. Categories of NCSE, classified
according to the degree of disturbed
consciousness
NCSE with coma
NCSE without coma
Generalized
Typical absence status
Atypical absence status
Myoclonic absence status
Focal
Aura continua
With vegetative symptoms
With sensory symptoms
With visual symptoms
With olfactory symptoms
With gustatory symptoms
With emotional symptoms
Aphasic SE
SE with dyscognitive symptoms
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disease or at their initial presentation (Bauer G, Trinka E,unpublished data). The cause of NCSE was remote symp-tomatic in 47%, idiopathic in 45%, and remained
unknown (cryptogenic) in 48%. Forty-six percent hadfocal SE, 21% had a generalized NCSE in the context ofidiopathic (or genetic) generalized epilepsies, and 22%had atypical absence status in the context of Lennox-Gas-taut syndrome. Table 3 details their different types of sta-tus epilepticus.
Causes of Absence StatusEpilepticus
Absence status (AS) is best described as a confusionalstate of variable intensity, ranging from simple cognitiveslowing to catatonic stupor, lasting for hours to days orweeks (Andermann & Robb, 1972). The EEG showsbilateral rhythmic, synchronous, and mostly symmetricparoxysmal activity, which can be continuous or discon-tinuous (Bauer & Trinka, 2010; Fig. 3). It is important torecognize that AS is a heterogeneous condition, whichmay occur in patients with preexisting idiopathic general-ized epilepsy (typical AS) or during the course ofchronic symptomatic generalized epilepsy, such as Len-nox-Gastaut syndrome (atypical AS). Of interest, some
Table 3. Types of NCSE in 220 patients with
epilepsy and a history of NCSE (Bauer &
Trinka, data on file)
n %
Generalized (106 = 48.2%)
Typical absence SE 57 25.9
Atypical absence SE 49 22.3
Localized/lateralized (100 = 45.5%)
Focal simple (58 = 26.4%)
Aura continua 11 5.0
Vegetative 8 3.6
Aphasic 27 12.3
Pure frontal 9 4.1
Psychosis 3 1.4
Focal complex (42 = 19.1%)
Continuous 30 13.7
Discontinuous 12 5.5
Unclassified 14 6.3
Total 220 100.1
Figure 3.
Typical absence status epilepticus in an older patient (V.J., female, 74 years. tc 0.3 F30). This patient had scattered
generalized tonicclonic seizures since age of 54 years. Her EEG showed periodically repeated generalized 3/s spike
and wave, with no major diffuse slow activity between periods (note the reduced time calibration). EEG kindly
provided by Prof. Dr. G. Bauer, Innsbruck. The patient displayed discontinuous psychic functions, and was amnesic
for the abnormal condition. Recovery was immediate after intravenous diazepam.
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patients develop AS later in life, occasionally de novo(Andermann & Robb, 1972; Thomas et al., 1992), or itmay occur as a late exacerbation of an idiopathic general-ized epilepsy syndrome (Bauer et al., 2007). There mayalso be a fourth group of AS, comprising absences withvery clear focal characteristics. This group may be consid-ered as a transitional form between AS and dyscognitivefocal SE of frontal origin (Bauer et al., 2006; Thomas,2011).Many cases of AS have nonspecific precipitating fac-
tors. The most important are antiepileptic drug (AED)withdrawal or impaired adherence, alcohol, sleep depriva-tion, and sleepwake cycle disturbance. Other nonspecificfactors include stress, fatigue, fever, mild head trauma, ormetabolic derangement after surgery (Thomas & Zifkin,2008; Thomas &Gelisse, 2009).Several idiopathic generalized epilepsy syndromes may
be aggravated by inappropriate AEDs: carbamazepine,phenytoin, tiagabine, or other c-aminobutyric acid(GABA)ergic medications (Snead & Hosey, 1985; Knakeet al., 1999; Thomas et al., 2006a,b; Trinka et al., 2002).Thomas et al. reported 14 patients with idiopathic general-ized epilepsy treated with either carbamazepine alone orwith other potentially aggravating drugs, for example,phenytoin, vigabatrin, or gabapentin. Ten of these casesdeveloped AS; in half, the AS was atypical. All theirpatients had a clear seizure aggravation, with developmentof new seizure types before AS developed (Thomas et al.,2006a,b). The prognosis was invariably good with full sei-zure control in all patients after switching to appropriatedrugs.In late-onset AS, other drug-related factors play an
important clinical role (Thomas et al., 1992; Thomas &Andermann, 1994). Most importantly, psychotropic medi-cationor its withdrawalmay provoke late-onset AS(Fernandez-Torre, 2001). In addition, many other drugs,for example, theophylline, baclofen, metformin, andcimetidine, may exacerbate absences later in life (for areview see Thomas & Snead, 2007).There are metabolic and toxic factors in many patients,
