Long term prognosis of symptomatic occipital lobe epilepsy ... - sepeap

94 H. Montassir et al.
Perinatal history and neurological sequelae (Table 2)................................................................. 94
Characteristics of epileptic seizure and clinical course of epilepsy (Table 3 and Figs. 1 and 2)........................ 95
EEG and MRI findings (Table 4 and Figs. 3—5) ......................................................................... 97
Discussion ............................................................................................................... 97
References .............................................................................................................. 99
Introduction
Glucose is essentially important for brain metabolism. It
is well known that severe neonatal hypoglycemia results
in posterior cerebral injury. The neurological sequelae
of severe neonatal hypoglycemic encephalopathy include
developmental delay, learning or behavioral problems,
epilepsy, and visual impairment. Although the prevalence
of epilepsy in neonatal hypoglycemic encephalopathy was
quite high, studies about epilepsy secondary to neonatal
hypoglycemia are sparse (Norden, 2001). Caraballo et
al. (2004) reported that prognosis of symptomatic occipital
lobe epilepsy following neonatal hypoglycemia was
mostly good. In our own experience, symptomatic occipital
lobe epilepsy secondary to neonatal hypoglycemia is
intractable to treatment with high prevalence of status
epilepticus in infancy but remits in late childhood. Longitudinal
clinical course of epilepsy secondary to neonatal
hypoglycemia are not fully described. In this study, we
sought to examine the long-term prognosis and longitudinal
clinical course of symptomatic occipital lobe epilepsy
secondary to neonatal hypoglycemia.
Subjects and methods
We retrospectively extracted subjects from the database of outpatients
who were referred to our child neurology clinic at Tottori
University Hospital from 1980 to 2006 (12,463 patients). We
extracted the data of 2028 epileptic patients from our database.
Then, 81 patients with occipital lobe epilepsy were extracted.
Patients with symptomatic occipital lobe epilepsy who had neonatal
hypoglycemia were the subjects of this study. Occipital lobe
epilepsy was defined as having ictal semiology identical to occipital
lobe seizures, which include eye deviation or eye blinking with
staring, ictal vomiting, or visual hallucination (Williamson et al.,
1992), and interictal paroxysmal waves in the posterior derivation.
Patients with occipital lobe epilepsy who had occipital lobe
injuries other than neonatal hypoglycemia were excluded. Severe
hypoxic-ischemic brain injury is a high risk for the occurrence of
epilepsy regardless of hypoglycemia, while the mild to moderate
type is not (Zafeiriou et al., 1999; Pisani et al., 2009). Therefore,
patients with severe cerebral palsy who are not able to walk independently
were excluded, while those with mild cerebral palsy were
included. Epilepsy patients with preterm birth (less than 35 weeks
gestation) or those with inborn errors of metabolism, congenital
anomalies, brain malformation, or chromosomal abnormality were
also excluded, even if they had histories of neonatal hypoglycemia
(Table 1).
Neonatal hypoglycemia was defined as whole-blood glucose concentration
below 35 mg/dL, 40 mg/dL, and 45 mg/dL during 0—3 h,
3—24 h, and after 24 h after birth, respectively (Srinivasan et al.,
1986).
Onsets of epilepsy, major seizure types, and clinical course of
epilepsy, EEG and neuroimaging findings were studied from their
medical records. Status epilepticus was defined as clinical seizure
lasting more than 30 min. MRI (1.5 T or 3.0 T recently) was performed
repeatedly and included T1-, T2-, and FLAIR imaging. Mental
or intellectual status was evaluated using the Wechsler intelligence
scale for children or the Enjoji development scale. ‘‘Normal’’ was
defined when IQ or DQ was more than 70, ‘‘mild’’ mental retardation
(MR) or developmental delay was defined when it was between
50 and 70, ‘‘moderate’’ when it was between 20 and 50, and
‘‘severe’’ when it was below 20. We also reviewed clinical and
laboratory data during perinatal periods.
This study was approved by the ethical committee in Tottori
University.
Results
The most common epileptic syndrome of occipital lobe
epilepsy was idiopathic childhood occipital epilepsy
(Panayiotopoulos syndrome and Gastaut type) and this was
found in 54 of the patients. Twenty-one patients with occipital
lobe epilepsy were excluded and finally 6 patients (5
males and 1 female) were the subjects of the study (Table 2).
Perinatal history and neurological sequelae
(Table 2)
Perinatal histories and neurological sequelae are shown in
Table 2. Patients 1—4 were taken care of in our neonatal
intensive care unit and Patients 5 and 6 were treated in other
hospitals. Perinatal histories closely correlated with neonatal
hypoglycemia were highly present: low birth weight for
gestational age in 5, low Apgar score after 1 min in 3, and
neonatal seizure in 5. Severe neonatal hypoglycemia with a
serum glucose level of less than 15 mg/dL was reported in
3 patients and hypoglycemia was prolonged more than 10 h
Table 1
Inclusion and exclusion criteria.
Inclusion criteria (no. of patients)
Exclusion criteria
Outpatients (12,463)
OLE with occipital
injuries other than
neonatal
hypoglycemia
Epilepsy patients (2028)
Severe CP with
inability to walk
Occipital lobe epilepsy (81) LBW (less than 35
weeks of gestation)
Neonatal hypoglycemia (6) Inborn errors of
metabolism
Congenital anomalies
Brain malformations
Chromosomal
abnormalities
CP: cerebral palsy; no.: number; OLE: occipital lobe epilepsy;
LBW: low birth weight.