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The mortality rate ranges from 3–7% in a mean follow up period of 8.5 to 9.7 years. Death is often related to accidents.
Panayiotopoulos syndrome probably affects 13% of children aged 3 to 6 years who have had 1 or more afebrile seizures and 6% of such children in the 1- to 15-year age group. All races and both sexes are affected.
Panayiotopoulos syndrome is remarkably benign in terms of its evolution. The risk of developing epilepsy in adult life is probably no more than of the general population. Most patients have one or 2-5 seizures. Only a third of patients may have more than 5 seizures, and these may be frequent, but outcome is again favorable. However, one fifth of patients may develop other types of infrequent, usually rolandic seizures during childhood and early teens. These are also age-related and remit before the age of 16 years. Atypical evolutions with absences and drop attacks are exceptional. Children with pre-existing neurobehavioral disorders tend to be pharmacoresistant and have frequent seizures though these also remit with age.
Formal neuropsychological assessment of children with Panayiotopoulos syndrome showed that these children have normal IQ and they are not on any significant risk of developing cognitive and behavioural aberrations, which when they occur they are usually mild and reversible. Prognosis of cognitive function is good even for patients with atypical evolutions.
However, though Panayiotopoulos syndrome is benign in terms of its evolution, autonomic seizures are potentially life-threatening in the rare context of cardiorespiratory arrest.
Consistent risk factors include:
- Severity of seizures, increased refractoriness of epilepsy and presence of generalized tonic-clonic seizures: the most consistent risk factor is an increased frequency of tonic–clonic seizures.
- Poor compliance. Lack of therapeutic levels of anti-epileptic drugs, non-adherence to treatment regimens, and frequent changes in regimens are risk factors for sudden death.
- Young age, and early age of seizures onset.
- Male gender
- Poly-therapy of epilepsy. It remains unclear whether this is an independent risk factor or a surrogate marker for severity of epilepsy.
- Being asleep during a seizure is likely to favour SUDEP occurrence.
LGS is seen in approximately 4% of children with epilepsy, and is more common in males than in females. Usual onset is between the ages of three and five. Children can have no neurological problems prior diagnosis, or have other forms of epilepsy. West syndrome is diagnosed in 20% of patients before it evolves into LGS at about 2 years old.
The cause of FIRES is not known. It does not happen twice in the same family, but the medical community does not know if it is genetic. It happens in boys more than girls. After the initial status, life expectancy is not affected directly. Issues such as overdose of medications or infections at a food tube site are examples of things that would be secondary to the status.
Dravet syndrome is a severe form of epilepsy. It is a rare genetic disorder that affects an estimated 1 in every 20,000–40,000 births.
Following a first seizure, the risk of more seizures in the next two years is 40%–50%. The greatest predictors of more seizures are problems either on the electroencephalogram or on imaging of the brain. In adults, after 6 months of being seizure-free after a first seizure, the risk of a subsequent seizure in the next year is less than 20% regardless of treatment. Up to 7% of seizures that present to the emergency department (ER) are in status epilepticus. In those with a status epilepticus, mortality is between 10% and 40%. Those who have a seizure that is provoked (occurring close in time to an acute brain event or toxic exposure) have a low risk of re-occurrence, but have a higher risk of death compared to those with epilepsy.
Both medication and drug overdoses can result in seizures, as may certain medication and drug withdrawal. Common drugs involved include: antidepressants, antipsychotics, cocaine, insulin, and the local anaesthetic lidocaine. Difficulties with withdrawal seizures commonly occurs after prolonged alcohol or sedative use, a condition known as delirium tremens.
The lack of generally recognized clinical recommendations available are a reflection of the dearth of data on the effectiveness of any particular clinical strategy, but on the basis of present evidence, the following may be relevant:
- Epileptic seizure control with the appropriate use of medication and lifestyle counseling is the focus of prevention.
- Reduction of stress, participation in physical exercises, and night supervision might minimize the risk of SUDEP.
- Knowledge of how to perform the appropriate first-aid responses to seizure by persons who live with epileptic people may prevent death.
- People associated with arrhythmias during seizures should be submitted to extensive cardiac investigation with a view to determining the indication for on-demand cardiac pacing.
- Successful epilepsy surgery may reduce the risk of SUDEP, but this depends on the outcome in terms of seizure control.
