ABDOMINAL EPILEPSY IN CHRONIC RECURRENT ABDOMINAL PAIN

Artículo completo
Introduction:
Complaints of abdominal pain are frequently encountered by pediatricians in the everyday outpatient department. The etiology of this vague symptom encompasses all from indigestion to intussusceptions. Amongst these varied causes, Abdominal epilepsy ( AE) is relatively uncommon and thus frequently ignored or overlooked. Trousseau in 18681 first brought the concept of AE and later Stille in 1912 suggested that periumbilical pain might be a form of “masked epilepsy”, followed by Wilson in 1940 suggesting that visceral discomfort might be epileptic 1. Abdominal pain as an ‘epileptic equivalent’ is rare & nearly always associated with a history of transient impairment of consciousness or with typical convulsions as stated by Apley2.In this study an attempt will be made to find the incidence of AE in children suffering from chronic recurrent abdominal pain, with the help of clinical symptoms & Electroencephalogram (EEG), and to study the response to empirical anti epileptic drug (AED).
Subjects and Methods:
The study was carried out in the department of Pediatrics, Krishna Institute of Medical Sciences University, Karad, India. Prospective study involves 150 children, age group 6-15 yrs, suffering from chronic recurrent abdominal pain. Chronic recurrent abdominal pain (i.e. pain severe enough to affect child’s activity or 3 episodes of abdominal pain within 3 months and abdominal pain associated with nausea, vomiting, bloating, headache, diarrhoea) from May 2007 to March 2010. Children below 6 yrs and above 15 yrs of age and were excluded from the study due to unable to give proper history. All children were investigated thoroughly. EEG was done in every child to correlate findings of EEG with clinical diagnosis of AE.
Results:
Out of the 150 cases, EEG changes were seen in 111(74%) patients, between the age group of 6-15yrs with chronic recurrent abdominal pain.. Out of the 111 patients with an abnormal EEG suggestive of AE, 75 were girls (67.56%) and 36 were boys (32.43 %) . Out of 111 abnormal EEG cases, 39 cases(35.13%) have temporal type of EEG changes, 36 cases(32.43%) have fronto-temporal type of EEG changes, 33 cases (29.72%) have generalized type of EEG changes , and 3 case( 2.70%) having parieto-temporal type of EEG changes and most common pattern being sharp wave in 99(89.18%) cases and 12 (10.81%) cases with spike and wave pattern. The age and sex distribution were as follows with maximum affected being females between the age group 9-12 yrs. All 150 patients, along with chronic recurrent abdominal pain, had others neurological symptoms (Table 1).
Out of the 111 (74%) patients with abnormal EEG, all the patients had symptomatic improvement after treatment with anti epileptic drug oxcarbazepine. And out of the 39(24%) patients with a normal EEG record, 27(18%) patients had asymptomatic improvement after treatmentand 12 (8%)patients with normal EEG, however did not have any significant improvement in the symptoms after treatment with oxcarbazepine .
Table 1. Pattern of symptoms
Symptoms Cases Percentage
Abdominal Pain 150 100%
Headache 30 20%
Vomiting & Nausea 27 18%
Giddiness 21 14%
Loose stool 3 2%
Discussion
AE is now considered a definite clinical entity3. It is characterized by (1) otherwise unexplained, paroxysmal gastrointestinal complaints, (2) symptoms of a central nervous system disturbance, (3) an abnormal electroencephalogram (EEG) with findings specific for a seizure disorder and (4) improvement with anti convulsant drugs4. Functional gastro-intestinal abnormalities may be distinguished from AE by detailed history taking and a high index of suspicion5. No history of febrile seizure or CNS infection was reported in any of our cases.
The pathophysiology of AE remains uncertain. Temporal lobe seizure activity usually arises in or involves the amygdala. Patients having seizures involving the temporal lobe invariably have gastrointestinal symptoms , since discharges arising in the amygdala can be transmitted to the gut via dense projections to the dorsal motor nucleus of the vagus6 . AE patients usually have specific EEG abnormalities, particularly a temporal lobe seizure disorder, although some studies had reported an extra-temporal origin (parietal or even frontal)7,8. EEG forms an important supportive evidence for the diagnosis of epilepsy, however the final diagnosis is clinical based.
Table 2. Incidences of AE in various previous studies as:
Serial No. Authors Total no of children studied Children with EEG suggestive of abdominal epilepsy Incidence of abdominal epilepsy based on EEG
1 Livingston(1951)11
14 11 78.5%
2 Douglas, E.F.,
White, P.T(1971)1 28 5 17%
3 Kellway et al(1960)12 599 511 86%
4 George H.Schade et al(1960)13 46 22 46.5%
5 John Apley& Norah
Naish3(1957)2 97 14 14.4%
6 Our study 150 111 74%

In our study of the 111 children with AE (based on EEG & symptoms), it was found that the incidence was more in girls, than in boy. Neuroendocrine dysfunction has been described in women with temporal lobe epilepsy, but the relationship of such abnormalities to the occurrence of GI symptoms has not been studied in such patients.
Historically, patients of AE were being treated using various drugs like diphenylhydantoin, mephobarbital, Phenobarbital, phenytoin, valproic acid, carbamazepine and primidone by various authors. A sustained response to anticonvulsants has been accepted as one of the criteria for the diagnosis of patients with AE5,9. In our study all the 150 children were treated with oxcarbazepine, irrespective of abnormal or normal EEG. On follow up all the 111(74%) of who had an abnormal EEG, and 27(18%) patients with a normal EEG had significant decrease in all the symptoms. 12(8%) patients did not respond to treatment. All the patients were advised to continue AED and follow up till the patient was symptom free of a normal EEG was recorded or maximum upto a period of 2 yrs.
Patients with epilepsies may have normal interictal records of EEG & treatment should not be based on EEG alone; correlation with the clinical condition is important10. To conclude therefore, a diagnosis of abdominal epilepsy must be considered in children with chronic recurrent abdominal pain, especially in those with suggestive history, and an EEG can save a child from lot of unnecessary investigations and suffering.

Bibliografía del artículo
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