Panayiotopoulos syndrome (PS) is a childhood-related idiopathic benign susceptibility to focal, mainly autonomic, seizures and autonomic status epilepticus.Affected children have normal physical and neuropsychological development. Autonomic manifestations are the cardinal seizure symptoms in PS, and have immense pathophysiological, clinical and treatment implications. All functions of the autonomic system may be affected during the ictus. Nearly half of these seizures last between 30 min and 7 hours, and constitute autonomic status epilepticus.
Demographic Data
Age at onset is 1–14 years with a peak at 4–5 years; in 76% of cases, onset occurs at 3–6 years of age. Boys and girls are equally affected.4Children of all races are vulnerable. Prevalence is around 13% in children 3–6 years old with one or more non-febrile seizures and 6% in the 1–15-year age group. In the general population, 2–3/1000 children may be affected. These figures may be higher if cases that are currently considered to have atypical features are included.
Clinical Manifestations
Seizures comprise an unusual constellation of autonomic, mainly emetic, symptoms, behavioural changes, unilateral deviation of the eyes and other more conventional ictal manifestations.Consciousness and speech, as a rule, are preserved at seizure onset. The seizure commonly starts with autonomic manifestations (81%), which are mainly emetic (72%). In a typical presentation, the child is fully conscious, able to speak and understand, complains “I feel sick”, looks pale and vomits.
He complained of nausea and he looked pale. Five min later he vomited while still standing… He gradually became disorientated, but was still able to walk. However, 10 min from onset his eyes turned to the right and he became unresponsive.
Ictus Emeticus
The full emetic triad (nausea, retching, vomiting) culminates in vomiting in 74% of seizures; in others, only nausea or retching occur and, in a few cases, emesis may not be apparent. Emesis is usually the first apparent ictal symptom, but may also occur long after the onset of other manifestations.
Panayiotopoulos syndrome has been recognised in the new diagnostic scheme as: “Early onset benign childhood occipital epilepsy (Panayiotopoulos type)”. However, PS is not “occipital” epilepsy:
(a). Onset is with autonomic manifestations, which are unlikely to be of occipital origin. Of all the other seizure symptoms, only eye deviation, which is often not the first ictal symptom, may originate from the occipital lobes.
(b). Interictal occipital spikes may never occur.
(c). Even ictal EEG has documented anterior or posterior origin.
Currently, most authors prefer the eponymic nomenclature “Panayiotopoulos syndrome” to include all patients with this syndrome irrespective of EEG spikes or topographic terminology4;14;76;77;79–82;84 as in the original study of Panayiotopoulos.70
In that study of 900 seizure-patients of all ages, only 24 had ictal vomiting and all of these were children.70 Of these 24 children with ictal vomiting:
(a). 21 had normal development with EEG occipital spikes (12 patients), extra-occipital spikes (5 patients), brief generalised discharges (1 patient) or normal EEG (3 patients)
(b). 3 had an abnormal neurological state (symptomatic childhood autonomic epilepsy).
Of the 21 idiopathic patients (which constitutes what is now known as Panayiotopoulos syndrome), attention was directed towards the predominant group of occipital spikes and occipital paroxysms (hence the name“occipital epilepsy” or“epilepsy with occipital paroxysms”).85 The fact that the other 9 patients without occipital spikes had the same disorder with those of occipital spikes was documented much later.86 The terms “early onset” and “late onset” have been used adjunctively with “childhood occipital epilepsy” or “epilepsy with occipital paroxysms” in order to discriminate between PS (with median age of onset in early childhood) and G-ICOE (with median age of onset in late childhood). It should be clarified that these terms (“early onset” and “late onset”) were first introduced at a time that G-ICOE was the only recognised syndrome associated with “occipital paroxysms”85 and prior to the documentation that PS manifests with multi-focal EEG spikes with one-third not having occipital spikes. For those few that they may disapprovecertain eponyms (see for example reference87) the most precise descriptive term I can propose for PS is “benign childhood autonomic seizures and autonomic status epilepticus” and not “early onset benign childhood epilepsy with occipital spikes”.
Typically, nausea is the first complaint of a child who suffers a seizure (while awake or who wakes from sleep) prior to vomiting and other ictal manifestations. This initial stage does not suggest an epileptic seizure; the child simply complains of feeling sick and being unwell, and looks pale. The patient may be quiet or agitated, vacant or restless but fully conscious and able to understand and answer questions. Ictus emeticus at this stage is no different from any other disease that causes emesis – just a child who feels sick or wants to be sick.