although the precise incidence is not known. Examplesinclude hyponatremia, hypoglycemia decompensatedchronic renal failure, hepatic failure, and hypocalcemia(for review see Thomas & Snead, 2007). There have beenseveral cases of AS following the use of contrast-enhanc-ing products during myelography or carotid angiography(Pritchard & ONeil, 1984; Vollmer et al., 1985; Coeytauxet al., 2000). Some cases of transient global amnesia afterangiography may in fact also be epileptic in nature (Baueret al., 2005).AS probably occurs most frequently in the context of
electroclinical syndromes. Aside from childhoodabsence epilepsy, juvenile absence epilepsy, and juve-nile myoclonic epilepsy, there are other syndromes asso-ciated with AS as a key clinical feature: AS may occur
in eyelid myoclonia with absences (Jeavons syndrome)(Yang et al., 2008), idiopathic generalized epilepsy withphantom absences (Panayiotopoulos et al., 2001), per-ioral myoclonias with absences (Agathonikou et al., 1998),or absences status epilepsy (Genton et al., 2008). Theprognosis in these syndromes (not yet fully accepted inthe ILAE classification) is generally good, and patientsrespond well to appropriate AEDsvalproate in mostcases. However, this is not true of AS associated withring chromosome 20, where prolonged confusionalstates are notoriously resistant to AEDs and there havebeen lethal cases (Jacobs et al., 2008). The EEG showsbilateral high-voltage slow waves, sometimes with inter-mingled spikes and frontal accentuation. There is notypical clinical picture, except for mild cognitive impair-ment (Fig. 4).
Causes of Focal NonconvulsiveStatus Epilepticus
Focal NCSE (as with AS) encompasses a wide range ofclinical symptoms. Previously the term complex focal orcomplex partial SE was used, which may be replaced infuture by dyscognitive SE. These forms usually havestructural abnormalities and clinical focal signs that mustbe identified to guide appropriate drug treatment (Fig. 2).Most of the published literature concerns patients with
temporal or extratemporal lobe epilepsy of remote symp-tomatic cause, whose NCSE is either as the presentingsymptom or develops during the course of the disease(Tomson et al., 1992, Kaplan et al., 1996; Scholtes et al.,1996). As with AS, there are often nonspecific risk factors,but more often status occurs in these patients without spe-cific provoking factors. In a review of 70 patients withfocal NCSE of frontal origin, more than one fourth had nohistory of epilepsy. Forty-five percent had a focal frontal
Figure 4.
Clinical course of convulsive status epilepticus.
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lesion. The etiology was most often a brain tumor (benignor malignant), or a posttraumatic or a postsurgical lesion(Thomas & Zifkin, 2008).Rare causes of focal NCSE include intravenous contrast
media, or drugs such as ciprofloxacin, lithium intoxica-tion, theophylline, vigabatrin, tiagabine, or crack cocaine(Thomas et al., 2006b). Mesial temporal focal NCSE canalso be the presenting symptom of the increasingly recog-nized nonparaneoplastic limbic encephalitis, related tovoltage-dependent potassium channels (VGKC/LGI1)(Irani et al., 2010), NMDA receptors (Vincent & Bien,2008), or antibodies against glutamic acid decarboxylase(Malter et al., 2010). Some of them lead to a specific sei-zure type (e.g., faciobrachial dystonic seizures associatedwith anti-VGKC/LGI1 antibodies), preceding the onset ofthe limbic encephalitis (Irani et al., 2011a,b). It is impor-tant to note that paraneoplastic limbic encephalitis mayalso present with focal NCSE (Dalmau et al., 2008), indi-cating the need for a comprehensive search and rigoroustreatment of any underlying primary neoplasm. We do notyet know the full spectrum of this new group of immune-mediated encephalopathies (Table 4).The outcome for focal NCSE is less favorable than that
for AS. Long-lasting focal status, especially of temporallobe origin, may cause brain edema identifiable on mag-netic resonance imaging (MRI) (Bauer et al., 2006). Thesepatients may also have severe and prolonged amnesia(Engel et al., 1978; Treiman et al., 1981). However, manypatients presenting with focal NCSE have acute or remotesymptomatic epileptogenic lesions, making it difficult todisentangle the dysfunction due to the epileptic activityfrom the effect of the structural lesion (Hilkens & DeWeerd, 1995; Kaplan, 1996; Trinka et al., 2002). How-ever, focal NCSE occurring with an acute lesion mostlikely contributes substantially to the associated neuro-logic dysfunction (Hilkens & De Weerd, 1995; Bauer &Trinka, 2010). Therefore, patients with focal NCSE needprompt and vigorous treatment, tailored to the underlyingcause.
