Subdural hemorrhage, intradural hemorrhage and hypoxia in the pediatric and perinatal post mortem: Are they related? An observational study combining the use of post mortem pathology and magnetic resonance imaging

Neuroimaging of Neonatal Stroke: Venous Focus

Perinatal venous infarcts are underrecognized clinically and at imaging. Neonates may be susceptible to venous infarcts because of hypercoagulable state, compressibility of the dural sinuses and superficial veins due to patent sutures, immature cerebral venous drainage pathways, and drastic physiologic changes of the brain circulation in the perinatal period. About 43% of cases of pediatric cerebral sinovenous thrombosis occur in the neonatal period. Venous infarcts can be recognized by ischemia or hemorrhage that does not respect an arterial territory. Knowledge of venous drainage pathways and territories can help radiologists recognize characteristic venous infarct patterns. Intraventricular hemorrhage in a term neonate with thalamocaudate hemorrhage should raise concern for internal cerebral vein thrombosis. A striato-hippocampal pattern of hemorrhage indicates basal vein of Rosenthal thrombosis. Choroid plexus hemorrhage may be due to obstruction of choroidal veins that drain the internal cerebral vein or basal vein of Rosenthal. Fan-shaped deep medullary venous congestion or thrombosis is due to impaired venous drainage into the subependymal veins, most commonly caused by germinal matrix hemorrhage in the premature infant and impeded flow in the deep venous system in the term infant. Subpial hemorrhage, an underrecognized hemorrhage stroke type, is often observed in the superficial temporal region, and its cause is probably multifactorial. The treatment of cerebral sinovenous thrombosis is anticoagulation, which should be considered even in the presence of intracranial hemorrhage. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Frequency of macroscopic intradural hemorrhage with and without subdural hemorrhage in early childhood autopsies

Some authors have suggested that in the fetus, neonate and infant, intradural hemorrhage (IDH) is relatively common and often presents alongside subdural hemorrhage (SDH). These authors have theorized that pediatric SDH may result from an IDH due to blood leakage from a dural vascular plexus. In this study, we report the inter-observer variation for detection of IDH from a retrospectively collected series of pediatric autopsy photographs, with and without SDH. Autopsy photographs of the falx and tentorium from 27 neonatal, infant and early childhood autopsies were assessed by two independent consultant forensic pathologists blinded to all case histories for the presence and extent (focal or diffuse) of IDH. Inter-observer agreement between the pathologists was calculated using Cohen’s kappa coefficient. The occurrence of subdural hemorrhage was also recorded at autopsy. A kappa coefficient value of 0.669 (p = 0.001), indicated a substantial level of agreement for the presence/absence of IDH between the pathologists. For the extent of IDH a kappa coefficient value of 0.6 (p = 0.038) indicated a moderate level of agreement. The pathologists agreed on the presence of IDH in 10 of the 27 cases. Subdural hemorrhage was recorded for 8 out of 27 cases. Of these 8 cases, it was agreed that 4 had IDH. Using standardized methods of image capture and assessment, inter-observer agreement for the presence/absence of IDH was substantial. In this paper, we report a much lower frequency of macroscopic IDH occurring alongside SDH than previous studies, which included both gross observation of IDH and histological examination.

Non-Traumatic Acute Subdural Hemorrhage Due To Cranial Venous Hypertension

Acute subdural hemorrhage is typically associated with a history of head trauma, and as such it is a finding with significant potential medicolegal consequences. In this article, 37 adult and post-infantile pediatric sudden death autopsy cases with small volume ("thin film" or "smear") acute subdural hemorrhage are presented-in which there is either no further evidence of head trauma or only features of minor head injury. The possible underlying pathophysiological mechanisms are explored, and it is concluded that a common thread in many of these cases is likely to have been cranial venous hypertension at around the time of death. These findings may have implications in instances where small volume subdural hemorrhage is identified in the absence of other evidence of significant head injury.

Intracranial hemorrhage in term neonates

BACKGROUND

Intracranial hemorrhage (ICH) is an uncommon but important cause of morbidity and mortality in term neonates; currently, ICH is more frequently diagnosed because of improved neuroimaging techniques.

PURPOSE

The study aims to evaluate the clinical characteristics and neuroimaging data (pattern, size, distribution) of neonatal ICH.