On returning home from school, she looked tired and had a nap. After half an hour, she woke up looking pale and complained of feeling sick. She ran to the toilet and vomited repeatedly. Then her eyes deviated to one side and she became unresponsive and flaccid for 10 min. Soon after, she started recovering, answering simple questions and 1 hour later she was playing again as if nothing had happened.
Timing of the Vomiting
When vomiting occurs, it commonly starts 1–5 min after the onset of nausea, while the child is still conscious and otherwise well. Less often, vomiting may occur later during other more conventional seizure symptoms.
Intensity and Duration of Vomiting
This varies considerably from mild to often severe and repetitive. Usually, the child vomits 3–5 times; however, some children may repeatedly vomit for hours leading to dehydration, while others may vomit only once.
Other Autonomic Manifestations
Autonomic manifestations other than ictus emeticus may occur concurrently or appear later in the course of the ictus. These include pallor and less often flushing or cyanosis, mydriasis and less often miosis, cardiorespiratory and thermoregulatory alterations, coughing, incontinence of urine and/or faeces, and modifications of intestinal motility. Hypersalivation (probably a concurrent Rolandic symptom) may occur. Headache and more often cephalic auras may occur particularly at onset.
Pallor is one of the commonest ictal manifestations. It mainly occurs at onset, usually with emetic symptoms. Exceptionally, pallor may be among the first symptoms without apparent emesis.
Cyanosis is less common than pallor. It principally occurs during the evolution of the seizures, often while the child is unresponsive.
Incontinence of urine and faeces occur when consciousness is impaired prior to, or without, convulsions: “became unresponsive and incontinent of urine” is a common association. These symptoms do not occur at onset.
Autonomic auras consist of a subjective awareness of a change in the activity of autonomic nervous system function.88
Autonomic seizures consist of episodic altered autonomic function of any type at onset or as the sole manifestation of an epileptic event. These may be objective, subjective or both. They must be distinguished from secondary (indirect effects) on the autonomic system by other seizure symptoms.89
Pure autonomic seizures are those that consist solely of episodic altered autonomic function from onset to the end.
In the absence of a definition for autonomic status epilepticus, the terms I propose are:
Autonomic status epilepticus: is an autonomic seizure that lasts for more than 30 minutes.4;90
Pure autonomic status epilepticus is a pure autonomic seizure that lasts for more than 30 minutes.4;90
The emetic process consists of the triad of nausea, retching and vomiting, which are three separate functional entities occurring independently of each other and in any combination.
Vomiting refers to the forcible oral expulsion of gastric contents and is usually preceded by symptoms (e.g. pallor, salivation, sweating) attributed to autonomic nervous system discharges, which are not, however, essential for the act of vomiting.
Ictus emeticus: emetic manifestations (nausea, retching, vomiting alone or in combination) caused by seizure discharges.
Ictal vomiting: forcible oral expulsion of gastric contents due to seizure discharges.
Mydriasis is sometimes so prominent that it may be reported spontaneously.
Her pupils were as big as her eyes.
Mydriasis occurs concurrently with other marked autonomic manifestations. Dilated pupils may not be reactive to light.
Miosis is rare and occurs with other severe autonomic manifestations while the child is unresponsive.
Hypersalivation is also rare in PS, in contrast to its common occurrence in RS. Combined speech arrest and hypersalivation, as in RS, is even rarer.
Cephalic auras, though rare, are of interest, because they are considered to be autonomic manifestations and because of the diagnostic confusion they may cause with migraine if not properly evaluated. Cephalic auras commonly occur with other autonomic symptoms, mainly nausea, at seizure onset. Occasionally, the child may also complain of “headache” but whether the complaint of “headache” is a true perception of pain, discomfort or some odd sensation in the head is uncertain.
“funny feeling in my head”, “warm sensation’’, ‘‘pressure’’, ‘‘headache’’
Coughing may occur as an initial ictal symptom either with or without ictus emeticus. It is described as “strange coughing” or “cough as if about to vomit”.
Thermoregulatory Changes
Raised temperature may be subjectively or objectively documented during the seizure or immediately post-ictally. Whether this is a coincidental finding, a precipitating factor or an ictal abnormality is uncertain. It could be any of these. However, pyrexia recorded immediately after seizure onset is probably an ictal autonomic manifestation.
Abnormalities of Intestinal Motility
Diarrhoea (3%) is occasionally reported during the progression of seizures.
Figure 9.8
EEG of a 4-year-old boy with autonomic status epilepticus (more…)
Figure 9.8
.
EEG of a 4-year-old boy with autonomic status epilepticus recorded from onset to termination.
Top: High amplitude spikes and slow waves are recorded from the bifrontal regions prior to the onset of the electrical discharge, which is also purely bifrontal (arrow).
