Journal of Family and Community Medicine

ORIGINAL ARTICLE
Year
: 2003  |  Volume : 10  |  Issue : 2  |  Page : 37--42

Newly diagnosed seizures in adolescents: A comparative study


Hassan M Ismail 
 King Fahd Hospital of the University, Al-Khobar, Saudi Arabia

Correspondence Address:
Hassan M Ismail
P.O. Box 40152, Al-Khobar 31952
Saudi Arabia

Abstract

Objective: To study the clinical, EEG and CT profile in a hospital population of adolescents with newly diagnosed recurrent seizures. Methods: The clinical profiles obtained from history including detailed descriptions of the seizures, examination, electroencephalographic (EEG) and computed tomography (CT) findings were recorded prospectively for all 14 to18-year-old patients who were referred to the electrodiagnostic service at King Fahd Hospital of the University, Al- Khobar, Eastern Province, Saudi Arabia from 1st January 1996 to 31st December 1997. The data were entered into a standard dbase file and analyzed using a personal computer. The results were compared with 2 previous concomitant subsets of data obtained from 263 children ≤13 years (72%) and 73 adults >18 years (20%) over the same study period. Results: Twenty-nine patients (14 males and 15 females, a mean age of 15.7 years) with newly diagnosed recurrent seizures were studied. A positive family history of seizures was found in 10.3%. The main seizure types were partial in 11 (37.9%), partial with secondary generalization in 6 (20.7%) and generalized in 12 (41.4%). The types of epileptic syndromes included localization-related 15 (51.7%), generalized 12 (41.4%) and undetermined 2 (16.9%). The EEG was abnormal in 21 (72.4%) with epileptiform activity, focal in 11 (52.4%), generalized in 9 (42.8%) and none-epileptiform activity in 1 (4.8%). The cranial CT findings were normal in 21 patients (72.4%) and abnormal in 8 (27.6%) patients, with focal lesions in 6 (75%) and generalized cerebral atrophy in 2 (25%). The frequency of adolescents presenting with newly-diagnosed seizures was 8% of the total study population of 365 patients including children and adults. Conclusion: The results showed that partial and partial with secondary generalization seizures and the localization-related epileptic syndrome are the most frequent seizure and epileptic syndrome types in adolescents. The least frequent of newly diagnosed seizures in adolescents compared to children and adults confirms the bimodality of peak frequency in the young and old that has been observed in the west.



How to cite this article:
Ismail HM. Newly diagnosed seizures in adolescents: A comparative study.J Fam Community Med 2003;10:37-42


How to cite this URL:
Ismail HM. Newly diagnosed seizures in adolescents: A comparative study. J Fam Community Med [serial online] 2003 [cited 2019 Nov 15 ];10:37-42
Available from: http://www.jfcmonline.com/text.asp?2003/10/2/37/97847


Full Text

 Introduction



Epileptic seizures result from temporary self-limited abnormal hypersynchronous electrical discharges of cortical neurons leading to an altered state of brain function; whereas epileptic syndromes are chronic disorders characterized by unprovoked and usually unpredictable recurrent seizures. [1],[2] The International League Against Epilepsy (ILAE) played a major role in establishing and revising classifications for the different types of epileptic seizures and syndromes. [3],[4],[5] The annual incidence of epileptic seizures ranges from 20 to 70 per 100,000 [6],[7] and the point prevalence between 0.4 and 0.8%. [8] The proper management of epileptic seizures and the prediction of outcome and prognosis are dependent on ascertaining the type of seizure, epileptic syndrome and the underlying causes. [9] The latter are based primarily on the neurological history, examination, electro-encephalogram (EEG) and neuro-imaging. [2],[10] Recent studies considered clinico-electrical, imaging and pathological patterns of certain epileptic syndromes in children. [11] Similar prospective studies from our department examined the clinical patterns of newly-diagnosed seizures in children up to the age of 13 years [12] and adults >18 years. [13]

The aim of the present study is to examine the clinical, EEG and CT profile in a hospital population of adolescent patients between 14 and 18 years of age, who were referred to the Neurodiagnostic Laboratories of King Fahd Hospital of the University (KFHU), Al-Khobar, Saudi Arabia, between January 1996 and December 1997, with newly-diagnosed recurrent unprovoked seizures and compare these results with those obtained from previous concomitant subsets of children and adults.

 Methods



Consecutive patients between the ages of 14 and 18 years with newly-diagnosed recurrent seizures were seen in the Neurodiagnostic Laboratories of the Neurology Department at KFHU between January 1996 and December 1997. KFHU is a referral tertiary care hospital for the entire Eastern Province with an estimated population of three million. A pre-coded data form was completed to collect the relevant history, neurological examination and CT findings for every patient. Standard EEG records were obtained using a 21-channel Electroencephalograph (Model EEG-4421, Nihon Khoden Corporation, Tokyo, Japan). The same electroencephalographer read all the EEG records to minimize inter-observer variability. The data were entered into a standard data base file using a personal computer and analyzed using the SPSS statistical package. The present data from adolescents were compared with those obtained from two previous concomitant subsets, [12],[13] of a children's group ≤ 13 years (N=263) and an adult group > 18 years of age (N=73).

