seizure 部分知识点

岛民A

Generalized Tonic-Clonic Seizures(grand mal)

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1. Prodrome

• Hours before the seizure, patients may experience vague     prodromal symptoms, such as:
  
  
  
  
  • Sleep disturbances
  • Lightheadedness
  • Mood changes (anxiety, irritability)
  • Impaired concentration
    

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2. Ictal Phase

• Loss of consciousness: Patients lose consciousness completely     during the seizure.
• Tonic phase: Generalized muscle stiffness and contraction.
• Clonic phase: Rhythmic jerking movements in all limbs.
• Absence of auras or automatisms: These are typically absent     unless the seizure is secondary to a focal seizure that generalizes.
  

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3. Postictal Phase

• Confusion and lethargy: Patients often experience confusion and     fatigue after the seizure.
• Lactic acidosis:
  
  
  
  
  • Excessive muscle activity leads to hypoxia, anaerobic      respiration, and lactate accumulation.
  • Manifests as an anion gap metabolic acidosis (serum      bicarbonate ↓).
  • Usually transient and resolves within 2 hours; no need for IV      bicarbonate therapy.
    
• Other laboratory abnormalities:
  
  
  
  
  • Hyperprolactinemia: Serum prolactin levels rise (at least      three times baseline) within 30 minutes post-seizure (serum prolactin ↑),      which can help differentiate epileptic seizures from psychogenic      seizures, though results are unreliable (as syncope or stress can also      elevate prolactin).
  • Elevated creatine kinase (CK): A marker of muscle injury (CK      ↑).
  • Elevated white blood cell count, cortisol, neuron-specific      enolase (NSE), and lactate dehydrogenase (LDH): White blood cell count ↑,      cortisol ↑, NSE ↑, LDH ↑. These findings are nonspecific and not commonly      used for diagnosis.
    

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4. Diagnosis and Management

• Electroencephalogram (EEG): Helps guide decisions on long-term     anticonvulsant therapy.
• Monitor electrolytes and arterial blood gases: Until they     normalize.
• No specific treatment needed: Lactic acidosis typically     resolves on its own without intervention.
  

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ddx

• Sydenham chorea is a symptom     of rheumatic fever, typically occurring 1–8 months after group A     streptococcal infection.
• It is the most common form of acquired chorea in childhood.
• It presents with rapid, irregular, and non-stereotyped movements.
• Symptoms are usually generalized, involving the head,     neck, and limbs.
• Movements persist while awake and worsen over hours to     days.
  

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myoclonic（no stiffening phase）

Generalized Myoclonic Seizures &Juvenile Myoclonic Epilepsy (JME)

Generalized Myoclonic Seizures:

• Brief, sudden, shock-like muscle jerks (myoclonus) affecting the entire body.
• Occur without warning (no prodrome) and cause minimal      impairment of consciousness.
• No aura or postictal confusion.
  

Juvenile Myoclonic Epilepsy (JME):

• Onset in adolescence.
• Myoclonic jerks occur immediately after waking up.
• Often coexists with absence seizures and generalized      tonic-clonic seizures.
  

Juvenile Myoclonic Epilepsy (JME) follows an age-related seizure progression:

1️⃣ Childhood (~around 10 years old): Some patients may initially experience absence seizures.
2️⃣ Early adolescence (~12-18 years old): Morning myoclonic jerks typically emerge, often as the first manifestation of JME.
3️⃣ Mid-to-late adolescence (~14-20 years old): Some patients develop generalized tonic-clonic seizures (GTCs), often triggered by sleep deprivation or early morning awakening.

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Ddx

Convulsive Syncope

• Etiology: Caused by transient     cerebral hypoperfusion, often triggered by situational factors     (e.g., prolonged standing, dehydration, fear, pain).
• Clinical Features:
  
  
  
  
  • Brief loss of consciousness, often      with a prodrome (e.g., dizziness, nausea, tunnel vision).
  • Myoclonic movements or seizure-like activity due to reduced midbrain perfusion.
    

    Key Differentiation from Seizures:

• Typically shorter duration and lack of postictal      confusion.
• No tongue biting, no prolonged tonic-clonic phase, and rapid recovery.
• EEG in convulsive syncope is normal, whereas seizures show      abnormal epileptiform activity.
  

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ddx Breath-Holding Spells (BHS)

Definition: Reflexive episodes of prolonged     expiratory apnea, triggered by emotional distress, tantrums, or     minor injuries, leading to cyanosis/pallor, syncope, and/or anoxic     seizures.

Epidemiology:

• Occurs in children aged 6 months to 6 years, peaking at      6–18 months.
• Usually resolves by age 4–8 years.
  

Clinical Features:

• Triggers: Emotional distress,      pain, minor trauma.
• Sequence: Crying → Forced      exhalation → Breath-holding → Cyanosis (cyanotic BHS) or pallor      (pallid BHS) → Brief loss of consciousness (<1 min) → Rapid      recovery.
• Pallid BHS: Often triggered by      minor trauma and associated with bradycardia before syncope.
  

