New-Onset Seizure, Child Case File

New-Onset Seizure, Child Case File

Eugene C. Toy, MD, Ericka Simpson, MD, Pedro Mancias, MD, Erin E. Furr-Stimming, MD

CASE 44

An 8-year-old boy is brought into the emergency room (ER) by his mother after he awoke from sleep with right-mouth tingling followed by 1 minute of right facial twitching and drooling. During this spell, he had difficulty speaking. His mother says that when he was 1 year old he had an episode of generalized shaking while ill with a viral gastroenteritis and a fever of 38.9°C (102°F). On further questioning, she recalls that on one occasion when he was 4 years old, he awoke having urinated in his bed, bitten his tongue, and was lethargic for half a day. The family history is significant for childhood seizures in his father, who grew out of them by the time he was 13 years old. The patient has otherwise developed normally, scoring A’s in the gifted and talented school program. He has not had any recent fevers or head trauma. On examination, he appears slightly tired but otherwise back to his baseline. His temperature is 36.7°C (98°F); heart rate is 80 beats/min; respiration rate is 18 breaths/min; and blood pressure is 90/60 mm Hg. His examination is normal with appropriate comprehension and good fluency, normal fundoscopic examination without papilledema, no residual facial paresthesia, and no focal weakness or numbness. His reflexes are normoactive and his gait is steady. He has no skin lesions. He has no evidence of head trauma, and his neck is soft and supple. His heart, lung, and abdominal examinations are unremarkable.

▶ What is the most likely diagnosis?

▶ What is the next diagnostic step?

▶ What is the next step in therapy?

ANSWERS TO CASE 44:

New-Onset Seizure, Child                                                       

Summary: A healthy 8-year-old boy presents to the ER with a nocturnal episode of facial twitching and speech arrest. He has a history of a similar nocturnal event when he was 4 years old and a seizure associated with a fever when he was 1 year old. His father had childhood seizures. The patient’s development has been normal. His examination is unremarkable.

• Most likely diagnosis: Pediatric seizure disorder, history of febrile seizure
• Next diagnostic step: Rule out status epilepticus, electroencephalograph (EEG), magnetic resonance imaging (MRI)
• Next step in therapy: Observation in most cases

ANALYSIS

Objectives

1. Understand appropriate terminology to accurately describe seizures.
2. Understand common causes of seizures by age and epileptic syndromes of childhood.
3. Know a diagnostic and treatment approach to new-onset seizure in the pediatric population based on historic and examination findings.

Considerations

In the presented case, this 8-year-old boy experienced a characteristic nocturnal seizure with right facial twitching and drooling. His consciousness was preserved. Before 5 years of age, patients can also have secondary generalization, with spread from the facial twitching to involve whole-body tonic-clonic activity with incontinence, tongue-biting, and postictal confusion. The patient also has a history of a febrile seizure and family history of childhood seizures; therefore, this presentation is highly suggestive of benign rolandic epilepsy, which has an autosomal dominant pattern of inheritance (see Case 49). However, new-onset seizures in the pediatric population can be associated with a variety of acquired or inherited conditions that require a practical approach to diagnosis and management.

APPROACH TO:

New-Onset Childhood Seizure                                              

DEFINITIONS

SEIZURE: Single event characterized by abnormal excessive synchronized discharge of cortical neurons. Up to 10% of people will have a seizure at some point in their lives.

EPILEPSY: The tendency to have recurrent seizures with stereotyped cognitive or physical manifestations. The lifetime risk of epilepsy is 3.8%. Epileptic syndromes can be categorized broadly into generalized epilepsies and localization-related epilepsies.

GENERALIZED EPILEPSY: Recurrent seizures that arise from both cerebral hemispheres at once because of an inherited predisposition. These include absence seizures, tonic-clonic seizures, atonic seizures, and myoclonic seizures. They occur suddenly without auras or other focal symptoms.

LOCALIZATION-RELATED (FOCAL) EPILEPSY: Recurrent focal seizures that arise from a single unilateral brain region or multiple discrete areas in the brain. Idiopathic causes have a known genetic basis and include autosomal dominant benign rolandic epilepsy and temporal lobe epilepsy, whereas symptomatic causes involve acquired pathologies such as strokes, neoplasms, and congenital malformations. Cryptogenic causes are associated with clinical, mental, and developmental retardation with no obvious structural lesion.

SIMPLE PARTIAL SEIZURE: Focal seizure with no impairment of consciousness. Auras such as odd smell or taste are simple partial seizures.

COMPLEX PARTIAL SEIZURE: Focal seizure with impairment of consciousness during or after the event. Both simple and complex partial seizures can spread to produce secondary generalized tonic-clonic seizures with urinary incontinence, tongue-biting, and postictal confusion.

