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[A case of hemimegalencephaly: ictal EEG and SPECT]
Insights
This study reports a case of hemimegalencephaly in an infant, a rare brain malformation. Findings suggest the enlarged hemisphere plays a key role in seizure development and spread.
Area of Science:
- Neurology
- Developmental Neuroscience
- Pediatric Neurology
Context:
- Hemimegalencephaly is a rare congenital brain malformation characterized by unilateral hemispheric enlargement and ipsilateral ventriculomegaly.
- Infantile cases often present with severe neurological deficits, including intractable seizures and developmental delay.
- Diagnostic imaging plays a crucial role in understanding the pathophysiology of such rare conditions.
Purpose:
- To describe a case of hemimegalencephaly in a 1-month-old infant.
- To investigate the neurophysiological underpinnings of seizures in this condition using ictal electroencephalography (EEG) and single photon emission computed tomography (SPECT).
- To explore the potential role of the megalencephalic hemisphere in epileptogenesis.
Summary:
- A 1-month-old female infant presented with left-sided macrocephaly, intractable seizures, and delayed development, consistent with hemimegalencephaly.
- Ictal EEG revealed seizure activity originating in the left occipital lobe and spreading to the frontal lobe.
- Ictal SPECT demonstrated hyperperfusion in the left occipital and frontal lobes, while interictal SPECT showed increased tracer uptake in the left hemisphere, particularly the frontal lobe.
Impact:
- This case highlights the utility of combined EEG and SPECT in localizing seizure onset zones in infants with hemimegalencephaly.
- The findings suggest that the enlarged hemisphere in hemimegalencephaly may be intrinsically epileptogenic.
- Understanding the relationship between hemispheric hypertrophy and seizure propagation is crucial for potential therapeutic strategies.
Abstract:
A case of 1-month-old female infant with hemimegalencephaly was reported. This disorder is a rare malformation characterized by congenital hypertrophy of one hemisphere and ipsilateral ventriculomegaly. Clinical signs of the patient included a left sided macrocephaly, intractable seizures and delayed development. Ictal single photon emission computed tomography (SPECT) on the 49th day using 99mTc-HMPAO showed hyperperfusion in the left occipital and frontal lobes, when ictal EEG showed a sharp wave-burst appearing continuously in the left occipital lobe that spread to the left frontal lobe. Interictal SPECT on the 48th day demonstrated and increased tracer accumulation in the left hemisphere, especially in the left frontal lobe. In this case, the megalencephalic hemisphere might have an important role for epileptogenesis and its spread according to the ictal SPECT findings.