What Causes Seizures?

Identification of the specific cause of a seizure (Table 59-1) usually comes only after the patient is stable but may be very important in initiating appropriate treatment. Any time a patient has the new onset of seizures, you must first think of the dangerous and reversible causes. Chapter 37 discusses seizures in greater detail.

Table 59-1 Causes of Seizures

What Causes Seizure in a Child Who Has a Fever?

A “simple” febrile seizure is the most likely type of generalized tonic-clonic seizure in a febrile child between 6 months and 6 years of age (Table 37-1). Other seizures that occur with fever include “complex” febrile seizure, underlying epilepsy or metabolic disease with seizure triggered by fever, and seizure associated with central nervous system infection (Chapter 37).

How Do I Determine the Cause of a Seizure?

Your immediate reaction to a seizing patient should be to perform the ABCs (see Chapter 31) and to stabilize the patient. It is important to test for hypoglycemia and to identify hypoxemia with oximetry. Poisoning may have a characteristic toxidrome, which is a unique pattern of signs and symptoms affecting the heart rate, blood pressure, pupil size, and body temperature (Table 59-2). Electrolyte abnormalities and inborn errors of metabolism may be identified by blood chemistry tests. Central nervous system (CNS) infection usually has characteristic signs and will be detected with lumbar puncture and cultures. Concern about possible intracranial hemorrhage or tumor will prompt imaging studies. A seizing infant may be the victim of physical abuse (see Chapter 24 and the sections on altered level of consciousness and head trauma in this chapter). Finally, idiopathic epilepsy and febrile seizure are diagnoses of exclusion.

Table 59-2 Toxidromes (Selected List)

Do All Febrile Patients Who Have Seizures Need Lumbar Puncture?

Patients with a simple febrile seizure rarely require a lumbar puncture. If the patient is awake and alert after the seizure, you can rule out meningitis clinically with history and physical examination. On the other hand, a lumbar puncture must be done if the febrile child appears “toxic” or if there is obvious meningeal irritation (stiff neck, Kernig’s and/or Brudzinski’s sign). If the patient is sleepy after the seizure but seems to be slowly waking up, you can observe for a period of time. If the patient is not awake and alert after about 30 minutes, a lumbar puncture should be considered. Also, if the child is younger than 6 months, most authorities recommend a spinal tap after a seizure with fever.

What Should I Do If a Patient Is Seizing?

The key is to take a limited number of actions in a specific sequence that will keep you task-oriented (see Chapter 31):

After you have stabilized your patient and considered the dangerous and reversible causes of seizures, you should administer a medication to stop the seizure. Once the seizure has stopped, identify other seizure causes with a thorough history and physical examination and selected diagnostic and imaging tests.

When Should I Give an Anticonvulsant to a Patient Who Is Having a Seizure?

Anticonvulsants should only be administered after the steps discussed previously. If the seizure has gone on 5 minutes or more, you should consider anticonvulsant administration.

What Anticonvulsant Should I Use to Stop a Seizure?

The benzodiazepines (lorazepam, diazepam, midazolam) are usually used first because they have a short onset of action and are relatively safe. These may be given intravenously, intraosseously, or by rectal administration. Lorazepam is often considered the drug of choice for persistent seizures because of its longer duration of action. If these fail, an intravenous loading dose of phenobarbital or phenytoin is the next choice.

What Causes a Child to Have Difficulty Breathing?

Some important causes of respiratory distress that affect children include the following:

What Findings Help Me Identify Respiratory Distress?

Evaluation of the following will identify patients with ventilation prob-lems and difficulty breathing:

How Do I Treat an Infant Who Is Wheezing?

A wheezing infant younger than 1 year most likely has bronchiolitis, especially during the winter months. This is usually caused by RSV (Chapter 69). Most infants require only supportive treatment, but some may need more aggressive management. Hypoxia is a common complication of bronchiolitis and pulse oximetry is an important test. Administration of oxygen should be considered when the oxygen saturation is below 94%. Apnea is another potential complication of RSV bronchiolitis, especially in young infants, and will necessitate hospitalization when present. Because wheezing is a prominent clinical finding, many physicians empirically treat bronchiolitis with inhaled bronchodilators (nebulized albuterol or racemic epinephrine). Anecdotal evidence suggests that bronchodilator therapy results in short-term improvement of bronchiolitis, but systematic reviews of the literature have not provided evidence that bronchodilator treatment reduces rates of admission to hospital, improves oxygen saturation, or affects long-term outcome. Use of oral corticosteroids is not recommended for bronchiolitis. Wheezing is discussed further in Chapters 25 and 69.

Is Management Different for an Older Child with Wheezing?

Symmetrical, diffuse, polyphonic wheezing in a child older than 1 year or with recurrent wheezing is much more likely to be asthma (Chapter 69) than bronchiolitis. Bronchodilators and corticosteroids have documented efficacy, both acutely and long-term. Oxygen may be needed for severe asthma attacks, so pulse oximetry should be used for all patients. If asymmetrical, monophonic wheezing is detected, foreign- body aspiration must be considered. Imaging studies and bronchoscopy may be needed for diagnosis and management.

What Diagnoses Should I Consider When I See a Child Who Is Difficult to Arouse?

Altered level of consciousness and seizures have similar causes. Think about a cluster of causes that are prioritized by seriousness.

First, consider urgent, life-threatening problems:

Next, identify dangerous yet reversible causes:

Then, consider serious causes that require aggressive evaluation and management:

Finally, think about intussusception. The diagnosis is counterintuitive because it seems to have nothing to do with the CNS directly, but this gastrointestinal obstruction can present as lethargy without obvious gastrointestinal symptoms in a young child (usually between 3 months and 3 years of age, with a peak at 11 months). An experienced pediatrician will often think of this diagnosis and perform a rectal examination to look for blood in the stool. A child who presents late with intussusception may have enough injury to the bowel to present with “currant jelly stool,” a grossly bloody stool classic for this problem.