History and Physical
A 15-year-old right-handed boy consulted for left-sided hemiclonic motor seizures that evolved into bilateral tonic-clonic motor seizures. These were refractory to antiseizure medications (ASMs), and he subsequently developed episodes of convulsive status epilepticus that were also refractory. His past medical and family history was normal. He was very active in sports and excelled academically.
Postictal neurological examination demonstrated left-sided hemiparesis, with increased deep tendon reflexes in his left upper and lower extremities, and upgoing plantar response. Eleven months later, the patient started having nocturnal seizures with left hemiclonic rhythmic jerks and impairment of awareness.
Diagnostic Workup
Head CT showed right middle cerebral artery territory hypodensity ( Fig. 20.1 ). Cerebral angiography and carotid Doppler US were normal.
Right superior MCA infarct. Head CT shows cytotoxic edema involving the right frontal and anterior temporal cortex and white matter ( arrows ). MCA , Middle cerebral artery.
A prolonged video-EEG demonstrated continuous slow activity over the right hemisphere with frequent sharps, spikes, and slow waves over the right frontal region ( Fig. 20.2 ).
Electroencephalography (EEG) shows continuous slowing in the right hemisphere with frontotemporal predominance ( black rectangles ).
Transthoracic echocardiogram showed a mural thrombus in the left anterior mitral leaflet. Coagulation studies demonstrated protein C deficiency.
Clinical Differential Diagnosis
The differential diagnosis for acute-onset focal seizures or status epilepticus, encephalopathy, and hypotonic hemiplegia is broad and includes acute ischemic causes, either arterial ( Fig. 20.3 ) or venous stroke. Additional vascular causes include Sturge-Weber, moyamoya, arteriovenous malformations (AVMs), and vasculopathies. Inflammatory conditions include CNS demyelination and Rasmussen encephalitis. Tumors, infection, hemorrhage, and metabolic disorders may also cause transient weakness with seizures.
Acute ischemic strokes with restricted diffusion. (A) Complete right PCA territory infarct. (B) Distal right PCA territory infarct involving the occipital pole. (C) Left inferior MCA territory infarct. (D) Embolic infarcts in multiple arterial distributions secondary to metastatic undifferentiated pulmonary sarcoma. (E) Neonate with Streptococcus meningoencephalitis and bilateral basal ganglia microinfarcts suggesting mycotic vasculitis. MCA , Middle cerebral artery; PCA , posterior cerebral artery.
Pediatric stroke mimics include genetic conditions and inborn errors of metabolism ( Fig. 20.4 ) including hemiplegic migraine, hypokalemic periodic paralysis, and mitochondrial disorders ( POLG [DNA polymerase gamma]-related disorders and mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes [MELAS]). Many of these disorders are associated with subsequent development of epilepsy.
