The age of onset of CAE is usually between 4 and 10 years, with a peak between the ages of 5 and 7 [4][2]. The onset of absence epilepsy before age 4 should raise concern for an underlying glucose transporter type 1 (GLUT1) deficiency[4]. 

Regarding its clinical presentation, family members and teachers usually describe brief spells in which the patient has a loss of awareness, is unresponsive and has a behavioral arrest. They describe the patient during these spells as having “a blank stare”[2]. Episodes frequently occur, often 10 to more than 30 times throughout the day. Most children stop their activity completely, but some can continue the activity more slowly or in an unusual manner[1]. Some children have 3-Hertz regular eyelid fluttering[1][2]. Oral automatisms can also occur, especially with prolonged seizures or during hyperventilation. Children frequently have mild clonic or tonic movements in the first few seconds of the spell.  Pallor is frequently reported[1].  Urinary incontinence is rare. Spells usually last between 4 and 30 seconds. Hyperventilation, a state of arousal, sleep deprivation, and medication use can affect the duration of the seizure [1]. These seizures are not preceded by an aura and do not have a postictal state [7].

For JAE, the age of onset is classically between 10 and 19 years with a peak at 15 years [4]. Seizures are less frequent than in CAE but tend to last longer [3][4]. 

On physical examination, hyperventilation can trigger absence seizures. To test this, the examiner asks the child to blow repetitively for more than 2 minutes. It can be helpful to use a pinwheel or a paper because this encourages the child to cooperate more during testing. If hyperventilation is done successfully, the patient will develop seizures that can be seen clinically and /or on EEG. there is some evidence that absence seizures are more easily provoked when the person is in a sitting position[8].

Absence status consists of generalized, non-convulsive seizures characterized by impairment of awareness, and intermittently has other manifestations such as automatisms or subtle myoclonic, tonic, atonic, or autonomic phenomena. Patients usually have a previous diagnosis of generalized epilepsy. Absence status presents as a non-convulsive seizure lasting between a half hour and several days. It usually ends spontaneously and suddenly but should be treated with anti-seizure medications at the time of diagnosis[9].

EEG is the main diagnostic tool for the evaluation of absence epilepsy. In the case of childhood absence seizures, EEG shows bilaterally synchronous and symmetrical 3-Hertz spike-and-wave discharges that start and end abruptly. These discharges can sometimes have maximum frontal amplitude or begin with unilateral focal spikes[2]. In 50% of seizures in CAE, the initial discharge seen has a typical spike-and-wave morphology. The remaining 50% can show a single spike, polyspikes, or an atypical, irregular, generalized spike-and-wave[1]. The background is normal[4]. 

Atypical absence seizures show a more insidious onset and offset, slower spike-and-wave paroxysms (less than 3 Hertz), and an abnormal interictal background[4].  

Neuropsychological testing has shown that patients with CAE have cognitive deficits, especially involving attention, executive function, verbal and visuospatial memory. The difficulty with language and reading is also commonly reported. Depression, anxiety, and attention-deficit/hyperactivity disorder also have been reported more frequently in patients with CAE[1]. 

Since CAE is generalized epilepsy, imaging studies are not performed routinely.

In JAE, EEG demonstrates paroxysms of generalized 3- to 4-Hertz spike-and-wave or polyspike-and-wave discharges [4]. 

In the case of absence status, EEG shows continuous or nearly-continuous generalized spike-and-wave or polyspike-and-wave discharges at 2–4 Hertz.

The first-line treatment for absence epilepsy is ethosuximide. A randomized controlled trial performed in 2010 that included 446 children with CAE showed that ethosuximide and valproic acid were superior to lamotrigine [10]. However, this study had a low seizure-free rate with 53% of patients in the ethosuximide group, 58% on the valproic acid group, and 29% of patients taking lamotrigine. The group that received valproic acid had significantly lower scores on attentional measures as compared to the ethosuximide and lamotrigine groups. For this reason, ethosuximide is the preferred agent for the treatment of absence epilepsy. An study showed that only one quarter of children with absence epilepty became seizure free with levetiracetam. Whne effective, leveteriacetam can control absence epilepsy at a relatively low dose (usually less then 40 mg/kg/day)[11]. 

The most frequent side effects of ethosuximide are abdominal pain and nausea. For this reason, ethosuximide should be taken with meals. Other medications that can be used for management of CAE include valproate, lamotrigine, and topiramate. Second-line medications that can be used as adjunct therapy include valproic acid, zonisamide, and levetiracetam.

It is important to note that some sodium channel blockers like phenytoin, carbamazepine, gabapentin, pregabalin, and vigabatrin can worsen absence seizures [4]. 

Women of childbearing age not using contraception should not be treated with valproic acid; the preferred agent is ethosuximide.

Some experts suggest that a ketogenic or a medium chain triglyceride diet may be beneficial, but good evidence to support their use is lacking.

The differential diagnosis for staring spells includes absence epilepsy, focal seizures with alteration of awareness, and non-epileptic paroxysmal events. 

Focal epilepsy with alteration of awareness (previously called complex partial epilepsy) can also present with behavioral arrest and automatisms. However, these seizures are usually less frequent than absence seizures. Patients can have generalized seizures with focal epilepsy. Semiology of automatisms can vary depending on the area of the cerebral cortex where the seizures originate. 