Causes of ComatoseNonconvulsive Status
EpilepticusComatose forms of NCSE need further attention. It is
important from the clinical standpoint (1) to clarifywhether the coma is caused by the epileptic seizure or sta-tus, or by the brain disorder itself, (2) to assess the contri-bution of epileptic activity to the depth of coma, (3) toconsider whether treatment improves prognosis in thesepatients or not, and (4) to implement an appropriate treat-ment in these critically ill patients. Unlike in other formsof NCSE, the cause of the comatose patients SE cansometimes only be identified from the history, the tempo-ral pattern of coma, and the neurologic signs. The epilepticetiology is most often confirmed only by the presence ofcontinuous or discontinuous epileptiform discharges onthe EEG (Lowenstein & Aminoff, 1992; Jordan, 1999;Brenner, 2005). A frequently used, but not universallyaccepted, classification of patients in comatose status usesthe dichotomy of generalized versus focal or lateralizedEEG discharges (Brenner, 2004). The EEG is absolutelynecessary to make this distinction. In this review we usedthe terms coma with generalized epileptiform dis-charges (or coma-GED) and coma with lateralized epi-leptiform discharges (or coma-LED) (Bauer & Trinka,2009). The etiology in these patients is almost alwaysacute symptomatic, encompassing a wide variety of
Table 5. Etiologic factors and EEG pattern in
comatose NSCE
Etiology EEG pattern
coma-GED Diffuse primary or
secondary brain
disturbances (anoxic,
toxic, metabolic,
infectious, degenerative)
Space-occupying lesions
with brainstem
compression (direct or
due to tentorial
herniation)a
Known epilepsies?
Continuous generalized
spiking
Periodic spiking
Burst suppression pattern
in different variations
Other generalized
periodic abnormalities
Bilateral triphasic waves
coma LED Focal brain lesions (in
most cases acutely
acquired) In rare cases
diffuse abnormalities
(aminophylline,
intoxiation, some forms
of diabetic coma)
Known epilepsies?
Continuous focal spiking
PLEDs and Bi-PLEDS
Unilateral burst
suppression pattern
unilateral triphasic waves
Bi-PLED, bilateral periodic epileptiform discharges; GEDs,
generalized epileptiform discharges; LED, lateralized epilepti-
form discharges; PLEDs, periodic epileptiform discharges.aMight also present as coma-LED.
Table 4. Immunologic disorders causing
status epilepticus
Paraneoplastic encephalitis
Hashimoto encephalopathy
Anti-NMDA-receptor encephalitis
Anti-VGKC-receptor encephalitis
Rasmussen encephalitis
Cerebral lupus
Adult-onset Still disease
Anti-GAD antibody associated encephalitis
Goodpasture syndrome
Thrombotic thrombocytopenic purpura
Antibody-negative limbic encephalitis
NMDA, N-methyl-D-aspartate; GAD, glutamate acid dec-
arboxylase.
