Epilepsy%20(pediatric) Diagnosis

Three Levels of Diagnosing Epilepsy

• Seizure type
• Focal onset
• Generalized onset
• Unknown onset
• Unclassified
• Epilepsy type
• Focal
• Generalized
• Combined generalized and focal
• Unknown
• Epilepsy syndrome wherein specific syndromic diagnosis can be made

Seizure Description

• Pertinent details to be obtained from patient: Frequency of attacks, triggering factors, symptoms before, during and after the attacks, duration of symptoms, injury incurred and incontinence
• Pertinent details to be obtained from witness: Frequency of attacks, detailed observations before and during the attacks (eg physical symptoms, psychic symptoms and level of consciousness) and symptoms following the attacks

Investigate Triggering Factors

• Visual stimulation (eg photic stimulation), drug-induced (eg alcohol), sleep deprivation or metabolic causes (eg hyponatremia, hypoglycemia or hypocalcemia)

Seizure Types

May be self-limited type, as focal, generalized, or unknown, or continuous type, as in status epilepticus; precipitating factors should also be determined

Focal Onset

• Affects only a portion of the brain, typically involving part of 1 lobe of 1 hemisphere
• Patient awareness can be subcategorized to focal aware seizure and focal seizures with impaired awareness
  • When a patient is aware of self and his surroundings during a seizure, this is referred to as retained awareness
  • Impaired awareness is the presence of any significant impairment of awareness during a seizure episode
  • Focal aware seizure replaces the term “simple partial seizure”
  • Focal impaired awareness seizure corresponds to the prior term “complex partial seizure”
• Can also be subgrouped to with motor and nonmotor signs and symptoms
  • Motor onset seizure types include tonic, clonic, atonic, myoclonic (simple or multiple jerks, often upper limbs), hyperkinetic, epileptic spasms and automatisms
  • Nonmotor onset seizure types include autonomic, behavior arrest, cognitive, emotional and sensory
• Focal to bilateral tonic-clonic is a special type of seizure that was previously termed partial onset with secondary generalization
• Classification of seizures should be based on the earliest prominent motor onset or nonmotor onset feature

Generalized Onset

• Nearly always consciousness is lost except in myoclonic seizures and clinical features together with electroencephalographic changes indicate involvement of bilateral hemispheres of the brain at the onset of seizure
• Divided into motor and nonmotor (absence) seizures
• Further subdivisions of motor generalized-onset seizures include myoclonic, tonic, tonic-clonic, clonic, atonic (sudden loss of head posture, limbs and/or body), myoclonic-atonic, myoclonic-tonic-clonic and epileptic spasms
• Further subdivisions of nonmotor generalized-onset seizures include typical, atypical, myoclonic and eyelid myoclonia

Unknown Onset

• Onset of seizure may be missed or obscured
• Subgroup includes motor, epileptic spasms (includes infantile spasm), tonic-clonic, nonmotor and behavior arrest

Epilepsy Types

Generalized Epilepsy

• EEG shows generalized spike-wave activity
• May have a range of seizure types including absence, myoclonic, atonic, tonic, tonic-clonic seizures, and myoclonic-tonic-clonic seizures
• Idiopathic/Genetic Generalized Epilepsy
  • Well-recognized and common subgroup that encompass 4 well-established epilepsy syndromes: Childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and generalized tonic-clonic seizures alone

Focal Epilepsy

• Diagnosis is made on clinical grounds supported by EEG findings of focal epileptiform discharges
• Include unifocal and multifocal disorders as well as seizures involving one hemisphere
• Range of seizure types that can be seen include focal aware seizures, focal impaired awareness seizures, focal impaired awareness seizures, focal motor seizures, focal non-motor seizures, focal to bilateral tonic-clonic seizures

Combined Generalized and Focal Epilepsy

• Patients who have both generalized and focal seizures
• Diagnosis is made on clinical grounds supported by EEG findings of both generalized spike-wave and focal epileptiform discharges but epileptiform activity is not required for diagnosis

Unknown Epilepsy

• For patients who have epilepsy but the clinician is unable to determine if the epilepsy type is focal or generalized due to insufficient information available

• A cluster of features incorporating clinical presentation, seizure types, EEG and imaging features that present together, often supported by specific etiological findings (structural, genetic, metabolic, immune, infectious)
• Often with age-dependent features such as age at onset and remission, seizure triggers, diurnal variation and prognosis
• No correlation with an etiologic diagnosis and may only serve as a guide in therapeutic decisions

Neonatal and Infantile Period Onset Syndromes

• Self-limited epilepsy syndromes: Self-limited neonatal epilepsy, self-limited familial neonatal epilepsy, self-limited familial neonatal-infantile epilepsy, self-limited (familial) infantile epilepsy (formerly called benign familial/nonfamilial infantile seizures, genetic epilepsy with febrile seizures plus (GEFS+) spectrum, myoclonic epilepsy in infancy
• Developmental and epileptic encephalopathies (DEE): Early infantile developmental and epileptic encephalopathy, epilepsy of infancy with migrating focal seizures, infantile epileptic spasms syndrome, Dravet syndrome (previously known as severe myoclonic epilepsy of infancy), etiology-specific syndromes (eg KCNQ2-DEE, CDKL5-DEE, PCDH19 clustering epilepsy, glucose transporter 1 deficiency syndrome, pyridoxine-dependent DEE, Sturge-Weber syndrome, gelastic seizures with hypothalamic hamartoma)