- The use of anti suffocation pillows have been advocated by some practitioners to improve respiration while sleeping, but their effectiveness remain unproven because experimental studies are lacking.
- Providing information to individuals and relatives about SUDEP is beneficial.
West syndrome is a triad of developmental delay, seizures termed infantile spasms, and EEG demonstrating a pattern termed hypsarrhythmia. Onset occurs between three months and two years, with peak onset between eight and 9 months. West syndrome may arise from idiopathic, symptomatic, or cryptogenic causes. The most common cause is tuberous sclerosis. The prognosis varies with the underlying cause. In general, most surviving patients remain with significant cognitive impairment and continuing seizures and may evolve to another eponymic syndrome, Lennox-Gastaut syndrome. It can be classified as idiopathic, syndromic, or cryptogenic depending on cause and can arise from both focal or generalized epileptic lesions.
Epilepsy with myoclonic-astatic seizures has a variable course and outcome. Spontaneous remission with normal development has been observed in a few untreated cases. Complete seizure control can be achieved in about half of the cases with antiepileptic drug treatment (Doose and Baier 1987b; Dulac et al. 1990). In the remainder of cases, the level of intelligence deteriorates and the children become severely intellectually disabled. Other neurologic abnormalities such as ataxia, poor motor function, dysarthria, and poor language development may emerge (Doose 1992b). However, this proportion may not be representative because in this series the data were collected in an institution for children with severe epilepsy.
The outcome is unfavorable if generalized tonic-clonic, tonic, or clonic seizures appear at the onset or occur frequently during the course. Generalized tonic-clonic seizures usually occur during the daytime in this disorder, at least in the early stages. Nocturnal generalized tonic-clonic seizures, which may develop later, are another unfavorable sign. If tonic seizures appear, prognosis is poor.
Status epilepticus with myoclonic, astatic, myoclonic-astatic, or absence seizures is another ominous sign, especially when prolonged or appearing early.
Failure to suppress the EEG abnormalities (4- to 7-Hz rhythms and spike-wave discharges) during therapy and absence of occipital alpha-rhythm with therapy also suggest a poor prognosis (Doose 1992a).
Epilepsy is a relatively common disorder, affecting between 0.5-1% of the population, and frontal lobe epilepsy accounts for about 1-2% of all epilepsies. The most common subdivision of epilepsy is symptomatic partial epilepsy, which causes simple partial seizures, and can be further divided into temporal and frontal lobe epilepsy. Although the exact number of cases of frontal lobe epilepsy is not currently known, it is known that FLE is the less common type of partial epilepsy, accounting for 20-30% of operative procedures involving intractable epilepsy. The disorder also has no gender or age bias, affecting males and females of all ages. In a recent study, the mean subject age with frontal lobe epilepsy was 28.5 years old, and the average age of epilepsy onset for left frontal epilepsy was 9.3 years old whereas for right frontal epilepsy it was 11.1 years old.
Temporal lobe epilepsy (TLE) is not a classic syndrome but mentioned here because it is the most common epilepsy of adults. It is a symptomatic localization-related epilepsy and in most cases the epileptogenic region is found in the midline (mesial) temporal structures (e.g., the hippocampus, amygdala, and parahippocampal gyrus). Seizures begin in late childhood and adolescence. Most of these patients have focal seizures sometimes preceded by an aura, and some TLE patients also have secondary generalized tonic-clonic seizures. Often seizures do not sufficiently respond to medical treatment with anticonvulsants and epilepsy surgery may be considered.
Between 10 and 30% of people who have status epilepticus die within 30 days. The great majority of these people have an underlying brain condition causing their status seizure such as brain tumor, brain infection, brain trauma, or stroke. However, people with diagnosed epilepsy who have a status seizure also have an increased risk of death if their condition is not stabilized quickly, their medication and sleep regimen adapted and adhered to, and stress and other stimulant (seizure trigger) levels controlled.
However, with optimal neurological care, adherence to the medication regimen, and a good prognosis (no other underlying uncontrolled brain or other organic disease), the person—even people who have been diagnosed with epilepsy—in otherwise good health can survive with minimal or no brain damage, and can decrease risk of death and even avoid future seizures.
