Febrile Convulsion: Prognostic Criteria for Recurrence

49 infants and children (29 boys and 20 girls) between the ages ~f 3 nlonthes and 5 Years, fulfilling the criteria of Fc were studied dusing the acute phase of the illness; both clinically and electroencephalographically and were followed up fox I2 nzonths with the main airn of defining the inlportant risk factors for recurrence of F.C. Recurrence was reported if2 13 cases (26.5%) during that period s f follow up. Various clinical and EEG findings were correlated statistically the following 5 risk factors for recurrence identified: I . Positive neurological findings. 2. Type of seizures. 3. Duration of fits. 4. Family history of FC, and 5. Positive EEC findings., INTRODUCTION AND AIM OF WORK Febrile convulsion is not synon~ I I I O U S with convulsion with fever. In the concensus statement (Nelson and Ellenberg, 1981) a febrile convulsion is defined as an event in infancy or childhood, usually occurring between 3 months and 5 years ot' age associated with fever but without evidence of intracranial infection or defined cause. Seizures with fever in children who have suffered a previous non febrile seizures are excluded. This definition could be criticized according to Aicardi (1986). Wallace (1988) defined Febrile ~ o n v u l s i o n as any seizure of cerebral origin which occurs in association with any febrile illness. However, inclusion of children with seizures suffering from Tarkhan, M. N. et a1 ... Meningitis, Encephalitis, Reyes Syndrome or cerebral Malaria seems questionable. The diagnosis is justified only if the body temperature is 38"C, rectal temperature or more. Simple FC are generalized and last less than 15 minutes and do not recur within 24 hours and do not exhibit post-ictal neurological abnormalities. Complex or coniplicnted FC are focal or longer than 15 minutes or recur within 24 hours. Simple FC are always generalized, conlplex FC are partial or generalized, (Knudsen, 1990). FC are now recognized as a benign condition and the long term prognosis is excellent for the vast majority of children. Most of the studies done showed that the risk of epilepsy subsequent to FC ranges from 2-7% (Knudsen, 1990). The most common secluela of a 1st FC is recurrent FC, occurring i n about 40% of cases, (Kn udsen, 1990). Regarding the role of EEC in the acute phase of the febrile convulsion, the literature showed some controversy about the value of EEG in giving a real indication of the likelihood of of recurrence of febrile seizures or expectancy of epilepsy (Lennox, 1949; Lerique, 1955). Laplane et a1 (1959) and FrantZen et a1 (1968) reported that, during the I st week after febrile convulsion between 30% and 70% of children have nomial EEG. Slowing of the background rhythm was in one third of the patients in some studies (Laplan et al, 1958; Baniberger and Matthes, 1959 amd Frantzen et al, 1968), rind In 88% of the patients in one study (Gregory stores, 1990). The last author reported that, this activity is predominantly posterior in distribution and although mostly bilateral, is often asymmetrical or even unilateral. When EEG changes were related to changes in temperature over a 24 hours period of continuous recording, Minchom and Wallace (1984) were unable to demonstrate any relationship between the frequency of the background rhythm and the height of pyrexia. Spikes or spike and slow wave discharges, localized or generalized are rare in the early post-ictal period in febrile convulsion as reported by Gregory stores (1990). Frantzen et a1 ( 1968) gave a figure of 1.4% and kajitrtni et a1 (1981) reported 3% of their patients. Both these figures are close to the 1.9% given by EegOlofsson (197 1) as the incidence of fmal sharp activity in normal young children. In the lights of the previous literatures this current study was carried to describe the EEG changes seen out with 2 aims. The first was the in those cases during the acute re-evauation of some clinical asphaseof the illness, correlating them pects of children with febrile conclinically and assessing the progvi~lsion and defining the group at nostic value of EEG at that early risk of recurrence. The second was stage of the illness. SUBJECTS AND METHODS This study was carried out on 49 infants and children who presented to the pediatric and Neurology department of A 1 Salama Hospital, Jeddah, Saudi Arabia i n the duration between April 1989 to March 1990, fulfilling the above mentioned criteria of febrile convulsion. On presentation, all of them had the convulsion for the first time in their life and were brought to the hospital within few hours from developing the seizures. They were 29 boys and 20 girls with their age ranging between 3 months up to 5 years. Cases which had previous history of a febrile fits were not included in the study. Each patient was submitted to full clinical assessment carried out by the pediatrician and neurologist. Temperature was taken rectally and routine blood test as well as other necessary investigations as chest Xray were done. Analysis of the history data including perinatal history, seizures description, history of febrile as well as afebrile seizures in the family members weretaken. The aim of the clinical assessment was the diagnosis of underlying cause of fever aided by the necessary investigations, and to search for any neurological or developmental abnormality. During their hospital stay, the patients were managed aiming at reducing body temperature and giving the specific medication for the underlying cause of fever. Following discharge from the hospital, patients' parents were instructed to bring their kids at regular intervals to the Outpatient Department. Some of the patients had more than one year duration of follow up, all of them had at least 6 months duration of follow up with the main aim of recording any febrile seizure recurrence. All patients had an awake interictal EEG done maximallywithin 12 hours from developing the fits. This EEG was carried out using 16 164 Tarkhan, M. N. et a1 ... channel EEG machine with the apNo provocation was carried out, plication of small sized rubberhead mostly, due to lack of cooperation cap and saline electrodes through of the kids. Filter used was 60 Hz, the standard 10-12 placement sysspeed was 30m/sec., average sensitern using different transverse, lontivity was SOuv/cm and time congitudinal and Gasteau montages. stant was 0.53 Hz 0.3 second.