Bottom: First clinical symptoms with three or four coughs and marked tachycardia appeared 13 min after the onset of the electrical discharge, when this had become bilaterally diffuse. Subsequent clinical symptoms were tachycardia, ictus emeticus (without vomiting) and impairment of consciousness. No other ictal manifestations occurred until termination of the seizure with diazepines 70 min after onset.
Another lengthy autonomic seizure was recorded on video EEG 1 year later. The onset of symptoms was different with mainly tachycardia and agitation.
From Panayiotopoulos (2004)90 with the permission of the Editor ofEpilepsy and Behaviour. Figure courtesy of Dr Michael Koutroumanidis, MD from the Department of Clinical Neurophysiology and Epilepsies, Guy’s & St. Thomas’ NHS Trust, UK.
Figure 9.9
Ictal EEGs in Panayiotopoulos syndrome (top) and Gastaut-type (more…)
Figure 9.9
.
Ictal EEGs in Panayiotopoulos syndrome (top) and Gastaut-type childhood occipital epilepsy (bottom).
Top: Samples of continuous EEG recording from the onset to the end of a 9-minute seizure during sleep stage II in an 8-year-old girl. Clinically, the seizure manifested with awakening, eyes opening, frequent vomiting efforts and complaints of frontal headache.102 The ictal EEG started with remission of the interictal occipital paroxysms and the appearance of occipital sharp rhythms progressing to monomorphic rhythmic theta activity in the bi-occipital regions, but mainly involving the right hemisphere in a wider posterior distribution. The slow activity slowed down with the progress of the seizure and ended without postictal abnormalities. The ECG showed significant tachycardia during the ictus.102
Bottom: Ictal EEG during a visual seizure in a boy with Gastaut-type childhood occipital epilepsy. The seizure starts in the left occipital region with fast rhythms associated with visual symptoms. This spreads, 4 s later, to the parietal regions and the child sees a bundle of coloured balloons swinging in his right hemifieId. This lasted for 40 s and was followed by slow waves that progressively became slower and diffuse over the whole brain. At this stage, he complained of clouded vision. This boy was normal physically and intellectually, and also had a normal CT brain scan. At the age of 3 years, he had a nocturnal, left hemiconvulsion. His first EEG showed occipital paroxysms with fixation-off sensitivity. Since the age of 4 years, he had started having frequent, brief visual seizures (simple, coloured, visual hallucinations) provoked by sudden darkness.
From Beaumanoir (1993)102 and reproduced with the kind permission of the author and the publisher John Libbey
Breathing and cardiac irregularities are rarely reported, but may be much more common in a mild form. Breathing changes prior to convulsions include descriptions of “heavy, irregular, abnormal breathing” or “brief cessation of breathing for a few seconds”. Tachycardia is a consistent finding, sometimes at the onset, of ictal EEG (Figures 9.8
and 9.9
).
Cardiorespiratory arrest is exceptional, but is potentially fatal without immediate medical intervention (case 37 in ref4).
At the age of 3 years, while dozing in his mother’s car, his head went back, eyes were “rolling”, colour clay-like grey, pupils dilated, unresponsive and incontinent of urine. Arms were initially rigid, but then he became floppy. At this stage, 5–10 min from onset, a Swiss paediatrician who happened to be present diagnosed cardiopulmonary arrest and resuscitated him: “Lips blue and then white. No respiration. No heart beat and wide pupils without reaction to light. External heart massage and mouth-to-nose resuscitation, less than 1 minute. Total time of asystole reckoned to be 2 min. Unconsciousness went on for 20 min then he started to cry and he recognised his mother”. He was well after a few hours’ sleep.4
I have been made aware of three other children with PS and cardiorespiratory arrest. Sadly, one of them died. Though tragic and exceptional, this should be expected to happen in view of the frequent occurrence of autonomic status epilepticus in children (page 239).
Ictal Syncope
Ictal syncope is an intriguing and important ictal feature of PS.4 It is a common and dramatic occurrence. In at least one-fifth of seizures, the child becomes‘completely unresponsive and flaccid like a rag doll’ before and often without convulsions or in isolation.
Cephalic auras are ictal symptoms of non-specific sensory perceptions involving or limited to the head.91
While talking to her teacher, suddenly and without warning, she fell on the floor pale, flaccid and unresponsive for 2 min. She had a complete recovery, but 10 min later she complained of feeling sick, vomited repeatedly and again became unresponsive and flaccid with pupils widely dilated for 1 hour. She had an unremarkable recovery and was normal after a few hours’ sleep.
She complained of ‘dizziness’ and then her eyes deviated to the left, she fell on the floor and she became totally flaccid and unresponsive for 5 min.
