Abstract
Introduction:
Febrile seizure is an important issue in pediatric practice. Even some pediatricians do not have a proper approach to febrile seizure, making the sick child undergo complex laboratory tests or invasive procedures or even long-term treatment with anticonvulsant drugs. In spite of multiple studies, many controversies have still remained about the significance of febrile seizure. The goal of this study is to assess the prevalence distribution of routinely requested laboratory tests results in simple febrile seizure.
Materials and Methods:
In a descriptive study, 549 patients with simple febrile seizure were studied. The routine lab tests including complete blood count, electrolyte, urine analysis, and cerebrospinal fluid (CSF) analysis had already been performed for all patients and the results had been recorded in their medical data. These results were collected and statistically analyzed through SPSS software.
Results:
About 58.7% of our cases were male. Most of the cases were 12–24 months old and the mean body temperature of them was 38.2°C. 99.3% of blood sugar tests, 98% of blood calcium tests, 100% and 99.5% of sodium, and potassium tests, respectively, 100% of blood creatinine, 96.9% of blood urea nitrogen, and 99.1% of urine analysis tests were normal. CSF analysis was done in only 49 cases and the results were normal in all of them.
Conclusion:
The percentage of abnormal laboratory test results was not statistically significant in febrile seizure and shows that performing all these tests in all patients with simple febrile seizure as routine is not necessary.
Keywords: Children, electrolyte, febrile seizures, fever, laboratory test
Introduction
Febrile seizure is a common pediatric problem. In USA, half a million children suffer from convulsion accounting for 3–4% of young children. Febrile seizure is the most common type of pediatric convulsion which has a prevalence of 2–5% in children between 6 months to 5 years old with a pick in 9–30 months. It is rare in other ages and indicate abnormal neurologic background while the febrile seizure is a benign process.[1]
Recurrence of febrile seizure is 30%, but epilepsy is reported only in 2% of the cases. Researchers have showed that fever leads to convulsion by reducing the cerebral threshold. Positive familial history has been reported in 25–40% of the cases with an autosomal dominant heredity.[1,2]
Fever etiology in the febrile seizure is viral infections in 80% of cases, which involve upper respiratory tract, gastroenteritis, otitis media, pneumonia, urinary infection, roseola infantum, etc.[1,3]
Although febrile seizure is a benign process and has no effect on intelligence even in recurrence cases, convulsion makes the family stressful and parents are always afraid of its recurrence.[2] On the other hand, because of the high prevalence of febrile seizure, it's of great importance to manage them well and not waste money and time. Despite the prevalence of febrile seizure, there are disagreements on how to evaluate, manage it, and its prognosis. Papers has been written but no comparison has been done.[2,3]
Some research has been done on how to deal with febrile seizure, but no agreement has been achieved on necessary tests and in pediatric textbooks no consensus is seen.[1,3,4,5,6,7]
Thus, a research has been designed to study simple febrile seizure patients to survey the necessity of common tests (cerebrospinal fluid [CSF] test, biochemistry, urine) and compare the results with other studies (Medical Audit) to enhance patient treatment and reduce the expenditure if possible. In addition, it is intended to reduce kids’ hospitalization.
Materials and Methods
In a cross-sectional descriptive study, 549 patients with simple febrile seizure who were admitted to Amir Kabir Hospital between March 21, 2007 and September 22, 2007 were surveyed. Required information was extracted from the patient file. Since similar sample evaluation, complete documentation and pilot evaluation were done before this research, study were done 3 months retrospectively and 3 months prospectively.
First, medical history was gathered by interns and examination was done accurately, temperature, age, and gender were recorded. After diagnosis confirmation, the laboratory tests were requested routinely such as complete blood count (CBC), glucose, calcium, sodium, potassium, blood urea nitrogen (BUN), creatinine, urine test and culture, and cerebral fluid CSF (if necessary) and the results were recorded.
Results were compared with a normal range based on Nelson textbook of Pediatrics. Then, results were put into percentages and conclusion was performed and announced. Sampling and test similarity were observed.
Complete blood count, glucose, calcium, electrolytes, BUN, and creatinine samples were sent to the laboratory.
Blood complete count was done using cell-counter MS 9. Glucose was measured with Pars Azma glucose kit and spectrophotometry. Calcium level was obtained with Darman Kav calcium kit and spectrophotometry. Sodium and potassium level was obtained with flame photometry. BUN was measured with Pars Azma kit, urine culture, and cerebral fluid CSF was done manually. Urine culture of all patients was analyzed with cultivation method using the urine bag.
A total of 49 patients had lumbar puncture indication and in them CSF was sampled and analyzed without any dissatisfaction of parents (lumbar puncture's indication was suspected meningitis and meningismus symptoms).
The patients with a history of nonfebrile seizure or who have left hospital with their responsibility or those who did not have test results in their records (due to any reason) were excluded.
Data were analyzed by means of SPSS-16 by SPSS Inc statistic software. Descriptive statistics comprising of frequency, percentage, mean, and standard deviation were utilized.
