ictal and interictal spect in a newborn infant with intractable seizure

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Acta PBdiatr 86: 1379-81. 1997 CASE REPORT Ictal and interictal SPECT in a newborn infant with intractable seizure E KO$’, A Serdaroilu2, 6 Kapucu’, Y Atalay I, K Gucuyener2 and T Atasever3 Departments of Neonatology’, Paediatric Neurology‘ and Nuclear Medicine ’, Faculty of Medicine, Gazi University,Ankara, Turkey KOG E, Serdaroglu A, Kapucu 0, Atalay Y, Giiciiyener K, Atasever T. Ictal and interictal SPECT in a newborn infant with intractable seizure. Acta PEdiatr 1997; 86: 1379-81. Stockholm. ISSN 0803-5253 Neonatal seizures can be difficult to classify according to partial vs generalized onset based on clinical appearance, electroencephalogram (EEG) or other adjunctive imaging techniques. Single-photon emission computed tomography (SPECT) has proven to be useful in adults; however, its use is limited in the paediatric age group, particularly in neonates. A case of a 12-d-old infant with intractable seizures is reported, on whom an interictal Tc-99m HMPAO SPECT showed an area of hypoperfusion in the left temporal cortex, whereas the ictal SPECT revealed prominent hyperperfusion in the same area. The EEG of the infant demonstrated generalized epileptiform activity, while computed tomography and magnetic resonance (MR) imaging findings were normal. This case indicates that the use of SPECT may provide valuable data in evaluation of neonatal seizures, particularly with poorly localized EEG changes and normal MRI scans. 0 Newborn, seizure, single-photon emission computed tomography E KOG, Hatir sok 15/2 Gaziosmanpaga 06700, Ankara, Turkey Despite the fact that they are associated with significant mortality and the risk of major neurodevelopmental sequa- lae (l), controversies still exist in the diagnosis and man- agement of neonatal seizures. Clinical observation of events presumed to be seizures has been the basis of our information; electroencephalogram (EEG) and video-EEG monitoring have significantly added to our knowledge. However, at times when the EEG fails to identify the nature of seizure onset and particularly in cases where computed tomography (CT) and magnetic resonance (MR) imaging detect no lesion, additional diagnostic tools are required to identify and evaluate the brain area responsible for the refractory seizures. Single photon-emission computed tomography (SPECT) using cerebral blood flow markers is being used increas- ingly to investigate patients with intractable seizures (2,3). Studies in adults have shown that ictal and post-ictal SPECT are superior to interictal studies for seizure focus localization (4, 5). Ictal SPECT has been performed in a limited number of paediatric cases (6-8) and to our knowl- edge, there is only one report in the literature about ictal SPECT in newborn period (9). In this paper, we report a case of an intractable neonatal seizure with normal CT and MR imaging findings and an ictal SPECT suggesting a focal mechanism of seizure onset. Case report A 12-d-old male infant was referred to our outpatient clinics due to persisting generalized seizures since his second day of life. His history included an uncomplicated pregnancy and the baby was born at term to a 22-y-old mother via vaginal delivery. At birth, Apgar scores at 1 and 5min were 7 and 9, respectively, and umbilical artery blood pH taken shortly after delivery was 7.25. Birth asphyxia was not reported. On admission, physical and neurological examination of the infant as well as the results of routine haematological, biochemical and serological testings were normal. Screen- ing tests for inborn errors of metabolism (serum and urinary amino acids, serum and cerebrospinal fluid lactic acid and pyruvic acid, serum biotidinase activity) were negative. On the first day of his admission he had several seizures each lasting up to 5 min, characterized by upward deviation of the eyes with predominant involvement of the right-hand side of his body, culminating in generalized tonic convul- sion. Seizures were reduced to one or two attacks a day for the following days with a phenobarbital level of 42 pg/ml. However, after a few days, attacks increased in both fre- quency and severity. Despite the treatment with phenobar- bital, phenytoin, benzodiazepins and carbamezapine in various combinations, the patient was having as many as 10 seizures a day lasting 4-5 min. The interictal EEG showed diffuse temporal epilepti- form activity lateralized to the left hemisphere with tem- poral and central regional onset. The patient’s seizures were documented by EEG-video studies and demonstrated electrographil: correlation. CT did not detect any lesion. MR images obtained by using IT superconductive MR unit (Signa, GE, MS, Milwaukee, USA) was normal (Fig. lA, B). 0 Scandinavian University Press 1997. ISSN 0803-5253.