I proposed the descriptive term‘ictal syncope’4;90 to describe this state, because‘unresponsiveness with loss of postural tone’ are the defining clinical symptoms of syncope.92;93 Other authors prefer‘syncope-like symptoms’.94
Ictal Behavioural Changes
Ictal behavioural changes usually consist of restlessness, agitation, terror or quietness, which appear at the onset of seizures, often concurrently with emetic or other autonomic manifestations. These symptoms are often similar to those occurring in ‘benign childhood epilepsy with affective symptoms’ (page 254).
He was happily playing and asking questions when he started complaining that he was feeling sick, and became very pale and quiet. He did not want to drink or eat. Gradually, he was getting paler and paler, and kept complaining that he felt sick. He then became restless and frightened. Ten min from the onset, his head and eyes slowly turned to the left. The eyes were opened, but fixed to the left upper corner. We called his name, but he was unresponsive. He had completely gone. We tried to move his head, but this was fixed to the left. There were no convulsions. This lasted for another 15 min when his head and eyes returned to normal and he looked better, although he was droopy and really not there. At this stage he vomited once.
At age 9 years, on return from school, he looked tired and pale. He said that his head was killing him “something that would cause me to be sick”. In 10 min, he started screaming and banging his head on the wall. Within the next 20 min, he gradually became disorientated and floppy ‘like a rag doll’. He was staring.
Conventional Seizure-Symptoms
In PS, pure autonomic seizures and pure autonomic status epilepticus occur in 10% of patients. They start and end solely with autonomic symptoms. In all others, autonomic manifestations are followed by conventional seizure-symptoms and these in order of prevalence are:
- Impairment of consciousness (94%)
- Deviation of the eyes (60–80%)
- Hemiconvulsions (26%)
- Generalised convulsions (20%)
- Speech arrest (8%)
- Visual hallucinations (6%)
- Other manifestations occur less than 3% each.
Impairment of Consciousness
Though initially fully conscious, the child gradually or suddenly becomes confused and unresponsive. Impairment of consciousness may be mild or moderate, with the child retaining some ability to respond to verbal commands, but often talking out of context. Complete unresponsiveness is probably exceptional at the beginning of the seizure. In diurnal seizures observed from onset, clouding of consciousness usually starts after the appearance of autonomic and behavioural symptoms, becoming progressively worse until complete unresponsiveness is reached. Good awareness may be preserved throughout the ictus in around 6% of seizures.
‘Ictal syncope’ denotes transient loss of consciousness and postural tone that occurs in a seizure before or without convulsions.Transient loss of consciousness and postural tone’ are the defining symptoms of syncope irrespective of underlying cause Ictal syncope is purely a name for a cluster of seizure symptoms that, until now, have lacked a descriptive term. Ictal syncope does not occur or may be very rare in other types of seizures, except in postictal states after GTCS.
Deviation of the Eyes
Unilateral deviation of the eyes with, or rarely without, ictal vomiting is a common ictal manifestation, which seldom occurs at onset. The eyes shift to the extreme of one side and the head may also turn ipsilaterally. This pursuit-like deviation of the eyes may be brief (for min) or prolonged (for hours). It may be continuous or less often intermittent, with eyes returning to the midline and shifting again towards the same side. The eyelids remain open, but may be half open or open wide and, at this stage, consciousness is often, but not invariably, impaired.
Deviation of the eyes may occur without vomiting in 10–20% of patients and, in some children, the eyes may be open wide and remain in the midline before other convulsions occur.
Other ictal symptoms in order of prevalence are speech arrest (8%), hemifacial spasms (6%), visual hallucinations (6%), OPL movements (3%), unilateral drooping of the mouth (3%), eyelid jerks (1%), myoclonic jerks (1%), ictal nystagmus and automatisms (1%). These probably reflect the primary area of seizure discharge generation. The seizures may end with hemiconvulsions often with Jacksonian march (19%) or generalised convulsions (21%).
Ictal visual symptoms, such as elementary visual hallucinations, illusions or blindness, occur after more typical seizure symptoms of PS.
Hemiconvulsive (2%) or generalised convulsive status (2%) is exceptional.
The same child may have seizures with marked autonomic manifestations and seizures in which autonomic manifestations may be inconspicuous or absent. Seizures without autonomic manifestations are rare (7%).4
The clinical seizure manifestations are roughly the same irrespective of EEG localisations though there may be slightly less autonomic and slightly more focal motor features at onset in children without occipital spikes.4
Seizures without Autonomic Manifestations
Such seizures are rare (7%) and occur in patients who may also have additional autonomic seizures.