Patients name and information was privately recorded and no investment was imposed to families. Tests were taken with satisfaction of patients and families. Helsinki declaration was observed in all stages of the research. This research plan was confirmed by research ethics committee.
Results
In this study, 570 patients’ records were analyzed, 5 of whom had left hospital on the own responsibility, 16 of which had not complete recordings. Thus, 21 patients were excluded. From 549 patients who were checked, 322 were males (58.7%), and 227 were females (41.3%).
Minimum, maximum, and mean age were 6 months, 60 months, and 26.1 months, respectively. Most patients were between 12 and 24 months old [Table 1].
Table 1.
Age distribution in simple febrile seizure patients admitted in Amir Kabir Hospital of Arak in March 2007-June 2007
Mean temperature of 549 simple febrile seizure cases was 38.2°C. Most recorded, minimum, and maximum temperature were 38.1, 37.5, and 41, respectively [Table 2].
Table 2.
Temperature distribution in simple febrile seizure patients admitted in Amir Kabir Hospital of Arak in March 2007-June 2007
Minimum and maximum glucose levels were 65 mg/dl and 280 mg/dl (only in one patient), respectively [Table 3].
Table 3.
Glucose level distribution in simple febrile seizure patients admitted in Amir Kabir Hospital of Arak in March 2007 to June 2007
Eleven patients had abnormal calcium levels and three patients had abnormal potassium. Sodium levels were normal. 494 patients (90%) had normal leucocyte numbers and 55 patients had abnormal leucocyte numbers which has been defined as leukocytosis (white blood cell [WBC] >15,000) [Table 4].
Table 4.
Descriptive statistics of tests in simple febrile seizure patients admitted in Amir Kabir Hospital of Arak in March 2007 to June 2007
Five patients had an active urinalysis and urine culture was positive in all of them.
Blood urea nitrogen and creatinine of 549 patients were studied: All patients’ creatinine level was normal. 18 patient had abnormal BUN, 8 (1.4%) with low BUN, and 10 (1.7%) with high BUN levels.
Forty-nine patients were candidates for lumbar puncture and all the results were normal. Thirty-six patients were under 18 months old and 13 were above 18 months old.
Discussion
In our study on simple febrile seizure patients:
Patients’ sex distribution showed males with febrile seizure were more than female which confirmed pediatric textbooks.[1,2,3,8,9,10,11]
Mean temperature was 38.2°C and 38.1°C was the most recorded result. Most patient had a temperature between 38°C and 39°C which is on the contrary to Nelson textbook of pediatrics (39–39.5°C).[1] This might be because prehospital administration of antipyretic medication by parents of children, since some of the children has a temperature below 38°C.
In age distribution of 549 admitted patients:
No one was below 6 months old, which confirmed Nelson textbook of pediatrics.[1,4] Two cases were above 5 years old who were not included in the study based on the definition (note that they may be included according to some pediatric textbooks and no need to neurogenic evaluation).[12]
In this study, most of the patients were between 12 and 24 months old which did not show any conflict with previous information (14–18 months).
In laboratory tests, only five patients had abnormal glucose level all of which were hyperglycemia cases.
In this study, blood sugar (BS) above 200 mg/dl was important for us which included only four patients, one of which had a BS level of 280 mg/dl they had no history of diabetes mellitus or family history. If BS level of these cases were measured again, glucose tolerance test might be needed to check them for R/O of diabetes mellitus. On the other hand, this raise in glucose level may be normal to patient's stress, health problem, hunger or sports. These changes are also considered normal in the 1st h of deep sleeps. To conclude further tests were needed which were not done, thus, no conclusion may be done. After all, this problem is not related to this study since hypoglycemia is important in convulsions and no case has been reported with hypoglycemia.
This study shows that, BS test is not necessary for simple febrile seizure patients, which confirms many researches and in Oski's pediatric it is mentioned that BS test is not needed in patients with simple febrile seizure.[3] Mikati and Rahi suggested BS level checking in patient who had a long postictal period but other papers do not agree.[5] On the contrary, Nelson textbook of pediatrics and Lie's study in 2006 and Warden et al. study, only suggested BS as a routine test.[1,8,4,13]
In calcium level checking of 549 patients, few cases had hypocalcemia and hypocalcemia. Hypocalcemia is important in simple febrile seizure and reported results are not lower than 7 mg/dl to lead to convulsion. In the explanation of hypocalcemia, standing or prolonged activity before the test, venous ischemia or hemolysis during sampling, long maintenance of blood sample, long-term closure of tourniquet, and dehydration should be considered. Ionized calcium is important in this case, but we could only measure total calcium level.
Finally, calcium measurement seems not to be a necessary test in patients with simple febrile seizure, which confirmed most papers.
In Oski's pediatric textbook, calcium level test is not mentioned. Mikati and Rahi suggested calcium level only in a patient with long postictal periods. Lie suggested to check calcium level only if there is a point is patient's medical history. Other studies suggested that there is no need to measure calcium level.[3,5,7,13,14,15,16,17,18,19]
No abnormal sodium level was measured. Hypernatremia and hyponatremia both may lead to convulsion.
