Epidural haemorrhage of the cervical spinal cord: a post-mortem artefact?

Spinal cord injury as an indicator of abuse in forensic assessment of abusive head trauma (AHT)

Abusive head trauma (AHT) in children is notoriously one of the most challenging diagnoses for the forensic pathologist. The pathological "triad", a combination of intracranial subdural haematoma, cerebral oedema with hypoxic-ischaemic changes and retinal haemorrhages, is frequently argued to be insufficient to support a corroborated verdict of abuse. Data from all available English-language scientific literature involving radiological and neuropathological spinal cord examination is reviewed here in order to assess the contribution of spinal cord changes in differentiating abusive from accidental head trauma. In agreement with the statistically proven association between spinal subdural haemorrhage (SDH) and abuse (Choudhary et al. in Radiology 262:216-223, 2012), spinal blood collection proved to be the most indicative finding related to abusive aetiology. The incidence of spinal blood collection is as much as 44-48% when all the spinal cord levels are analysed as opposed to just 0-18% when the assessment is performed at cervical level only, in agreement with the evidence of the most frequent spinal SDH location at thoracolumbar rather than cervical level. In this review, the source of spinal cord blood collection and how the age of the child relates to the position of spinal cord lesions is also discussed. We concluded that the ante mortem MRI examination and post mortem examination of whole-length spinal cord is of fundamental interest for the assessment of abuse in the forensic setting.

En Bloc Examination of the Neck in Pediatric Homicide Cases: A Proper Way for Complete Assessment of Neck Trauma

The necks of infants and young children are not only anatomically different from adults, but are also supported by much weaker musculoskeletal systems and are therefore prone to trauma as a result of extension/flexion (shaking) or contact trauma to the head. Shaking cervical spine injuries can occur at much lower levels of head velocity and acceleration than those reported for shaken baby syndrome. The proper method for a comprehensive and detailed examination of the neck in pediatric homicide and suspected homicide cases is the en bloc examination of the neck, because the standard examination of the spinal cord not only distorts the anatomical relationship of the cord and osteocartilagenous structures, but also excludes the cervical nerves, ganglia, and the vertebral arteries from being evaluated. Interpretation of gross and microscopic findings using this method requires experience and knowledge of the anatomical relationship and common artifacts, such as epidural, focal intradural, or even isolated nerve hemorrhage to avoid misinterpretation. It is our opinion that this method should be applied to all pediatric homicide or suspected homicide cases, but is not suited for routine or nonsuspicious cases as it will add to the time and cost of medical examiner's operations.

MR Imaging of the Cervical Spine in Nonaccidental Trauma: A Tertiary Institution Experience

BACKGROUND AND PURPOSE

Cervical MR imaging has demonstrated a utility for detecting soft tissue injury in nonaccidental trauma. The purpose of this study was to identify the incidence and types of cervical spine injury on MR imaging in nonaccidental trauma and to correlate cervical spine injury with parenchymal injury on brain MR imaging and findings on head CT.

MATERIALS AND METHODS

A retrospective review of children diagnosed with nonaccidental trauma in a tertiary referral pediatric hospital over 8 years was performed. Inclusion criteria were children younger than 5 years of age, a confirmed diagnosis of nonaccidental trauma, and cervical spine MR imaging within 1 week of presentation. Brain and cervical spine MR imaging, head CT, cervical radiographs, and skeletal surveys were reviewed.

RESULTS

There were 89 patients included in this study (48 males; mean age, 9.1 months [range, 1-59 months]). Cervical spine injury on MR imaging was found in 61 patients (69%). Ligamentous injury was seen in 60 patients (67%), with interspinous ligaments being most commonly involved. Abnormal capsular fluid (atlanto-occipital and atlantoaxial) was present in 28 patients (32%). Cervical spine injury on MR imaging was significantly associated with parenchymal restricted diffusion on brain MR imaging and parenchymal injury on head CT (P = .0004 and P = .0104, respectively). Children with restricted diffusion on brain MR imaging were 6.22 (point estimate) times more likely to have cervical spine injury on MR imaging.

CONCLUSIONS

There is a high incidence of cervical spine injury in pediatric nonaccidental trauma. Positive findings may affect management and suggest a traumatic etiology.

Pitfalls and Artifacts in the Neck at Autopsy

The diagnosis of strangulation at autopsy is a persistent challenge for the forensic pathologist. The main difficulty is interpreting the observations made at the postmortem table and deciding whether the observations are a sufficient basis to render an expert opinion that death was caused by external compression of the neck. This may have considerable importance to the criminal justice system and may lead to a conviction for murder. There are five main pitfalls and artifacts encountered in the neck at postmortem examination. These five areas provide the majority of the interpretative difficulties experienced by the pathologist. These challenges include: 1) developmental anatomy of the hyoid bone; 2) triticeous cartilages; 3) Prinsloo-Gordon hemorrhage; 4) postmortem hypostatic hemorrhage; and 5) resuscitation-related neck injury. This review explores these five areas. Awareness of the pitfalls and artifacts in the neck is essential for a satisfactory and evidence-based approach to interpreting observations of the neck at autopsy.