Case 3 of ref had three seizures with ictus emeticus. An additional lengthy diurnal seizure manifested only with deviation of the eyes and mild impairment of consciousness prior to generalised convulsions.
Duration of Seizures and Autonomic Status Epilepticus
Nearly half (44%) of the seizures last for more than 30 min and can persist for up to 7 hours (mean about 2 hours), constituting autonomic status epilepticus. The rest of the seizures (54%) last from 1–30 min with a mean of 9 min. Lengthy seizures are equally common in sleep and wakefulness. Even after the most severe seizures and status, the patient is normal after a few hours’ sleep. There is no record of residual neurological or mental abnormalities. The same child may have brief and lengthy seizures. Hemi-convulsive or convulsive status epilepticus is exceptional (4%).
Despite the high incidence of autonomic status epilepticus, convulsive status epilepticus is exceptional in PS.
Circadian Distribution
Two-thirds of seizures start in sleep; the child may wake up with similar complaints while still conscious or else may be found vomiting, conscious, confused or unresponsive.
Clinically, while asleep, “he suddenly got up with both eyes open, vomited several times and then showed a prolonged atonic state with cyanosis and irregular respiration for 3 min” (from ictal EEG documentation by Oguni and associates
The same child may suffer seizures while asleep or awake.
A 10-year-old boy of normal development suffered an episode of autonomic status epilepticus at 5 years of age. Half an hour after he had gone to sleep, he woke up looking pale and then complained that he felt sick before vomiting repeatedly. Within min his eyes deviated and fixed laterally, and soon after he became flaccid ‘like a rag doll’, unresponsive, and incontinent of urine and faeces. His breathing was short and shallow, and stopped for a few seconds before he started vomiting again. Two hours after onset, he had brief hemiconvulsions with Jacksonian marching for 5 min. On arrival at hospital, he was recovering and his temperature was mildly raised to 37.40 C. A CT brain scan, CSF examination and relevant blood tests were normal. Triple treatment for encephalitis was started, though he was entirely normal and apyrexial after a few hours of sleep. EEG the next day showed a few scattered occipital and central spikes. Treatment was stopped 4 days later.
A similar autonomic status epilepticus occurred 6 months later on a ferryboat while on holiday. He said that he felt sick and looked pale. He vomited a couple of times, and then his eyes turned to one side and he talked out of context and vomited again. “Then I knew that he was having another fit” his mother said. “He was as if drifting in and out of sleep. He did not become unconscious, but he was continuously vomiting for several hours.” On arrival at hospital 3 hours later, he was improving and able to talk and walk. He was diagnosed and treated for dehydration. He was normal the next morning. A new EEG showed repetitive multifocal spike-wave complexes.
No further seizures occurred in the next 5 years, and his development and EEG were normal.
Precipitating Factors
There are no apparent precipitating factors other than sleep. Fixation off sensitivity is an EEG phenomenon, which may not be clinically important.
Many seizures have been witnessed while a child is travelling in a car, boat or aeroplane. There are two explanations for this: (a) the seizures are more likely to be witnessed during travelling; or (b), children are more vulnerable because travelling also precipitates motion sickness which is particularly common in children.
Aetiology
PS, like RS, is probably genetically determined. Usually, no family history of similar seizures exists, though siblings with PS or PS and Rolandic epilepsy have been reported. There is a high prevalence of febrile seizures (about 17%). Also, there may be a high incidence of abnormal birth deliveries, but these all need re-evaluation.
PS, Rolandic epilepsy and all other benign childhood focal seizures are probably linked together by a common, genetically determined, mild and reversible functional derangement of the brain cortical maturational process that I proposed to call ‘benign childhood seizure susceptibility syndrome’
Childhood autonomic status epilepticus, though common and specific in childhood, is ignored in all classifications even now, long after its first description by Panayiotopoulos.The new ILAE diagnostic schemerecognises four forms of focal status epilepticus
(a). Epilepsia partialis continua of Kozhevnikov
(b). Aura continua
(c). Limbic status epilepticus (psychomotor status)
(d). Hemiconvulsive status with hemi-paresis
From a clinical point of view aura continua is classified into:
(1) somatosensory, i.e. dysaesthesia phenomena that involve the trunk, head and extremities,
(2) aura continua that involve the special senses (visual, auditory, vertiginous, gustatory and olfactory).
(3) aura continua with predominantly autonomic symptoms, and with psychic symptoms.
It is anticipated that future revisions of the ILAE classifications will recognise this type of age-related autonomic status epilepticus. This is mandated by its high prevalence and its high rate of misdiagnosis and mismanagement. Four-fifths of childhood autonomic status epilepticus occur in PS and the remaining one-fifth occurs in symptomatic childhood epileptic disorders.Ignoring these facts, as indeed happens even now, results in avoidable morbidity and probably mortality.