Childhood Onset Syndromes

• Self-limited focal epilepsies (SeLFEs): Self-limited epilepsy with centrotemporal spikes (SeLECTS), self-limited epilepsy with autonomic seizures (SeLEAS) (formerly called Panayiotopoulos syndrome, early onset/benign occipital epilepsy), childhood occipital visual epilepsy (COVE) (formerly called late onset/benign occipital epilepsy or idiopathic childhood occipital epilepsy–Gastaut type), photosensitive occipital lobe epilepsy (POLE) (formerly called idiopathic photosensitive occipital lobe epilepsy)
• Generalized epilepsy syndromes: Childhood absence epilepsy, epilepsy with myoclonic absence, epilepsy with eyelid myoclonia (previously known as Jeavons syndrome)
• Developmental and/or epileptic encephalopathies: Epilepsy with myoclonic-atonic seizures (formerly known as Doose syndrome), Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, febrile infection-related epilepsy syndrome (FIRES) (previously also known as acute encephalitis with refractory, repetitive partial seizures, or devastating epileptic encephalopathy in school-aged children)

Epilepsy Syndromes Presenting at Variable Age

• Generalized epilepsy syndromes, with polygenic etiologies: Idiopathic generalized epilepsies (juvenile absence epilepsy, juvenile myoclonic epilepsy, epilepsy with generalized tonic-clonic seizures alone)
• Self-limited focal epilepsy syndromes with presumed complex inheritance: COVE, POLE
• Focal epilepsy syndromes with genetic, structural, or genetic-structural etiologies: Sleep-related hypermotor (hyperkinetic) epilepsy, familial mesial temporal lobe epilepsy, familial focal epilepsy with variable foci, epilepsy with auditory features
• A combined generalized and focal epilepsy syndrome with polygenic etiology: Epilepsy with reading-induced seizures
• Epilepsy syndromes with developmental encephalopathy, epileptic encephalopathy, or both, and epilepsy syndromes with progressive neurological deterioration: Progressive myoclonus epilepsies and FIRES

• Should include but is not limited to: Age of onset, family history, social history, alcohol and drug use, and past medical history including head injury, febrile convulsions, diseases in other organ systems
• A clear history from the parent of the patient and an eyewitness to the attack is the most important diagnostic information and should be the mainstay of diagnosis

• Detect signs of disorder associated with epilepsy (eg sign of head trauma, ear or sinus infection, congenital abnormalities, focal or diffuse neurologic abnormalities, diseases in other organ systems)

• This condition may cause neurobiologic, cognitive, psychological and social disturbances
• It is recommended that all patients having a first seizure be referred to a specialist as soon as possible
• Diagnosis of epilepsy should be made by a pediatric neurologist or a child physician with expertise in childhood epilepsy

• Blood glucose level
• Creatinine and electrolytes
• Liver function tests (LFTs)
• Serum Ca and Mg levels
• Serum prolactin (PRL) level
  • Obtained at 10-20 minutes after a suspected seizure may differentiate generalized tonic-clonic seizures or complex partial seizures from psychogenic non-epileptic seizures among older children
  • Serum PRL determined more than 6 hours after a suspected seizure should represent the baseline PRL level

Electroencephalography (EEG)

• Presence of abnormal electric activity
• Location of seizure focus
• Type of seizure disorder
• Must be performed only after clinical evaluation by an expert in epileptic disorders
• Limitations

• Abnormalities are common in migraine patients and patients with psychotic illness, psychotropic medication
• Abnormal EEG should therefore not be interpreted as confirming a diagnosis of epilepsy
• May be normal in a number of epileptic patients
• A normal result should not be interpreted as excluding a diagnosis of epilepsy
• Should be performed in all children with recurrent epileptic seizure
• A repeat EEG and a sleep EEG should be done in children with recurrent epileptic seizures and normal standard EEG
• An ictal EEG should be performed when diagnosis is uncertain

• In children, an initial work up of presumed ‘idiopathic generalized epilepsy’ syndrome should include an EEG
• Consider video EEG for refractory epilepsy with “normal EEG”

Brain Imaging

• Computed tomography (CT) scan, magnetic resonance imaging (MRI)
  • MRI is brain imaging of choice in patients with epilepsy
  • CT may be used if urgent assessment of seizures is necessary or MRI is contraindicated

Recommended Diagnostic Testing in Patients <25 Years Old

• EEG should be performed to assist in classification of seizures and epilepsy
• Most children with epilepsy should have an elective MRI scan
• Brain imaging is not required if firm diagnosis of ‘idiopathic generalized epilepsy syndrome’ is made based on clinical history and EEG, there is complete and rapid response to 1st-line anticonvulsant medication
• If firm diagnosis of ‘idiopathic generalized epilepsy syndrome’ is not made, both EEG and brain imaging are necessary