Neurología, Clase 16

Estatus Epiléptico: Definición y Clasificación

Introducción al Estatus Epiléptico

• La presentación del tema es realizada por un grupo de estudiantes, incluyendo a Caseros Ramos Lexi y otros compañeros.

• Se establece la diferencia entre convulsión, epilepsia y estatus epiléptico: una convulsión es temporal, mientras que la epilepsia implica predisposición a convulsiones. El estatus epiléptico se caracteriza por convulsiones prolongadas.

Importancia del Estatus Epiléptico

• El estatus epiléptico es una emergencia neurológica con alta mortalidad y puede causar daño cerebral significativo, incluyendo muerte neuronal.

• La resistencia a los anticonvulsivos es una causa común de este estado crítico.

Definición según ILAE

• Según la ILAE (2015), el estatus epiléptico resulta de fallas en la supresión de crisis epilépticas y el inicio de mecanismos anormales que prolongan las crisis.

• Se identifican dos tiempos críticos:

• Tiempo 1: Crisis continuas donde se debe iniciar tratamiento.

• Tiempo 2: Consecuencias a largo plazo como daño neuronal requieren un tratamiento más agresivo.

Clasificación del Estatus Epiléptico

Tipos de Estatus Epilépticos

• La clasificación incluye:

• Tónico-clónico: Crisis que duran hasta 5 minutos; después se considera estatus epiléptico si persiste más allá de ese tiempo. Complicaciones pueden surgir tras 30 minutos.

• Focal con alteración de conciencia: Primer tiempo definido en 10 minutos; daño neuronal ocurre después de 60 minutos.

• Ausencia: Menos frecuente, primer tiempo entre 10 a 15 minutos; el daño neuronal no está bien definido en el segundo tiempo.

Etiología y Epidemiología del Estatus Epiléptico

Causas Comunes

• Las causas incluyen suspensión de medicamentos antiepilépticos, enfermedades cerebrovasculares o encefalitis aguda, así como factores remotos como tumores o demencia. También hay causas desconocidas mencionadas en estudios locales en Perú sobre pacientes adultos en emergencias hospitalarias entre marzo de 2018 y enero de 2019.

Estadísticas Epidemiológicas

• La incidencia reportada es de aproximadamente 12,6 casos por cada 100,000 habitantes.

• Morbilidad entre el 20% al 50% y tasa de mortalidad entre el 15% al 33%, dependiendo del tipo específico del estatus epiléptico observado en estudios realizados en EE.UU., donde se registraron entre 120,000 a180,000 casos anuales con predominancia masculina.

Clasificación Adicional del Estatus Epiléptico

Estado Convulsivo vs No Convulsivo

• Se distingue entre estado epiléptico convulsivo (presencia clara de actividad motora tónica-clónica sostenida) y no convulsivo (sin actividad motora evidente). Esta clasificación ayuda a entender mejor las características clínicas asociadas al estado epiléptico prolongado.

Factores Asociados

Understanding Epileptic States: Complex Diagnoses and Treatments

Overview of Epileptic States

• The diagnosis of epileptic states is complex, often presenting with mental state alterations such as confusion, psychosis, lethargy, or coma.

• More than half of cases arise from acute medical conditions like toxic organ failure, alcohol withdrawal, benzodiazepine withdrawal, or drug toxicity.

• Non-convulsive status epilepticus treatment can significantly impact morbidity and mortality through induced hypotension and prolonged cardiac arrhythmias.

Classification of Seizures

• Seizures are classified electroclinically based on whether they are focal or generalized; this classification has clinical implications.

• In focal onset seizures, it is crucial to identify any underlying causal lesions; generalized epilepsy requires avoiding certain anticonvulsants like phenytoin and carbamazepine.

• Proper classification of the type of epileptic state is essential for determining morbidity and guiding appropriate treatment strategies.

Types of Generalized Seizures

• Generalized convulsive seizures can be primary or secondary; secondary ones depend on a focal onset.

• Non-convulsive generalized seizures include atypical absence seizures and other non-convulsive types that may have focal origins.

Non-Convulsive Status Epilepticus

• Non-convulsive status epilepticus presents complexities in classification based on consciousness levels and clinical/electroencephalographic characteristics.

• Typical absence seizures show characteristic bilateral synchronized spike-and-wave discharges at frequencies commonly around 3 Hz.

Characteristics of Absence Seizures

• Atypical absence seizures occur at lower frequencies (1 to 2.5 Hz), primarily affecting infants and children with specific epileptic encephalopathies like Lennox-Gastaut syndrome.

• Myoclonic absences present with synchronized myoclonic jerks coinciding with spike-and-wave discharges but are less frequent in generalized genetic epilepsy.

Focal Onset Seizures

• Focal non-convulsive states often originate in the temporal or frontal lobes; these are more common in adults with established focal epilepsy histories.

• Continuous partial epilepsy occurs without consciousness alteration but may involve sensory phenomena known as aura continua.

Understanding Status Epilepticus

Overview of Status Epilepticus

• The discussion begins with an introduction to status epilepticus, particularly focusing on its relationship with coma and severe consciousness alteration.