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Page 1: Ictal and interictal SPECT in a newborn infant with intractable seizure

Acta PBdiatr 86: 1379-81. 1997

CASE REPORT

Ictal and interictal SPECT in a newborn infant with intractable seizure E KO$’, A Serdaroilu2, 6 Kapucu’, Y Atalay I , K Gucuyener2 and T Atasever3 Departments of Neonatology’, Paediatric Neurology‘ and Nuclear Medicine ’, Faculty of Medicine, Gazi University, Ankara, Turkey

KOG E, Serdaroglu A, Kapucu 0, Atalay Y, Giiciiyener K, Atasever T. Ictal and interictal SPECT in a newborn infant with intractable seizure. Acta PEdiatr 1997; 86: 1379-81. Stockholm. ISSN 0803-5253

Neonatal seizures can be difficult to classify according to partial vs generalized onset based on clinical appearance, electroencephalogram (EEG) or other adjunctive imaging techniques. Single-photon emission computed tomography (SPECT) has proven to be useful in adults; however, its use is limited in the paediatric age group, particularly in neonates. A case of a 12-d-old infant with intractable seizures is reported, on whom an interictal Tc-99m HMPAO SPECT showed an area of hypoperfusion in the left temporal cortex, whereas the ictal SPECT revealed prominent hyperperfusion in the same area. The EEG of the infant demonstrated generalized epileptiform activity, while computed tomography and magnetic resonance (MR) imaging findings were normal. This case indicates that the use of SPECT may provide valuable data in evaluation of neonatal seizures, particularly with poorly localized EEG changes and normal MRI scans. 0 Newborn, seizure, single-photon emission computed tomography

E KOG, Hatir sok 15/2 Gaziosmanpaga 06700, Ankara, Turkey

Despite the fact that they are associated with significant mortality and the risk of major neurodevelopmental sequa- lae (l), controversies still exist in the diagnosis and man- agement of neonatal seizures. Clinical observation of events presumed to be seizures has been the basis of our information; electroencephalogram (EEG) and video-EEG monitoring have significantly added to our knowledge. However, at times when the EEG fails to identify the nature of seizure onset and particularly in cases where computed tomography (CT) and magnetic resonance (MR) imaging detect no lesion, additional diagnostic tools are required to identify and evaluate the brain area responsible for the refractory seizures.

Single photon-emission computed tomography (SPECT) using cerebral blood flow markers is being used increas- ingly to investigate patients with intractable seizures (2,3). Studies in adults have shown that ictal and post-ictal SPECT are superior to interictal studies for seizure focus localization (4, 5). Ictal SPECT has been performed in a limited number of paediatric cases (6-8) and to our knowl- edge, there is only one report in the literature about ictal SPECT in newborn period (9).

In this paper, we report a case of an intractable neonatal seizure with normal CT and MR imaging findings and an ictal SPECT suggesting a focal mechanism of seizure onset.

Case report A 12-d-old male infant was referred to our outpatient clinics due to persisting generalized seizures since his

second day of life. His history included an uncomplicated pregnancy and the baby was born at term to a 22-y-old mother via vaginal delivery. At birth, Apgar scores at 1 and 5min were 7 and 9, respectively, and umbilical artery blood pH taken shortly after delivery was 7.25. Birth asphyxia was not reported.

On admission, physical and neurological examination of the infant as well as the results of routine haematological, biochemical and serological testings were normal. Screen- ing tests for inborn errors of metabolism (serum and urinary amino acids, serum and cerebrospinal fluid lactic acid and pyruvic acid, serum biotidinase activity) were negative.