Pathophysiology
Autonomic symptoms of any type are often encountered in seizures, focal or generalised, in adults or children and they are implicated in occurrences of sudden death. However, autonomic seizures and autonomic status with ictus emeticus and ictal syncope, with the symptomatology and the sequence as detailed in this chapter, are specific in childhood. This clinical picture does not occur in adults: only about 30 cases of ictal vomiting have been reported, but not in the same sequence as in children – adult patients usually have amnesia about the vomiting, which often occurs after the seizure has started with other symptoms (see page 373).An explanation for this is that children are vulnerable to emetic disturbances as exemplified by the ‘cyclic vomiting syndrome’, a non-seizure disorder of unknown aetiology that is also specific to childhood. Ictal syncope is even more difficult to explain.
Symptoms at the onset of seizures are important, because they indicate the possible location of the epileptic focus. However, autonomic and emetic disturbances are of uncertain value with regard to localisation in PS and may occur in seizures starting from the anterior or posterior regions. The localisation of ictal vomiting in adults does not appear to apply in children (page 373).
Clinical and EEG findings indicate that, in PS, there is a diffuse cortical hyperexcitability, which is maturation-related. This diffuse epileptogenicity may be unequally distributed, predominating in one area, which is often posterior. The preferential involvement of emetic and other autonomic manifestations may be attributed to epileptic discharges triggering low-threshold emetic centres and hypothalamus of vulnerable children.In other words, it is likely that in vulnerable children a “weak” epileptic electrical discharge (irrespective of localisation) activates at its onset susceptible autonomic centres to autonomic seizures and autonomic status epilepticus. This is prior to the generation of clinical manifestations from brain regions that are topographically related to the ictal electrical discharge (occipital, frontal, central, parietal and less often temporal) with seizure thresholds higher than those of the autonomic centers.
Diagnostic Procedures
By definition, in an idiopathic syndrome, neurological and mental states and high resolution MRI are normal. The most useful laboratory test is the EEG The most important determinant of the neurodiagnostic procedures is the state of the child at the time of first medical attendance.
- The child has a typical brief or lengthy seizure of PS, but has fully recovered before arriving at the accident and emergency department or being seen by a physician. A child with the distinctive clinical features of PS, particularly ictus emeticus and lengthy seizures, may not need any investigations other than EEG. However, because approximately 10–20% of children with similar seizures may have brain pathology, an MRI may be indicated.
- The child with a typical lengthy seizure of PS has partially recovered, though is still in a postictal stage, tired, mildly confused and drowsy on arrival at the accident and emergency department or when seen by a physician. The child should be kept under medical supervision until full recovery, which is the rule after a few hours of sleep. Then guidelines are the same as above
- The child is brought to the accident and emergency department or is seen by a physician while ictal symptoms continue. This is the most difficult and challenging situation. Symptoms may dramatically accumulate in succession, and demand rigorous and experienced evaluation. A history of a previous similar seizure is reassuring and may help to avoid unnecessary investigation.
Electroencephalography
In about 90% of cases, the EEG reveals functional, mainly multi-focal, high amplitude sharp-slow wave complexes Spikes may appear anywhere. They are often independent, and occur at various posterior locations and, less often anterior locations, in the same or the contralateral hemisphere, and may appear as cloned-like, repetitive, multifocal spike-wave complexes. In order of prevalence, the complexes most commonly occur in occipital, frontal and centrotemporal regions; right and left regions are equally involved. Midline spikes occur in 17% of cases.
Occipital paroxysms in their classical form with fixation-off sensitivity from the initial study of Panayiotopoulos (1981).Top: EEGs from two patients with PS and G-ICOE. In routine EEG, repetitive, high amplitude, occipital sharp and slow wave complexes (occipital paroxysms) occur immediately after the eyes are closed and persist for as long as the eyes remain closed. The EEG normalises immediately after the eyes are opened and for as long as the eyes remain open. The activation of the occipital paroxysms is due to the elimination of central vision and fixation (left of the vertical bar, symbol of eyes with glasses) and inhibition by fixation (right of the vertical bar, symbol of eyes without glasses).
Bottom: Effect of darkness on occipital paroxysms:
(a). Complete darkness activates the occipital paroxysms even when eyes are open.
(b). The occipital paroxysms become continuous in darkness irrespective of whether the eyes are open or closed.
Modified from Panayiotopoulos (1981) and reproduced with the permission of the Editor ofNeurology.
