Benign neonatal seizures

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Benign neonatal seizures include two disorders: self-limited (benign) neonatal seizures and self-limited (benign) familial neonatal seizures.

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Self-limited neonatal seizures

Self-limited neonatal seizures are a diagnosis of exclusion. 90% occur within the first 4-6 days of life, thus coining the term "fifth day fits". Seizures typically resolve by six weeks of life. Some suspected etiologies include rotavirus infections, de-novo (first time) mutations in genes encoding for voltage-gated potassium channels (KCNQ2, KCNQ3), and acute zinc deficiency in cerebrospinal fluid. [1]

Presentation

Most frequently the seizure is focal tonic and involves the head, face, and limbs. [1] Focal tonic seizures are defined as sustained flexion or extension of muscle groups. [2] Focal clonic seizures can also occur, which are defined as rhythmic movements of muscle groups. [2] Seizures can alternate sides and progress to bilateral tonic seizures. There may also be associated apnea in a third of patients. The duration of the seizure is typically 1-3 minutes but may evolve to status epilepticus, a medical emergency in which a seizure lasts longer than five minutes. [1] [3]

Diagnosis

The patient should be evaluated for a broad range of etiologies, including basic testing starting with a thorough history and examination, labs, blood culture, lumbar puncture, urine culture, and neuroimaging. Additional testing should be done to evaluate for congenital infections, metabolic disturbances, inborn errors of metabolism, drug withdrawal, and trauma. Given this is a diagnosis of exclusion, diagnosis should include no family history of neonatal seizures or epilepsy, appropriate APGAR score, and normal neurological exam and neuroimaging findings. [1] [3]

Treatment

Anti-seizure medications are acutely administered. Treatment includes phenobarbital, benzodiazepines, levetiracetam, and phenytoin. These medications can be given alone or in combination. [1] Additionally, phenytoin/fosphenytoin or carbamazepine (sodium channel blockers) are especially efficient for managing patients with a diagnosed channelopathy. [3] Long-term management is not required and anti-seizure medications can be stopped once beyond the six week period of recurrence risk. [1] [3]

Self-limited familial neonatal seizures

Self-limited familial neonatal seizures are autosomal dominant in inheritance and involve mutations in voltage-gated potassium channels, KCNQ2 and KCNQ3. Up to 15% of carriers may be symptomatic. [1] There may be cases of later-onset seizures or more severe epilepsy syndromes associated with a mutation in SCN2A, which encodes for voltage-gated sodium channels. [3]

Presentation/Diagnosis

Similar to non-familial neonatal seizures, familial seizures may be focal, multifocal clonic, or tonic. The key to diagnosis is a family history of similar events and a normal neurological exam. Seizures occur between a few days to a few weeks of life and resolve by 5 months of age (range 5 days to 2 years). An EEG taken between seizures is typically normal. [1] [3] Diagnostic testing is similar to that of self-limited neonatal seizures.

Treatment

Seizures respond to oxacarbazepine or carbamazepine and there has proven to be good long-term neurologic outcome. In a subset of cases, such as patients with KCKNQ2 mutations and SCN2A-associated seizures, there is a higher chance of patients needing to remain on medication. [1] [3]

Related Research Articles

<span class="mw-page-title-main">Epilepsy</span> Group of neurological disorders causing seizures

Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. An epileptic seizure is the clinical manifestation of an abnormal, excessive, and synchronized electrical discharge in the neurons. The occurrence of two or more unprovoked seizures defines epilepsy. The occurrence of just one seizure may warrant the definition in a more clinical usage where recurrence may be able to be prejudged. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain. These episodes can result in physical injuries, either directly, such as broken bones, or through causing accidents. In epilepsy, seizures tend to recur and may have no detectable underlying cause. Isolated seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to the alarming nature of their symptoms.

<span class="mw-page-title-main">Phenytoin</span> Anti-seizure medication

Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures and focal seizures, but not absence seizures. The intravenous form, fosphenytoin, is used for status epilepticus that does not improve with benzodiazepines. It may also be used for certain heart arrhythmias or neuropathic pain. It can be taken intravenously or by mouth. The intravenous form generally begins working within 30 minutes and is effective for roughly 24 hours. Blood levels can be measured to determine the proper dose.

