What is abdominal epilepsy

Abdominal epilepsy is a very rare form of temporal lobe epilepsy that’s more likely to occur in children where the seizure activity (uncontrollable jerking and shaking movements often called a “fit”) with awareness disturbance and abnormal EEG specific for a seizure disorder causing abdominal pain, nausea and vomiting with improvement in abdominal epilepsy symptoms following the introduction of antiepileptic drugs ¹⁾, ²⁾, ³⁾, ⁴⁾, ⁵⁾, ⁶⁾, ⁷⁾, ⁸⁾, ⁹⁾, ¹⁰⁾, ¹¹⁾, ¹²⁾, ¹³⁾, ¹⁴⁾, ¹⁵⁾, ¹⁶⁾, ¹⁷⁾. According to International League Against Epilepsy, abdominal epilepsy is considered to be part of simple or complex partial seizures ¹⁸⁾. However, making diagnosis for abdominal epilepsy can be very challenging; some patients with abdominal epilepsy have been considered to have psychogenic abdominal pain and treated without improvement ¹⁹⁾. Others have been exposed to explorative laparotomy without significant findings to explain the symptoms ²⁰⁾, ²¹⁾.

Recurrent episodes of abdominal pain are common in children (and adults) is not an easy symptom to diagnose, particularly in young children, and other diagnosis should be considered such as irritable bowel syndrome, porphyria, cyclical vomiting, intestinal malrotation, peritoneal bands, and abdominal migraine ²²⁾. Psychological and emotional factors may also play an important role in some patients with gastrointestinal disorders ²³⁾. Abdominal epilepsy is more commonly a diagnosis of exclusion. 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 ²⁴⁾.

Patients with abdominal epilepsy usually have specific EEG abnormalities, particularly of a temporal lobe seizure disorder ²⁵⁾, while patients with migraine have normal EEGs or present unspecific abnormalities ²⁶⁾. Previous reports 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 ²⁷⁾, ²⁸⁾.

Abdominal epilepsy begin in the areas of the brain called the temporal lobes. The temporal lobes process emotions and play a role in short-term memory. People who have temporal lobe seizures often experience an aura. The aura may include sudden emotion such as fear or joy. It also may be a sudden taste or smell. Or an aura may be a feeling of deja vu, or a rising sensation in the stomach. During the seizure, people may lose awareness of their surroundings. They also may stare into space, smack their lips, swallow or chew repeatedly, or have movements of their fingers.

Abdominal epilepsy is well documented among children but is recognized only infrequently in adults ²⁹⁾, ³⁰⁾. The lack of reports in adults could be because of a lack of recognition of abdominal epilepsy in adults ³¹⁾. The age at onset of symptoms and age at diagnosis in most of the cases is the 4th and 5th decade which is again in stark contrast with other forms of epilepsy ³²⁾, ³³⁾, ³⁴⁾, ³⁵⁾, ³⁶⁾. Literature also shows a gender preference with female preponderance in abdominal epilepsy, an observation which requires further investigation and evaluation.

The cause of abdominal epilepsy remains unknown and not well understood ³⁷⁾, ³⁸⁾. Some possible causes have been considered, such as prematurity, febrile seizures, and neuroendocrine dysfunction, but they are not convincing ³⁹⁾. There is a report of a case of abdominal epilepsy due to a cerebral tumor (astrocytoma) in the temporal area ⁴⁰⁾. More recently, another case report showed brain cortex malformation such as bilateral perisylvian polymicrogyria at MRI associated with abdominal epilepsy ⁴¹⁾. When the abdominal pain presents as a short sudden onset episode followed by either awareness disturbance or a set of brief unconscious behaviors with repetitive motor activities that are associated with impaired awareness (also known as automatism), an epileptic seizure is easily considered and, in those cases, temporal lobe is the most probable origin of the seizure ⁴²⁾.

The variability of clinical presentation in abdominal epilepsy indicates a spectrum of both gastrointestinal and central nervous system (brain and spinal cord) signs and symptoms. The gastrointestinal signs and symptoms include all or a combination of the following: recurrent abdominal pain, nausea, vomiting, bloating and diarrhea ⁴³⁾. A similar diversity of central nervous system signs and symptoms has been reported, which includes confusion, fatigue, headache, dizziness and fainting ⁴⁴⁾. In a case series, the authors found that the most common presenting symptoms of abdominal epilepsy were sudden onset abdominal pain and vomiting ⁴⁵⁾. The central nervous system signs and symptoms in their patients were subtle, with only one patient presenting with headache as a predominant symptom ⁴⁶⁾. With such a diverse array of clinical signs and symptoms, abdominal epilepsy is often misdiagnosed or not suspected ⁴⁷⁾.

