AE primarily affects the paediatric population, with fewer occurrences reported in the adolescent and adult populations. Our two patients sought medical care in childhood, but they likely did not receive a diagnosis of AE until adolescence or later due to the similarity of their abdominal pain symptoms to those of other nonabdominal epileptic disorders. This similarity often leads to misdiagnosis as porphyria, cyclic vomiting syndrome, copper poisoning, enteritis, peptic ulcer, or abdominal migraines, especially when patients have recurrent episodes over a period of years and various examinations fail to detect significant abnormalities or even when symptoms resolve on their own without the need for medication intervention; these conditions can easily be misdiagnosed as psychogenic disorders. Consequently, the diagnosis of AE may be delayed until adolescence or even later, as was the case for our patients. Upon further history-taking, both patients exhibited significant postseizure neurological symptoms, including loss of consciousness following abdominal pain. Consequently, we promptly initiated comprehensive 24-hour ambulatory EEG monitoring upon admission, leading to a swift diagnosis of AE upon symptom resolution with antiepileptic drug use.
AE is a type of temporal lobe epilepsy that usually presents with abdominal auras and is characterized by recurrent episodic paroxysms of abdominal and periumbilical pain with various abdominal symptom(e.g.,abdominal pain, nausea, vomiting and hunger, and have been reported to be the most common aura in temporal lobe epilepsy)(Table 1). Epilepsy and migraine are frequent comorbid conditions and shared genetic susceptibility[1].Abdominal migraine shares many characteristics with epilepsy that presents with abdominal pain, including auras, abdominal pain, nausea, vomiting, and headache. Therefore, when a patient with epilepsy accompanied by abdominal pain experiences a headache, distinguishing it from abdominal migraine can be quite challenging.The sudden onset, spontaneous resolution, and relatively brief duration of episodes can assist in the accurate and early diagnosis of focal epilepsy with ictal abdominal pain.Another useful distinguishing factor is the localization of the ictal pain, which typically occurs in the periumbilical or upper abdominal region and seldom spreads to other areas of the body, as observed in our patients.
Table 1
Clinical characteristics of reported cases of abdominal epilepsy
| Reference | Age | Sex | Gastrointestinal symptoms | non-gastrointestinal symptoms | Episode duration | EGG | Treatment | Outcome |
| Cerminara C et al.[17] | 8 | M | abdominal pain | Lethargy | Few minutes to 1 hour | rhythmic spikes and sharp waves | carbamazepine | Seizure free |
| Tatum KB et al.[18] | 48 | F | abdominal clonic movements | tachycardic, hypertensive, Diaphoretic, Lassitude, subjective bilateral leg trembling | Few minutes to 1 hour | repetitive myogenic artifact obscuring the tracing | lorazepam | Seizure free |
| 67 | M | abdominal twitching | GTCS | Few minutes | Normal | surgical epilepsy | - |
| 55 | F | nausea vomiting | numbness, intense tingling in toes | 1–2 minutes | continuous left hemispheric slowing | craniotomy and radiotherapy | focal seizures |
| Kraimer KL et al.[19] | 16 | M | tabdominal pain | Long-term use of antiepileptic drugs leads to deficits in the neuropsychological state of patients | several hours | rare epileptiform discharges in the centrofrontal region | Vagal nerve stimulation therapy | Abdominal attack aborted, Intellectual indices, mild word retrieval improvemen |
| Hayashida A et al[20] | 71 | F | nausea, vomiting | headache | Few minutes | sharp waves in the left cerebral hemisphere | levetiracetam ,clonazepam | Seizure free |
| Yunus Y et al.[21] | 5 | F | | Tiredness, lethargy | 1–2 minutes | generalized spike especially precipitated by hyperventilation | valproate | Seizure free |
| Dutta SR et al[22] | 15 | M | abdominal pain, vomiting | lethargy | 30 minutes to 1 h | high-voltage generalised slowing. | oxcarbazepine | Seizure free |
| 13 | F | abdominal pain | | 10–30 minutes | generalised spike and wave discharges | oxcarbazepine | Seizure free |
| 50 | M | intermittent abdominal, vomiting | | Few minutes | left temporal dysrhythmia in the form of slowing | oxcarbazepine | Seizure free |
| 52 | F | vomiting | paroxysmal headache | Few minutes | right frontal focal discharge with generalisation | oxcarbazepine | Seizure free |
| Eschle D et al.[23] | 37 | M | abdominal pain | typical seizure | seconds to hours | left-sided selective amygdalohippocampectomy | carbamazepine | Seizure free |
| Franzon RC et al.[13] | 6 | F | abdominal pain | | seconds to few minutes | spikes and slow waves over left temporal lobe | Left temporal lobe tumor resection | Seizure free |
