Neonatal intracranial aneurysms: case report and review of the literature.

Intracranial aneurysms in the neonate, presenting in the first 4 weeks of life, are exceedingly rare. They appear to have characteristics, including presentation and location, that vary from those found in adults. The authors present a case of a 28-day-old neonate with a ruptured distal middle cerebral artery (MCA) aneurysm. Initial noninvasive imaging with transfontanelle ultrasound and CT confirmed intraparenchymal and subarachnoid hemorrhage. Contrast-enhanced MRI revealed a 14-mm ruptured fusiform MCA aneurysm that was not identified on time-of-flight magnetic resonance angiography (MRA). Microsurgical treatment was performed with partial neurological recovery. A comprehensive review of the literature from 1949 to 2017 revealed a total of 40 aneurysms in 37 neonates, including the present case. The most common presenting symptom was seizure. Although subarachnoid hemorrhage was the most common form of hemorrhage, 40% had intraparenchymal hemorrhage. The median aneurysm size was 10 mm (range 2-30 mm) and the most common location was the MCA, with two-thirds of cases involving the distal intracranial vasculature. Over the last 10 years, there has been a trend of increasing noninvasive diagnosis of ruptured cerebral aneurysms in neonates, with CT angiography and contrast-enhanced MRI being the most useful diagnostic modalities. The use of contrast-enhanced MRI may improve sensitivity over time-of-flight MRA. Microsurgical treatment was the most common treatment modality overall, with increased use of endovascular treatment in the last decade. Most patients underwent microsurgical vessel ligation or endovascular parent vessel occlusion. There were high rates of neurological recovery after microsurgical or endovascular treatment, particularly for patients with distal aneurysms.