 Results



A total of 29 patients, 14 males and 15 females (mean age 15.8 and 15.7 years respectively) were seen. The main clinical diagnoses were partial and complex partial seizures 11 (37.9%), partial with secondary generalization 6 (20.7%) and generalized seizure in 12 (41.4%). The main epileptic syndromes included localization related 15 (51.7%), generalized 12 (41.4%) and undetermined 2 (6.9%). It was noted that 24 (82.2%) of the patients presented within a year from the onset of seizures. A positive family history of seizures was present in 3 (10.3%). The EEG was abnormal in 21 (72.4%) patients. The abnormalities in this group included focal epileptiform activity in 11 (52.4%), generalized epileptiform activity in 9 (42.8%) and non-epileptiform in 1 patient (4.8%). Cranial computed tomography (CT) was normal in 21 patients (72.4%) and abnormal in 8 (27.6%) with focal lesions in 6 patients (75%) and generalized atrophy in 2 (25%). The frequency of the seizure and epileptic syndrome types and the EEG and CT abnormalities compared to the previous children and adult groups are given in [Figure 1] and [Figure 2] respectively. The abnormal CT findings are given in [Table 1]. The generalized seizure type was predominant in the children's group, whereas the partial and secondarily generalized seizures were predominant in the adult and adolescent groups. As for the types of epileptic syndromes, the generalized and undetermined types were more frequent in the children's group compared to the localization-related type which was more frequent in the adolescent and adult groups. The percentages of abnormal EEGs were similar for the three groups forming approximately two thirds of the total. However, the abnormal epileptic activity was equally distributed between focal and generalized in the adolescent group compared to predominantly generalized in the children group and predominantly focal in the adult group. As for the cranial CT abnormalities, cerebral atrophy was commonest in the children's group compared to focal abnormalities in the adolescent and adult groups. The frequency of newly-diagnosed seizures in adolescents was 8% of the total study population, ranking the least compared to the children's group (72%) and adult group (20%) over the same study period. {Figure 1}{Figure 2}{Table 1}

 Discussion



In order to make the right diagnosis, select the appropriate anti-epileptic drug and consider the underlying possible etiologies with a view to predict prognosis and outcome, classification of types of epileptic seizures and syndromes is mandatory. [2],[10],[14],[15] The lower number of patients in this age group compared to the children and adults groups over the same study period probably reflects the variation of incidence as shown in a Canadian study where the highest incidence was in the under one-year-old (118/100,000), 46/100,000 for 1 to 10-year-old and 21/100,000 for 11 to 15-year-old. [16] A similar decline in incidence with age was also observed in a study done in USA. [17] Our results also reflect a delay in diagnosis where 82.2% of patients presented within a year compared to the 50% reported by Gumnit. [18] The proportion of patients with partial and partial with secondary generalization (58.6%) and generalized (41.4%) were similar to the results of 52% and 39% respectively published by the British National General Practice population-based study in newly- diagnosed epileptic seizures. [19],[20] The distribution of epileptic syndromes in our patients was localization-related (51.7%), generalized (41.4%) and undetermined (6.9%) shows a similar trend to those reported from the UK where 58% were localization-related, 23% generalized and 19% undetermined [14] The EEG was abnormal in 72% of our patients compared to 68% in the UK study. [14] The abnormal epileptic activity for adolescents was focal epileptiform in 34.5%, generalized in 48.3% and non-epileptiform in 17.2% showing a closer similarity to the adult group with focal activity in 48.9% and the children's group with generalized activity in 50.6%. [12],[13] However, the EEG showed considerable variations and overlap among the different seizure types as previously reported. [12],[20] The cranial CT abnormalities were present in 27.6% compared to 39.5% in children [12] and 39.7% in adults. [13] However, whereas cerebral atrophy was the main CT finding (64%) in children, [12] focal abnormalities were predominant (75%) in adolescents compared to 65.5% in adults. [13] Furthermore, the cranial magnetic resonance imaging (MRI), functional and quantitative, is currently considered the neuroimaging method of first choice for patients with epilepsy. [21],[22],[23] In one study, 98 out of 111 children and adolescents with partial epilepsy, had both cranial CT and MRI. [21] Of these, 31% had negative CT and positive MRI lesions that most likely account for their epilepsy.