In blood potassium level measurements, few abnormal results were obtained in the form of hyperkalemia. Both hyperkalemia and hypokalemia may lead to convulsion. No hypokalemia was reported and hyperkalemia seems to be due to technical error in measurements (sample hemolysis or patient's movement after the closure of tourniquets may lead to false hyperkalemia). Since potassium was not measured again, no conclusion may be done. It can be concluded that it's necessary to measure potassium level of blood. It is confirmed by many papers and pediatrics major references. Electrolytes tests are required only in dehydration situation such as severe gastroenteritis which are rare cases and are not expected in patients with simple febrile seizure.
In Nelson textbook of pediatrics and Lie's paper, electrolytes analysis is suggested only according to clinical status.[1,8,13] In Warden et al. study, electrolytes analysis is suggested only when the patient is suspected to have electrolytes disorder, but in Oski's pediatric textbook and Patricai A. Gaffney paper it's been stated that there is no necessity to measure electrolytes levels.[3,4,18]
In WBC test of 549 patients, few cases of leukocytosis were reported. It would be related to background upper respiratory tract infection of the patients. WBC tests are routinely done to find hyperthermia causes, like other infectious diseases of children.[9]
On the other hand, leukocytosis may happen due to patient's stress, which is a probability in children with convulsion.
In Patrica A. Gaffney's paper, it's been stated CBC will be useful for hyperthermia evaluation for kids under 2 years because of the high prevalence of bacteremia.[18] In Nelson textbook of pediatrics, CBC is suggested only according to clinical status.[8] In Mikati paper, CBC is suggested only in patients with long postictal periods.[5]
On the other hand, in Peter Camfield's paper, it has been stated that CBC is not necessary because bacteremia is not prevalent.[20]
In another study on 62 kids with simple febrile seizure done in a hospital in Turkey, it is stated that temporary leukocytosis may be seen in these patients without any bacterial infection.[7]
In BUN and creatinine level measurement of 549 patients, creatinine level of all patients was normal. In BUN there were some abnormal cases. BUN below normal is not valuable in this study (since it's normal in the starvation condition, low-protein diet, and in infants). Other cases were near the upper threshold and justifiable according to patients’ dehydration and hyperthermia. Most of high BUN levels were reported in patients with temperature above 39°C. This shows low importance of BUN and creatinine level measurement in kids with simple febrile seizure.
In Lie paper, BUN measurement is necessary only if there is a point in medical history or clinical examination.[13] In Nelson textbook of pediatrics and Oski's pediatric textbook, BUN and creatinine measurement is of no importance.[1,3,8]
In urine test and culture of the 549 patients, only few cases had positive urine test whose urine culture was positive. Statistical results show low importance of urine analysis in patients with a simple febrile seizure. In Lie's study in 2006 it is stated:
Urine analysis of patients, with positive urinary infections as a leading factor for hyperthermia, is suggested.[13]
All the 59 patient who took lumbar puncture had normal results. Three-fourths of them were under 18 months infants. This results show that simple febrile seizure is a benign disease and without neurologic abnormalities in background. In Peter Camfield's paper, lumbar puncture is needed only when patient is suspected to have meningitis. In Gerber and A. Gaffney's study lumbar puncture is necessary for infants under 12 months old, since meningitis’ symptoms are not clear.[20,21] Lumbar puncture is also helpful for patients between 12 and 18 months old, since meningitis symptoms may be mistaken but for kid above 18 months old, lumbar puncture is not a common procedure which is similar to Mikati and Rahi study.[5]
In another study of Warden et al., lumbar puncture is suggested for kids above 18 months old with following criteria.[4]
Presence of irritability and difficulty in feeding
Evidence of meningitis
Long postictal phase or prior receiving of antibiotics.
In Lie's paper, lumbar puncture has an indication if disease last at least 3 days, vomiting or sleepiness at home or meningitis occurrence.[13]
Chen et al. in 2010 suggested that electrolytes, BS, and emergent brain imaging studies should be arranged based on detailed history-taking and thorough physical examinations, but should not be performed routinely.[22]
Conclusion
In this study, abnormal test results were rare which shows that routine laboratory tests are not important in patients with a simple febrile seizure. These tests are not needed to be done in all patients and indications may differ from patient to patient according to physician's idea and examinations.
Constraints and limitations
Self-responsibility for leaving the hospital before sampling, incomplete medical histories and recordings in some patient files are of this study's constraints. Furthermore, not being able to have specific persons for sampling and ionized calcium measurement in laboratory tests were some limitations in the current study.
Acknowledgments
There is no doubt that conduction of the present study might not be feasible without cooperation of the patients, the respected colleagues therefore we express our high gratitude and acknowledgement to the aforementioned persons and organizations and other colleagues in this researching project.
Footnotes
Source of Support: Nil.
Conflict of Interest: None declared.
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