Absence seizures are one of several kinds of generalized seizures. In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures ; however, usage of this terminology is no longer recommended. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy. Absence seizures are most common in children. They affect both sides of the brain.

<span class="mw-page-title-main">Oxcarbazepine</span> Anticonvulsant medication

Oxcarbazepine, sold under the brand name Trileptal among others, is a medication used to treat epilepsy. For epilepsy it is used for both focal seizures and generalized seizures. It has been used both alone and as add-on therapy in people with bipolar disorder who have had no success with other treatments. It is taken by mouth.

In the field of neurology, seizure types are categories of seizures defined by seizure behavior, symptoms, and diagnostic tests. The International League Against Epilepsy (ILAE) 2017 classification of seizures is the internationally recognized standard for identifying seizure types. The ILAE 2017 classification of seizures is a revision of the prior ILAE 1981 classification of seizures. Distinguishing between seizure types is important since different types of seizures may have different causes, outcomes, and treatments.

Dravet syndrome (DS), previously known as severe myoclonic epilepsy of infancy (SMEI), is an autosomal dominant genetic disorder which causes a catastrophic form of epilepsy, with prolonged seizures that are often triggered by hot temperatures or fever. It is very difficult to treat with anticonvulsant medications. It often begins before one year of age, with six months being the age that seizures, char­ac­ter­ized by prolonged convulsions and triggered by fever, usually begin.

Benign familial neonatal seizures (BFNS), also referred to as benign familial neonatal epilepsy (BFNE), is a rare autosomal dominant inherited form of seizures. This condition manifests in newborns as brief and frequent episodes of tonic-clonic seizures with asymptomatic periods in between. Characteristically, seizure activity spontaneously ends during infancy and does not affect childhood development. However, some studies have reported that a minority of children with BFNS consequently develop intellectual disability. Additionally, BFNS increases lifetime susceptibility to seizures as approximately 14% of those afflicted go on to develop epilepsy later in life. There are three known genetic causes of BFNE, two being the voltage-gated potassium channels KCNQ2 (BFNC1) and KCNQ3 (BFNC2) and the third being a chromosomal inversion (BFNC3). There is no obvious correlation between most of the known mutations and clinical variability seen in BFNE.

Juvenile myoclonic epilepsy (JME), also known as Janz syndrome or impulsive petit mal, is a form of hereditary, idiopathic generalized epilepsy, representing 5–10% of all epilepsy cases. Typically it first presents between the ages of 12 and 18 with myoclonic seizures. These events typically occur after awakening from sleep, during the evening or when sleep-deprived. JME is also characterized by generalized tonic–clonic seizures, and a minority of patients have absence seizures. It was first described by Théodore Herpin in 1857. Understanding of the genetics of JME has been rapidly evolving since the 1990s, and over 20 chromosomal loci and multiple genes have been identified. Given the genetic and clinical heterogeneity of JME some authors have suggested that it should be thought of as a spectrum disorder.

<span class="mw-page-title-main">Ring chromosome 20 syndrome</span> Medical condition

Ring chromosome 20, ring-shaped chromosome 20 or r(20) syndrome is a rare human chromosome abnormality where the two arms of chromosome 20 fuse to form a ring chromosome. The syndrome is associated with epileptic seizures, behaviour disorders and intellectual disability.

<span class="mw-page-title-main">KvLQT2</span> Protein-coding gene in humans

Kv7.2 (KvLQT2) is a voltage- and lipid-gated potassium channel protein coded for by the gene KCNQ2.

<span class="mw-page-title-main">KvLQT3</span> Protein-coding gene in the species Homo sapiens

Kv7.3 (KvLQT3) is a potassium channel protein coded for by the gene KCNQ3.

Progressive Myoclonic Epilepsies (PME) are a rare group of inherited neurodegenerative diseases characterized by myoclonus, resistance to treatment, and neurological deterioration. The cause of PME depends largely on the type of PME. Most PMEs are caused by autosomal dominant or recessive and mitochondrial mutations. The location of the mutation also affects the inheritance and treatment of PME. Diagnosing PME is difficult due to their genetic heterogeneity and the lack of a genetic mutation identified in some patients. The prognosis depends largely on the worsening symptoms and failure to respond to treatment. There is no current cure for PME and treatment focuses on managing myoclonus and seizures through antiepileptic medication (AED).

