Acta PRdiatr Scand 79: 1092-1098, 1990
Gamma-Aminobutyric Acid Concentration in Lumbar Cerebrospinal Fluid from Patients with Febrile Convulsions and Controls KJELD SCHMIEGELOW,' ANDERS H. JOHNSEN,* FINN EBBESEN,3 TORBEN MORTENSEN,4 ANNA MOURIER BERG,5 INGRID THORN,6 LISELOTTE SKOV,7 JOHN R. 0STERGAARD8 and OLE S0RENSEN9 From the Departments of Paediatrics University Hospitals, 'Copenhagen, 6Gentofte, 'Glostrup, and 'Hvidovre, 4NrestvedHospital, 'Holbrek Hospital, 'Herning Hospital, 'Hjorring Hospital; and 2Department of Clinical Chemistry, University Hospital, Copenhagen
ABSTRACT. Schmiegelow, K., Johnsen, A. H., Ebbesen, F., Mortensen, T., Berg, A. M., Thorn, I., Skov, L., Ostergaard, J. R. and Serensen, 0. (Departments of Paediatrics at the University Hospitals of Copenhagen, Gentofte, Glostrup, and Hvidovre; Naestved Hospital, Holbaek Hospital, Herning Hospital, Hjmring Hospital, Department of Clinical Chemistry, University Hospital, Copenhagen). Gammaaminobutyric acid concentration in lumbar cerebrospinal fluid from patients with febrile convulsions and controls. Acta Paediatr Scand 79: 1092, 1990. The cerebrospinal fluid (CSF) concentration of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) was analysed in 41 children with febrile convulsions (FC), 41 febrile controls of similar age (control group l ) , and 59 controls, who had no fever and/or were outside the age range for FC (control group 2). A significant correlation between CSF-GABA and age was demonstrated for controls ( 1 2) (r=0.63, p 38.0"C at the time of admission (Table 1). All controls had a normal neurologic history, including no previous registered event of FC. Patients with FC included 24 boys and 17 girls. Median age at onset of FC was I year 5 months (range: 7 months-5 yr 6 months). Median body temperature at the time of admission was 39.5"C (38.0-40.9). Twenty-five patients had complex seizures, i.e. multiple seizures within 24 h from onset, focal seizures, or duration of seizures > 15 min (12,2, and 16 patients, respectively). Five of these 25 patients had combinations of these adverse features. Median duration of convulsions was 5 min (range: 1-90 min). Six patients had a prior history of FC. Beyond this, all patients had a previous normal neurological status. Control group I comprised all febrile children (median body temperature: 39.8"C, 38.0-40.4) between 6 months and 6 years (median age: 1 year 7 months, 7 months-5 yr 1 I months) not having FC. There were 30 boys and 1 1 girls. Control group 2. This group was complementary to control group 1, encompassing all remaining children without FC irrespective of age and temperature. Thirty-seven were boys and 22 girls. Median age of control group 1 + 2 was 1 year 2 months (range 0 months-14 yr 8 months). Lumbarpuncture. For all patients, the last aliquot (0.3-0.5 ml) of the CSF sampled was used for GABA-analysis. Immediately after the puncture, the samples were placed on ice and stored at -20°C within 15 min. This method of sampling and storage guarantees stability of GABA (20, 21). For FC-patients, the lumbar puncture was in all cases done less than an hour and a
Table 1. Etiology of fever in patients with febrile seizures and controls Control group
Fever of unknown origin Upper respiratory infection Otitis media Pneumonia Influenla Infectious. monomucleosis Mumps Exanthema subitum Typhoid fever Gastroenteritis Sepsis St reptococcosis Urinary tract infection
Patients with febrile seizures
1
2"
16 17 2 2
13 7 1 13
17 6 1
7 2
1 1
2 1
1
Patients with body temperature > 38°C.
1
1094 K. Schmienelow et al.
Acta Paediatr Scand 79
half from the onset of FC. Rectal Diazepam was administered 2-45 min (median: 10 min) prior to the spinal puncture in 21 FC patients. GABA-analysis. After thawing at 4"C, 20% 5-sulfosalicylic acid was added to 120 p1 of CSF to a final concentration of 4%. The samples were mixed, placed at 4°C for at least 10 min, remixed and centrifuged (4000 g) for 10 min at 0°C. GABA was measured in 125 pl of the supernatant by ion exchange chromatography and post-column derivatization with o-phtaldialdehyde in the presence of mercaptoethanol on a LKB amino acid analyzer 4400 (Nacitrate, 3-buffer system) Biochrome, Cambridge, England). The fluorescence was detected with a Waters fluorometer 420 (excitation filter 338 nm, emission filter 425 nm long pass). Standard solutions of GABA were prepared in 1 M HCI. The detection limit was 15 nmol/l. All samples were measured in duplicates on separate days. The coefficient of variation for control samples included in each series of analyses was 0.07. Statistical analysis. Subsets of patients were compared using the Wilcoxon Rank-sum test. Linear regression analyses were done using the least-squares method. The study was approved by the local ethics committees.
