Authors :
Presenting Author: Shivangi Pandya, MBBS, MMed (IM), MRCP (UK) (Neurology) – National University Hospital Singapore
Prakash Paliwal, MBBS, MRCP (UK), FAMS, FRCPEd – Paliwal Neurology Clinic, Gleneagles Hospital Singapore; Rahul Rathakrishnan, MBBS, MRCP (UK), FAMS, FRCPEd – National University Hospital, Singapore; Leonard Yeo, MBBS, MRCP (UK) (Neurology) – National University Hospital, Singapore
Rationale:
Estimates of seizure recurrence following a first unprovoked seizure are drawn from observational studies and may be difficult to generalize to the larger, more heterogeneous population. We sought to assess the relation of early electroencephalography (EEG) findings to the long-term outcomes over 15 years of patients presenting with a first unprovoked convulsive seizure to the emergency room (ER) at our institution.
Methods:
We followed prospectively a cohort of 80 patients presenting to the ER at our institution between January 2008 to January 2011 with first unprovoked convulsive seizures. All patients underwent routine 30-min EEG in the ER prior to discharge and specialist review was arranged in the epilepsy clinic within 2 weeks. Management decisions were at the discretion of the treating neurologist. Seizure recurrence was assessed during a follow up of between 9 months and 3 years in the initial study and extended to 15 years in this study.
Results:
Of the 80 patients, 30 (37.5%) had an abnormal initial EEG. Of the 30, 16 of these (53.3%) had a recurrence within 15 years and were thus diagnosed with epilepsy. Interestingly, the remaining 14 (46.7%) did not have recurrence, although, based on current guidelines, may have been potentially diagnosed with epilepsy at presentation. The EEG abnormalities in this group were interictal epileptiform abnormalities (ten), slowing (three), or both (one).
Of the remaining 50 with a normal initial EEG, 15 (30.0%) had epilepsy at the end of 15 years. Of these, only five (33.3%) had first recurrence within initial three years. A chi-square test of independence showed that the relation between abnormal EEG and the eventual diagnosis of epilepsy at the end of 15 years was significant, χ
2 (1, N=80) = 4.3011, p=.038. Patients with an abnormal EEG were more likely to be diagnosed with epilepsy at the end of a period of 12 to 15 years.
The impact of early anti-seizure medication (ASM) use on seizure recurrence was reviewed:
17 of 80 (21.2%) deemed to be at high recurrence risk were started on ASM during the early specialist review, 11 (64.7%) were diagnosed with epilepsy, while the remaining 6 (35.2%) had no recurrence at the end of 15 years. In comparison, only 21 of 63 (33.3%) not initially started on ASM eventually had epilepsy.
Conclusions:
This study suggests that an early EEG is useful as patients with an abnormal early EEG are more likely to be eventually diagnosed with epilepsy in the longer-term period. Due to the implications of making (and potentially missing) a diagnosis of epilepsy, patients should be appropriately counselled on diagnostic decision-making and management strategies. An early specialist review would aid this process.
Funding:
Nil.