Ohtahara syndrome (OS), also known as Early Infantile Developmental & Epileptic Encephalopathy (EIDEE) is a progressive epileptic encephalopathy. The syndrome is outwardly characterized by tonic spasms and partial seizures within the first few months of life, and receives its more elaborate name from the pattern of burst activity on an electroencephalogram (EEG). It is an extremely debilitating progressive neurological disorder, involving intractable seizures and severe intellectual disabilities. No single cause has been identified, although in many cases structural brain damage is present.

SCN2A Protein-coding gene in the species Homo sapiens

Sodium channel protein type 2 subunit alpha, is a protein that in humans is encoded by the SCN2A gene. Functional sodium channels contain an ion conductive alpha subunit and one or more regulatory beta subunits. Sodium channels which contain sodium channel protein type 2 subunit alpha are sometimes called Nav1.2 channels.

<span class="mw-page-title-main">Rolandic epilepsy</span> Most common epilepsy syndrome in childhood, usually subsiding with age

Benign Rolandic epilepsy or self-limited epilepsy with centrotemporal spikes is the most common epilepsy syndrome in childhood. Most children will outgrow the syndrome, hence the label benign. The seizures, sometimes referred to as sylvian seizures, start around the central sulcus of the brain.

Sleep-related hypermotor epilepsy (SHE), previously known as nocturnal frontal lobe epilepsy, is a form of focal epilepsy characterized by seizures which arise during sleep. The seizures are most typically characterized by complex motor behaviors. It is a relatively uncommon form of epilepsy that constitutes approximately 9-13% of cases. This disorder is associated with cognitive impairment in at least half of patients as well as excessive daytime sleepiness due to poor sleep quality. This disorder is sometimes misdiagnosed as a non-epileptic sleep disorder. There are many potential causes of SHE including genetic, acquired injuries and structural abnormalities.

<span class="mw-page-title-main">Epilepsy in children</span>

Epilepsy is a neurological condition of recurrent episodes of unprovoked epileptic seizures. A seizure is an abnormal neuronal brain activity that can cause intellectual, emotional, and social consequences. Epilepsy affects children and adults of all ages and races, and is one of the most common neurological disorders of the nervous system. Epilepsy is more common among children than adults, affecting about 6 out of 1000 US children that are between the age of 0 to 5 years old. The epileptic seizures can be of different types depending on the part of the brain that was affected, seizures are classified in 2 main types partial seizure or generalized seizure.

Benign familial infantile epilepsy (BFIE) is an epilepsy syndrome. Affected children, who have no other health or developmental problems, develop seizures during infancy. These seizures have focal origin within the brain but may then spread to become generalised seizures. The seizures may occur several times a day, often grouped in clusters over one to three days followed by a gap of one to three months. Treatment with anticonvulsant drugs is not necessary but they are often prescribed and are effective at controlling the seizures. This form of epilepsy resolves after one or two years, and appears to be completely benign. The EEG of these children, between seizures, is normal. The brain appears normal on MRI scan.

An epilepsy syndrome is defined as "a characteristic cluster of clinical and Electroencephalography (EEG) features, often supported by specific etiological findings ."

A neonatal seizure is a seizure in a baby younger than age 4-weeks that is identifiable by an electrical recording of the brain. It is an occurrence of abnormal, paroxysmal, and persistent ictal rhythm with an amplitude of 2 microvolts in the electroencephalogram,. These may be manifested in form of stiffening or jerking of limbs or trunk. Sometimes random eye movements, cycling movements of legs, tonic eyeball movements, and lip-smacking movements may be observed. Alteration in heart rate, blood pressure, respiration, salivation, pupillary dilation, and other associated paroxysmal changes in the autonomic nervous system of infants may be caused due to these seizures. Often these changes are observed along with the observance of other clinical symptoms. A neonatal seizure may or may not be epileptic. Some of them may be provoked. Most neonatal seizures are due to secondary causes. With hypoxic ischemic encephalopathy being the most common cause in full term infants and intraventricular hemorrhage as the most common cause in preterm infants.

References

[1] [2] [3] [4] [5] [6]

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