Abdominal epilepsy, an uncommon cause of recurrent abdominal pain: a brief report

Abdominal epilepsy is an uncommon cause of recurrent abdominal pain.¹,² It is characterised by paroxystic episodes of abdominal pain, diverse abdominal complaints, definite EEG abnormalities and favourable response to the introduction of epilepsy drugs.¹

We describe four patients, with recurrent abdominal pain, without obvious associated symptoms suggestive of central nervous system abnormalities, but each had definite EEG abnormalities and a striking response to anticonvulsant drugs.

A 15‐year‐old boy presented with recurrent episodes of abdominal pain and vomiting for the past 12 years. The pain was localised in the epigastric region and its duration varied from 30 min to 1 h. The paroxysms were sudden in onset and subsided spontaneously. The episodes occurred every 3–4 months, and were followed by lethargy.

On investigating, the gastrointestinal barium study showed features suggestive of duodenal inversus.

While performing an exploratory laparotomy, it was noted that besides having intestinal malrotation, the patient also had multiple congenital bands with adhesions. Gastrojejunostomy and adhesionolysis were carried out.

During the postoperative follow‐up, the patient again developed symptoms of abdominal pain and vomiting.

A CT scan of the brain was performed, which was normal. However, the EEG recording showed right temporal focal seizure discharge with generalisation, with diffuse cortical dysfunction in the form of slowing (fig 1). An MRI of the brain was performed, which was found to be normal.

Figure 1 Awake EEG record showing high‐voltage generalised slowing.

The patient started treatment with oxcarbazepine and remained asymptomatic for 6 months. He again had a relapse of his symptoms. Doubting his compliance with the drug regimen, the serum oxcarbazepine level was tested and found to be sub‐therapeutic. A repeat EEG was carried out, which showed bursts of diffuse paroxysmal acute waves (fig 2). He restarted treatment with oxcarbazepine and subsequently his symptoms subsided.

Figure 2 EEG record showing focal spike and wave discharges with phase reversal from right temporal.

He has remained asymptomatic during the past 18 months of follow‐up, receiving regular drugs.

A 13‐year‐old girl presented with recurrent abdominal pain for the past 8 years. The pain was mainly periumbilical in distribution, colicky and paroxysmal in nature, non‐radiating and had no apparent relationship with meals. Each episode of pain used to last for 10–30 min, with spontaneous resolution of symptoms, and recurred 4–5 times in a month. There was no history of associated vomiting, headache or convulsions.

Her blood analyses were normal. Ultrasonography of the abdomen and BMFT were normal. A CT scan of brain showed mild ventriculomegaly. An MRI of the brain also failed to detect any structural anomalies. EEG record showed generalised spike and wave discharges (fig 3).

Figure 3 Awake EEG record showing generalised spike and wave discharges.

The patient started treatment with oxcarbazepine and has been asymptomatic for the past 20 months.

A 50‐year‐old man presented with a history of intermittent abdominal discomfort associated with repeated episodes of vomiting for the past 15 years. The paroxysms occurred 3–4 times in a year and were not associated with headache or convulsions.

He underwent an exhaustive investigation (including complete blood cell count, stool examinations for ova and parasites, abdominal ultrasound, and upper and lower gastrointestinal endoscopies). However, no abnormalities were detected.

He underwent an EEG examination during a typical paroxysm, which revealed left temporal dysrhythmia in the form of slowing (fig 4). He also underwent an MRI, which was normal. He did very well receiving treatment with oxcarbazepine. In the past 14 months of follow‐up, he has been asymptomatic.

Figure 4 EEG record showing left temporal dysrhythmia in the form of slowing.

A 52‐year‐old woman presented with paroxysmal headache, occurring 1–2 times a week, which was associated with vomiting for the past 15 years. The paroxysms were followed by increased sleep. She also complained of a vague abdominal discomfort, which occurred intermittently.

The peripheral blood picture, urine analysis, abdominal ultrasound scan, liver and renal function tests, serum amylase and urine spot test for porphyria were normal. Gastrointestinal barium and endoscopic studies were also normal. A CT scan of the brain also failed to detect any anomaly.

A provisional diagnosis of migraine was made and she started treatment with tab Ergotamine, but the symptoms persisted.

The treatment regimen was altered and she was treated with tab Flunarizine, but no improvement was noted.

An EEG was carried out, which showed right frontal focal discharge with generalisation (fig 5).

Figure 5 EEG record showing right frontal focal discharges.

The patient has been receiving treatment with tab Oxcarbazepine and has remained asymptomatic for the past 23 months of follow‐up.

Abdominal epilepsy is an uncommon syndrome in which gastrointestinal complaints result from seizure activity. It is characterised by (1) otherwise unexplained, paroxysmal gastrointestinal complaints; (2) symptoms of a central nervous system disturbance; (3) an abnormal EEG with findings specific for a seizure disorder; and (4) improvement with anticonvulsant drugs.³

A review of the history of this syndrome yielded 36 cases reported in the English literature in the past 34 years.³

Abdominal epilepsy is well documented among children, patients but is recognised only infrequently in adults.⁴ The paucity of reports in adults could be because of a lack of recognition of this syndrome in adults.

The variability of clinical presentation in abdominal epilepsy indicates a spectrum of both gastrointestinal and CNS manifestations. The gastrointestinal manifestations include all or a combination of the following: recurrent abdominal pain, nausea, vomiting, bloating and diarrhoea. A similar diversity of CNS manifestations has been reported, which includes confusion, fatigue, headache, dizziness and syncope. In our series, we found that the most common presenting symptoms were paroxysmal abdominal pain and vomiting. The CNS manifestations in our patients were subtle, with only one patient presenting with headache as a predominant symptom.⁴

Although its abdominal symptoms may be similar to those of the irritable bowel syndrome, abdominal epilepsy may be distinguished from the latter condition by the presence of altered consciousness during some of the episodes, a tendency towards tiredness after an episode, and an abnormal EEG.⁵ All our patients, had symptoms suggestive of a functional abdominal pain but with definite EEG changes.

In patients with abdominal symptoms and headache, it is often difficult to differentiate abdominal migraine from abdominal epilepsy, because of the overlap of symptoms. An EEG is a simple and non‐invasive investigation, which may be helpful to differentiate between the two entities, as patients with abdominal epilepsy usually have specific EEG abnormalities, particularly of a temporal lobe seizure disorder.⁴

Previous reports¹,⁴ have suggested that the most common findings on EEG recording in patients with abdominal epilepsy are a burst of sharp waves and/or spikes from one or both temporal regions. In our series, two patients had specific ECG abnormalities of a temporal lobe seizure disorder, whereas one had an EEG recording that showed generalised spike and wave discharges and an other had an EEG recording that showed right frontal focal discharge with generalisation.

A sustained response to anticonvulsants has been accepted as one of the criteria for the diagnosis of patients with abdominal epilepsy.⁴ However, there are no recommendations on the choice of anticonvulsant to be used. In our series, all patients were treated with oxcarbazepine. In these patients, the symptoms were well controlled in the average 18 months of follow‐up (range 14–23 months) and there were no reported adverse events. Only one patient had a relapse of symptoms because of non‐compliance with the drug regimen.

We suggest that in patients with paroxysms of abdominal pain, nausea and vomiting with or without CNS manifestations, the possibility of abdominal epilepsy should be considered after exclusion of more common aetiologies for the presenting complaints. The investigation in these patients should proceed with an EEG. Treatment typically begins with anticonvulsant drugs; oxcarbazepine is an effective anticonvulsant in this syndrome.