No single cause of OS has been identified. In most cases, there is severe atrophy of both hemispheres of the brain. Less often, the root of the disorder is an underlying metabolic syndrome. Although it was initially published that no genetic connection had been established, several genes have since associated with Ohtahara syndrome. It can be associated with mutations in "ARX", "CDKL5", "SLC25A22", "STXBP1", "SPTAN1", "KCNQ2", "ARHGEF9", "PCDH19", "PNKP", "SCN2A", "PLCB1", "SCN8A", and likely others.
Treatment outlook is poor. Anticonvulsant drugs and glucocorticoid steroids may be used to try to control the seizures, but their effectiveness is limited. Most therapies are related to symptoms and day-to-day living.
In the United States, about 40 cases of SE occur annually per 100,000 people. This includes about 10–20% of all first seizures.
Most generalized epilepsy starts during childhood. While some patients outgrow their epilepsy during adolescence and no longer need medication, in others, the condition remains for life, thereby requiring lifelong medication and monitoring.
Although the theory is controversial, there is a link between febrile seizures (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy, at least epidemiologically.
Possible causes include:
- Syncope (fainting)
- Reflex anoxic seizures
- Breath-holding spells of childhood
- Hypoglycaemia
- Cataplexy
- Hyperekplexia, also called startle syndrome
- Migraine
- Narcolepsy
- Non-epileptic myoclonus
- Opsoclonus
- Parasomnias, including night terrors
- Paroxysmal kinesigenic dyskinesia
- Repetitive or ritualistic behaviours
- Tics
- AADC Deficiency
In Europe the ketogenic diet is the diet that is most commonly recommended by doctors for patients with epilepsy. In this diet the ratio of fat to carbohydrates and proteins is 4:1. That means that the fat content of the consumed food must be around 80%, the protein content must be around 15%, and the carbohydrate content must be around 5%. For comparison the average western diet consists of a carbohydrate content of over 50%. After one year on the ketogenic diet the success rate (seizure reduction over 50%) is between 30 and 50% and the dropout rate is around 45%. Although the ketogenic diet can be very effective some families report that it's not compatible with daily life on the long run because it's too restrictive as bread pasta and sweets are forbidden in the ketogenic diet. In puberty with increasing autonomy it can be difficult for adolescents to follow the diet strictly. For this reason a fat ratio of 3: 1 instead of 4: 1 can be recommended to make meals more palatable. Side effects of the ketogenic diet can be constipation, tiredness and after a long term diet, in one out of 20 patients, kidney stones.
Deep brain stimulation of the anterior nuclei of the thalamus is approved for DRE in some countries in Europe, but has been and continues to only be used in a very few patients. After 5 years of DBS a seizure reduction of 69% and a 50%-responder rate of 68% was reported in a randomized-double blinded trial. The rate of serious device related events was 34% in this study.
Responsive neurostimulation (RNS) is approved for DRE in the USA and involves stimulation directly to 1 or 2 seizure foci when abnormal electrocorticographic activity is detected by the devices software. After 2 years of RNS a seizure reduction of 53% was reported in a randomized-double blinded trial as well as a rate of serious device related events of 2.5%.
Transcutaneous vagus nerve stimulation (tVNS) is approved for DRE in some European countries and involves externally stimulating the auricular branch of the vagus nerve in the ear. tVNS failed to demonstrate efficacy in a first randomized-double blinded trial: responder rates did not differ between active and control groups potentially indicating a placebo effect behind the 34% seizure reduction seen in the patients who completed the full follow-up period.
The causes of TLE include mesial temporal sclerosis, traumatic brain injury, brain infections, such as encephalitis and meningitis, hypoxic brain injury, stroke, cerebral tumours, and genetic syndromes. Temporal lobe epilepsy is not the result of psychiatric illness or fragility of the personality.
Generalized seizures can be either absence seizures, myoclonic seizures, clonic seizures, tonic-clonic seizures or atonic seizures.
Generalized seizures occur in various seizure syndromes, including myoclonic epilepsy, familial neonatal convulsions, childhood absence epilepsy, absence epilepsy, infantile spasms (West's syndrome), Juvenile Myoclonic Epilepsy and Lennox-Gastaut syndrome.
Ohtahara syndrome (OS), also known as early infantile epileptic encephalopathy with burst-suppression (EIEE), is a progressive epileptic encephalopathy. The syndrome is outwardly characterized by tonic spasms and partial seizures, 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 mental retardation. No single cause has been identified, although in many cases structural brain damage is present.