The emergency department (ED) notifies you that one of your patients is being evaluated for new-onset seizures. The 2-year-old boy was in his normal state of good health until this morning, when he complained of a headache and then fell to the floor. While waiting for the ED physician to come to the phone, you review the patient’s chart and find that he has had normal development. His family history is significant for a single seizure of unknown etiology in his father at 4 years of age. According to the ED physician, the boy’s mother saw jerking of both arms and legs. When the ambulance arrived 5 minutes later, the child had stopped jerking but was not arousable; his heart rate was 108 bpm, respiratory rate 16 breaths/min, blood pressure 90/60 mm Hg, and temperature 104°F (40°C). His blood sugar level was 135 mg/dL. By the time the child arrived to the ED, he was awake and he recognized his parents. His physical examination in the ED is significant only for a red bulging immobile tympanic membrane. His complete blood count and urinalysis are normal.
What is the most likely diagnosis?
What is the best management for this condition?
What is the expected course of this condition?
ANSWERS TO CASE 41: Simple Febrile Seizure
Summary: An otherwise normal 2-year-old boy, with a family history of a single seizure in his father at 4 years of age, has a brief, generalized, self-limited seizure associated with an elevated temperature. His examination is nonfocal. He has completely recovered within 1 to 2 hours of the seizure.
• Most likely diagnosis: Simple febrile seizure.
• Best management: Parental education, injury prevention during seizures, and fever control.
• Expected course: More seizures with fever may occur, but he is likely to “grow out” the condition by 5 to 6 years of age. He is likely to have no sequelae and is expected to have normal development.
1. Describe a typical febrile seizure.
2. Explain the typical course of febrile seizures.
3. List factors that increase the risk of further seizure activity.
This patient likely had a simple febrile seizure. The seizure was short, self-limited, and generalized without focal findings. The child had an elevated temperature and is between the ages of 6 months and 6 years. He had a short postictal state and then quickly returned to normal. He is old enough to have reliable neck examination findings and has no evidence of meningeal irritation. The father might have had a febrile seizure; data are insufficient to make that conclusion.
EPILEPSY: Recurrent seizure activity; may or may not have identifiable cause.
FEBRILE SEIZURE: A seizure occurring in the absence of central nervous system (CNS) infection with an elevated temperature in a child between the ages of 6 months and 6 years.
SEIZURE:Abnormal electrical activity of the brain resulting in altered mental status and/or involuntary neuromuscular activity.
A diagnosis of febrile seizure must be made only after considering CNS infection as the cause. Two classic physical findings suggest meningeal irritation: Kernig sign (patient is supine, leg flexed at the hip and knee at 90° angle, pain is induced with leg extension) and Brudzinski sign (while supine, passive neck flexion results in involuntary knee and hip flexion). If the neurologic examination is abnormalafter the seizure, the seizure occurred several days into the illness, or if the child is unable to provide adequate feedbackduring a neck examination, a lumbar puncture (LP) may be necessary. The meningeal signs described above usually are not reliable in children younger than 1 year; therefore, an LP is recommended for such patients with fever and seizure. Contrast-enhanced brain imaging should occur before LP when a space-occupying lesion, such as a brain abscess, is a possibility.
Febrile seizuresare a uniquely pediatric entity. Typically occurring between 6 months and 6 years of age, these convulsions are distressing to the parent but only occasionally pose a threat to the child. Febrile seizures are common, occurring in 2% to 4% of all children; they seem to have a genetic basis (many children have a family history of febrile seizure). Febrile seizure risk is increased (10%-20%) when a first-degree relative has been diagnosed with the same.
Febrile seizures frequently are classified as simple or complex; the distinction helps to clarify the recurrence risk and prognosis. Simple febrile seizures last less than 15 minutes without focal or lateralizing signs or sequelae. If more than one seizure occurs in a brief period, the total episode lasts less than 30 minutes. A complex febrile seizure lasts for more than 15 minutes and may have lateralizing signs. If several seizures occur in a brief period, the entire episode may last for more than 30 minutes.