A study that evaluated non-epileptic staring spells using video-EEG monitoring found that these episodes were often characterized by arrest of all activity, vague facial expression, and vision fixed on one point without blinking. When the duration of the events was quantified, staring episodes lasted anywhere between 3 and 74 seconds. In most children, it was difficult to determine the onset and end of the event. Most parents were not able to regain the child’s attention if they waved their hand in front of the child. Other more energetic measures like hand clapping or other loud sounds were successful at stopping the events in all children. A significant percentage of children (41%) were inactive at the onset of the stare, and 18% of children were watching television when the event began[12].

A retrospective chart review performed in a tertiary care epilepsy center showed that among 276 patients in the epilepsy monitoring unit to have their starring spells monitored, only 11% were deemed to have seizures [13]. Therefore, most staring spells are non-epileptic in nature. When patients present with staring spells, practitioners should be careful and not tell parents or other providers that these episodes are “absence seizures” before EEG evaluation is completed. The above-mentioned study developed a tool to determine the pretest probability of seizures in children presenting with staring spells. This tool accounts for patient variables such as results of previous EEG, previous use of antiseizure medications or treatments for psychiatric conditions, and duration of the spells [13]. 

Typical childhood absence epilepsy occurs in childhood and resolves by adolescence. Seizure freedom is reported in 57% to 74% of the patients. Patients who have generalized tonic-clonic seizures usually do not respond to initial ethosuximide monotherapy and do not achieve long term remission.

The risk for accidental injuries during absence seizures compared with controls is well reported[12]. As mentioned before, these patient have problems in the areas of attention, executive function, verbal and visuospatial memory. Difficulty with language and reading is also commonly reported. Depression, anxiety and ADHD have also been reported more frequently in patients with CAE[1].

A general pediatric neurologist or a pediatric epileptologist should be consulted when a patient has staring spells that are suspected to be seizures. Typically, an outpatient evaluation is a reasonable first step.

As explained above, most staring spells are non-epileptic in nature. When patients present with staring spells, practitioners should explain to caregivers that the differential diagnosis includes seizures, but they should avoid giving a specific diagnosis of “absence seizures” before EEG evaluation is completed. 

It can be very useful to request caregivers to take videos of staring spells, as this can help characterize them. Event calendars/logs can assist in understanding the frequency, pattern, and possible triggers. 

Caregivers of children with CAE should know that generalized tonic-clonic seizures are rare. For this reason, rescue medications such as rectal diazepam and intranasal midazolam are not routinely prescribed. Nevertheless, caregivers should be taught what to do if the child has a generalized tonic-clonic seizure. 

Caregivers often assume that, since absence seizures are very brief, they are harmless. On occasions they question the need to treat with medications, arguing that risks could outweigh benefits. In these situations, we recommend explaining that the child is experiencing frequent episodes of altered consciousness that can increase the risk of accidents. Seizures also can interfere with learning and have a negative impact on school performance.  

Activities like swimming, diving or rock climbing should only be permitted under supervision.

Driving is not permitted if seizures are not controlled with medications.

• Absence epilepsy is a primary generalized epilepsy.
• It is classified as typical or atypical absence depending on seizure characteristics and EEG pattern. 
• Absence seizures are characterized by behavioral arrest and EEG showing 3-Hertz spike-and-wave discharges. Episodes usually occur multiple times per day. 
• Absence seizures are seen in several generalized epilepsies including childhood absence epilepsy, juvenile absence epilepsy, and juvenile myoclonic epilepsy. 
• Episodes of behavioral arrest should be called “staring spells” until EEG evaluation is performed. A patient can only be diagnosed with absence epilepsy if they have characteristic seizure semiology and EEG findings. 
• Staring spells can be epileptic or non-epileptic, with the majority being non-epileptic. When episodes are epileptic in nature, they may be due to absence seizures or to focal seizures with impaired awareness (complex partial seizures) 
• The first-line treatment for absence seizures is ethosuximide. Other therapies include valproate, lamotrigine, and topiramate. Second-line medications that can be used as adjunct therapy include zonisamide and levetiracetam.
• Carbamazepine, phenytoin, gabapentin, vigabatrin, and other medications with similar mechanisms of action can worsen absence epilepsy. 
• Approximately 60% of patients with childhood absence epilepsy eventually achieve seizure freedom.
• Lack of response to ethosuximide and the presence of generalized tonic-clonic seizures have been associated with lack of seizure remission and life-long epilepsy. 

Absence seizures should be managed by a neurologist. However, the long-term care and monitoring are done by an interprofessional team that includes the neurologist (child neurologist in the case of the pediatric population), primary care provider, nurse, and pharmacist.

The pharmacist should educate the patient on the importance of medication compliance. In addition, the pharmacist should ask about any adverse reaction at the time of dispensing of the medication. The caregiver should be asked if the symptoms are controlled if not, the pharmacist should communicate with the interprofessional team about the need for change in dosage.

The primary care practitioner together with the neurologist should follow up on the liver function tests, amylase and complete blood count. In addition, birth control should be managed in women who are taking valproic acid. Finally, drug levels should be monitored periodically as these drugs have a narrow therapeutic index.

A few patients with intractable absence epilepsy may be candidates for the ketogenic diet. If this is the case a registered dietician with expertise in this type of diet should be consulted and evaluate the patient periodically. 

Finally, mental health providers may be involved in the patients care as many of these patients develop anxiety, depression, and stress.

Most of the patients need life long follow up and it is essential that the interprofessional team communicate with each other any time when there is a change in drug dose, change in drug type, or development of adverse drug reactions.