What is Juvenile Absence Epilepsy?
Idiopathic generalized epilepsy refers to a group of conditions that account for 20 to 40% of all cases of epilepsy. This group is known for certain types of seizures: ‘absence’ seizures where a person may appear to ‘zone out’ for a bit, ‘generalized tonic-clonic’ seizures which involve stiffening and jerking of the body, and ‘myoclonic’ seizures which cause quick, sudden jerks of a muscle or group of muscles. These conditions also show specific electrical patterns in the brain, determined by a test called an electroencephalogram (EEG).
According to the latest classification by the International Leaue Against Epilepsy (ILAE), idiopathic generalized epilepsies include types such as childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, and cases where a person only experiences generalized tonic-clonic seizures.
Juvenile absence epilepsy is a specific type of idiopathic generalized epilepsy that typically starts around the time of puberty. It’s characterized by both absence and generalized tonic-clonic seizures. In some cases, people with this condition may also experience myoclonic jerks, which are sudden, brief, involuntary jerks of a muscle or group of muscles.
What Causes Juvenile Absence Epilepsy?
While it’s not entirely clear that specific genes cause epilepsy, research has uncovered some connections. Certain variations of the GRIK1 gene were found to possibly make people more susceptible to epilepsy, according to a study by Sander and his team. Additionally, in just over 40% of cases, parents were closely related, and in roughly 42% of cases, there was a family history of epilepsy.
Risk Factors and Frequency for Juvenile Absence Epilepsy
Juvenile absence epilepsy is a type of epilepsy found mainly in children, making up 1 to 2% of childhood epilepsy cases and 15% to 20% of cases of idiopathic generalized epilepsy, meaning epilepsy of unknown cause. It affects both boys and girls equally. According to research, on average, children start showing signs of this condition around the age of 12. The disease is relatively rare, with an estimated 1 in 10,000 people affected.
Signs and Symptoms of Juvenile Absence Epilepsy
Juvenile absence epilepsy is a type of seizure disorder. The main symptom, seen in almost all patients, is what’s known as absence seizures – sudden moments of impaired consciousness. Other potential symptoms can include generalized tonic-clonic seizures, which are full body seizures seen in about 79% to 95% of patients, or myoclonic jerks, which are sudden, involuntary twitches occurring in 21% to 39% of patients. Additionally, a small number of patients (around 6%) may experience a condition called convulsive status epilepticus, which means they have an extended period of continuous seizures. In juvenile absence epilepsy, these absence seizures tend to be less frequent than in a similar condition known as Childhood Absence Epilepsy.
- Absence seizures – sudden moments of impaired consciousness
- Generalized tonic-clonic seizures – full body seizures (79%-95% of patients)
- Myoclonic jerks – sudden, involuntary twitches (21%-39% of patients)
- Convulsive status epilepticus – extended period of continuous seizures (about 6% of patients)
These absence seizures might have mild versions of other seizure symptoms attached to them too, like muscle stiffness or twitching, or even unconscious behaviors. Also, it’s worth noting that the less frequent, irregular occurrence of these absence seizures is what separates juvenile absence epilepsy from similar disorders, like juvenile myoclonic epilepsy.
Testing for Juvenile Absence Epilepsy
Childhood absence epilepsy and Juvenile Absence Epilepsy are types of conditions that fall under a group of disorders called idiopathic generalized epilepsies. These types of epilepsy share similarities in their symptoms, electrical brain activity patterns, and long-term outcomes.
If your child has one of these conditions, a brain wave test, known as an EEG, is often used for diagnosis. This test usually shows a certain pattern of activity, characterized by repeated spikes and waves about three to six times per second. Sometimes, these patterns might include what doctors call polyspikes.
Imaging tests of the brain, like an MRI, often don’t show any problems when dealing with these types of epilepsy. Occasionally, they might show some general changes, but these don’t typically affect the management of disease.
You should understand that even if an EEG comes back normal, but your child has a history of symptoms that seem like Juvenile Absence Epilepsy, your doctor may still diagnose this condition. This is because sometimes brain wave tests can miss the abnormal patterns. So, your child’s symptoms and medical history are vital tools for the doctor to confirm the diagnosis.
Treatment Options for Juvenile Absence Epilepsy
The most common initial treatment for this condition is with medications such as valproic acid or lamotrigine. While another medication named ethosuximide might help with a particular type of seizures known as absence seizures, it’s not effective for treating generalized tonic-clonic seizures, which are more severe. Hence, ethosuximide is not commonly the first choice of treatment if a patient experiences both types of seizures.