The EEG shows great variability in functional focal spikes at various electrode locations. All brain regions are involved, though posterior areas predominate ( Two-thirds of patients (68%) have at least one EEG with occipital paroxysms or, more commonly, occipital spikes, which are often (64%) concurrent with extra-occipital spikes in at least one EEG.4 The other third (32%) never show occipital spikes Instead, they have extra-occipital spikes (21%) only, a consistently normal EEG (9%) or brief generalised discharges only (2%). An EEG with multifocal spikes in more than two, and often many, brain locations occurs in one-third of patients; single spike foci are rare (9%). Cloned-like, repetitive, multifocal spike-wave complexes may be characteristic features when they occur (19%).They have never been studied or reported before in idiopathic epilepsies. On the contrary, multifocal repetitive spikes are considered to be suggestive of a bad prognosis and indicative of symptomatic epilepsies (page 169). Cloned-like, repetitive, multifocal spike-wave complexes do not determine the prognosis, because they occur equally in children with single or multiple seizures.
Spikes are usually of high amplitude and morphologically similar to CTS. They often show stable dipoles in the occipital regions.
Small and even inconspicuous spikes may appear in the same or a previous EEG of children with giant spikes. Though rare, positive spikes or other unusual EEG spike conFigurations may occur.
Brief generalised discharges of slow waves intermixed with small spikes may occur either alone (4%) or more often with focal spikes (15%).
The EEG spikes may be stimulus sensitive; occipital paroxysms are commonly (47%) activated by the elimination of central vision and fixation, while CTS may be elicited by somatosensory stimuli EEG occipital photosensitivity is an exceptional finding.
Functional spikes in whatever location are accentuated by sleep. If a routine EEG is normal, a sleep EEG should be performed. There is no particular relationship between the likehood of an abnormal EEG and the interval since the last seizure. EEGs recorded a short or long time after a seizure are equally likely to manifest with functional spikes, which may occur only once in serial routine and sleep EEGs.
The background EEG is usually normal, but diffuse or localised slow wave abnormalities may also occur in at least one EEG in 20% of cases, particularly postictally.
Cloned-like repetitive multifocal spike wave complexes are repetitive spike or sharp and slow wave complexes that appear concurrently in different brain locations of one or both hemispheres. There may be just two discrete foci unilaterally or contralaterally, but the complexes are usually multifocal and often give the impression of generalised discharges or secondary bilateral synchrony. They are stereotypically and identically repetitive in the same and often subsequent EEGs from the same patient, which is the reason that I coined the name ‘cloned-like’. On the surface, in routine EEG recordings, they appear synchronous but usually one spike focus leads the others by a few milliseconds. The leading focus commonly occurs alone without spikes in other locations. Cloned-like repetitive multifocal spike-wave complexes can occur without the primary spike and can be so abundant that they dominate the EEG and obscure its background, which is otherwise normal. On other occasions, they are scarce and appear in a well-organised EEG with normal background.
EEG abnormalities, particularly functional spikes, may persist for many years after clinical remission; they disappear when the patient reaches the mid-teens. Conversely, spikes may appear only once in one of a series of EEGs.
Frequency, location and persistence of functional spikes do not determine clinical manifestations, duration, severity and frequency of seizures, or prognosis.
Ictal EEG
Typical autonomic seizures and autonomic status epilepticus of PS have been documented by ictal EEG The seizure discharge consists mainly of rhythmic theta or delta activity, usually intermixed with small spikes. Onset is unilateral, often posterior, but may also be anterior and not strictly localised to one electrode. shows autonomic status epilepticus captured from the onset on video EEG. Ictal clinical manifestations may start minutes after the onset of the electrical seizure discharge
Differential Diagnosis
PS is easy to diagnose, because of the characteristic clustering of clinical seizure semiology, which is often supported by interictal EEG findings. However, despite sound clinical EEG manifestations, PS escaped recognition for many years for a number of reasons. Ictus emeticus is rarely considered a seizure event. When it is associated with a deteriorating level of consciousness, followed by convulsions, encephalitis or other acute cerebral insults are the prevailing diagnoses in the acute stage. If the child is seen after complete recovery, atypical migraine, gastroenteritis, motion sickness or a first seizure are likely diagnoses. Similarly, ictal syncope has only recently been recognised as an important clinical manifestation of PS; ictal syncope may be misdiagnosed as cardiogenic syncope, pseudoseizure or a more severe encephalopathic state.
The main problem is to recognise emetic and other autonomic manifestations as seizure events, and not to dismiss them or erroneously consider them as unrelated to the ictus and as a feature of encephalitis, migraine, syncope or gastroenteritis.
