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EEG

Based on low quality evidence the CFS CPG group recommends against getting an emergent EEG. Recommend close follow up with the patients primary care provider or neurology clinic referral after a CFS. The reported studies provide conflicting results regarding the utility of EEGs after a complex febrile seizure. 

Shah, James, & Elayaraja (2014) attempted a meta-analysis on the use of EEG and its timing after complex febrile seizure in children less than 5 years of age. From an extensive search that ended October 17 2013, they found no evidence in the form of a randomized control trial to support or refute obtaining an EEG after a complex febrile seizure. However, they comment on three cohort studies that report conflicting findings. Maytal, Steele, Eviatar, & Novak (2000) report no EEG with abnormality in 33 subjects within one week of a complex febrile seizure. Joshi, Wawrykow, Patrick, & Prasad (2005) reported that children with complex febrile seizure are 3.5 times more likely to EEG abnormalities within 7 days than subjects who had an EEG later than 7 days post event. Finally, Yucel, Aka, Yazicioglu, & Ceran, (2004) reported that 71/145 (45%) subjects had abnormal EEGs after complex febrile seizure. They conclude the reports are conflicting, and stronger studies should be conducted and reported.

Five studies were not included in Shah (2014) were identified.

  • Kanemura, Sano, Yamashiro, Sugita, and Aihara (2011) reported on 119 subjects who had an EEG after a febrile seizure. Twenty of whom had a complex febrile seizure. Of the 20 with complex febrile seizure, 11 subjects had no EEG abnormalities and 9 displayed abnormalities on EEG. Subjects who had complex febrile seizure had a significantly higher risk for the development of epilepsy than those with simple febrile seizures. (p< 0.05) No specific data given. 

  • Berzosa Lopez, Ramos Fernandez, Martinez Anton, Espinosa Fernandez, and Urda Cardona (2014) reported on 65 subjects with complex febrile seizure. EEG was performed on 62 of the subjects. Thirteen EEGs showed focal slow wave activity, three of which were associated to a focal seizure and 7 cases showed EEG alterations. However, none of the seven cases with EEG alterations had a recurrence in a minimum 12 month period.

  • Karimzadeh et al. (2013) evaluated 36 children after a complex febrile seizure. Early EEG abnormality was reported in 29/36 (80%) of the subjects (24-48 hours) and 25/36 (69%) Late EEG abnormality was reported in 25/36 (29%) of the subjects (69%). They conclude that EEG abnormalities are not influenced by the time of EEG recording.

  • Nordli et al. (2012) evaluated 191 normally developing children aged 1 month to 5 years of age who presented with febrile status epilepticus. The odds of focal slowing on the EEG were significantly increased by a focal complex febrile seizure adjusted OR =4.5, 95% CI [1.6,12.6] and the odds of focal slowing were significantly decreased with a high peak temperature (>/= 104 °F) adjusted OR= 0.2, 95% CI [0.06,0.69]

  • Kuang et al. (2014) reported retrospectively on 378 normally developing children with febrile seizures. They identified the following factors increased the risk of the child developing epilepsy: (a) a prolonged seizure, (b) the number of seizures, and (c) a family history of epilepsy.

These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.