METHODS

We reviewed MRI data from July 2004 to June 2015 for 42 term neonates with ICH who were less than 1 month old. We recorded clinical data and manifestations, mode of delivery, Apgar score at 1 and 5 min, associated hypoxic insult, birth trauma, neurological symptoms, EEG results, extent and site of hemorrhage, neurosurgical intervention, and developmental outcomes. The clinical outcome was determined for 27 neonates. Risk factors were assessed in relation to ICH.

RESULTS

A total of 42 neonates who presented with ICH underwent MR imaging 2 to 22 days postnatally (mean age 9.3 days). The majority of clinical symptoms were present in patients within the first 24 h of life (n = 31), but symptoms appeared until day 10 postnatally (mean 4.9 days, n = 11). Seizure or seizure-like activity was the most common presenting symptom (17/42, 40.5%), with apnea seen in another seven infants (7/42, 16.7%). The majority of infants had a normal prenatal course. Two patients had antenatally detected hydrocephalus. Ten had infratentorial hemorrhage, and two had supratentorial hemorrhage. A total of 30 infants had a combination of infratentorial and supratentorial hemorrhage. Subdural hemorrhage (SDH) was the most common type of hemorrhage (40/42, 95.2%), followed by nine cases of parenchymal hemorrhage, seven of subarachnoid hemorrhage, three of germinal matrix hemorrhage (GMH), and one of epidural hemorrhage (EDH). A total of 16 infants had two or more types of hemorrhage. SDH was identified along the tentorium (n = 38) as well as over the cerebellar hemispheres (n = 39), along the interhemispheric fissure (n = 10), and over the occipital (n = 13) or parietooccipital (n = 11) lobes. Intraparenchymal hemorrhage involved either the frontal (n = 4), parietal (n = 3), or cerebellar (n = 2) lobes. Traumatic delivery was suspected in 20 patients (47.6%), and perinatal asphyxia was present in 21 patients (50.0%). A low Apgar score at 5 min and a history of perinatal asphyxia were the factors that most predicted poor clinical outcomes (n = 12/27). Logistic regression analysis revealed that a history of perinatal asphyxia resulted in poor outcomes. No patients died. One infant required burr hole drainage of a right parietal EDH, one infant needed a subcutaneous reservoir, and three infants required a ventriculoperitoneal shunt for obstructive hydrocephalus.

CONCLUSION

SDH was the most common type of ICH in term infants. Combined supratentorial and infratentorial hemorrhage was more common than isolated infratentorial hemorrhage in these infants. A total of 44.4% of patients had poor outcomes, with perinatal asphyxia the most common statistically significant cause.

Infants dying suddenly and unexpectedly share demographic features with infants who die with retinal and dural bleeding: a review of neural mechanisms

The cause of death in infants who die suddenly and unexpectedly (sudden unexpected death in infancy [SUDI]) remains a diagnostic challenge. Some infants have identified diseases (explained SUDI); those without explanation are called sudden infant death syndrome (SIDS). Demographic data indicate subgroups among SUDI and SIDS cases, such as unsafe sleeping and apparent life-threatening events. Infants dying suddenly with retinal and dural bleeding are often classified as abused, but in many there is no evidence of trauma. Demographic features suggest that they may represent a further subgroup of SUDI. This review examines the neuropathological hypotheses to explain SIDS and highlights the interaction of infant oxygen-conserving reflexes with the brainstem networks considered responsible for SIDS. We consider sex- and age-specific vulnerabilities related to dural bleeding and how sensitization of the dural innervation by bleeding may influence these reflexes, potentially leading to collapse or even death after otherwise trivial insults.

Alternate theories of causation in abusive head trauma: what the science tells us

When cases of suspected abusive head trauma are adjudicated in courts of law, several alternative theories of causation are frequently presented. This paper reviews common theories and examines their scientific basis.

Subdural hemorrhage and hypoxia in infants with congenital heart disease

BACKGROUND AND OBJECTIVES

It has been suggested that there is a causal relationship between hypoxia and subdural hemorrhage (SDH) in infancy. The purpose of this study was to review the incidence of SDH in infants with congenital heart disease and explore the relationship between SDH and hypoxia.

METHODS

Review of data collected for a prospective longitudinal cohort study of infants undergoing surgery for congenital heart disease in New Zealand and Australia. Infants underwent serial MRI scans of the brain in the first 3 months of life. All oxygen saturation recordings and MRI results were extracted and infants assigned to categories by degree of hypoxia. The data were then examined for any statistically significant relationship between hypoxia and SDH.