RESULTS Patients with FC did not differ significantly from control group 1 in respect to gender, age, body temperature, or CSF-GABA (Table 2). Patients with multiple FC, with focal FC, with a previous history of FC, and patients who received rectal Diazepam prior to the lumbar puncture did not differ significantly in respect to CSF-GABA when compared to the remaining patients with FC (Table 2). However, patients with duration of FC > 15 min had a somewhat lower CSF-GABA than patients with duration of seizures < 15 min (Table 2). Linear regression analysis demonstrated the duration of FC to be significantly related to CSF-GABA (r=-0.29, p
Gamma-Aminobutyric Acid Concentration in Lumbar Cerebrospinal Fluid from Patients with Febrile Convulsions and Controls KJELD SCHMIEGELOW,' ANDERS H. JOHNSEN,* FINN EBBESEN,3 TORBEN MORTENSEN,4 ANNA MOURIER BERG,5 INGRID THORN,6 LISELOTTE SKOV,7 JOHN R. 0STERGAARD8 and OLE S0RENSEN9 From the Departments of Paediatrics University Hospitals, 'Copenhagen, 6Gentofte, 'Glostrup, and 'Hvidovre, 4NrestvedHospital, 'Holbrek Hospital, 'Herning Hospital, 'Hjorring Hospital; and 2Department of Clinical Chemistry, University Hospital, Copenhagen
ABSTRACT. Schmiegelow, K., Johnsen, A. H., Ebbesen, F., Mortensen, T., Berg, A. M., Thorn, I., Skov, L., Ostergaard, J. R. and Serensen, 0. (Departments of Paediatrics at the University Hospitals of Copenhagen, Gentofte, Glostrup, and Hvidovre; Naestved Hospital, Holbaek Hospital, Herning Hospital, Hjmring Hospital, Department of Clinical Chemistry, University Hospital, Copenhagen). Gammaaminobutyric acid concentration in lumbar cerebrospinal fluid from patients with febrile convulsions and controls. Acta Paediatr Scand 79: 1092, 1990. The cerebrospinal fluid (CSF) concentration of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) was analysed in 41 children with febrile convulsions (FC), 41 febrile controls of similar age (control group l ) , and 59 controls, who had no fever and/or were outside the age range for FC (control group 2). A significant correlation between CSF-GABA and age was demonstrated for controls ( 1 2) (r=0.63, p 38.0"C at the time of admission (Table 1). All controls had a normal neurologic history, including no previous registered event of FC. Patients with FC included 24 boys and 17 girls. Median age at onset of FC was I year 5 months (range: 7 months-5 yr 6 months). Median body temperature at the time of admission was 39.5"C (38.0-40.9). Twenty-five patients had complex seizures, i.e. multiple seizures within 24 h from onset, focal seizures, or duration of seizures > 15 min (12,2, and 16 patients, respectively). Five of these 25 patients had combinations of these adverse features. Median duration of convulsions was 5 min (range: 1-90 min). Six patients had a prior history of FC. Beyond this, all patients had a previous normal neurological status. Control group I comprised all febrile children (median body temperature: 39.8"C, 38.0-40.4) between 6 months and 6 years (median age: 1 year 7 months, 7 months-5 yr 1 I months) not having FC. There were 30 boys and 1 1 girls. Control group 2. This group was complementary to control group 1, encompassing all remaining children without FC irrespective of age and temperature. Thirty-seven were boys and 22 girls. Median age of control group 1 + 2 was 1 year 2 months (range 0 months-14 yr 8 months). Lumbarpuncture. For all patients, the last aliquot (0.3-0.5 ml) of the CSF sampled was used for GABA-analysis. Immediately after the puncture, the samples were placed on ice and stored at -20°C within 15 min. This method of sampling and storage guarantees stability of GABA (20, 21). For FC-patients, the lumbar puncture was in all cases done less than an hour and a
Table 1. Etiology of fever in patients with febrile seizures and controls Control group
Fever of unknown origin Upper respiratory infection Otitis media Pneumonia Influenla Infectious. monomucleosis Mumps Exanthema subitum Typhoid fever Gastroenteritis Sepsis St reptococcosis Urinary tract infection
Patients with febrile seizures
1
2"
16 17 2 2
13 7 1 13
17 6 1
7 2
1 1
2 1
1
Patients with body temperature > 38°C.
1
1094 K. Schmienelow et al.
Acta Paediatr Scand 79
half from the onset of FC. Rectal Diazepam was administered 2-45 min (median: 10 min) prior to the spinal puncture in 21 FC patients. GABA-analysis. After thawing at 4"C, 20% 5-sulfosalicylic acid was added to 120 p1 of CSF to a final concentration of 4%. The samples were mixed, placed at 4°C for at least 10 min, remixed and centrifuged (4000 g) for 10 min at 0°C. GABA was measured in 125 pl of the supernatant by ion exchange chromatography and post-column derivatization with o-phtaldialdehyde in the presence of mercaptoethanol on a LKB amino acid analyzer 4400 (Nacitrate, 3-buffer system) Biochrome, Cambridge, England). The fluorescence was detected with a Waters fluorometer 420 (excitation filter 338 nm, emission filter 425 nm long pass). Standard solutions of GABA were prepared in 1 M HCI. The detection limit was 15 nmol/l. All samples were measured in duplicates on separate days. The coefficient of variation for control samples included in each series of analyses was 0.07. Statistical analysis. Subsets of patients were compared using the Wilcoxon Rank-sum test. Linear regression analyses were done using the least-squares method. The study was approved by the local ethics committees.
RESULTS Patients with FC did not differ significantly from control group 1 in respect to gender, age, body temperature, or CSF-GABA (Table 2). Patients with multiple FC, with focal FC, with a previous history of FC, and patients who received rectal Diazepam prior to the lumbar puncture did not differ significantly in respect to CSF-GABA when compared to the remaining patients with FC (Table 2). However, patients with duration of FC > 15 min had a somewhat lower CSF-GABA than patients with duration of seizures < 15 min (Table 2). Linear regression analysis demonstrated the duration of FC to be significantly related to CSF-GABA (r=-0.29, p
