Abstract

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Isolated syncope is a rare manifestation of seizures in children and it's a poorly defined. A high index of suspicion is warranted when a child who's perfectly normal, devlops recurrent unexplained syncope. A detailed cardiac evaluation needs to be practised in such situation. Nevertheless, some children succumb to the illness despite rigorous management.

Introduction

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Episodic loss of consciousness presents as a diagnostic challenge to the physician as well as to the neurologist, many a time. Often, such episodes are named “epileptic” and even treated wrongly, depending upon the specific and non-specific inter-ictal EEG changes. When symptoms keep recurring, despite treatment, one would consider other organic and non-organic causes and invariably subject the patients to many diagnostic procedures with very little positive results. Changes in cardiac rhythms are known to occur during clinical seizures, but in situations where there is an epileptic discharge in EEG along with bradycardia and syncope, it is often referred as ictal bradycardia syndrome or ictal syncope[1]. Seizure related cardiac arrhythmias are mostly encountered in older children and adults only and very rare in infants [2]. The given case in an infant describes the initial difficulty in arriving at a diagnosis and the subsequent outcome.

Case Report

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A six months old girl was referred for recurrent breath holding attacks since the age of 4 months. She was born as term, IUGR and at 4 months age, she started developing frequent apnea, following prolonged incessant cry with momentary stiffness and up rolling of eyes. These were diagnosed initially as “breath holding spells” even though there were no definite precipitating events. Routine ECG and EEG could not reveal initially any specific abnormality except bradycardia. However she received oral iron syrup for some time with no improvement of symptoms and so parents stopped the drug. At six months of age, symptoms recurred with more severity and prolonged duration; at one instance she developed prolonged apnoea, requiring oxygen inhalation and bag and mask ventilation.  At that time, ECG revealed, prolonged sinus bradycardia, asystole, junctional escapes preceded by sinus tachycardia. Sick sinus syndrome (SSS) was diagnosed on this basis; oral beta-blocker treatment was (propronolol) started. Later permanent cardiac pacemaker was implanted (Intermedics S.A., Mode VV1 DASH rate adaptive pulse generator with rate of 80/mt) following left thoracotomy with an intramyocardial unipolar lead. With this, her symptoms improved dramatically without any recurrence and so she was labeled as SSS. After 2 weeks, she had a severe life threatening event; she collapsed with bradycardia and lost consciousness suddenly. She was intubated and ventilated for 48 hours. Pace maker function was checked and found to be normal. Phenobarbitone was given as loading dose with the probable diagnosis of autonomic seizures as, interestingly, a prolonged sleep EEG trace, at this time, revealed a left fronto temporal paroxysmal theta burst which was not documented before; this confirmed a diagnosis of ictal syncope. Carbamazepine was planned; however the next day, she developed one more prolonged episode of syncope, bradycardia and died as she could not be resuscitated.

Discussion

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Seizure related cardiac dysrhythms present mostly as tachyarrhythmia and bradycardia; asystole, on the other hand are exceptional and cause life threatening haemodynamic disturbances [3]. They invariably occur along with clinical seizures or as late as 60 minutes after the seizures [4]. The present case of ours, presenting as “breath-holding spell” was diagnosed initially as prolonged QT interval syndrome leading to syncope, which is often misinterpreted as the possible etiology. Long QT syndromes are associated with genuinely life threatening syncope, which may be simple or convulsive [5]. Later, sick sinus syndrome was diagnosed on her with the characteristic EKG abnormality. There was no history suggestive of typical clinical seizures in our patient, which prompted us to diagnose this as primary cardiac rhythm disorder, as the primary event was apnoea. The diagnosis of ictal bradycardia and syncope was contemplated, only, when a prolonged EEG trace was done, after one life threatening episode, showed left temporal focus, although routine EEG, in the past was normal. EEG findings in syncopial events are non-specific with slowing of the background rhythms, followed by high amplitude delta waves and then absolute flattening, depending upon the severity of cerebral hypo perfusion, but tend to improve in the reverse sequence as clinical improvement sets in gradually [6]. Ictal bradycardia syndrome may occasionally mimic syncope and so unless simultaneous EEG and ECG are not performed, the diagnosis of this unique disorder could be missed. Review of the literature also emphasizes the difficulties in the diagnosis and treatment of this rare condition.[7,8]  A possibility of dominant parasympathetic ictal stimulus following excitation of reticular formation, precipitating ictal bradycardia and sinus arrest cannot be ruled out. When autoregulation gets disrupted because of missing sympathetic innervations, especially in presence of associated cortical dysplasia, sudden cardiac ictal death might occur which could have been the reason in our patient.[9] ] Paroxysmal modification of autonomic parameters may be responsible for the cardiac rhythm and asystole.[10]  Besides, right insular irritation could cause tachycardia and left insula, bradycardia [11]. Ictal sinus arrests with temporal lobe focus and seizures (TLE) have been reported in the past that became
symptom free after epilepsy surgery.[12] This child, in spite of cardiac pacing and specific anti convulsant treatment, succumbed to the illness probably because of the underlying cortical abnormality controlling autoregulation. MRI study of brain was planned to delineate any dyspalstic abnormality of the brain but could not be done.

Conclusion

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The ictal bradycardia / syncope syndrome should be considered in patients with unusual or refractory episodes of syncope or in patients with history of both epilepsy and syncope. Correct diagnosis may be attained by simultaneous EEG / ECG at the time of syncope. At times, when the diagnosis could not be achieved, a video EEG recording of the ictal events becomes mandatory which could throw more light. Cardiac pacemaker implantation along with antiepileptic drug therapy may be necessary to minimize the attacks although permanent cure could be claimed with epileptic surgery.

References

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9. Manitius RS, Schuler P, Feistel H. Ictal syncope- cardiac sympathetic innervation disorder as etiology. Nervenarzt 1998; 69(8):712-6.
10. Kahane P, Di Leo M, Hoffman D. Ictal bradycardia in patient with hamartoma. Epilepsia 1999; 40(4):522-7.
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12. Blumhardt LD, Smith PE, Lane RD. Electro-cardiographic abnormalities of  temporal lobe seizures. Lancet 1986, 1:1051-6.

Source(s) of Funding

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No funding

Competing Interests

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No competing interests

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