EEG of a 10-year-old girl with autonomic seizures and autonomic status epilepticus identical to those of PS (case 60 in ref4). The neurological findings and development were normal. However, the EEG had features that were markedly different to the idiopathic cases (rectangle). This prompted an MRI examination, which showed an extensive dysembryoblastic neuroepithelial tumour in the right temporo-parieto-occipital regions, corresponding to severe EEG abnormalities in the same areas.
Since 7 years of age, she had experienced about 10 brief nocturnal seizures lasting 5–10 min each. During these episodes, she jumps out of bed, calls her parents, and complains of feeling sick and of headache. She screams and vomits, her eyes stare and roll, her eyelids blink, her pupils are dilated and she sweats profusely.
A dramatic diurnal autonomic status epilepticus occurred at school. She complained of frontal headache and she had gone out for fresh air when she started feeling “funny”. She screamed that she was hot, and she was sweating and vomiting. Subsequently, she became vacant, her speech slurred slightly, her eyes twitched and she dribbled a lot. She asked for water, but did not drink. She talked “gobbledegook” and gradually got worse. Her head deviated to the left and she became unresponsive. This was followed by a series of left hemiconvulsions lasting 5–10 min each. Convulsions were stopped with intravenous diazepam. She gradually recovered. The neurological examination was normal. She was amnesic of the events the next morning and she looked well, complaining only of photophobia.
The CT brain scan was normal. CSF and other relevant investigations were normal. She received triple therapy for encephalitis for 4 days after which she was discharged home.
Similarly, 10–20% of autonomic seizures and autonomic status epilepticus with a similar presentation to PS are due to heterogeneous cerebral pathology, such as focal or diffuse brain lesions of diverse aetiology. These autonomic seizures are also restricted to childhood. In these symptomatic cases, there is often abnormal neurological or mental symptomatology, abnormal brain imaging, and background EEG abnormalities Also, patients commonly have additional types of seizures without autonomic symptoms that continue in adult life. Management and treatment is similar to any other form of lesional epilepsy.
- Gastaut-type idiopathic childhood occipital epilepsy has entirely different clinical manifestations, despite common interictal EEG features when occipital paroxysms occur in PS. Visual seizures are predominant in G-ICOE. Visual symptoms in PS, when present, occur with other typical clinical, mainly autonomic, vomiting and behavioural manifestations. They are not the predominant seizure symptom. They are never the sole symptom of a seizure and do not occur alone. Usually, they develop after the seizure has started. Their presence signifies spreading of the discharge to the occipital regions of the brain. Exceptionally (in 1% of cases), visual symptoms occur at onset suggesting an occipital origin for the epileptic discharge in these patients.
- Rolandic seizures have different clinical manifestations. Emesis, when it occurs, is a concomitant symptom of PS.14 Conversely, in some cases of PS, there are concurrent Rolandic symptoms. This should not be a problem as the management and the prognosis of both syndromes is the same.
- Cases of PS with seizures occurring when the child is febrile may be diagnosed asfebrile seizures, but this again is of no prognostic significance.
An EEG demonstrating multifocal spikes may be indispensable in the diagnosis of patients with PS if clinical information is inadequate or emetic manifestations are inconspicuous.
Prognosis
PS is a remarkably benign condition despite the high incidence of autonomic status epilepticus. One-third of patients (27%) have only a single seizure, half (47%) have 2–5 seizures and only 5% have more than 10 seizures, which can sometimes be very frequent, but again the outcome is favourable. Furthermore, the active seizure period is very brief and remission commonly occurs within 1–2 years from onset. The risk of developing epilepsy in adult life is probably no more than that in the general population. However, one-fifth of patients (21%) may develop another type of infrequent, usually Rolandic (13%), seizures during their childhood and early teens. These seizures are also age-related and remit before the age of 16 years. Atypical evolutions with absences and drop attacks, such as those occurring in Rolandic epilepsy, are exceptional.
However, despite its benign course, some seizures of PS may occasionally manifest with potentially fatal autonomic symptoms, such as cardiorespiratory arrest.
Management
Current guidelines for febrile seizures, if appropriately modified, may provide the basis for similar guidelines for PS. Based on the risks and benefits of the effective therapies, continuous anticonvulsant therapy is not recommended for children with one or brief seizures. Most clinicians treat recurrent seizures with carbamazepine. Lengthy seizures are a medical emergency and rectal diazepam is prescribed for home administration.
See details in “Management of benign childhood focal seizures” (page 257).
Diagnostic tips
Paediatricians should be alerted by lengthy autonomic seizures and electroencephalographers by frequent multifocal spikes in a normal child with one or a few seizures.
In terms of the EEG, it is important to remember that frequent epileptogenic foci in a normal child with infrequent seizures should raise the possibility of the benign childhood focal seizures.
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Filed under: 02.epilepsy
