Febrile seizure
| Classification according to ICD-10 | |
|---|---|
| R56.0 | Febrile seizures |
| ICD-10 online (WHO version 2019) | |
A febrile seizure , formerly also known as a child's cramp, is an epileptic seizure that occurs in early childhood in connection with a febrile illness . As a typical occasional seizure, it is the most common form of an epileptic seizure in childhood. Inexperienced relatives almost always perceive it as a life-threatening event. Anticonvulsant medication can be administered for acute treatment of such a seizure . A long-term prophylaxis is not effective.
Frequency and age
It affects 2–5 percent of all children in Europe and North America, 5–10 percent in India and 6–9 percent in Japan. This usually occurs in the second year of life, a frequency can also be observed from five months and up to the age of four years. The peak age of occurrence is between the 14th and 18th month of life. Febrile seizures are very rare before the 7th month and after the 5th year of life. Due to the age distribution, a connection with the brain structure of children of the corresponding age is obvious; however, it is not known why not all children experience febrile seizures. The children's brain structures responsible for a febrile seizure are also still unknown.
causes
In order to meet the definition of the International League Against Epilepsy ( ILAE), it must not be caused by an infection of the brain , it should not have been preceded by any unprovoked seizures and there should not be any other disorder of the brain that causes an attack. The exact causes of febrile seizures are not known. In addition to fever as a necessary prerequisite, they are closely linked to a certain age, i.e. a special developmental phase of the brain and, in the case of a conspicuous familial accumulation ( predisposition ), also to a genetic predisposition.
infection
In principle, febrile seizures can occur with any infection outside the brain. However, viral infections, including those caused by human herpes virus 6 , the causative agent of three-day fever , are much more common than bacterial diseases. This suggests that pathogen-specific properties also favor the occurrence of fever-related seizures. A vaccination reaction , in particular fever after vaccinations against whooping cough and measles (e.g. six-fold vaccine ), can be accompanied by a febrile seizure.
genetics
The predisposed or familial occurrence of febrile convulsions is summarized under the designation familial fever-related convulsions (English familial febrile convulsions ; abbreviation FEB ). In families with an increased incidence of febrile seizures, six FEB loci ( gene locations ) that are associated with the promotion of febrile seizures have been identified on chromosome segments 8q13-q21 (FEB1), 19p (FEB2), 2q (FEB3), 5q (FEB4), 6q (FEB5) and 18p (FEB6). In addition, familial diseases are known in which generalized epilepsy occurs after a febrile seizure in childhood (up to 6 years of age) . This form is known as generalized epilepsy with febrile convulsions plus ( GEFS + ). Several genes are probably responsible for this form of febrile seizures that often occur in families . The mode of inheritance ( inheritance ) has not been fully clarified. The current data situation speaks for most familial febrile seizures for an autosomal - dominant inheritance with reduced penetrance .
Neurophysiological background
According to the current state of knowledge, the GABA-A receptor has a temperature-sensitive subunit, whereby an increase in temperature leads to a disruption of the GABAergic-inhibiting transmission. In the brain, GABA plays a central role in inhibiting and dampening neuronal excitations. It is therefore easy to understand that a blockage of precisely these transmitter- receptor systems caused by hyperthermia leads to a general hyperexcitability and tendency to seizures. On the other hand, it is known that endogenous pyrogens themselves can lower the brain's seizure threshold. These are, for example, tumor necrosis factor -alpha, interleukin-1 beta and interleukin-6 , which lead to fever by stimulating cyclooxygenase-2 with a subsequent increase in prostaglandin E2 . A lower fever only inhibits cyclooxygenase-2, but not the release of these pyrogens. However, an increased temperature itself can inhibit the release of these pyrogens. This can also explain why lowering the fever does not prevent febrile seizures.
Symptoms and clinical forms
A febrile seizure typically occurs when the body temperature rises rapidly from 39 ° C or higher and usually occurs as a generalized tonic-clonic seizure over the entire body. It begins with a sudden loss of consciousness , followed by contraction of all muscles ( tonic stiffening). Regular ( clonic ) convulsions follow after 10–30 seconds . The tonic phase may be absent, and there may also be atonic seizures, in which the muscles lose their tension and the children are completely flaccid. A febrile seizure usually lasts a few minutes (up to about 10). Most of the time, a period of drowsiness follows the seizure ( postictal drowsiness).
Uncomplicated (simple) febrile seizure
An uncomplicated or simple febrile seizure occurs when a generalized seizure occurs in a febrile child that lasts less than 15 minutes, does not recur within 24 hours and offers no indication of the beginning only in a circumscribed brain region (focal point). Furthermore, the affected child must not have previously had a seizure without a fever. Children with a history of simple febrile seizures have only a slightly higher risk of developing epilepsy later than their unaffected peers (see section on prognosis ).