The timing of the febrile seizure in relation to the temperature elevation is variable. Whereas many children will have a febrile seizure during the initial temperature upswing (many parents are unaware that the child is ill until the seizure and the subsequent temperature recording), some children will have seizures at other points during the febrile illness.
A febrile seizure usually is self-limited. Seizures lasting longer than 5 minutes may be interrupted with lorazepam or diazepam. Airway management is a priority, as benzodiazepines occasionally cause respiratory depression. Ongoing seizures unresponsive to lorazepam or diazepam can be interrupted with fosphenytoin.
The evaluation of a simple febrile seizure need not be extensive (Figure 41-1). Electroencephalography (EEG) is not recommended unless focal findings were present during or after the seizure, or if the seizure was prolonged. EEG is not predictive of future febrile or afebrile seizures. Laboratory studies (except as needed to determine the cause of fever) and brain imaging usually are not helpful. Imaging may be indicated for a complex febrile seizure or in patients with evidence of increased intracranial pressure. An LP is not routinely indicated, except as outlined above.
Figure 41-1. Algorithm for managing febrile seizures.
Prophylactic medications usually are not necessary. In the practice parameter published in 2008, the American Academy of Pediatrics emphasized that prophylactic medications for the usually benign condition of febrile seizures were not routinely useful.
Prognosis is generally good; most children who develop febrile seizures will not develop neurologic or developmental consequences. Children younger than 12 months at the time of their first seizure have a 50% to 65% chance of having another febrile seizure; older children have a 20% to 30% chance of recurrence. The chance of developing epilepsy increases from 0.5% in the general population to 1% in the child with a febrile seizure history. Children at highest risk for developing epilepsy following a febrile seizure often have preexisting neurologic problems and have complex febrile seizures; these children have 30 to 50 times the baseline risk of developing epilepsy.
41.1 Paramedics bring a 7-month-old infant to the ED with seizure activity. The father reports the infant was in a normal state of health until approximately 3 days ago when she developed a febrile illness, diagnosed by her physician as a viral upper respiratory tract infection. Approximately 30 minutes ago she began having left arm jerking, which progressed to whole-body jerking. The episode spontaneously ceased on the way to the hospital. Vital signs include heart rate 90 bpm, respiratory rate 25 breaths/min, and temperature 100.4°F (38°C). Your examination reveals a sleeping infant in no respiratory distress. The child’s anterior fontanelle is full. The oropharynx is clear, and crusted mucus is found in the nares. The tympanic membranes are dark and without normal landmarks. The lungs are clear, and the heart and abdominal examinations are normal. She has a bruise over the occiput and several parallel bruises along the spine. Which of the following is the best next step in management?
A. Computed tomography (CT) of the head
B. Electroencephalogram (EEG)
C. Lumbar puncture
41.2 A 2-year-old boy who had a simple brief febrile seizure comes to your clinic a day after his ED visit. He is currently afebrile, is happily pulling the sphygmomanometer off the wall, and is taking antibiotics for an ear infection diagnosed the previous day. His mother wants to know what to expect in the future regarding his neurologic status. You correctly tell her which of the following?
A. He has no risk of further seizures because he was age 2 years at the time of his first febrile seizure.
B. He will need to take anticonvulsant medications for 6 to 12 months to prevent further seizure activity.
C. You want to schedule an EEG and a magnetic resonance scan of his head.
D. Although he does have a risk of future febrile convulsions, seizures of his type are generally benign and he is likely to outgrow them.
E. This is an isolated disorder, and his children will not have seizures.
41.3 A 10-month-old boy presents to the ED with a 1-day history of fever to 104°F (40°C), increased irritability, decreased breast-feeding, and refusal of solid foods. The parents brought him in after two 30-second episodes of generalized jerking that occurred over a 20-minute span. Your examination reveals an awake but lethargic infant. The anterior fontanelle is flat, the tympanic membranes and oropharynx are moist and not erythematous, the lungs are clear, and the heart and abdominal examinations are normal. He has no focal neurologic findings. Which of the following is the best next step in management?