STATUS EPILEPTICUS: Historically defined as a neurologic emergency in which a seizure persists or recurs for 30 minutes without return to baseline mentation. In 2015, the International League Against Epilepsy (ILAE) revised the definition with two operational dimensions: the first time point (t1) is the length of the seizure that leads to “continuous seizure activity”; and the second time point (t2) is the time of ongoing seizure activity after which there is a risk of long-term consequences. For generalized convulsive status epilepticus, t1 and t2 are defined as 5 minutes and 30 minutes, respectively.

CLINICAL APPROACH

Common Causes of Pediatric Seizures

From the neonatal period until 3 years of age, the most common cause of seizures is prenatal injury, followed in order of decreasing occurrence by perinatal injury, metabolic defects, congenital malformations, central nervous system (CNS) infections, and postnatal trauma. In children between 3 and 20 years of age, genetic predisposition is the most common cause, followed by infections, trauma, congenital malformations, and metabolic defects. The four most common hereditary epilepsies are febrile convulsions, benign rolandic epilepsy, childhood absence epilepsy, and juvenile myoclonic epilepsy. The first three syndromes resolve spontaneously. Febrile seizures are very common, occurring in 3% to 5% of children between 6 months and 3 years of age during illness with high fevers, and should disappear by 5 years (only 2% go on to develop epilepsy). Absence epilepsy is a generalized epilepsy characterized by brief staring spells with behavioral arrest and EEG pattern of generalized 3-Hz spike-and-wave discharges provoked by hyperventilation. Juvenile myoclonic epilepsy involves myoclonic seizures that occur shortly after awakening and generalized tonic-clonic seizures that are triggered by sleep deprivation, and it responds well to antiepileptic treatment with valproic acid.

Diagnostic Evaluation of a New-Onset Seizure in a Child

The first priority in any seizure patient is to determine that active seizures have stopped. Status epilepticus is a neurologic emergency because of the potential of permanent brain injury and complications such as hypoxia and autonomic instability. A patient may not be overtly convulsing but still have impaired mentation with subtle focal twitching in a condition called nonconvulsive status epilepticus, which carries similar morbidity. When status epilepticus is suspected, airway protection, breathing, and circulation (ABC) measures should be mobilized, and antiepileptic medications should be expeditiously administered, beginning with benzodiazepines and phenytoin. STAT chemistries should be checked for correctible metabolic abnormalities such as hypoglycemia and hypocalcemia, as well as other tests as indicated, such as toxicology. When status epilepticus has been ruled out or addressed, it will be important to obtain an accurate history and examination of the child to rule out head trauma, infection, developmental abnormalities, and focal neurologic deficits. These atypical features should alert the physician to a symptomatic epilepsy that can be caused by focal etiologies such as stroke, neoplasm, infection, and congenital malformations. Historical description of the seizure can also help to differentiate this patient’s localization-related symptomatology from a generalized epilepsy such as absence seizures, which involve staring spells, or primary generalized tonic-clonic seizures.

The EEG can clarify any question of nonconvulsive status epilepticus in somnolent patients and is recommended to evaluate all first childhood seizures for classification (except febrile seizures in children aged <5 years). Up to 50% of epilepsy patients will have a normal first EEG. MRI should be performed, particularly with an abnormal developmental history or physical examination. If the history and examination suggest infection, a lumbar puncture should be performed and empiric antibiotics initiated promptly. In the neonate with seizures and a suspected metabolic abnormality, serum ammonia level, and both serum and urine organic acids should be sent.

The patient should be admitted for further monitoring and treatment if altered mental status or focal deficits are slow to resolve, if seizures or a malignant underlying etiology persists, or if there are abnormal findings such as fevers and papilledema. A neurologist should be consulted to assist with diagnosis, therapy, family counseling, and follow-up.

TREATMENT

Transfer to the intensive care unit for intubation, continuous EEG, and cardiovascular monitoring is necessary when status epilepticus fails to respond to benzodiazepines and phenytoin and requires further suppression with midazolam or phenobarbital. For new-onset seizures, treatment should be directed at the underlying etiology.

Between 20% and 70% of people with a first unprovoked generalized tonic-clonic seizure will never have a second seizure, so initiation of antiepileptic agents is usually postponed until the second seizure unless there is a high suspicion that epilepsy will ensue. These higher-risk patients are those with focal neurologic deficits, mental retardation, or MRI or EEG abnormalities. Primary generalized epilepsies such as absence seizures respond better to valproate and ethosuximide, while localization-related epilepsies should be treated with medications such as phenytoin or carbamazepine. Patients with benign rolandic epilepsy have infrequent seizures and will generally do fine with mere observation. Should the seizures worsen, a medication for partial seizures can be instituted. The patient’s parents should be counseled about the importance of not leaving the child in the tub or pool alone, or unmonitored where a seizure can put the child in danger. Teenage patients should be forbidden to drive until they have been seizure-free for at least 6 months.

