Infantile Acute Subdural Hematohygroma: A Clinical and Neuroimaging Analysis of 18 Cases

Abstract

<i>Objective</i>: Even after the advent of magnetic resonance imaging (MRI), few studies have focused on the clinical profiles and neuroimaging characteristics of acute subdural hematohygroma (ASDHy) in infants. The present study attempted to elucidate the pathogenesis of ASDHy by analyzing the clinical and neuroimaging findings of ASDHy. <i>Materials & Methods</i>: The subjects were 18 patients (eight males and ten females) younger than 2 years with ASDHy. Their median age at diagnosis was 3.8 months (range: 2-10 months), and 15 (83%) were younger than 4 months. Imaging studies found no evidence of any primary brain injury. <i>Results</i>: Five patients experienced a fall, and 13 (72%) had no history of head trauma. The presenting symptoms and signs were the acute onset of generalized convulsive seizures and or repeated vomiting. Retinal hemorrhage occurred in 14 patients (78%). The imaging studies revealed a large amount of bilateral, subdural fluid collection with an intensity higher than that of cerebrospinal fluid on MRI. Benign enlargement of the subarachnoid space (BESS) was found in 14 patients (78%), an enlarged sylvian fissure (LSF) was found in all the patients (100%), and greater, left-sided enlargement was evident in 16 patients (89%). Two patients underwent subdural drainage, and 16 patients (89%) were conservatively managed. All the patients had a favorable outcome. <i>Conclusions</i>: ASDHy is a self-limiting disorder associated with retinal hemorrhage and a benign clinical course. Most cases develop in early infancy. LSF presumably loosens the tight fixation of the temporal lobes at the middle cranial fossa, thereby increasing the rotational force of the brain even during mild or unnoticeable impacts. Increased cranio-cerebral disproportion, including BESS and LSF, is a structural vulnerability which can lead to ASDHy in early infancy.