A. Intravenous ceftriaxone
B. Admission overnight for observation
C. Computed tomography of the head
D. Discharge from ED to follow up with his primary care provider in 24 hours
E. Lumbar puncture
41.4 The father of a 4-year-old girl calls your clinic to report her second febrile seizure. He states that this seizure was identical to the first one that happened 4 months ago: she developed an elevated temperature and within a short time had a generalized convulsion lasting 90 seconds. She was sleepy for approximately 2 minutes afterward. Upon awaking, she was given ibuprofen. She is now running around the house, chasing the family’s chihuahua. The parents wonder if she needs to take anticonvulsants now that she has had another seizure. You should tell the father which of the following?
A. Febrile seizures frequently are recurrent but usually have no significant long-term effect.
B. You will prescribe an anticonvulsant because it will reduce the risk of future epilepsy.
C. You will order an EEG and CT scan of her head to be done on an outpatient basis.
D. He needs to take his daughter to the hospital for inpatient admission.
E. He should stop the ibuprofen and observe the fever curve.
41.1 A. This child’s history is worrisome for trauma. The fontanelle is full, bruises are found along the spine and on the occiput, and she has hemotympanum. A CT scan is of paramount importance; this child likely had a seizure from acute intracranial hemorrhage associated with physical abuse. Although this child is febrile and within the proper febrile seizure age range, the history and physical findings are more consistent with a diagnosis other than febrile seizure. Performing an LP in a patient who may have increased intracranial pressure is not advisable, an EEG would probably not reveal the diagnosis, and phenobarbital is not immediately necessary in a patient who is not actively seizing.
41.2 D. Part of the anticipatory guidance for parents of children with febrile seizures is to impress upon them that the child may have another febrile seizure; it is similarly important to emphasize the usual benign nature of this condition. In a simple febrile seizure, imaging and EEG generally are not recommended, nor are prophylactic anticonvulsants. Because febrile seizures seem to have a genetic basis, it is possible that your patient’s children will also have febrile seizures.
41.3 E. Although this child ultimately may be diagnosed as having had a simple febrile seizure, the patient’s age (<1 year) precludes a reliable neck examination. An LP is required to evaluate the child for meningitis. Administering antibiotics before the LP (or other cultures are obtained) is inadvisable unless the patient’s condition is such that he would not tolerate the procedure.
41.4 A. Some children will develop recurrent febrile seizures. Anticonvulsants will decrease the risk of further febrile seizures, but they do not decrease the risk of developing epilepsy. The possible adverse reactions with antiepileptic medications are numerous, including severe allergic reactions and interference with school performance; often the benefit is not worth the risk. Fever reduction with medications is generally encouraged in children with a febrile seizure history. Hospital admission and diagnostic studies are not necessary in simple febrile seizures.
Febrile seizures usually are benign and self-limited. They do not require an extensive diagnostic evaluation unless they are prolonged or focal.
A diagnosis of febrile seizure must be made only after considering the possibility of central nervous system infection as the seizure cause.
Febrile seizures rarely lead to epilepsy; risk factors for nonfebrile seizures include preexisting developmental abnormalities and complex febrile seizures.
Bernard TJ, Knupp K, Yang ML, et al. Febrile seizures. In: Hay WW, Levin MJ, Sondheimer JM, Deterding RR, eds. Current Diagnosis & Treatment Pediatrics. 20th ed. New York, NY: McGraw-Hill; 2011:720-722.
Feigin RD. Bacterial meningitis beyond the newborn period. In: McMillan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:924-933.
Fishman MA. Febrile seizures. In: McMillan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:2297-2299.
Mikati MA. Febrile seizures. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics, 19th ed. Philadelphia, PA: Elsevier; 2011:2017-2018.
Murray TS, Baltimore RS. Bacterial meningitis. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:913-916.
Prober CG, Dyner L. Acute bacterial meningitis beyond the neonatal period. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics, 19th ed. Philadelphia, PA: Elsevier; 2011:2087-2095.
Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures. Febrile seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures. Pediatrics. 2008;121:1281-1286.
Takeoka M. Febrile seizures. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:2204-2206.