Although abdominal epilepsy abdominal symptoms may be similar to those of the irritable bowel syndrome (IBS), abdominal epilepsy may be distinguished from the irritable bowel syndrome (IBS) by the presence of altered consciousness during some of the episodes, a tendency towards tiredness after an episode, and an abnormal EEG ⁴⁸⁾.

There are 4 diagnostic criteria for abdominal epilepsy ⁴⁹⁾, ⁵⁰⁾, ⁵¹⁾, ⁵²⁾:

1. Unexplained, paroxysmal gastrointestinal complaints such as paroxysmal abdominal pain, nausea, bloating, and diarrhea,
2. Symptoms of a central nervous system disturbance such as dizziness, lethargy, headache, confusion, fainting, and transient blindness,
3. Abnormal EEG with findings specific for a seizure disorder, and
4. Improvement with anti-epileptic drugs.

The diagnosis of abdominal epilepsy should be considered in patients with recurrent attacks of severe abdominal pain after exclusion of other common conditions. A high index of suspicion is required to diagnose abdominal epilepsy especially in resource‐limited settings where in most cases, EEG is not readily available.

Treatment of abdominal epilepsy typically begins with anti-epileptic drugs. A sustained response to anti-epileptic drugs has been accepted as one of the criteria for the diagnosis of patients with abdominal epilepsy ⁵³⁾. However, there are no recommendations on the choice of anticonvulsant to be used ⁵⁴⁾.

Figure 1. Abdominal epilepsy EEG findings

Footnote: EEG findings of a 20-year-old male patient with abdominal epilepsy. 30-minute awake EEG showing sharp wave discharges in the right temporal leads, which were highly suggestive of an epileptogenic focus arising from the right temporal lobe.

Abbreviations: EEG = electroencephalography.

[Source ⁵⁵⁾ ]

Abdominal epilepsy cause

The cause of abdominal epilepsy remains unknown and not well understood ⁵⁶⁾, ⁵⁷⁾. Some possible causes have been considered, such as prematurity, febrile seizures, and neuroendocrine dysfunction, but they are not convincing ⁵⁸⁾. Abdominal sensations reproduced by stimulating the insula and sylvian fissure, suggest that these areas may have an important role in explaining the origin of abdominal epilepsy ⁵⁹⁾. Phan et al. ⁶⁰⁾, reported an unusual case of abdominal pain (‘thumping pain’ deep in his epigastrium and left hypogastrium, abdominal twitching and sweating lasting 20 minutes) occurring in the setting of parietal lobe hemorrhage 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 abdominal pain has been related to brain tumors and brain disorders ⁶¹⁾, ⁶²⁾. Previous reports on abdominal pain have shown right parieto-occipital encephalomalacia, biparietal atrophy and bilateral perisylvian polymicrogyria ⁶³⁾. Patients with abdominal epilepsy usually present with abnormal EEG demonstrating temporal lobe seizure disorders, although extratemporal origin such as parietal and temporal regions has also been reported ⁶⁴⁾.

There is a report of a case of abdominal epilepsy due to a cerebral tumor (astrocytoma) in the temporal area ⁶⁵⁾. More recently, another case report showed brain cortex malformation such as bilateral perisylvian polymicrogyria at MRI associated with abdominal epilepsy ⁶⁶⁾. When the abdominal pain presents as a short sudden onset episode followed by either awareness disturbance or a set of brief unconscious behaviors with repetitive motor activities that are associated with impaired awareness (also known as automatism), an epileptic seizure is easily considered and, in those cases, temporal lobe that involves the amygdala is the most probable origin of the seizure ⁶⁷⁾. The amygdala relays neurotransmission to gastrointestinal tract via dense direct projections to the dorsal motor nucleus of the vagus nerve through which gastrointestinal symptoms are said to originate. The hypothalamus is also thought to activate sympathetic pathways from amygdala to gastrointestinal tract to induce gastrointestinal symptoms.

