Acute enlargement of subdural hygroma due to subdural hemorrhage in a victim of child abuse

Highlights

• Postmortem CT showed subdural hygroma and hydrocephalus clinically.

• Subdural hygroma would be developed from previous subdural hemorrhage/hematoma.

• Intracranial hypertension was suggested by microbleeding in the brain stem.

• Subdural hygroma was enlarged by hemorrhage, leading to intracranial hypertension.

• The pathogenesis of the death could be explained by the autopsy with postmortem CT.

Abstract

An 11-month-old female baby was found dead by her mother. Cranial postmortem CT prior to the forensic autopsy showed dilatation of bilateral extra-axial spaces and ventricles. The autopsy revealed a new linear fracture of the left parietal bone and occipital bone, and a healed linear fracture of the right parietal bone and occipital bone like a mirror image of the left one as well. Intracranially, 230 ml of subdural fluid were collected, which was mixed with blood. There was a fresh hemorrhage around a bridging vein of the left parietal lobe and the dura mater. Moreover, the outer side of the cerebrum and the inner side of the dura mater were covered by a thin membrane, which mater might have been previously formed because of being positive for Fe-staining and anti-CD68 antibody. A subdural hematoma might have been developed when the right side of the skull was previously fractured, which was transformed into a subdural hygroma. Subsequently, it is likely that, after the left side fracture of the skull occurred, the subdural hygroma rapidly enlarged due to hemorrhaging from the bridging vein, which resulted in intracranial hypertension, because microbleeding was detected in the brain stem. Accordingly, we diagnosed the cause and manner of death as intracranial hypertension due to subdural hemorrhage in subdural hygroma, and homicide, including child abuse, respectively.

Introduction

Subdural hygroma (SDH) is characterized by subdural fluid collection whose CT value is between 10 HU and 16 HU, or less than 20 HU [1], [2], [3]. The ages of patients with SDH are diphasic; children aged less than 10 years, particularly less than 2 years, or men aged above 60 years, which may be attributed to the broad subdural space of children and elderly people [4], [5]. Whereas SDH is a common complication of blunt head injuries in adults, the etiology of SDH in infants and children has been reported as surgical procedure, complications of leptomeningeal infections or unexplained, in addition to post-traumatic [1], [4]. Although the subdural fluid would be considered cerebrospinal fluid (CSF) and leak from the subarachnoid space through a damaged arachnoid membrane, expanding into the subdural space, it can sometimes appear xanthochromic, yellow or slightly hemorrhagic [2], [5]. Moreover, subdural fluid collection might be related to the impairment of CSF absorption by arachnoid granulations [2], [3]. In other words, SDH occurs traumatically, spontaneously or post-surgically, and its pathogenesis is still unclear [1], [2], [3], [4], [5], [6].

Herein we present an autopsy case of SDH induced by head injury inflicted by an assault several months before death, which suddenly enlarged by subdural hemorrhage due to head injury from an assault a few days before death, resulting in death. Also, we investigated the mechanism of the development of SDH, on the basis of the findings of postmortem cranial CT imaging, as well as those of macroscopic and microscopic examinations.