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Table 6. Causes of epilepsia partialis continua (according to Tan et al., 2010)
Age period EPC type 1 (static cause) Diagnostic test
EPC type 2 (progressive
cause) Diagnostic test
Infancy Hemimegalencephaly Mitochondrial disease
(Alper disease)
Serum and cerebrospinal
fluid lactate, muscle
biopsy biopsy,
mitochondrial DNA
(mutation of POLG1)
Childhood Focal cortical dysplasia
Sturge-Weber
syndrome focal cortical
dysplasia
Rasmussen syndrome Cerebrospinal fluid
oligoclonal banding,
immunoglobulin G index
Tuberous sclerosis Repeated skin
examination
Mitochondrial
encephalomyopathy, lactic
acidosis and stroke-like episodes
(MELAS)
Serum and cerebrospinal
fluid lactate, muscle
biopsy, mitochondrial
DNA
Neurocysticerosis Immunoelectrotransfer
blot assay
Delayed type of measles
encephalitis (complication of
measles in
immunocompromised children)
Immunosuppresive
treatment, contact with
measles
(Tick-borne) encephalitis Cerebrospinal fluid study
serologic test for virus
Gliomatosis cerebri
Other foreign tissue
lesions Nonketotic
(ketotic) hyperglycemia
Serum glucose, urinary
ketones
Adults Cerebrovascular
disorders (stroke;
intracranial bleeding,
cerebral venous
thrombosis, vasculitis)
Adult-onset Rasmussens
syndrome
Cerebrospinal fluid
oligoclonal banding,
immunoglobulin G index
Nonketotic (ketotic)
hyperglycemia
Serum glucose Creutzfeldt-Jakob disease 14-3-3 protein in
cerebrospinal fiuid
Focal cortical dysplasia Myoclonus epilepsy with ragged
red fibers (MERRFs)
Serum and cerebrospinal
fluid lactate, muscle
biopsy, mitochondrial
DNA
Paraneoplastic limbic
encephalopathy
Cerebrospinal fluid study,
chest computed
tomography, anti-Hu
test
Kufs disease Skin or rectal mucosal
biopsy
Neoplasms
Tuberculous meningitis
(tuberculoma)
(Tick-borne) encephalitis
Cerebrospinal fluid study,
chest XR, tuberculin skin test
Cerebrospinal fluid
study, serologic test for
virus
Autoimmune thyroid
encephalopathy
Thyroid function tests,
antithyroglobulin
antibody,
antimicrosomal antibody
Behcet disease Neuroimaging, recurrent
oral and genital
ulceration, skin lesions,
HLA-B5 positivity
Sjogren syndrome Hypergammaglobulinemia
positive antinuclear
antibody, anti-SSA, SSB,
rheumatoid factor
Multiple sclerosis Cerebrospinal fluid
oligoclonal banding
HIV encephalopathy
Immunoglobulin G index
Serologic test for HIV
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systemic diseases or CNS disorders. Table 5 shows the eti-ologic factors and EEG patterns found in coma-GED andcoma-LED. Unlike in AS and focal NCSE, these patientsare often resistant to treatment, and the prognosis dependsentirely on the course of the underlying disorder.Advanced convulsive SE becomes oligosymptomatic withfewer motor symptoms; deep coma is the leading symp-tom, hence the term subtle status (Treiman et al., 1984).The causes are identical to convulsive SE.
Causes of Epilepsia PartialisContinua
Epilepsia partialis continua (EPC) is a special type offocal status epilepticus (Table 1), first described byKojewnikov in 1894; he considered it as a peculiar formof cortical epilepsy. EPC is characterized by spontane-ous regular or irregular clonic muscle twitching of cere-bral cortical origin, sometime aggravated by action orsensory stimuli, confined to one part of the body, andcontinuing for a period hours days, or weeks (Obesoet al., 1985). EPC, also called Kojewnikov syndrome,occurred in patients with Russian springsummer tick-borne encephalitis; EPC typically develops 23 weeksafter the end of the acute illness (Zemskaya et al., 1991).EPC was later recognized to occur in several neurologic
disorders, with age of onset ranging from infancy to adult-hood, and even in the elderly. The prevalence, based onthe EPC case registry of the British Neurological Surveil-lance Unit, is
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causes, and the available literature is mostly confined tosingle case reports or small case series. This overview isbased on a systematic search of all available English liter-ature between 1990 and 2008 (Tan et al., 2010). Theauthors identified 181 causes of SE after reviewing 513articles. The causes fell into five categorical groups:
1. Immunologically mediated disorders (Table 4).2. Mitochondrial diseases (Table 7).3. Uncommon infective disorders (Table 8).4. Genetic disorders (Table 9).5. Drugs or toxins.
Table 10 lists other uncommon causes of SE. It cannotbe overemphasized that the knowledge of the range ofconditions is important to clinical practice; the underlyingdisorder must be treated to achieve full seizure control.The tables are derived from the article by Tan et al. (2010)and reflect the current state of knowledge on these causesof SE.