Differentiation from seizures:

  




• No postictal confusion, no       prolonged tonic-clonic movements.
• Provoked by emotional/physical stimuli, whereas seizures often occur spontaneously.
• ECG is warranted if BHS is       frequent, prolonged (>1 min), or if there is a family history of       arrhythmias.
  

Diagnosis & Management:

• Clinical diagnosis; routine      testing not required.
• Iron-deficiency anemia screening      (CBC, serum ferritin), as iron supplementation may reduce frequency.
• Reassurance is key; no special      precautions needed.
• If atypical (e.g., prolonged apnea, frequent spells), consider      EEG to rule out epilepsy or ECG for arrhythmia evaluation.
  

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ddx Psychogenic Nonepileptic Seizures (PNES)

Definition: PNES are seizure-like     episodes of psychiatric origin, which mimic epileptic seizures but     lack neurophysiological abnormalities on video EEG or neuroimaging.
Key Features Differentiating PNES from Epileptic Seizures:

• Prolonged seizure duration      (typically >2 minutes)
• Closed eyes during the episode      (vs. open eyes in true seizures)
• Unimpaired awareness (e.g.,      partially responsive or purposeful movements)
• No postictal confusion or lethargy
• Lack of typical seizure-related injuries (e.g., tongue biting, incontinence)
  

Epidemiology & Risk Factors:

• More common in women
• Strongly associated with psychiatric comorbidities,      including:
  
  
  
  
  
  • Depression, anxiety, PTSD
  • Personality disorders (e.g., borderline personality disorder)
    

Diagnosis & Management:

• Diagnosis confirmed with video EEG      (shows no epileptiform activity during events).
  
  
  
  
  • Explain the diagnosis supportively      to help the patient gain insight.
  • Refer for psychotherapy (e.g., cognitive behavioral      therapy) to address underlying psychiatric issues.
  • Antiepileptic drugs are not effective and should not be used.
    

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Breakthrough Seizure

• Definition: A seizure occurring in     a patient with epilepsy after a period of remission while on antiepileptic     drugs.
  

Common Causes:

• Missed doses of medication
• New drug interactions
  

Triggers:

  




• Alcohol consumption
• Recreational drug use
• Sleep deprivation
• Illness (e.g., infection)
  

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Status Epilepticus Management andCortical Laminar Necrosis (CLN)

First-line Treatment:

• Parenteral benzodiazepines (e.g.,      lorazepam, midazolam) are used for early status epilepticus      (seizures lasting 5-20 minutes).
• Benzodiazepines increase GABAergic transmission,      reducing neuronal excitability and aborting the seizure.
• If IV access is not possible, alternative routes (e.g.,      intramuscular, rectal, buccal, nasal) should be used.
• If initial treatment is ineffective, benzodiazepines should be      repeated every 5-10 minutes.
• Investigate and treat rapidly reversible causes of      seizures (e.g., hypoglycemia, hyponatremia, hypocalcemia).
  
• Second-line Treatment (for persistent     status epilepticus lasting 20-40 minutes):
  
  
  
  
  • Intravenous fosphenytoin, levetiracetam,      or valproate are used.
    

Refractory Status Epilepticus     (seizures lasting > 40 minutes):

• May require repetition of second-line therapy or induction      of coma (e.g., IV propofol, thiopental, midazolam, pentobarbital).
  

Cortical Laminar Necrosis (CLN):

• Status epilepticus can lead to irreversible      CNS tissue damage, including cortical laminar necrosis (CLN),      which causes permanent neurological deficits.
• CLN is associated with repeated seizures, hypoxia, and hypoglycemia.
• Symptoms vary depending on the affected cortical area and can      include motor dysfunction, vision impairment, and aphasia.
• CLN increases the risk of further seizures and cortical      damage.
• Imaging (e.g., diffusion-weighted      imaging) shows cortical hyperintensity in CLN.
  

ddx：Migraine with Aura and AlternativeDiagnosis

Migraine with Aura:

• Migraines can be accompanied by an aura, which includes      positive and negative focal neurologic symptoms (e.g., visual      disturbances, paresthesias, pareses).
• Auras develop gradually (usually >5 minutes), last      no longer than 1 hour, and are completely reversible.
• Hemiplegic migraine specifically      involves motor weakness as part of the aura.
• Prodromes (e.g., depression,      euphoria) may occur 24–48 hours before the headache, but the headache      itself is the defining feature of a migraine.
• Aura without headache (silent      migraine) is uncommon but can occur in some patients, but most hemiplegic      migraine patients have a headache with each attack
  

Differential Diagnosis:

• Migraines can cause focal neurological symptoms,      including arm weakness and speech impairments, but rarely      produce multiple simultaneous focal neurological deficits.
• Migraines do not typically involve loss of consciousness      or altered mental status, indicating the need to consider alternative      diagnoses.
  

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  Conversiondisorder is an unconscious response to psychological stress, either acuteor remote, that manifests as a neurological disorder and is distressing for thepatient.