• Risk factors for critically ill patients include young age, history of brain injury, and conditions like acute brain lesions or seizures.

Consequences and Types of Status Epilepticus

• Generalized convulsive status epilepticus can lead to continuous seizure activity even after the initial movements cease.

• Non-convulsive status epilepticus may arise from a brief seizure, manifesting as prolonged confusion, often termed postictal state.

Specific Syndromes Related to Neonatal and Infantile Epilepsy

• Various severe syndromes present during neonatal or infant periods include West syndrome, Dravet syndrome, and Lennox-Gastaut syndrome.

• Electrical status epilepticus during sleep is rare but characterized by specific wave patterns; other syndromes like Landau-Kleffner syndrome involve progressive language loss starting between ages three to six.

Controversies in Diagnosis and Treatment

• There is ongoing debate regarding whether changes in the state of epilepsy are causative or symptomatic of clinical dysfunction.

Pathophysiology of Seizures

• The pathophysiology involves sustained crisis initiation that requires treatment within five minutes due to normal mechanism failure leading to neuronal excitability.

• A reduction in inhibitory neurotransmitter GABA occurs alongside increased excitatory neurotransmitters (glutamate and aspartate), resulting in hyperexcitability.

Emergency Considerations

• After five minutes without intervention, neurological emergencies become critical; spontaneous remission becomes less likely over time.

Neurotransmitter Dynamics During Seizures

• Normal synaptic function relies on adequate GABA concentration; disruptions lead to receptor endocytosis affecting neurotransmission efficacy.

• Increased calcium influx continues the release cascade despite reduced receptor availability for GABA, perpetuating excitatory states.

Understanding the Mechanisms of Hypoxia and Epileptic Status

Physiological Responses to Hypoxia

• The body may enter a state of hypoxia, prompting hyperventilation as a compensatory mechanism. This response is crucial for maintaining glucose levels to keep the brain active, given its high glucose consumption.

• Continuous muscle contractions can lead to lactic acidosis. After several minutes, this may result in rhabdomyolysis as the autonomic system attempts to compensate by increasing blood flow to the brain.

• To enhance cerebral blood flow, the body raises blood pressure and heart rate while initiating hyperglycemic pathways. However, this compensation is temporary and can lead to vasogenic edema.

• Cerebral vessels require high resistance for nutrient delivery; thus, they undergo dilation to reduce resistance and allow nutrient influx, which exacerbates edema.

• Systemic complications arise including respiratory, cardiac, renal, and metabolic issues leading ultimately to neuronal injury due to continuous depolarization and neurotransmitter release.

Clinical Manifestations of Epileptic Status

• Clinical signs of status epilepticus mirror those of regular seizures but with prolonged duration. Symptoms are classified based on motor manifestations into convulsive and non-convulsive types.

• Convulsive seizures include generalized tonic-clonic (most severe), focal motor (localized jerking), while non-convulsive seizures encompass focal with altered consciousness (previously known as complex partial).

• Non-convulsive types also include absence seizures or myoclonic jerks characterized by rapid muscle spasms in generalized epilepsy cases. Tonic or atonic seizures are common in children or patients with encephalopathies.

Classification of Epileptic Status

• Classification can be qualitative (nature of alteration: conscious vs unconscious states like confusion or coma) or quantitative (measuring consciousness level using scales from alertness to unresponsiveness).

• Qualitative assessments categorize consciousness levels into mild (alert but disoriented), moderate (responsive only to intense stimuli), and severe (no response at all).

Electroencephalogram Observations

• Characteristics vary between convulsive types; for simple focal seizures there’s no consciousness alteration but localized movements such as eyelid twitching or hand jerking occur.

• In myoclonic convulsions, irregular multifocal contractions manifest briefly without rhythm.

• Tonic convulsions show sustained muscle contractions across limbs accompanied by vegetative disturbances observable via EEG patterns indicating 10–25 Hz spikes with moderate amplitude.

• Clonic convulsions present arrhythmic asymmetric contractions frequently seen in children; EEG shows generalized discharges with medium frequency slow waves.

Understanding Non-Convulsive Epileptic States

Types of Non-Convulsive Seizures

• Non-convulsive seizures can be categorized into several types, including simple focal seizures where consciousness remains unaffected. Symptoms may vary and include sensory, psychic, vegetative, or behavioral manifestations.

• In complex focal non-convulsive seizures, also known as cognitive seizures, there is an alteration in consciousness accompanied by behavioral disturbances and focal automatisms. The EEG may show normal activity or focal spike-wave patterns.

• Subtle focal non-convulsive seizures are characterized by subtle facial movements observable post-seizure. The EEG typically reveals lateralized spike-wave activity.

• In generalized non-convulsive states, there is a decrease in consciousness with potential behavioral changes such as hallucinations and rhythmic blinking. The EEG shows 2 to 3 Hz spike-wave patterns.

• The typical absence state involves brief episodes with abrupt onset and cessation. EEG during these episodes appears normal interictally but shows significant alterations during the absence state.

