Case 2: Seizures in a Neonate

A term male newborn is transferred to a tertiary care center 8 days after birth for evaluation of seizures. The neonate is born to a 35-year-old gravida 1 para 0 woman after a spontaneous pregnancy complicated by diet-controlled gestational diabetes and fetal pyelectasis, which resolved at 32 weeks. Prenatal maternal laboratory studies were unremarkable, and the only maternal medication used during pregnancy was a multivitamin. Both parents are known biotinidase deficiency carriers. Labor is spontaneous but complicated by 4 hours of failure to progress in an asynclitic presentation, which is converted to emergent cesarean section because of late decelerations without recovery. Estimated gestational age is 39 1/7 weeks based on estimated date of conception, but postdelivery examination reveals dry and peeling skin consistent with a gestational age of 41 weeks. Apgar scores are 3, 7, and 9 at 1, 5, and 10 minutes, respectively, and continuous positive airway pressure is required after delivery for respiratory distress. The neonate’s birthweight is 3.180 kg (32nd percentile), length is 50.4 cm (52nd percentile), and head circumference is 35.3 cm (63rd percentile).The neonate is initially transferred from the birth hospital to an outside NICU for monitoring of respiratory status with reportedly unremarkable physical examination findings. On admission to the outside NICU, blood cultures are sent and capillary blood gas measurements are unremarkable. Empiric antibiotics are deferred. Abnormal movements observed on day 2 after birth are described as rhythmic, involving more than 1 extremity, and sometimes resolving with holding. At the time, the infant’s condition is stable with 2 L nasal cannula at a fraction of inspired oxygen of 21% and he is breastfeeding on demand. The neonate is also noted to have significant right-sided torticollis.Because of concern for seizures, electroencephalography (EEG) is performed, which reveals status epilepticus and numerous focal seizures over the left parasagittal region with rare left frontal and midline focal seizures. Phenobarbital treatment is started, but the seizures continue; levetiracetam is added, after which seizures are no longer observed on EEG. Cranial ultrasonography performed on day 3 after birth has unremarkable findings and neurologic examination reveals global hypotonia, but the child is able to move all extremities with no focal deficits, has normal sensation and reflexes, and no abnormal movements. Echocardiography reveals a small patent foramen ovale but findings are otherwise unremarkable.Brain magnetic resonance imaging (MRI) performed on day 4 after birth reveals patchy cytotoxic edema predominantly involving the cortex of the left parietal lobe, with associated white matter edema and petechial hemorrhage. There is trace overlying subarachnoid hemorrhage, as well as small, bilateral, dependent subdural hematomas. The calvarium and skull base are noted to be intact and there is no frank vascular thrombosis. Magnetic resonance spectroscopy reveals diminished spectral peaks in the left parietal region, in particular N-acetylaspartate with no lactate. This is interpreted as nonspecific but compatible with parenchymal injury from ischemia. Laboratory studies the same day reveal unremarkable electrolytes, prothrombin time, and partial thromboplastin time.The neonate is transferred to our center for additional evaluation and management. MRI on day 8 after birth reveals evolving parenchymal injury, interpreted as subacute venous infarctions, and small parieto-occipital subdural hematomas (Figs 1A,B). Physical examination reveals widely patent sutures with an asymmetric head shape, with the left side of the calvarium taller than the right. There is slight facial asymmetry and torticollis, but no facial twist. A linear depression approximately halfway between the coronal and lambdoid sutures, similar on palpation to major sutures, is apparent, and an additional diagnostic study is ordered.Hemorrhagic contusion leading to seizures.Although the focal onset of the seizures and initial MRI findings raise concern for hemorrhagic venous infarction, the physical examination suggested another etiology. Palpation of cranial sutures revealed a normal metopic suture, normal anterior fontanelle with bilateral coronal sutures, patent sagittal suture, and symmetric occiput with no tilt of the skull base and no displacement of the ears. When pressure was applied, there was palpable movement near the vertex of the head posterior to the left coronal suture, with separation between the 2 halves of the parietal bone. No similar movement was noted on the right side.The MRI had shown no obvious bony abnormalities. Computed tomography (CT) revealed a complex left parietal bone fracture overlying the area concerning for infarct (Figs 2A,B). Reevaluation of earlier MRI scan suggested that the area of suspected infarct was, more likely, a hemorrhagic parenchymal contusion which then resulted in seizures. The presenting portion of the infant’s skull during pushing coincided with the region of the fracture, suggesting that mechanical pressure during labor caused the fracture and brain contusion. After identification of the fracture on CT, volume-rendered bone reformats allowed the fracture to be more clearly visualized (Fig 2C). The infant had no other signs of metabolic bone disease. The presentation was not consistent with biotinidase deficiency and the patient was later found not to be affected.Repeat CT 6 months later showed normal bone healing (Figs 3A,B) and cystic encephalomalacia at the site of fracture. Seizures resolved after the neonatal period, and on evaluation at age 2 years, he was seizure free, though he did have spasticity consistent with cerebral palsy. Laryngoscopy performed because of persistent stridor and dysphagia revealed bilateral vocal fold immobility, necessitating close clinical monitoring and thickened feeds. At 15 months of age, his spasticity, stridor, and vocal fold mobility had steadily improved and his language and cognitive development were appropriate.Skull fractures secondary to birth trauma are relatively rare, with an estimated incidence of 1 in 7,000 to 25,000 deliveries. (1) Risk factors for skull fractures at birth are similar to those for head and neck injuries in general and include macrosomia, prematurity, abnormal fetal presentation, prolonged labor, multiparity, and instrumental deliveries and should be considered in any newborn with a cephalohematoma or subarachnoid hemorrhage. (2) Depressed skull fractures, also known as “ping pong ball” type fractures, involve inward buckling of the skull and are commonly associated with forceps-assisted deliveries (3) but have been observed in the absence of any risk factors. (4) Linear skull fractures, such as the current case, can be seen with other types of birth trauma such as prolonged arrest of labor. (2)(5)Although skull fractures may be diagnosed with radiography, their interpretation is complicated by the presence of normal open sutures in the neonate. The most appropriate first-line test in a case of suspected skull fracture is a low-dose CT with 3-dimensional reconstructions. (7) Neurosurgical consultation is appropriate in most cases, but intervention is infrequently required. (2)(3) Although rare, infants should be monitored for growing skull fractures, which usually develop from linear fractures, as they may require neurosurgical intervention and have been observed after forceps-assisted delivery. (6)Neonatal seizures occur at a rate of approximately 1.8 to 3.5 per 1,000 live births. (7) Although reports vary, up to 37% of newborns with cranial birth injuries have been reported to have seizures, but only a small fraction of total cranial birth injuries are skull fractures. (2)(8) Unlike the case presented here, both depressed and linear skull fractures rarely result in neurologic deficits and do not typically require treatment. (1)(4) It is also important to note that neurologic examination alone may not be a good predictor of the presence of a skull fracture. For example, a recent study found that of 8 infants with fractures associated with birth trauma, only 4 had documented abnormal neurologic findings before discovery of the fracture. (5)A final consideration is that the incidence of brain cancer after head CT is increased, depending on both age and frequency. (9) It remains uncertain how current dose-modulating techniques frequently used in pediatric hospitals will affect this incidence. New “black bone” MRI techniques have been developed that provide high image contrast between bone and surrounding tissues, allowing the calvarium to be evaluated without radiation exposure. (10) This technique can only be performed during acquisition, so it should be requested at the time the MRI is ordered.