| Harshe DG et al.[24] | 45 | F | abdominal pain, vomiting | tachycardia, hypertension | 10–15 minutes | spike and slow wave complexes in bilateral leads | valproate | Seizure free |
| Balabhadra A et al.[25] | 20 | M | epigastric abdominal pain | Lethargy syncope | 8–12 minutes | sharp wave discharges in the right temporal leads. | oxcarbazepine | Seizure free |
| Present | 55 | F | abdominal pain | syncope | 0.5-1 hour | bilateral spikes and slow waves | valproate | Seizure free |
| Present | 28 | M | abdominal pain | syncope | 1 minute | intermittent high-amplitude sharp waves and spike-slow wave complexes | oxcarbazepine | Seizure free |
Postictal states are transient brain conditions following seizures (most common complex partial and tonic-clonic seizures),typically characterized by neurological deficits such as confusion, weakness, memory impairment, and headache, often associated with EEG slowing or suppression.The mechanism of the postictal state is related to cortical inhibition, which facilitates the development of these postictal events by suppressing and terminating the seizure, leading to changes in membrane receptors, alterations in neurotransmitter release, and changes in cerebral blood flow.
Treatment of AE using antiseizure medications is generally successful, with a very low rate of relapse.There are no current recommendations on the type of antiseizure medications,clinically used options include oxcarbazepine, carbamazepine, valproate, and lorazepam, among others,Table 1 highlights the clinical features and treatment plans of recently reported AE patients, with oxcarbazepine being the preferred medication, consistent with findings from numerous studies.(Table 1)
Approximately 1% of all epilepsy cases are AE. However, the pathogenesis of AE remains poorly understood.The brain-gut-microbiota axis, which governs inflammatory pathways, plays a pivotal role in AE pathogenesis[2–5]. The dysregulation of this axis, characterized by imbalances in neural networks, neuroendocrine signalling, and immune responses, may contribute to the development of epilepsy.Gómez-Eguílaz et al.[6] found a reduction in seizure frequency by 50% in about 28.9% of patients with drug-resistant epilepsy when supplied with a probiotic mixture as adjuvant therapy for four months.On the one hand, the gut microbiota can modulate brain activity by the peripheral production of GABA, metabolizing serotonin precursor,on the other hand,the bacterial production of short-chain fatty acids, which have anti-inflammatory effects.He et al.[7]successfully treated a girl with long-term Crohn’s disease and epilepsy for 17 years with fecal microbiota transplantation, which could prevent seizure relapse during 20 mo of follow-up,However, we need more time to have a valuable experience with the efficacy of fecal microbiota transplantation in treating epilepsy.Thus, prebiotics, probiotics, synbiotics, postbiotics and fecal microbiota transplantation are probable methods to treat epilepsy via modulation of the microbiota-gut-brain axis[8].
Additionally, cortical dysregulation in the autonomic nervous system, manifested by disruptions in ion channels and synaptic protein expression, has been implicated in AE pathophysiology[9, 10]. Lesions affecting the central autonomic nervous system, particularly in subcortical and hypothalamic regions, may disrupt visceral sensory perception and consciousness, further linking AE to the cortical hub of the autonomic nervous system[11]. Notably, EEG abnormalities, primarily in the temporal lobes, are common in patients with AE, suggesting the involvement of a neuroexcitatory pathway involving the amygdala and the dorsal motor nucleus of the vagus nerve[12]. While temporal lobe epilepsy (TLE) is a common condition, various aetiological factors, including prematurity, cortical malformations, and brain tumours, may contribute to the development of AE[13, 14],,surgical treatment can alleviate the condition.Moreover, insular and opercular regions have emerged as potential sources of visceral sensations[15], increasing the complexity of AE diagnosis. These advancements underscore the multifactorial nature of AE pathogenesis and emphasize the importance of further research to fully elucidate its underlying mechanisms and develop targeted therapies.
Hence, the consideration of AE is warranted when the following scenarios are present[16]: (1) paroxysmal gastrointestinal and autonomic symptoms, such as abdominal pain, vomiting, nausea, flushing, palpitation, or stuttering, without apparent causes; (2) central nervous system (CNS) disturbance, such as alterations in mental status, headache, dizziness, or convulsions; (3) abnormal EEG findings suggestive of epileptic activity; and (4) symptom improvement with antiseizure medications.