Abdominal epilepsy symptoms

Abdominal epilepsy is considered to be one of the rare causes of abdominal pain ⁶⁸⁾. Abdominal epilepsy is characterized by: (1) unexplained, paroxysmal episode of abdominal pain, diverse abdominal complaints, (2) symptoms of a central nervous system (brain and spinal cord) disturbance, (3) an abnormal EEG with findings specific for a seizure disorder and (4) improvement with anti-epileptic drugs ⁶⁹⁾, ⁷⁰⁾, ⁷¹⁾, ⁷²⁾, ⁷³⁾, ⁷⁴⁾, ⁷⁵⁾, ⁷⁶⁾, ⁷⁷⁾, ⁷⁸⁾, ⁷⁹⁾, ⁸⁰⁾, ⁸¹⁾, ⁸²⁾, ⁸³⁾, ⁸⁴⁾.

In a study, all the 150 children had chronic recurrent abdominal pain ⁸⁵⁾. The other commonly associated symptoms were headache, lightheadedness, dizziness, nausea, vomiting and loose stools ⁸⁶⁾. History of aura or prodrome, as suggested by Gowers in 1907, or post-ictal phenomenom like exhaustion or sleep, as reported by Livingstone et al. in 1971 ⁸⁷⁾.

Zinkin and Peppercorn ⁸⁸⁾ in their review of abdominal epilepsy have covered 36 cases reported in literature. Abdominal epilepsy presents with gastrointestinal-symptoms such as abdominal pain (periumbilical, left upper and right lower quadrant), which is of varying intensity and quality. Abdominal pain is often associated with nausea and vomiting. Common neurological symptoms present in most cases are post-ictal lethargy/drowsiness, generalized tonic-clonic seizure (grand mal seizure), sweating/ paraesthesias, pain and blindness ⁸⁹⁾. This case too presented with episodic abdominal pain and extreme anxiety and headache ⁹⁰⁾. With such a diverse array of clinical signs and symptoms, abdominal epilepsy is often misdiagnosed or not suspected ⁹¹⁾.

Symptoms of abdominal epilepsy are somewhat similar to irritable bowel syndrome (IBS). These symptoms include ⁹²⁾:

• Abdominal pain that comes in waves
• Nausea
• Cyclic vomiting
• Bloating
• Cramping
• Diarrhea
• Headaches
• Anxiety
• Fatigue

These symptoms can occur together or separately. Unlike irritable bowel syndrome (IBS), abdominal epilepsy also may be distinguished by the instances of altered consciousness during some (but not necessarily all) of the episodes. This can include confusion, jerking movements, or unresponsiveness. People with abdominal epilepsy also tend to be tired after an episode.

Abdominal epilepsy diagnosis

To diagnose abdominal epilepsy, your doctor thoroughly reviews your symptoms and medical history. You may have several tests to diagnose epilepsy and to detect the cause of seizures. They may include:

• A neurological exam. This exam tests your behavior, movements, mental function and other areas. The exam helps diagnose epilepsy and determine the type of epilepsy you may have.
• Blood tests. You may need to give a blood sample to check your blood sugar levels and look for signs of infections or genetic conditions. You also may have the levels of salts in your body checked. These salts are known as electrolytes and control the balance of fluids.
• Lumbar puncture, known as a spinal tap. If an infection is suspected as the cause of a seizure, you may need to have a sample of cerebrospinal fluid removed for testing.
• An electroencephalogram (EEG). Electroencephalogram (EEG) is the most common test used to diagnose epilepsy. In this test, electrodes attached to your scalp record the electrical activity of your brain. The electrical activity shows up as wavy lines on an EEG recording. The EEG may reveal a pattern that tells whether a seizure is likely to occur again. EEG testing also may help exclude other conditions that mimic epilepsy. Depending on the details of your seizures, this test may be done at a clinic, overnight at home or over a few nights in the hospital. If you have epilepsy, it’s common to have changes in the pattern of brain waves. These changes occur even when you’re not having a seizure. Your doctor may monitor you on video during an EEG to detect and record any seizures. This may be done while you’re awake or asleep. Recording the seizures may help determine what kind of seizures you’re having or rule out other conditions.
• High-density EEG. In a variation of an EEG test, you may have a high-density EEG. For this test, electrodes are placed closer together compared with a conventional EEG. High-density EEG may help more precisely determine which areas of your brain are affected by seizures.
• Genetic testing. In some people with epilepsy, genetic testing may give more information about the condition and how to treat it. Genetic testing is most often performed in children but also may be helpful in some adults with epilepsy.
• Neuropsychological tests. These tests assess thinking, memory and speech skills. The test results help determine which areas of the brain are affected by seizures.