Our results showed that partial and partial with secondary generalization seizures are the most frequent seizure types; and the commonest epileptic syndrome was the localization-related type in this adolescent group. Thus, they are comparable to the adult results [13] and previous population- and hospital-based reports. [14],[20],[24] The least frequent of newly diagnosed seizures in adolescents (8%) compared to children (72%) and adults (20%) over the same study period confirm the bimodality of peak frequency of newly-diagnosed seizures in the young and old as previously reported in the West. [16],[17]

References

1Pedley TA, Bazil CW, Morrell MJ. Epilepsy. In: Rowland LP ed. Merritt's Neurology, 10 th ed. Philadelphia: Lippincott Williams & Wilkins, 2000, pp 813-33.
2Porter RJ. Diagnosis: seizures and epilepsy. In: Epilepsy 100 elementary principles. 2nd edition, MPN 20, London: W.B. Saunders company, 1989; pp 19-32.
3Commission on classification and terminology of the International League Against Epilepsy. Proposal for revised clinical and electroencephalographic classification of epileptic seizures. Epilepsia 1981; 22:489-501.
4Commission on classification and terminology of the International League Against Epilepsy. Proposal for revised clinical and electroencephalographic classification of epileptic seizures. Epilepsia 1989; 30:389-99.
5Manford M, Hart YM, Sander JWAS, Shorvon SD. The syndromic classification of the International League Against Epilepsy applied to epilepsy in a general population. Arch Neurol 1992; 49:801-8.
6Shorvon SD. Epidemiology, classification, natural history and genetics of epilepsy. Lancet 1990; 336: 93-6.
7Bell GS, Sander JW. The epidemiology of epilepsy: the size of the problem. Seizure;11 Suppl A:306-14.
8Hauser WA, Annegers JF, Kurland LT. Prevalence of epilepsy in Rochester, Minnesota: 1940-1980. Epilepsia 1991; 32:429-45.
9Brodie MJ, French JA. Management of epilepsy in adolescents and adults. Lancet 2000; 356:323-9.
10Chadwick DW. Diagnosis of epilepsy. Lancet 1990; 336:291-5.
11Duchowny M, Jayakar P, Resnick T, Levin B, Alvarez L. Posterior temporal epilepsy: electroclinical features. Ann Neurol 1994; 35:427-31.
12Al-Sulaiman AA, Ismail HM. Clinical pattern of newly diagnosed seizures in Saudi Arabia: a prospective study of 263 children. Child's Nerv Syst 1999;15:468-71.
13Ismail HM, Al-Sulaiman AA, Abolenin AA, et al. Newly diagnosed seizures in adults. Neurosciences J 2003;8(2):104-06.
14King MA, Newton MR, Jackson GD, Fitt GJ, Mitchell LA, Silvapulle MJ. Epileptology of the first-seizure presentation: a clinical, electroencephalographic and magnetic resonance imaging study of 300 consecutive patients. Lancet 1999; 352:1007-11.
15Hopkins A, Garman A, Clarke C. The first seizure in adult life: value of clinical features, electroencephalography and computerized tomography scanning in prediction of seizure recurrence. Lancet 1988; i:721-6.
16Camfield CS, Camfield PR, Gordon K, et al. Epilepsy in childhood and adolescence: a population-based study in Nova Scotia from 1977 to 1985. Epilepsia 1996; 37:19-23.
17Hauser WA, Annegers JF, Kurland LT. Incidence of epilepsy and unprovoked seizures in Rochester, Minnesota: 1935-84. Epilepsia 1993; 34:453-68.
18Gumnit RJ. The epilepsy handbook. The practical management of seizures. 2nd ed. New York: Raven Press; 1995.
19Sander JW, Hart YM, Johnson AL, Shorvon SD . National General Practice Study of Epilepsy: newly diagnosed epileptic seizures in a general population. Lancet 1990; 336:1267-71.
2020. Cockerell OC, Johanson AL, Sander JWAS, Shorvon SD. Prognosis of epilepsy: a review and further analysis of the first nine years of the British National General Practice Study of epilepsy, a prospective population- based study. Epilepsia 1997; 38:31-46.
21Rest M, Palma M, Dicuonzo F, et al. Imaging studies in partial epilepsy in children and adolescents. Epilepsia 1994;35(6):1187-93.
22Liu RS, Lemieux L, Bell GS, et al. A longitudinal quantitative MRI study of community-based patients with chronic epilepsy and newly diagnosed seizures: methodology and preliminary findings. Neuroimage 2001;14(1Pt1):231-43.
23Liu RS, Lemieux L, Bell GS, et al. The structural consequences of newly diagnosed seizures. Ann Neurol 2002;52(5):573-80.
24Abduljabbar M, Ogunniyi A, Daif AK, Al-Tahan A, Al-Bunyan M, Al-Rajih S. Epilepsy classification and factors associated with control in Saudi adult patients. Seizure 1998; 7:501-4.