Complicated (atypical) febrile seizure
A complicated or atypical febrile seizure is present if it is focal-shaped (focal-like means: the attack does not go out of consciousness from the beginning, only parts of the body are affected), if it lasts for more than 15 minutes, or if the febrile seizure resolves within 24 hours or repeated in the same episode of fever. After a complicated febrile seizure, the risk of developing epilepsy later is slightly higher.
Diagnosis and differential diagnosis
The diagnosis of febrile seizure can usually be made by a careful review of the medical history and physical examination . It can be difficult to distinguish it from seizure-like events from other causes, such as a circulatory fainting , reflex syncope or just chills . Inflammatory diseases of the brain or meninges ( encephalitis , meningitis ) must be excluded from the differential diagnosis. If there is the slightest suspicion, an examination of the cerebral fluid obtained by means of a lumbar puncture is necessary. However, if there are no other signs of meningitis, a febrile seizure does not automatically entitle you to such an examination. Imaging methods such as computed tomography and magnetic resonance tomography are used in particular for clinical signs of encephalitis or to rule out abscesses , malformations and brain tumors . Other causes for the occurrence of a seizure ( hypoglycemia , derailment in the mineral balance) in the context of a febrile illness or poisoning must also be excluded and the cause of the fever determined. A comprehensive survey of the neurological status is intended to reveal underlying abnormalities in the nervous system. The electroencephalogram (EEG) is unnecessary for the first uncomplicated febrile seizure. After repeated, complicated febrile convulsions, it can provide clues to the presence of a form of epilepsy of the brain.
therapy
Treatment of acute febrile convulsions
90% of all uncomplicated febrile seizures end on their own within minutes. The treatment of acute febrile convulsions is otherwise essentially based on the treatment of an epileptic seizure. In contrast to this, due to the “benign nature” of most febrile seizures, an emphasis on security and the wait-and-see attitude is even more evident. Pointed, sharp or angular objects should be removed immediately from the vicinity of a child with ongoing febrile seizures to minimize the risk of injury. Breathing should be observed, although blue discoloration of the skin ( cyanosis ) is not uncommon. A reduction in the number of breaths per minute is also not uncommon and can give the observer (mostly parents) the impression that breathing has stopped. Therefore, it is particularly important to remain level-headed.
If a febrile seizure lasts from 10 to a maximum of 15 minutes or if breathing stops permanently, the febrile seizure must be interrupted. If there is a prolonged, atypical or complicated febrile seizure (focal signs), diazepam to be administered rectally (as an enema) can be used for this purpose . If a previous febrile seizure was particularly severe or atypical, it can also be used to prevent the development of an atypical or severe seizure. In addition to diazepam, other short-acting antiepileptic drugs such as clonazepam , chloral hydrate or the sedative midazolam are also effective .
Prophylaxis of febrile seizures
Since fever is a prerequisite for the occurrence of febrile convulsions, one should be entitled to believe that fever-lowering measures also have a preventive effect - but various clinical studies provide no proof of this. Antipyretic drugs ( antipyretics ) should therefore not be prescribed to prevent new attacks, but rather to alleviate general symptoms caused by fever such as fatigue, accelerated pulse and accelerated breathing.
Another way to prevent febrile convulsions from recurring is to give the anticonvulsant diazepam orally . Its effectiveness in preventing febrile seizures is controversial, but there is general agreement that it is likely to be effective. When a febrile episode begins, diazepam is administered for a maximum of two days. The side effects can be barely noticeable, but can also be very pronounced: tiredness, drowsiness, balance disorders, confusion and easy excitability are possible. Routine prophylaxis in all children with febrile seizures is therefore not indicated. Rather, the potential benefits must be carefully weighed against the existing risks. Another disadvantage of the prophylactic administration of diazepam in episodes of fever is that it could mask neurological warning symptoms of an underlying cerebral disease.
The long-term administration of anti- convulsive drugs ( anticonvulsants ) has shown in recent studies no effectiveness in preventing recurrent febrile seizures. This has long been recognized for carbamazepine and phenytoin , but is now equally valid for phenobarbital , which should only be used very critically because of the impairment of mental abilities, and valproate . Therefore it is no longer listed in the corresponding recommendation of the American Academy of Paediatrics.
forecast
The overall prognosis for febrile seizures is very good. Population-based studies could neither show an increased mortality nor the increased occurrence of damage to the nervous system in the form of paralysis, mental impairment or memory disorders. There also seems to be no connection between febrile seizures and sudden infant death syndrome .