RESULTS

One hundred fifty-two infants underwent MRI scans, and 66 (43%) had 145 loci of SDH. New SDH was seen in 12 infants after cardiac surgery. Of the loci of SDH, 63 (43%) were supratentorial, and most of these were interhemispheric, parietal, or temporal. SDH present on the first MRI persisted beyond 28 days of life in 8 infants. There was no demonstrable relationship between SDH and hypoxia.

CONCLUSIONS

Asymptomatic SDH is common in young infants with congenital heart disease, at a frequency similar to that of those without congenital heart disease. These SDHs may occur in locations where they occur in abusive head trauma, but they are typically small and resolve within 3 months of birth. We were unable to demonstrate any association between hypoxia and SDH in this cohort.

Hearing loss in the shaken baby syndrome

OBJECTIVES

To evaluate hearing in children diagnosed with shaken baby syndrome.

METHODS

A retrospective study conducted in a pediatric tertiary care center between 2006 and 2012. Children diagnosed with shaken baby syndrome were included for hearing evaluation by conventional audiometry, distortion product otoacoustic emissions and auditory brainstem responses.

RESULTS

Twenty-eight children were included (22 boys and 6 girls). The mean age of children at presentation was 8 months (range 1-26 months) and the mean delay before audiometric evaluation was 30 months (range 1-87 months). One child was diagnosed as having a moderate sensorineural hearing loss. The tympanic membrane mobility was normal (type A) for both ears in 22 children, one child had a reduced tympanic mobility in one ear, two children had a negative pressure, one child had a functional trans-tympanic tube and test was not performed in 2 patients.

CONCLUSION

This is the first study reporting hearing loss as a possible result of shaken baby syndrome. However, further studies with larger number of children would be preferable. We recommend hearing evaluation for these children to rule out hearing loss.

Intracranial haemorrhage: an incidental finding at magnetic resonance imaging in a cohort of late preterm and term infants

BACKGROUND

Intracranial haemorrhage (ICH) in term newborns has been increasingly recognised but the occurrence in late preterm infants and the clinical presentation are still unclear.

OBJECTIVE

To investigate the appearance of intracranial haemorrhage at MRI in a cohort of infants born at 34 weeks' gestation or more and to correlate MRI findings with neonatal symptoms.

MATERIALS AND METHODS

We retrospectively reviewed neonatal brain MRI scans performed during a 3-year period. We included neonates ≥34 weeks' gestation with intracranial haemorrhage and compared findings with those in babies without intracranial haemorrhage. Babies were classified into three groups according to haemorrhage location: (1) infratentorial, (2) infra- and supratentorial, (3) infra- and supratentorial + parenchymal involvement.

RESULTS

Intracranial haemorrhage was observed in 36/240 babies (15%). All of these 36 had subdural haemorrhage. Sixteen babies were included in group 1; 16 in group 2; 4 in group 3. All infants in groups 1 and 2 were asymptomatic except one who was affected by intraventricular haemorrhage grade 3. Among the infants in group 3, who had intracranial haemorrhage with parenchymal involvement, three of the four (75%) presented with acute neurological symptoms. Uncomplicated spontaneous vaginal delivery was reported in 20/36 neonates (56%), vacuum extraction in 4 (11%) and caesarean section in 12 (33%). Babies with intracranial haemorrhage had significantly higher gestational age (38 ± 2 weeks vs. 37 ± 2 weeks) and birth weight (3,097 ± 485 g vs. 2,803 ± 741 g) compared to babies without intracranial haemorrhage and were more likely to be delivered vaginally than by caesarian section.

CONCLUSION

Mild intracranial haemorrhage (groups 1 and 2) is relatively common in late preterm and term infants, although it mostly represents an incidental finding in clinically asymptomatic babies; early neurological symptoms appear to be related to parenchymal involvement.