You also may have brain imaging tests and scans that detect brain changes:

• Magnetic resonance imaging (MRI). An MRI scan uses powerful magnets and radio waves to create a detailed view of your brain. An MRI may show changes in the brain that could lead to seizures.
• Computerized tomography (CT). A CT scan uses X-rays to obtain cross-sectional images of your brain. CT scans can reveal changes in your brain that might cause a seizure. Those changes may include tumors, bleeding and cysts.
• Positron emission tomography (PET). A PET scan uses a small amount of low-dose radioactive material that’s injected into a vein. The material helps reveal active areas of the brain and detect changes.
• Single-photon emission computed tomography (SPECT). Single-photon emission computerized tomography (SPECT) test is used if MRI and EEG didn’t pinpoint the location in the brain where the seizures start. A SPECT test uses a small amount of low-dose radioactive material that’s injected into a vein. The test creates a detailed 3D map of the blood flow in your brain that happens during a seizure. Your doctor also may conduct a type of SPECT test called subtraction ictal SPECT coregistered to MRI (SISCOM). The test overlaps the SPECT results with brain MRI results. The test may provide even more-detailed results. This test is usually done in a hospital with overnight EEG recording.

Along with your test results, a combination of other techniques may be used to help pinpoint where in the brain seizures start:

• Statistical parametric mapping (SPM). Statistical parametric mapping (SPM) looks at the areas of the brain with increased blood flow during seizures. It’s compared to the same areas of the brains of people who don’t have seizures. This provides information about where seizures begin.
• Electrical source imaging (ESI). Electrical source imaging (ESI) is a technique that takes EEG data and projects it onto an MRI of the brain. This is done to show areas where seizures are occurring. This technique provides more-precise detail than does EEG alone.
• Magnetoencephalography (MEG). Magnetoencephalography (MEG) measures the magnetic fields produced by brain activity. This helps find the potential areas where seizures start. MEG can be more accurate than EEG because the skull and tissue surrounding the brain interfere less with magnetic fields. MEG and MRI together provide images that show areas of the brain both affected by seizures and not affected by seizures.

Diagnosis of your seizure type and where seizures begin gives you the best chance for finding an effective treatment.

There are 4 diagnostic criteria for abdominal epilepsy ⁹³⁾, ⁹⁴⁾, ⁹⁵⁾, ⁹⁶⁾:

1. Unexplained, paroxysmal gastrointestinal complaints such as paroxysmal abdominal pain, nausea, bloating, and diarrhea,
2. Symptoms of a central nervous system disturbance such as dizziness, lethargy, headache, confusion, fainting, and transient blindness,
3. Abnormal EEG with findings specific for a seizure disorder, and
4. Improvement with anti-epileptic drugs.

The diagnosis of abdominal epilepsy should be considered in patients with recurrent attacks of severe abdominal pain after exclusion of other common conditions. A high index of suspicion is required to diagnose abdominal epilepsy especially in resource‐limited settings where in most cases, EEG is not readily available.

Abdominal epilepsy differential diagnosis

The most common differential diagnosis for abdominal epilepsy is abdominal migraine as they have many overlapping features. Duration of the symptoms may be used to differentiate the two entities; the duration is longer in abdominal migraine than in abdominal epilepsy. The EEG is usually abnormal in abdominal epilepsy and may be used to confirm the diagnosis of abdominal epilepsy ⁹⁷⁾.

Patients with abdominal epilepsy may have the following possible variations in the EEGs:

1. Patients may have normal EEG patters in the inter-ictal periods and diagnosis must not be purely based on an EEG ⁹⁸⁾.
2. Extra-temporal origins of epileptic foci; secondary generalization.
3. There are strong suggestions that EEG conducted after the first 24 hours after the epileptic episode can detect abnormalities to a greater extent ⁹⁹⁾.

Abdominal epilepsy treatment

Treatment can help people diagnosed with abdominal epilepsy have fewer seizures or even completely stop having seizures. Most people with epilepsy can become seizure-free by taking one anti-seizure medicine, which is also called an anti-epileptic medicine. Others may be able to decrease the number and intensity of their seizures by taking more than one medicine.

There are more than 20 different types of anti-seizure medicines available. Most people with epilepsy will stop having seizures after trying just one or two anti-seizure medicines.

