Investigators at UCSF, British Columbia, and Toronto studied the pattern and areas of brain injury on MRI at third day of life of children with infantile spasms following neonatal hypoxic-ischemic encephalopathy (H-IE). Among a cohort of 176 term newborns with H-IE, 8 (4.5%) developed infantile spasms (hypsarrhythmia in 5 or modified hypsarrhythmia in 3). Neonatal seizures occurred in 6 (75%) patients who developed infantile spasms and in 9 (56.3%) controls that did not. Patients with infantile spasms showed no significant differences in perinatal and neonatal course when compared with 16 controls without spasms. Development of infantile spasms after neonatal H-IE was significantly associated with basal ganglia/thalamus and total brain injury (p = 0.001), extent of cortical injury greater than 50% (p = 0.01), injury to the midbrain (p = 0.007) and hypothalamic abnormalities (p = 0.01). Infantile spasms were significantly associated with medically refractory epilepsy and moderate to severe developmental delay. Spasms were diagnosed at a median age of 3.5 months (range 2-9 months); and at 3 months of age or younger in half of the infantile spasm patients. [1]
COMMENTARY. Neonatal H-IE is a relatively common precursor of infantile spasms and hypsarrhythmia. Several studies have shown that the earlier the diagnosis of infantile spasms and treatment with ACTH, the better the response and prognosis [2, 3]. The MRI is of value in the early diagnosis of infantile spasms following H-IE. Injury to the basal ganglia/thalamus and total brain injury on the third day of life are significantly associated with infantile spasms and outcome, particularly in patients with extensive cortical injury and/or injury to the midbrain. Injury to the pons or medulla is not associated with development of infantile spasms [4].
The predictive value of the EEG during early infancy for later development of West syndrome in premature infants with cystic periventricular leukomalacia (PVL) is demonstrated in a study of 19 infants with EEGs recorded at 3 months of corrected age [5]. Paroxysmal discharges during early infancy are correlated with later development of West syndrome. Prolonged EEG depression at > 21 days of age in term and near-term infants with H-IE is a predictor of the later development of West syndrome [6].
In an ongoing investigation at Lurie Children's Hospital, Chicago, the predictive value of a pre-hypsarrhythmia pattern in serial EEGs during the first 6 months following H-IE is in progress, with a view to prevention of West syndrome by early administration of ACTH [Millichap JJ, prepublication observations].