Nontraumatic intradural and subdural hemorrhage and hypoxic ischemic encephalopathy in fetuses, infants, and children up to three years of age: analysis of two audits of 636 cases from two referral centers in the United Kingdom

We analyzed the presence or absence of intradural hemorrhage (IDH) and subdural hemorrhage (SDH) and the degree of hypoxic-ischemic encephalopathy (HIE) in the brain of all nonmacerated fetuses of >24 weeks, neonates, and children up to 3 years of age who died of natural causes over a defined period. We looked into the cause of death and the performance of cardiopulmonary resuscitation in our cohort. The IDH was classified as macroscopic or negative/microscopic only; the HIE was classified as absent, indeterminate, or definite. In fetuses, SDH with IDH was present in 22%; IDH alone was present in 31%, and there was no or minimal hemorrhage in 47% of cases. In infants and children SDH with IDH was present in 19%; IDH alone was present in the 32%, and there was no or minimal hemorrhage in 49% of cases. There was a statistically significant correlation between SDH and HIE, especially in infants and children (P < 0.001). When cases were grouped per age, a significant association between age and hemorrhage (P < 0.0001) was demonstrated, SDH being more common in infants ≤1 month corrected age. Intradural hemorrhage can be the source of thin-film SDH in fetuses, infants, and young children. The presence of SDH is associated with hypoxia. Intradural and subdural hemorrhages are more common in autopsies of infants under 1 month corrected age. Although more rare, they can also be found in children between 1 month and 3 years of age in the absence of trauma.

The pathophysiology of brain swelling associated with subdural hemorrhage: the role of the trigeminovascular system

INTRODUCTION

This paper reviews the evidence in support of the hypothesis that the trigeminal system mediates brain swelling associated with subdural bleeding. The trigeminovascular system has been extensively studied in migraine; it may play an important but under-recognized role in the response to head trauma. Nerve fibers originating in trigeminal ganglion cells are the primary sensors of head trauma and, through their collateral innervation of the intracranial and dural blood vessels, are capable of inciting a cascade of vascular responses and brain swelling. The extensive trigeminal representation in the brainstem initiates and augments autonomic responses. Blood and tissue injury in the dura incite neurogenic inflammatory responses capable of sensitizing dural nerves and potentiating the response to trauma.

DISCUSSION

The trigeminal system may provide the anatomo-physiological link between small-volume, thin subdural bleeds and swelling of the underlying brain. This physiology may help to explain the poorly understood phenomena of "second-impact syndrome," the infant response to subdural bleeding (the "big black brain"), as well as post-traumatic subdural effusions. Considerable age-specific differences in the density of dural innervation exist; age-specific responses of this innervation may explain differences in the brain's response to trauma in the young. An understanding of this pathophysiology is crucial to the development of intervention and treatment of these conditions. Antagonists to specific neuropeptides of the trigeminal system modify brain swelling after trauma and should be further explored as potential therapy in brain trauma and subdural bleeding.

The "Shaken Baby" syndrome: pathology and mechanisms

The "Shaken Baby" syndrome (SBS) is the subject of intense controversy; the diagnosis has in the past depended on the triad of subdural haemorrhage (SDH), retinal haemorrhage and encephalopathy. While there is no doubt that infants do suffer abusive injury at the hands of their carers and that impact can cause catastrophic intracranial damage, research has repeatedly undermined the hypothesis that shaking per se can cause this triad. The term non-accidental head injury has therefore been widely adopted. This review will focus on the pathology and mechanisms of the three physiologically associated findings which constitute the "triad" and are seen in infants suffering from a wide range of non-traumatic as well as traumatic conditions. "Sub" dural bleeding in fact originates within the deep layers of the dura. The potential sources of SDH include: the bridging veins, small vessels within the dura itself, a granulating haemorrhagic membrane and ruptured intracranial aneurysm. Most neuropathologists do not routinely examine eyes, but the significance of this second arm of the triad in the diagnosis of Shaken Baby syndrome is such that it merits consideration in the context of this review. While retinal haemorrhage can be seen clinically, dural and subarachnoid optic nerve sheath haemorrhage is usually seen exclusively by the pathologist and only rarely described by the neuroradiologist. The term encephalopathy is used loosely in the context of SBS. It may encompass anything from vomiting, irritability, feeding difficulties or floppiness to seizures, apnoea and fulminant brain swelling. The spectrum of brain pathology associated with retinal and subdural bleeding from a variety of causes is described. The most important cerebral pathology is swelling and hypoxic-ischaemic injury. Mechanical shearing injury is rare and contusions, the hallmark of adult traumatic brain damage, are vanishingly rare in infants under 1 year of age. Clefts and haemorrhages in the immediate subcortical white matter have been assumed to be due to trauma but factors specific to this age group offer other explanations. Finally, examples of the most common causes of the triad encountered in clinical diagnostic and forensic practice are briefly annotated.