Clinical Implications of Non-Convulsive States

• During the absence state or new-onset non-convulsive status epilepticus, symptoms like amnesia and stupor may occur alongside slow wave activity (0.5 to 4 Hz spikes).

• Non-convulsive epileptic states during sleep progressively deteriorate cognitive function, particularly noted in children and adolescents. EEG findings typically show persistent spike-wave patterns (1.5 to 3.5 Hz).

• Greater alterations in consciousness correlate with increased risk for brain damage and poorer patient prognosis; thus, clinical criteria are essential for assessing severity.

Diagnosis of Convulsive vs Non-Convulsive Status Epilepticus

Initial Diagnosis Steps

• An initial clinical diagnosis can often be made based on visible signs of a seizure lasting over five minutes or two consecutive seizures without recovery of consciousness.

Differential Diagnosis Considerations

Encephalopathies

• Differential diagnoses include encephalopathies where patients might not respond but exhibit abnormal movements; the EEG will show a slow background rhythm.

Functional Disorders

• In functional disorders, patients may respond well indicating awareness; bilateral movements could be present while the EEG remains normal.

Movement Disorders

• Patients with movement disorders might display good responses but have repetitive movements like tremors; their EEG could also appear normal.

Basilar Territory Stroke

• For basilar territory strokes presenting with specific syndromes (e.g., miosis), differential diagnosis requires careful observation since they can mimic epileptic states despite having a normal EEG.

Importance of Electroencephalogram (EEG)

• An EEG is crucial for diagnosing non-convulsive status epilepticus; it helps classify patients based on observed patterns such as spikes or sharp waves that indicate ongoing seizure activity.

Epileptic Diagnosis and Treatment Insights

Understanding EEG Patterns in Epilepsy

• The presence of focal or generalized anomalies with a frequency greater than 2.5 Hz in an EEG can confirm a diagnosis without needing additional criteria.

• If the EEG shows patterns with a frequency less than 2.5 Hz, along with rhythmic activity above 0.5 Hz, additional diagnostic criteria must be applied.

• Subtle clinical phenomena such as rapid eyelid movements or fixed gaze may indicate the need for further evaluation in patients suspected of having epilepsy.

Evolution of Seizure Patterns

• Typical temporal evolution of seizures starts focal, propagates, and eventually generalizes before termination; this pattern is expected to be reflected in the EEG.

• A clear change in EEG patterns can lead to a definitive diagnosis if no convulsive epilepsy or encephalopathy is present.

Medication Administration and Clinical Improvement

• Antiepileptic medications are administered when the EEG results are inconclusive; improvement should be observed within one minute or after three doses.

• Common antiepileptics include phenytoin, valproate, levetiracetam, vigabatrin, and lacosamide.

Differential Diagnosis Considerations

• Conditions that may overlap with non-convulsive status epilepticus include delirium, toxic metabolic encephalopathy, drug withdrawal syndromes, and postictal states.

• Other neurological conditions like transient global amnesia or central nervous system infections (e.g., meningitis) could also mimic seizure activity.

Initial Management Strategies

• A thorough clinical history is essential to identify prior epilepsy episodes and potential causes such as infections or trauma.

• Immediate assessment includes ensuring airway patency and monitoring vital signs while looking for signs of trauma or infection.

First-Line Treatment Approaches

• Benzodiazepines are typically used first-line to quickly halt seizures; options include intravenous lorazepam or intramuscular midazolam.

• If seizures persist despite initial treatment, additional anticonvulsants like levetiracetam may be introduced based on access routes available.

Non-Conventional Treatment Protocol for Non-convulsive Status Epilepticus

• In cases where intravenous access is not possible, alternative administration routes (intramuscular/nasal/buccal/rectal) should be utilized cautiously.

Optimizing Treatment for Epileptic States

Importance of Treatment Compliance

• Emphasizes the need to optimize treatment as some patients do not adhere to previous treatments, indicating a gap in compliance that needs addressing.

Aggressive Treatments in Status Epilepticus

• Discusses aggressive medications like midazolam, propofol, ketamine, pentobarbital, and thiopental used to induce coma during severe epileptic states.

• Highlights the necessity of aggressive treatment following convulsive status epilepticus due to worse outcomes compared to non-convulsive states.

Situations for Aggressive Treatment

• Identifies specific scenarios where aggressive treatment is warranted:

• Non-convulsive status post-convulsive seizures.

• Frequent non-convulsive seizures in acute brain injuries.

• Post-anoxic brain injury with coma.

• Notes that if prognosis is poor, aggressive treatment should be avoided.

Understanding Status Epilepticus

• Defines status epilepticus as continuous seizures lasting more than five minutes or shorter seizures without recovery of consciousness for over 30 minutes.

• Clarifies the distinction between convulsions (any motor act) and epilepsy (two or more seizures within 24 hours).

Types and Management of Seizures

• Describes various types of status epilepticus: convulsive (focal, absence, myoclonic), emphasizing rapid intervention when seizures exceed five minutes.