My child recently had a convulsion. He seemed fine when he went to bed, but a few hours later I heard his crib shaking. He was burning up with fever, but nothing showed up in the tests done in the Emergency Room. The doctor said it was probably due to a viral infection. What do you recommend? J. P.

Dear J. P.:

While physicians are always anxious to do something, there are times when no treatment is the best course. A febrile seizure or febrile convulsion, which your child appears to have experienced, is one of the most common types of seizure. As the name implies, the seizure is associated with the presence of a fever. Febrile seizures are most commonly seen between the ages of six months and five years. It has been my experience that the primary determining factor as to whether or not a seizure will occur is not the height of the fever, but the rate of rise in body temperature. Most cases occur just as you describe. The child is put to bed without any sign of illness. Later in the evening or during the night the parents are alerted by the sound of the infant thrashing about, at which time a high fever is present.

Fever reducing medications have been shown to be of no value in preventing febrile seizures. This may be because by the time a fever is recognized the danger has generally passed. Thankfully, anticonvulsant medications, which from the 1970s through much of the 1990s were widely prescribed to infants and children who had experienced a febrile seizure, are no longer recommended. The drugs were ineffective when used intermittently (probably for the same reason that fever reducers are ineffective) and caused behavioral changes, weight disturbances, decreased learning capacity, and in some instances fatal reactions involving the liver and pancreas when taken on an ongoing basis. Spinal taps, which were once done routinely, are now rarely performed.

While febrile seizures are dramatic and frightening, they are not dangerous. They do not predispose to epilepsy later in life nor do they cause damage to the brain. Up to 4 percent of children will have at least one febrile seizure before their sixth birthday. Approximately 1/3 of those who have one episode will have additional febrile seizures, but multiple episodes are no more dangerous or significant than a single seizure.