Acute symptomatic seizures are seizures occurring in close temporal relationship with an acute central nervous system (CNS) insult. The objective of the study was to determine the frequency of presentation and etiological risk factors of acute symptomatic seizures among adult medical admissions. It was a two-year retrospective study of the medical files of adults patients admitted with acute symptomatic seizures as the first presenting event. There were 94 cases of acute symptomatic seizures accounting for 5.2% (95% CI: 4.17–6.23) of the 1,802 medical admissions during the period under review. There were 49 (52.1%) males and 45 (47.9%) females aged between 18 years and 84 years. The etiological risk factors of acute symptomatic seizures were infections in 36.2% (
Acute symptomatic seizures are clinical seizures occurring in close temporal relationship with an acute central nervous system (CNS) insult, which may be metabolic, toxic, structural, infectious, or inflammatory [
Acute symptomatic seizures represent about 40% of all cases of afebrile seizures in developed countries and more than half in some geographic areas, for example, where cysticercosis is endemic [
Treatment of acute symptomatic seizures requires the simultaneous treatment of the underlying aetiology and the use of anticonvulsant drugs [
When seizures complicate acute neurological disorders, they add an additional layer of complexity to patient management [
This was a retrospective study of medical records of adults patients admitted with acute symptomatic seizures as the first presenting event at medical wards of the Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi. NAUTH is the largest medical referral centre in Anambra State, Southeast Nigeria. Anambra State occupies an area of 4,844 Km sq. and has a population of 4,182,032 according to the 2006 Nigeria population census. The average attendance of NAUTH has been on the increase since inception of the hospital and currently the average annual attendance is 117,351 patients (103,601 outpatients and 13,750 inpatients) accounting for a 2.8% medical coverage of population of over four million of Anambra State. The current annual adult medical admissions of NAUTH are about 1,992 accounting for 14.5% (
The medical records of all medical wards admissions from January 2005 to December 2006 were retrieved from the records department of the hospital and reviewed. Those who presented with seizures as a presenting complaint were selected and analysed. Data extracted from the medical record files included demographic data (age and sex), relevant history and clinical examination findings, available investigation results, and diagnosis. All cases of acute symptomatic seizures are reviewed by the neurologists in our centre.
Acute symptomatic seizure was defined as a clinical seizure occurring in close temporal relationship with an acute central nervous system (CNS) insult, which may be metabolic, toxic, structural, infectious, or inflammatory [
Seizures were defined as acute symptomatic ones if they occurred within one week of stroke, central nervous system infection, or systemic infection or if they occur in the presence of severe metabolic derangements documented by biochemical abnormalities obtained within the immediate period of the metabolic event. The definitions used for the various etiologic agents are as follows.
Seizures following stroke were defined as acute symptomatic ones if they occurred within seven days of stroke. Stroke was defined as sudden onset focal or global neurological deficit of vascular origin lasting for more than 24 hours or resulting in death. Stroke type was categorized using the World Health Organisation stroke criteria and/or brain CT scan.
Seizures occurring in relation to meningoencephalitis and sepsis in our study were defined as acute symptomatic ones if they occurred within seven days of the events. The diagnosis of meningoencephalitis was based on documentation of fever, headache, alteration in the level of consciousness and signs of meningism on examination, and a positive cerebrospinal fluid result with or without isolation of pathogen. Sepsis was diagnosed based on documented clinical and laboratory (hematologic indices) evidence of systemic infection in a patient who does not meet the criteria of meningoencephalitis as defined above.
Metabolic causes of seizures were diagnosed based on documentation of appropriate laboratory results obtained within the periods of the seizures and other relevant clinical data. Uremic encephalopathy was diagnosed as cause of seizure based on documentation of azotemia within the periods of the seizures in a patient with relevant clinical history and findings. Hepatic encephalopathy was diagnosed as cause of acute symptomatic seizures if seizures occurred during the period of overt neuropsychiatric symptoms in a patient with history of liver disease.
Acute symptomatic seizures associated with hypertensive encephalopathy were defined as seizures occurring in patients with severe elevation of blood pressure, altered mental status, or evidence of diffuse brain dysfunction with prompt response to antihypertensive therapy.
The cases of acute symptomatic seizures relating to alcohol use were seizures occurring in patients with history of chronic alcohol abuse, presence of alcohol withdrawal symptoms, and seizures within 48 hours of last drink.
The diagnosis of brain space occupying lesions for cases with HIV/AIDS was based on clinical history, examination findings, and/or brain CT scan.
Eleven patients had brain CT scan; of these patents ten were cases of acute symptomatic seizures due to stroke while one was due to HIV infection.