Therapeutic ConsiderationsGiven the wide variety of clinical presentations of SE,
ranging from life-threatening conditions to seeminglyharmless ones, it is important to tailor the treatment to thetype of status and to the underlying disorder. The clinicalpresentation of SE determines the aggressiveness treat-ment. All treatment concepts on convulsive SE are basedon a staged approach (Fig. 4). In the early phase of convul-sive SE, large randomized controlled trials support the useof intravenous benzodiazepines. Alternatively, the intra-muscular route is effective in the prehospital setting(Silbergleit et al., 2012). In stage two, AEDs were used,but it must be emphasized that there are no clinical trialsto inform the best drug treatment at this stage (Cock andESETT Group, 2011). Phenytoin, levetiracetam, and valp-roic acid are most often used (Shorvon et al,. 2008). Thenewer AED lacosamide has also gained acceptance in thecommunity, but data on its effectiveness in convulsive
Table 9. Status epilepticus due to genetic diseases
Chromosomal aberrations
Inborn errors of
metabolism
Malformations of
cortical development
Neurocutaneous
syndromes Others
Ring chromosome 20 Porphyria Focal cortical
dysplasias
Sturge-Weber
syndrome
Retts syndrome
Angelman syndrome Menkes disease Hemimegalencephaly Tuberous sclerosis Dravet syndrome and
SCN1A gene mutation
spectrum
Wolf-Hirschhorn syndrome Wilsons disease Polymicrogyria Migrating partial seizures
in infancy
Fragile X syndrome Alexanders disease Heterotopias Pyeridoxine dependency
X-linked mental retardation
syndrome
Gobalamin C/D
deficiency
Schizencephaly Familial hemiplegic
migraine
Ring chromosome 17 Ornithine transcarbamylase
(OTC) deficiency
Hyperprolinemia
Maple-syrup urine disease
3-Methylcrotonyl CoA
carboxylase deficiency
Lysinuric protein intolerance
Hydroxyglutaric aciduria
Metachromatic
leukodystrophy
Kufs disease
Late infantile ceroid
lipofuscinosis
Beta-ureidopropionase
deficiency
Laforas disease
Dentato-rubro-pallido-luysian
atrophy
Infantile-onset
spinocerebellar ataxia
Wrinkly-skin syndrome
Neurocutaneous
melanomatosis
Neuroserpin mutation
Wolfram syndrome
Autosomal recessive
hyperekplexia
Cockayne syndrome
Cerebral autosomal
dominant arterio-pathy
with subcortical infarcts
and leuko
encephalopathy
(CADASIL)
3-Hydroxyaxyl
CoA dehydrogenase
deficiency
Carnitine
palmitoyltransferase
Succinic semildehyde
dehydrogenase deficiency
Jeavons syndrome
Robinow syndrome
LYK5 mutation
MECP2 mutation
Malignant hyperpyrexia
Epilepsia, 53(Suppl. 4):127138, 2012doi: 10.1111/j.1528-1167.2012.03622.x
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status are limited (Hfler et al., 2011; Trinka, 2011). Fromstage three onward, intensive care unit treatment and gen-eral anesthesia are the mainstays of drug treatment. Again,there are no randomized controlled trials informing theeffectiveness of individual drugs in this stage. Midazolamseems to be better tolerated than pentobarbital/thiopentaland propofol (Shorvon & Ferlisi, 2012). A fourth stage ofstatus was recently introduced (Shorvon & Trinka, 2011),and a treatment protocol was proposed by Shorvon andFerlisi (2011). Needless to say, all general measures forintensive care treatment have to be applied at the begin-
ning of status (Shorvon et al., 2008). There is generalagreement that AS, dyscognitive status and other forms offocal nonconvulsive SE do not require the same aggres-sive treatment as convulsive SE. Most patients in ASrespond promptly to a benzodiazepine or valproic acid. Infocal NCSE the potential risks of treatment, especiallyintubation and sedation, must be weighed against the ben-efits of seizure control in preventing neuronal damage andlong-term consequences.
Disclosure of Conflictof Interest
AZ has no conflict of interest to declare. JH has received speakershonoraria from UCB and travel grants from UCB, Eisai, and Gerot. EThas acted as a paid consultant to Eisai, Medtronics, Bial, and UCB. Hehas received research funding fromUCB, Biogen-Idec, and Sanofi-Aven-tis, and speakers honoraria fromBial, Cyberonics, Desitin Pharma, Eisai,Gerot, Bhringer, Sanofi, Medis, and UCB. We confirm that we haveread the Journals position on issues involved in ethical publication andaffirm that this report is consistent with those guidelines.
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