On the first day of his admission he had several seizures each lasting up to 5 min, characterized by upward deviation of the eyes with predominant involvement of the right-hand side of his body, culminating in generalized tonic convul- sion. Seizures were reduced to one or two attacks a day for the following days with a phenobarbital level of 42 pg/ml. However, after a few days, attacks increased in both fre- quency and severity. Despite the treatment with phenobar- bital, phenytoin, benzodiazepins and carbamezapine in various combinations, the patient was having as many as 10 seizures a day lasting 4-5 min.

The interictal EEG showed diffuse temporal epilepti- form activity lateralized to the left hemisphere with tem- poral and central regional onset. The patient’s seizures were documented by EEG-video studies and demonstrated electrographil: correlation. CT did not detect any lesion. MR images obtained by using IT superconductive MR unit (Signa, GE, MS, Milwaukee, USA) was normal (Fig. lA, B).

0 Scandinavian University Press 1997. ISSN 0803-5253.

Page 2: Ictal and interictal SPECT in a newborn infant with intractable seizure

SPECT Baseline SPECT brain perfusion imaging was performed during interictal period, within 15 min of an intravenous injection of 101 MBq of Tc-99m HMPAO (Amersham- Ceretec. Amersham. UK) in a quiet room. Chloral hydrate was administered for sedation. A dual-headed gamma camera (GE, Optima, Milwaukee, USA} equipped with high resolution collimator was used for imaging. The interictal SPECT study revealed prominent hypoperfusion in the left temporal cortex (Fig. 2).

Ictal SPECT study was performed on a separate day. The patient was video-EEG monitored. Tc-99m HMPAO was reconstituted at the bedside, and injected at the onset of seizure via a previously inserted two-way intravenous catheter. Repositioning of the patient for the ictal study was carefully done, based on his previously recorded posi- tion at the interictal study, and SPECT imaging was per- formed with the same acquisition parameters. Ictal SPECT revealed a prominent hyperpesfusion in the left temporal cortex occupying a larger area than baseline hypoperfusion region (Fig. 2 ) .

At present. the baby is 6 months old and his current regimen is valproat (30 mg/kg/d). Although the fre- quency and severity of the seizures diminished, the patient still has 1-2 seizures a day lasting 1-2 min, as he is still on anticonvulsive treatment.

Fig. 1. ( A ) Axial T I - ( T ~ E / N E X - 5 - t 0 0 1 1 0 i 3 ) and ( B j PD-weighted 12000/30/1 ) MR images deinoiistrare no ob\ ious signal change.

Fiy. 3. .4 rq t ie i i t i~ l t ran \ -a \ i ; i l SPEC'T \lice\ of the patient. Upper rou : inrerictal study: decreased perfusinn in the left temporal cortex. Lower row: ictal \ tud) : prominent i n ixa \ ed perfutitrii i n the left temporal cortex f a r r o w )

Page 3: Ictal and interictal SPECT in a newborn infant with intractable seizure

ACTA PEDIATR 86 (1997) SPECT in n newborn irIfin~t I 38 I

Discussion could not be identified by any conventional evaluation

Seizures are a serious manifestation of brain dysfunction in a significant number of affected neonates, since a signifi- cant number of them die, or end up with neurologic sequa- lae. Although clinical observations, EEG evaluation and neuroimaging modalities have added much to our knowl- edge, many areas of uncertainty remain to be solved.

Blood flow revealed by SPECT reflects brain metabo- lism in the interictal and ictal states, and thereby is useful in localization of seizure focus (4, 5 , 10). Several studies demonstrated a higher sensitivity of immediate postictal SPECT than interictal SPECT (4,5). Interictal brain perfu- sion SPECT imaging in focal epilepsy often reveals an area of reduced blood flow at the seizure site (1 1). The mecha- nism of reduced blood flow and metabolism observed in the interictal phase is unexplained (12). Regional cerebral blood flow to the epileptic focus increases by up to 300% during a seizure. Thus, the high first extraction of Tc-99m HMPAO with prolonged retention makes imaging of ictal cerebral flow feasible (12). Although the need for evalua- tion of SPECT for the intractable seizures of paediatric age group is increasing, ictal SPECT has been performed in a limited number of cases (6,7).