Of all children with febrile seizures, around a third develop a febrile seizure again later - in around two thirds of all children it remains a one-off event. The greatest risk factor for a relapse is the age at the first event: the younger the child is, the more likely it is to have a second febrile seizure. The occurrence of febrile convulsions in relatives (positive family history) also increases the likelihood of a relapse. Other risk factors are a low body temperature at the first event and multiple seizures in the same fever episode. More than half of all recurrences occur in the first year and more than 90% occur within the first two years after the first event. If two years have passed without an attack after the first febrile seizure, a relapse is therefore considered to be very unlikely. Febrile seizures and recurrent febrile seizures usually occur during the first two days of a febrile episode and no longer if it has lasted for a longer period of time.
The risk of developing epilepsy after a febrile seizure is slightly higher than that of the rest of the population, at 2–4%. A slightly higher percentage of children suffer another epileptic seizure after a febrile seizure without a fever, without resulting in epilepsy. In contrast to the risk factors for repeated febrile seizures, the likelihood of epilepsy increases with a positive family history of epilepsy, with complicated febrile seizures and when there was previously delayed development of motor and mental abilities. Without these risk factors, epilepsy occurs in 1% of children with febrile seizures, with one risk factor it increases to 2%, and with two or all three factors it increases to up to 10%. One of the most controversial questions regarding epilepsy is the connection between febrile seizures and symptomatic temporal lobe epilepsy . Today's view is most likely to assume that prolonged febrile convulsions and the later development of temporal lobe epilepsy are related to pre-existing damage to the temporal lobe and that the febrile convulsions are not the cause of the lesions .
reception
In Zola's A Leaf of Love , the character Lucien Deberle has febrile seizures.
Individual evidence
- ↑ A. Müller, RW Schlecht, Alexander Früh, H. Still The way to health: A faithful and indispensable guide for the healthy and the sick. 2 volumes, (1901; 3rd edition 1906, 9th edition 1921) 31st to 44th edition. CA Weller, Berlin 1929 to 1931, Volume 2 (1929), pp. 53-55: The child cramps (Fraisen or Gichten) .
- ↑ a b c d e f g h i C. Waruiru, R. Appleton: Febrile seizures: an update In: Arch Dis Child 2004; 89: 751-756 PMID 15269077
- ↑ Peter-Johannes Selg: Risk factor analysis for febrile seizures - retrospective data analysis of a case series. (Dissertation, p. 14)
- ↑ a b c d Hartmut Siemes, Blaise FD Bourgeois: Seizures and epilepsies in children and adolescents. Thieme, Stuttgart-New York 2001, ISBN 3-13-127031-4 .
- ^ Suga et al .: Clinical characteristics of febrile convulsions during primary HHV-6 infection . In: Arch Dis Child 2000; 82: 62-66, PMID 10630916 .
- ↑ M. Mantegazza et al .: Identification of an Nav1.1 sodium channel (SCN1A) loss-of-function mutation associated with familial simple febrile seizures. In: Proc Natl Acad Sc USA. 2005; 102: 18177-18182 PMID 16326807 , full text online
- ↑ Generalized Epilepsy with Febrile Seizures plus; GEFS +. In: Online Mendelian Inheritance in Man . (English).
- ↑ JQ Kang et al .: Why does fever trigger febrile seizures? GABAA receptor gamma2 subunit mutations associated with idiopathic generalized epilepsies have temperature-dependent trafficking deficiencies. In: J Neuroscience 2006; 26: 2590-2597
- ↑ MA Galic, K. Riazi, QJ Pittman: Cytokines and brain excitability. In: Frontiers in neuroendocrinology. Volume 33, number 1, January 2012, pp. 116-125, doi: 10.1016 / j.yfrne.2011.12.002 , PMID 22214786 , PMC 3547977 (free full text) (review).
- ↑ Koncar-Zeh, J. (2005): “The influence of hyperthermia on the intracellular expression of proinflammatory cytokines in human monocytes” . Dissertation 2005.
- ^ AS El-Rhadi, W. Barry: Do antipyretics prevent febrile convulsions? In: Arch Dis Child. 2003; 88: 641-642 PMID 12818921
- ↑ Strengell, T. et al. (2009): "Antipyretic Agents for Preventing Recurrence of Febrile Seizures - Randomized Controlled Trial" . Arch Pediatr Adolesc Med 163 (9): 799-804. PMID 19736332
- ↑ From Emile Zola Ein Blatt Liebe , 1877
Web links
- Fever - kindergesundheit-info.de: independent information service of the Federal Center for Health Education (BZgA)
