Prediction of Febrile Seizures in Siblings: A Practical Approach


Synopsis: The cumulative risk of febrile seizures (FS) of children whose sibling febrile seizures is increased twice of that in the general population. Increased risk factors include a positive FS family history, and recurrences and young age of the sibling at the time of FS.

Source: Vining EPG. Gaining a perspective on childhood seizures. N Engl J Med 1998;338:1916-1918.

In order to estimate the risk of febrile seizures (FS) in siblings of children who had experienced a FS, van Esch and associates at the Sophia Hospital in Rotterdam prospectively studied 129 children with FS.1 Thirteen parents and 12 siblings had experienced FS accounting for a six-year cumulative risk of FS of 7%. The risk of FS was increased in relatives of children with recurrent FS (12%), and they occurred in 10% of siblings, compared to 4% in a similar population without affected siblings.

If two or three risk factors, such as a positive history of FS in a parent, young age, or recurrent FS were present in the proband, the risk of FS in a sibling was 46%.

In an editorial in the New England Journal of Medicine, Vining examines issues critical to the pediatrician's perception and response to seizures. She emphasizes that seizures do not "beget" seizures or cause subsequent epilepsy and the benign nature of uncomplicated febrile seizures in children.


van Esch et al conducted a prospective study to determine the risk of FS in siblings of children who have experienced a FS. It is well recognized that febrile seizures tend to occur in families.1 Both the risk of febrile seizures as well as epilepsy is higher in siblings of children who have had a febrile seizure. It is estimated that the risk of febrile seizure in younger siblings of those children with febrile seizure is in the range of 10-20%, although it may be even greater if the parents had a history of febrile seizure. van Esch et al's study collaborates this increased risk and adds additional factors that are of prognostic value in counseling families in which a child has had a FS.

The incisive and comprehensive editorial by Vining is reassuring. She points out that, as indicated by a recent study by Verity and associates, seizures per se do not cause epilepsy or significantly effect long-term behavioral and intellectual outcomes.3 Recurrent seizures are probably caused by the brain's underlying predisposition to the development of epilepsy. The fear that damage may be caused by seizures leads to anxiety and may be an impetus to institute anticonvulsant therapy after an FS, which may be unnecessary and potentially harmful. (Dr. Young is a pediatric neurologist and Chief of Pediatrics at the Hospital of St. Raphael, New Haven, CT.)


    1. van Esch A, et al. Prediction of febrile seizures in siblings. Eur J Pediatr 1988;157:340-344.

    2. Berm AT, et al. A prospective study of recurrent febrile seizures. N Engl J Med 1992;327:1122-1127.

    3. Hirtz DG. Febrile seizures. Pediatr Rev 1997;18:5-8.

    4. Verity CM, et al. Long-term intellectual and behavioral outcome of children with febrile convulsions. N Engl J Med 1998;338:1723-1728.