Patients with epilepsy and those below 18 years of age were excluded (patients below 18 years are admitted to the hospital paediatric unit).
There were 94 cases of acute symptomatic seizures accounting for 5.2% (95% CI: 4.17–6.23) of the 1,802 medical admissions during the period under review. There were 49 (52.1%) males and females 45 (47.9%) but the observed difference was not statistically significant
The etiological risk factors of acute symptomatic seizures were infections in 36.2% (
Classes of etiological risk factors of acute symptomatic seizures.
Disease class | Frequency ( |
Diseases | Frequency ( |
Percentage (%) |
---|---|---|---|---|
Infectious | 34 (36.2%) | Meningoencephalitis | 13 | 13.8 |
HIV/AIDS |
11 | 11.7 | ||
Sepsis | 7 | 7.4 | ||
Cerebral malaria | 2 | 2.1 | ||
Cerebral abscess | 1 | 1.1 | ||
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Stroke | 28 (29.8%) | Haemorrhagic stroke | 14 | 14.9 |
Ischaemic stroke | 9 | 9.6 | ||
Subarachnoid haemorrhage | 5 | 5.3 | ||
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Metabolic | 17 (18.1%) | Hyperglycaemia | 6 | 6.4 |
Hypoglycaemia | 5 | 5.3 | ||
Uraemia | 3 | 3.2 | ||
Hepatic | 2 | 2.1 | ||
Hyponatremia | 1 | 1.1 | ||
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Toxic | 7 (7.4%) | Poisoning |
4 | 4.3 |
Alcohol | 3 | 3.2 | ||
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Others | 8 (8.5%) | Hypertensive encephalopathy | 5 | 5.3 |
Uncertain | 3 | 3.2 |
The group designated “uncertain” did not have sufficient data to be classified into any of the groups as defined above and where indicated as patients living with epilepsy. Two cases of seizures due to brain tumours that presented during the period under review were excluded as acute symptomatic ones since they belong to the group progressive symptomatic according to the proposed ILEA definition as they occur in the context of an evolving clinical condition [
Figure
Age distribution of the two major causes of acute symptomatic seizures.
The prevalence of acute symptomatic seizures among medical admissions found in our study was 5.2% (95% CI: 4.17–6.23). This is more than 2.1% reported among neurological intensive care patients in India and 3.5% reported among medical intensive care unit patients in the USA [
There was an insignificant male preponderance of acute symptomatic seizures in our study. The risk of acute symptomatic seizures in males is almost double that of females in population based studies [
Infectious causes were the most frequent cause of acute symptomatic seizures in our study accounting for 36.2% (
Human immunodeficiency virus (HIV) infection was the etiological risk factor for 11.7% (
In our study neurocysticercosis was not among the causes of acute symptomatic seizures. This may indicate a low frequency of neurocysticercosis in our environment or under diagnosis of the condition due to lack of adequate facilities to make the diagnosis. Neurocysticercosis has been rarely reported in Nigeria hospitals studies even with the reports on the high prevalence of cysticercosis in meat in various parts of the country [
Cerebral malaria which is a common cause of acute febrile seizures in children in developing countries including Nigeria accounted for only 2.1% (
Stroke was a common cause of acute symptomatic seizures in our study accounting for 29.8% (
Metabolic derangements accounted for 18.1% (
In our study poisoning and alcohol related causes were implicated in 4.3% (
This study however had several limitations owning to the retrospective nature of the study and the frequent problems of poor record keeping associated with such studies. However, notwithstanding these limitations the findings afford a baseline for further studies on this subject in developing nations. The study was among medical admissions and so did not include etiologic risk factors like traumatic brain injuries which are managed primarily by the neurosurgical teams. Cases of acute symptomatic seizures developing in patients admitted without seizures as the first presenting feature were also not captured because of problems of inadequate documentations not infrequent with retrospective studies like this present study. This study was also limited by unavailability of high yield neurologic investigative modalities (like serological test, electroencephalography, viral studies, neuroimaging, and others) that would have enhanced accurate delineation of the differential diagnosis of the causes of acute symptomatic seizures. This is because of the absence of such facilities and for those that are available their high cost limits their use since patients pay out of pocket for medical facilities in the countries.
Infections and stroke were the prominent causes of acute symptomatic seizures. This an evidence of the “double tragedy” facing developing countries, the unresolved threat of infectious diseases on one hand and the increasing impact of noncommunicable diseases on the other one. The need for further studies in this area has been made bare given the high frequency of this condition found in this study.
The authors declare that there is no conflict of interests regarding the publication of this paper.