CASE CORRELATION

• See also Case 45 (Febrile Seizures) and Case 49 (Benign Epilepsy with Centrotemporal Spikes)

COMPREHENSION QUESTIONS

Match the following etiologies (A-E) to the clinical situations 44.1 to 44.4 (more than one answer may be correct):

A. Symptomatic seizure

B. Cryptogenic seizure

C. Primary generalized epilepsy

D. Localization-related epilepsy

E. Simple partial seizure

44.1 A 7-year-old boy is brought to clinic by his mother after he persistently complains of smelling a foul odor not apparent to anyone else.

44.2 An 8-year-old girl develops seizures. She has dysmorphic facies and is in special education. Her MRI and EEG are normal.

44.3 A 5-year-old girl is noted by her teacher to have sudden staring spells with blinking while in class.

44.4 A 3-year-old boy is brought for multiple episodes of right arm stiffening followed by generalized shaking. He is found on MRI to have a left parietal brain tumor.

ANSWERS

44.1 E. There is no indication that this child is unconscious or has a postictal state. There is no motor activity. The only symptoms are “smelling a foul odor,” which is an aura. Auras are simple partial seizures. Other simple partial seizures may include sensations of falling, other hallucinations (taste, hearing, sight), sense of spatial distortion, or labored speech. Usually, the patient has a memory of the event.

44.2 B. This 8-year-old girl with normal brain imaging but dysmorphic facies and developmental delay has what is called “cryptogenic seizure,” which means a seizure with etiology not yet determined but with a likely underlying cause. This is distinguished from idiopathic seizures, in which there is no cause determined but is thought to have a strong genetic component.

44.3 C. The description of the “staring episodes” is classic for absence seizures. These episodes are associated with impaired consciousness; in other words, the patients have no memory of the event. The typical absence seizure is abrupt, lasts from a few seconds to 30 seconds, is associated with cessation of activity, does not have a postictal phase, and resolves abruptly, with the patient continuing activity and usually unaware of the seizure. Absence seizures are a form of primary generalized epilepsy and respond well to ethosuximide.

44.4 A and D. This child has both a symptomatic seizure and a localization-related epilepsy. A symptomatic seizure is caused by a previously known or suspected CNS disorder and will continue. The partial seizures with secondary generalization are symptomatic from an identified lesion (brain tumor) and will likely continue to recur without antiepileptic therapy.

    CLINICAL PEARLS    

▶ A new-onset seizure in a child often does not progress to epilepsy and can be followed for recurrence before considering the initiation of an antiepileptic agent. ▶ Status epilepticus is a neurologic emergency and can be the presentation of a patient’s first seizure. It does not necessarily signify an increased risk for epilepsy. ▶ Persisting altered mental status can be the only manifestation of nonconvulsive status epilepticus, and there should be a low threshold for treating with benzodiazepines or phenytoin while awaiting EEG confirmation. ▶ The history with an accurate description of the seizure and epilepsy will usually provide the highest diagnostic and prognostic yield out of all diagnostic tests available. ▶ Primary generalized epilepsies have the best prognosis. ▶ Benign rolandic epilepsy, febrile seizures, absence seizures, and juvenile myoclonic epilepsy are the four most common inherited epilepsies, and children will usually “grow out of” the first three. ▶ Broad-spectrum antiepileptic drugs such as valproate are better for treating generalized epilepsy, whereas narrow-spectrum drugs such as phenytoin and carbamazepine are more suited for localization-related epilepsy.

REFERENCES

American Academy of Pediatrics. Neurodiagnostic evaluation of the child with a simple febrile seizure. Pediatrics. 2011;127(2): 389. 

Appleton R, Macleod S, Martland T. Drug management for acute tonic-clonic convulsions including convulsive status epilepticus in children. Cochrane Database Syst Rev. 2008;(3):CD001905. 

Brophy GM, Bell R, Claassen J, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17(1):3-23. 

Chowdhury A, Brodie MJ. Pharmacological outcomes in juvenile myoclonic epilepsy: support for sodium valproate. Epilepsy Res. 2016;119:62-66. 

Glauser TA, Cnaan A, Shinnar S, et al. Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy: initial monotherapy outcomes at 12 months. Epilepsia. 2013;54(1):141-155. 

Guerrini R. Epilepsy in children. Lancet. 2006;367(9509):499-524. 

Hesdorffer DC, Logroscino G, Benn EK, Katri N, Cascino G, Hauser WA. Estimating risk for developing epilepsy: a population-based study in Rochester, Minnesota. Neurology. 2011;76(1):23-27. 

Pina-Garza JE. Fenichel’s Clinical Pediatric Neurology: A Signs and Symptoms Approach. 7th ed. London, UK: Elsevier; 2013. 

Trinka E, Cock H, Hesdorffer D, et al. A definition and classification of status epilepticus—report of the ILAE Task Force on Classification of Status Epilepticus. Epilepsia. 2015;56(10):1515-1523.

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