It’s important to note that valproic acid can have side effects, including causing birth defects if used during pregnancy and weight gain, which can be a concern for young female patients. Because of these potential side effects, lamotrigine may be a better choice for this group of patients.
While Juvenile absence epilepsy, a type of epilepsy common in adolescents, typically responds well to medication, some medicines can actually worsen seizures. These include phenytoin, carbamazepine, oxcarbazepine, gabapentin, pregabalin, and vigabatrin, and doctors generally avoid these medications when treating this condition.
What else can Juvenile Absence Epilepsy be?
Here are some examples of different types of epilepsy commonly seen in children:
- Benign epilepsy of childhood with centrotemporal spikes
- Benign familial neonatal convulsions
- Benign idiopathy neonatal convulsions
- Benign partial epilepsy of childhood with occipital paroxysms
- Benign epilepsy with affective symptoms
- Childhood absence epilepsy
What to expect with Juvenile Absence Epilepsy
In a long-term study conducted by Trinka et al., it was found that 62% of patients with Juvenile Absence Epilepsy (JAE) – a type of childhood epilepsy that causes periods of “blanking out” – had gone into remission. This means their symptoms had decreased or disappeared entirely. Interestingly, approximately 18% of JAE patients went on to develop another form of epilepsy known as juvenile myoclonic epilepsy.
A separate study that looked at the outcomes of all forms of absence epilepsies – seizures where the person seems to “zone out” for a few seconds – found that half of the patients later developed generalized tonic-clonic seizures. These seizures, also known as grand mal seizures, involve a loss of consciousness and violent muscle contractions. Among these patients, the rate of complete seizure freedom was 78% for those only with absence seizures and 35% for those who went on to develop additional tonic-clonic seizures.
Other studies have reported a range of remission rates for JAE, from 21% to 89%. In one study, it was found that all patients with JAE experienced a relapse of symptoms after stopping their anti-epileptic drugs (AEDs), and 25% of those who continued on AEDs also experienced a relapse. Interestingly, in one study, only 3 out of 9 seizure-free JAE patients experienced a relapse after stopping their medication.
Although many patients respond well to treatment and achieve good control of their seizures, often, long-term use of anti-epileptic medication is necessary to manage symptoms properly.
Possible Complications When Diagnosed with Juvenile Absence Epilepsy
SUDEP, or Sudden Unexpected Death in Epilepsy, is a feared outcome of having epilepsy. A larger number of general tonic-clonic seizures (major seizures) is seen as a risk factor for SUDEP, but it has also been observed in a variety of other forms of epilepsy. Some forms of epilepsy are generally considered mild, but SUDEP can still occur.
It’s often believed that Childhood Absence Epilepsy has a better long-term outlook compared to Juvenile Absence Epilepsy, although data doesn’t completely back up this assumption. The occurrence of general tonic-clonic seizures is generally an indicator of worse outcomes.
Previously, individuals with absence epilepsy (the ‘petit mal’ or ‘spacing out’ type of seizures) were believed to have normal cognitive functions. However, recent studies have revealed weaknesses in areas like behavior, emotion, intelligence, executive functioning, attention, and language.
In fact, cognitive development was not necessarily linked to being seizure-free. Just over half of the individuals underperformed academically in a range from mild to severe, and just over a third had other conditions that could impact their learning.
- Risks of Epilepsy: SUDEP (Sudden Unexpected Death), severe seizures, a range of epilepsy types
- Outcomes of Childhood vs. Juvenile Absence Epilepsy: commonly believed better outlook for Childhood Absence Epilepsy potentially misleading, occurrence of severe seizures signals worse outcomes
- Cognitive Effects: Newer studies indicate potential weaknesses in behavior, emotion, executive functioning, intelligence, attention, and language; over half of patients study underperform academically, and around a third have conditions impacting learning
Preventing Juvenile Absence Epilepsy
Patients should be advised about the importance of avoiding certain behaviors or factors that can make their medical condition worse. These factors could include not getting enough sleep or consuming alcohol. Breathing too quickly (hyperventilation) could also trigger absence seizures, which are brief episodes during which the patient appears to be staring off into space. Therefore, it’s crucial for patients to be aware and steer clear of these triggers.