  Possiblesymptoms include altered motor function, non-epileptic seizures, and/orweakness

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Todd Paralysis (TP) vs. Stroke/TIA

Todd Paralysis (TP)

• Definition: Transient focal     weakness following a seizure, typically resolving within 48 hours.
• Cause: Likely due to exhaustion     of the primary motor cortex.
• Duration: Lasts from a few     minutes to 36 hours.
• Common Triggers: Most often occurs     after focal seizures, with or without secondary generalization.
• Symptoms: Postictal paresis or     paralysis, potentially affecting one limb or half of the body.
  

Stroke/TIA

Key Differences:

• Persistent symptoms in stroke/TIA      vs. transient weakness in TP.
• Symptoms localize to a single vascular territory in stroke/TIA, whereas TP follows a postictal pattern.
• Muscle pain is common in TP,      but not typical in stroke/TIA.
  

Diagnosis & Imaging

• Clinical diagnosis is key but may     require imaging to rule out stroke.
  

Diffusion-weighted MRI:

• Detects ischemia within 30 minutes (useful for stroke      differentiation).
• Identifies hyperacute hemorrhage if present.
  

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Absence Seizures(petite mal)

Clinical Features:

• Brief episodes of unresponsiveness with interrupted      activity and anterograde amnesia.
• Postural tone and staring are maintained throughout the episode.
• May include subtle automatisms (e.g., lip-smacking,      eye fluttering, head nodding).
• No prodromal symptoms, postictal lethargy, or confusion.
  

Duration & Frequency:

• Typically last < 20 seconds but can occur hundreds      of times per day.
• Atypical absence seizures may last      > 30 seconds, have a more gradual onset, and allow for some      responsiveness.
  

EEG Findings:

• 3 Hz spike-and-slow-wave complexes      are characteristic of childhood absence epilepsy.
  

Key Differentiation:

• Unlike other seizures, absence seizures do not have a      postictal phase.
  

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Atonic Seizures（drop seizure）

Clinical Features:

• Sudden, transient loss of muscle tone (lasting < 2 seconds).
• May result in head nodding or drop attacks.
• No aura, postictal confusion, or lethargy.
  

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Focal Seizures with Impaired Awareness(Formerly Complex Partial Seizures)

Cause: Abnormal electrical activity     in a specific lobe of the brain, often due to structural     abnormalities (e.g., encephalitis, developmental disorders, trauma,     stroke).
Phases:

• Aura: May include gustatory      (e.g., muddy taste, temporal lobe), visual (occipital lobe), sensory      (parietal lobe), or motor (frontal lobe) disturbances.
• Ictal Phase: Impaired      awareness, staring, automatisms (e.g., facial grimacing, hand      gestures), sometimes focal motor activity.
• Postictal Phase: Confusion,      lethargy, amnesia, may vary based on lobe involvement.
  

Lobe-Specific Features:

• Temporal lobe: Gustatory aura,      déjà vu, auditory hallucinations.
• Frontal lobe: Hyperkinetic      movements, bicycling motions, rapid onset and offset.
• Parietal lobe: Sensory      disturbances (e.g., tingling, numbness).
• Occipital lobe: Visual      hallucinations, blindness, flashing lights.
  

Diagnosis:

• EEG: Focal epileptiform discharges      (location depends on seizure origin).
• MRI: To identify structural      abnormalities.
  

Treatment:

• First-line: Lamotrigine,      levetiracetam.
• Refractory cases: Surgical      intervention (especially for temporal lobe epilepsy).
  

Prognosis: Variable, but temporal     lobe epilepsy tends to have poorer seizure control, with only     ~40% achieving remission on medication alone.

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Simple Febrile Seizures

Definition & Characteristics

• Occur in children 6 months to 5 years old
• Generalized tonic-clonic seizures,      lasting <15 minutes
• Do not recur within 24 hours
• No focal neurological deficits and      rapid recovery
  

Diagnosis & Management

• No specific workup needed if fever      cause is known and neurological exam is normal
• Antipyretic therapy (NSAIDs like      ibuprofen or acetaminophen) helps symptom relief and fever reduction
• Dehydrated children with reduced      oral intake may require hospital admission for IV fluids
  

Hospital Admission Criteria

• Recurrent seizures
• Neurological abnormalities
• Failure to return to baseline after seizure
  

EEG & Further Evaluation

• EEG is not required unless the      seizure is complex or neurological exam is abnormal
  

Risk Factors

• High fever, viral infections      (e.g., HHV-6, influenza)
• Family history of febrile seizures
• Recent immunization (e.g., DTaP,      MMR)
  

Prognosis & Parental Reassurance

• Most children recover quickly and can be discharged
• Low risk of recurrence and long-term neurological      complications
  

Emergency Treatment

• Lorazepam is used to abort      prolonged (≥5 min) or repetitive febrile seizures
  

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Epilepsy
mutiple，unprovoked

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Aura
An aura in seizures occurs when the seizure activity affects a sufficient portion of the brain to produce symptoms but not enough to impair consciousness. It is often considered a focal aware seizure and may serve as a warning sign for a larger seizure.




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