Examples of anti-epileptic medications that have been used to treat abdominal epilepsy include:

• Carbamazepine (Carbatrol, Carnexiv, and Tegretol)
• Clonazepam (Klonopin)
• Diazepam (Valium and Diastat AcuDial)
• Oxcarbazepine (Oxtellar XR and Trileptal)
• Phenytoin (Dilantin and Phenytek)
• Valproate sodium (Depacon)

Other medications that are geared toward the treatment of seizures may also be helpful. Unfortunately, there are no studies that systematically compare medication efficacy in the treatment of abdominal epilepsy. This is largely due to rarity of the condition.

Historically, patients of abdominal epilepsy were being treated using various anti-seizure drugs. Schade et al. ¹⁰⁰⁾ used diphenylhydantoin, mephobarbital, phenobarbital and primidone. The best results obtained from their study were with the use of diphenylhydantoin combined with one of the barbiturates ¹⁰¹⁾. Livingstone et al. ¹⁰²⁾ used diphenylhydantoin in all 14 patients with abdominal epilepsy. Three patients did not respond to diphenylhydantoin and hence the drug was discontinued and these patients were later started on 3-methylhydantoin and mesantoin. Douglas et al. ¹⁰³⁾ used phenobarbital and diphenylhydantoin in the treatment of their patients with abdominal epilepsy. Peppercorn and Herzog ¹⁰⁴⁾ used phenobarbital, phenytoin, valproic acid and carbamazepine for the treatment of their patients with abdominal epilepsy. A sustained response to anti-convulsants has been accepted as one of the criteria for the diagnosis of patients with abdominal epilepsy ¹⁰⁵⁾, ¹⁰⁶⁾. In another study, all the 150 children were treated with oxcarbazepine, irrespective of abnormal or normal EEG ¹⁰⁷⁾. On follow-up, all the 111 (74%) patients had an abnormal EEG and 27 (18%) patients with a normal EEG had significant decrease in all the symptoms ¹⁰⁸⁾. Twelve (8%) patients did not respond to treatment. None of the other studies conducted have started anti-epileptic medicine in patients with a normal EEG ¹⁰⁹⁾. Balabhadra et al ¹¹⁰⁾ recommended 450mg oxcarbazepine twice daily as very effective in the management of abdominal epilepsy for their patient.

All the patients were advised to continue anti-epileptic drug and follow-up till they were symptom free or a normal EEG was recorded or, maximum, up to a period of 2 years ¹¹¹⁾. Anti-epileptic drug was started in another group of children with normal EEGs suffering from chronic abdominal pain as abnormal brain waves are not always present in children suffering from epilepsy, and the presence of a normal EEG need not necessarily eliminate the diagnosis of abdominal epilepsy in any given case if history and therapeutic test validate such a diagnosis, as was stated by Livingstone et al ¹¹²⁾. Patients with epilepsies may have normal EEG in between their epileptic episode, and treatment should not be based on EEG alone; correlation with the clinical condition is important ¹¹³⁾.

Anti-seizure medicines may have some side effects. Mild side effects include:

• Fatigue
• Dizziness
• Weight gain
• Loss of bone density
• Skin rashes
• Loss of coordination
• Speech problems
• Memory and thinking problems.

More-serious but rare side effects include:

• Depression
• Suicidal thoughts and behaviors
• Severe rash
• Inflammation of certain organs, such as the liver.

For the best seizure control possible with medicine, follow these steps:

• Take medicines exactly as prescribed.
• Always call your doctor before switching to a generic version of your medicine or taking other medicines. This includes medicines you get with or without a prescription and herbal remedies.
  Never stop taking your medicine without talking to your doctor.
• Tell your doctor immediately if you notice new or increased feelings of depression or suicidal thoughts. Also contact your doctor right away if you have changes in your mood or behaviors.
• Tell your doctor if you have migraines. You may need an anti-seizure medicine that can prevent your migraines and treat epilepsy.

The goal of anti-epileptic medicine is to find what works best for you and causes the fewest side effects. Sometimes a doctor might recommend more than one medicine.

Abdominal epilepsy prognosis

Although there is no cure for abdominal epilepsy, the prognosis and outlook for abdominal epilepsy are considered to be very good ¹¹⁴⁾. Many people respond to first-line anti-epileptic medication treatments and experience a significant reduction in their symptoms. The key to having a good outlook for abdominal epilepsy is coming to a diagnosis quickly so that treatment may begin as soon as possible, along with close follow-up with your doctor.