Recently, Denays et al. (13) performed SPECT in high- risk neonates to predict cerebral palsy and reported that compared to conventional investigations, 99m-Tc-HMPAO brain SPECT did not provide additional predictive infor- mation and should not be performed in every high-risk neonate. Haddad et al. (14) studied cerebral perfusion using SPECT in neonates with brain lesions; they also concluded that the use of SPECT to assess alteration of cerebral perfusion in the neonatal period did not provide any addi- tional information to that which conventional neuroradio- logical investigations provide. An ictal SPECT study of a 16-d-old infant with seizures was reported by Green et al. (9), but in this case MR imaging provided evidence of focal atrophy overlapping with the focus found on ictal SPECT. In the present case, beside the diffuse EEG abnormalities shown on ictal and interictal EEG, CT and MR imaging detected no lesion. On the other hand, interictal brain perfusion SPECT showed wide hypoperfusion in the left temporal cortex and ictal SPECT revealed hyperperfusion in the same territory. Therefore, laterality of seizure onset

techniques, except SPECT. We conclude thatthe use of SPECT in neonatal period,

particularly when conventional investigations provide no information, may be of great importance in identification of seizure foci, and longitudinal follow-up of these cases could provide valuable data regarding the natural history of partial epilepsy.

References 1. Wical BS. Neonatal seizures and electrographic analysis: Evaluation

and outcomes. Pediatr Neurol 1994; 10: 271-5 2. Griinwald F, Durwen HF, Bockisch A, et al. Technetium-99m-

HMPAO brain SPECT in medically intractable temporal lobe epi- lepsy: A postoperative evaluation. J Nucl Med 1991; 32: 388-94

3. Lee BI, Markand ON, Wellman HN, et al. HIPDM-SPECT in patients with medically intractable complex partial seizures: ictal study. Arch Neurol 1988; 45: 397-402

4. Rowe CC, Berkovic SF, Austin M, et al. Postictal SPECT in epilepsy. Lancet 1989; 18: 389-92

5. Rowe CC, Berkovic SF, Austin MC, et al. Visual and quantitative analysis of interictal SPECT with technetium-99m-HMPAO in tem- poral lobe epilepsy. J Nucl Med 1991; 32: 1688-94

6. Uvebrandt P, Bjure J, Hedstrom A, Ekholm S. Brain single photon emission computed tomography (SPECT) in neuropediatrics. Neuro- pediatrics 1991; 22: 3-7

7. Chiron C, Rakynaud C, Dulac 0, et al. Study of the cerebral blood flow in partial epilepsy of childhood using the SPECT method. J Neuroradiol 1989; 16: 317-21

8. Adams C, Hwang PA, Gilday DL, et al. Comparison of SPECT, EEG. CT, MRI and pathology in partial epilepsy. Pediatr Neurol 1992: 8:

9. Green C, Buchhalter JR. Ictal SPECT in a 16-day-old infant. Clin 97- 102

Nucl Med 1993; 18: 768-70 10. Editorial SPECT and PET in epilepsy. Lancet 1989; 19: 135-7 11. Duncan S, Gillen G, Adams FG, Duncan R, Brodie MJ. Interictal

HMPAO SPECT: a routine investigation in patients with medically intractable complex partial seizures. Epilepsy R 1992; 12: 83-7

12. Murray IPC, Ell PJ, editors. Nuclear medicine in clinical diagnosia and treatment. 1st ed. Edinburgh: Churchill Livingstone, 1994:

13. Denays R, Van Pachderbeke T, Toppet V, et al. Prediction of cerebral palsy in high-risk neonates: a technetium-99m-HMPAO SPECT study. J Nucl Med 1993; 34: 1223-7

14. Haddad J, Constantinesco A, Brunot B, Messer J. A study of cerebral perfusion using single photon emission computed tomography in neonates with brain lesions. Acta Pediatr 1994: 83: 265-9

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Received Apr. 1, 1997. Accepted in revised form Aug. 1 I , 1997