Introduction

Recurrent episodes of abdominal pain are common in children and adults. Several pathological conditions can lead to paroxysmal gastrointestinal symptoms, such as porphiria, cyclical vomiting, intestinal malrotation, peritoneal bands, and abdominal migraine [1]. Psychological and emotional factors may also play an important role in some patients with gastrointestinal disorders. However, in a number of patients the episodic nature of abdominal pain can be suggestive for a diagnosis of epilepsy [1]. Epileptiform EEG abnormalities, loss or alteration of consciousness, and a good response to antiepileptic drugs are other features that can lead to a diagnosis of focal epilepsy with ictal abdominal pain [2, 3]. We describe one child affected by epilepsy which had recurrent and severe abdominal pain as the only manifestation of epileptic seizures.

Case report

An 8-year-old boy was born at 39 weeks of gestation by selective cesarean section. The pregnancy was complicated by a sudden reduction in fetal heart rate. All developmental milestones were regularly achieved. There was no family history of epilepsy. The boy experienced recurrent episodes of abdominal pain since about 6 months of age. He described the pain as “a sword that pierces my belly”, localized mainly in the epigastric region and its duration varied from a few minutes (more frequently) to 1 hour, with a frequency of 5–8 episodes per day. The intensive abdominal pain was almost always associated with pallor and nausea, but not accompanied by scream or cry. The attacks were sudden in onset and had spontaneous resolution. There was no impairment of consciousness, also in longer episodes, and he never had convulsions; the paroxysms were followed by increased sleep. He underwent a negative abdominal investigation including complete blood count, stool examinations for ova and parasites, abdominal ultrasound and upper gastrointestinal endoscopy. Physical and neurological examinations were normal.

Interictal EEG during wakefulness and sleep displayed bilateral spikes and diphasic sharp-waves localized over the temporal leads with a marked increase in frequency during drowsiness. A 24-hours EEG recording showed several bilateral synchronous and asynchronous temporal spikes during wakefulness and nocturnal sleep. At 9:30 in the morning a seizure characterized by severe abdominal pain in the epigastric region with nausea and pallor was recorded. The ictal EEG showed rhythmic spikes on the centro-temporal regions (Figure 1). Magnetic resonance imaging of the brain was normal. The patient started treatment with Carbamazepine (CBZ) (20 mg/kg/day) with a progressive decrease in seizure frequency. At the last follow-up, when he was 9-years old, he was seizure free.

Figure 1
figure 1

Ictal awake EEG showing runs of rhythmic spikes and sharp waves, over the right fronto-temporal electrodes. The onset and offset of abdominal pain are closely related to the beginning and end of the discharge.

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Discussion

Epigastric sensations are frequent symptoms in patients with partial epilepsy and may include abdominal pain, nausea, vomiting and hunger, and have been reported to be the most common aura in temporal lobe epilepsy [3–5]. Painful epileptic auras were reported in 4.1% of 25 patients with focal epilepsy by Nair et al. [6]. Abdominal pain was present in 5% of all abdominal auras in temporal lobe epilepsy and 50% in frontal lobe epilepsy [6]. However, gastrointestinal complaints, in particular abdominal pain, may be the only manifestation of epileptic activity [1, 3, 4, 7]. Unexplained paroxysmal gastrointestinal complaints, impairment of consciousness, and focal abnormal EEG are the main criteria to establish a diagnosis of focal epilepsy with ictal abdominal pain, but not all the criteria need to be present in each case [2, 3, 6]. In addition, a variety of migraine-like disturbances such as nausea, headache, dizziness, and visual hallucinations may be associated with pain during the attacks [4]. When the migraine-like symptoms are present it is often difficult to differentiate focal epilepsy with ictal abdominal pain from migraine or other neurological disorders, such as Panayiotopoulos syndrome. The abrupt onset, the spontaneous resolution, and the relatively short duration of episodes may be helpful for a correct and early diagnosis of focal epilepsy with ictal abdominal pain. Another helpful distinguishing feature of epilepsy with severe abdominal pain could be the localization of ictal pain, that is most commonly periumbilical or upper abdominal and rarely spreads to involve other body parts, such as in our patient [1–4].

EEG abnormalities have been reported in most patients with focal epilepsy and ictal abdominal pain [1, 4]. Few reports described ictal EEGs: during the seizure the EEG often shows a runs of high voltage slow waves and generalized spike and wave discharges [2–4, 8]. In our patient, 24-hours EEG was suggestive of a focal onset, as in two reports that showed clear focal EEG changes over the left hemisphere during an episode of abdominal pain [9, 10]. Table 1 shows the clinical characteristics of our patient and the previous pediatric cases described in literature (Table 1) [1–5, 7–13].

Table 1 Clinical characteristics of reported cases of abdominal epilepsy in pediatric population and in our patient
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The pathophysiology of focal epilepsy with ictal abdominal pain remains unknown. Abdominal sensations reproduced by stimulating the insula and sylvian fissure, suggest that these areas may have an important role in explaining the origin of focal epilepsy with ictal abdominal pain [3]. Phan et al. [14], reported an unusual case of ictal abdominal pain occurring in the setting of parietal lobe haemorrhage and suggested a possible role of the somatosensory area in pain perception. Supplementary motor area was considered as another possible location for abdominal pain. Occasionally focal epilepsy with ictal abdominal pain has been related to brain tumors and brain disorders [2, 8]. Previous reports on ictal abdominal pain have shown right parieto-occipital encephalomalacia, biparietal atrophy and bilateral perisylvian polymicrogyria [9].

In conclusion, our patient showed recurrent attacks of severe abdominal pain as the only manifestation of epileptic seizure. Focal epilepsy with ictal abdominal pain is a rare epileptic phenomenon that should be suspected in patients with unexplained paroxysmal abdominal pain and migraine-like symptoms. The correct diagnosis at the onset may be difficult to establish; in these cases prolonged EEG recordings with 24-hours monitoring must be considered to facilitate the clinical diagnosis.

Consent

Written informed consent was obtained from the patient’s parents for the publication of this report.