Spinal injuries in abusive head trauma: patterns and recommendations

A growing body of scientific evidence suggests that there is an association between occult spinal injury and abusive head trauma (previously known as shaken baby syndrome). Consideration needs to be given to the nature of these injuries, the possible causal mechanisms and what investigations should be undertaken to delineate the full extent of spinal involvement in infants with suspected abusive head trauma. This association has the potential to influence our understanding of the biomechanics and subsequent neuropathology associated with abusive head trauma.

Spinal subdural hemorrhage in abusive head trauma: a retrospective study

PURPOSE

To compare the relative incidence, distribution, and radiologic characteristics of spinal subdural hemorrhage after abusive head trauma versus that after accidental trauma in children.

MATERIALS AND METHODS

This study received prior approval from the Human Subjects Protection Office. Informed consent was waived. This study was HIPAA compliant. Two hundred fifty-two children aged 0-2 years treated for abusive head trauma at our institute between 1997 and 2009 were identified through retrospective chart review. A second group of 70 children aged 0-2 years treated at our institute for well-documented accidental trauma between 2003 and 2010 were also identified through retrospective chart review. All clinical data and cross-sectional imaging results, including computed tomographic and magnetic resonance imaging of the brain, spine, chest, abdomen, and pelvis, were reviewed for both of these groups. A Fisher exact test was performed to assess the statistical significance of the proportion of the spinal canal subdural hemorrhage in abusive head trauma versus that in accidental trauma.

RESULTS

In the abusive head trauma cohort, 67 (26.5%) of 252 children had evaluable spinal imaging results. Of these, 38 (56%) of 67 children had undergone thoracolumbar imaging, and 24 (63%) of 38 had thoracolumbar subdural hemorrhage. Spinal imaging was performed in this cohort 0.3-141 hours after injury (mean, 23 hours ± 27 [standard deviation]), with 65 (97%) of 67 cases having undergone imaging within 52 hours of injury. In the second cohort with accidental injury, only one (1%) of 70 children had spinal subdural hemorrhage at presentation; this patient had displaced occipital fracture. The comparison of incidences of spinal subdural hemorrhage in abusive head trauma versus those in accidental trauma was statistically significant (P < .001).

CONCLUSION

Spinal canal subdural hemorrhage was present in more than 60% of children with abusive head trauma who underwent thoracolumbar imaging in this series but was rare in those with accidental trauma.

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.

Is there a causal relationship between the hypoxia-ischaemia associated with cardiorespiratory arrest and subdural haematomas? An observational study

The aim of this study was to determine the frequency of subdural haematomas (SDHs) occurring in infants presenting following atraumatic cardiorespiratory collapse. This study was a review of retrospective case notes, brain imaging and post-mortem examinations carried out in the paediatric intensive care unit (PICU) and emergency department (ED) in a tertiary paediatric centre in the UK. The study included infants and children less than 4 years old dying in the ED or admitted to the PICU after atraumatic cardiorespiratory arrest. We identified macroscopic SDHs on brain imaging or post-mortem examination. Of those children who experienced a cardiorespiratory arrest from a non-traumatic cause and met inclusion criteria, 33 presented and died in the ED and 17 were admitted to the PICU. These children had a post-mortem examination, brain imaging or both. None of these infants had a significant SDH. One child had a small clot adherent to the dura found on post-mortem and two had microscopic intradural haemorrhage, but it is unclear in each case whether this was artefact, as each had otherwise normal brains. Subdural haematoma arising in infants or young children in the context of catastrophic cardiorespiratory compromise from a non-traumatic cause was not observed.

Hemorrhagic lividity of the neck: controlled induction of postmortem hypostatic hemorrhages

Postmortem hypostasis (livor mortis or lividity) is classically defined as the intravascular pooling of blood in gravitationally dependent parts of the body after death. However, intense lividity can be associated with small hemorrhages in the skin, so-called postmortem hypostatic hemorrhages (Tardieu spots). Postmortem hypostatic hemorrhages seem to contradict the usual understanding of lividity, since hemorrhage is by definition an extravascular phenomenon. Substantive medicolegal difficulties can arise if such hemorrhagic lividity develops in the necks of bodies that have ventral lividity due to prone position at the death scene. To study this phenomenon, we have developed a model for the controlled formation of hypostatic hemorrhages in human cadavers. In this model, extensive hypostatic hemorrhages or hemorrhagic lividity could be reproducibly but not universally induced in the soft tissues of the anterior neck and strap muscles. Histologic examination revealed hemorrhage that was microscopically indistinguishable from the acute hemorrhages observed in contusions. In addition, some larger areas of interstitially extravasated blood showed "buffy coat"-sedimentation separation of neutrophils that closely mimicked acute inflammation, further confounding the correct diagnosis. This research implies that hypostatic hemorrhages form after the progressive development of increasing gravitational hydrostatic pressure in an autolysing venous plexus. Thus, this phenomenon can mimic soft tissue injury ("pseudo-bruising") and the internal injuries related to strangulation. Caution must be exercised when diagnosing strangulation in bodies with anterior neck lividity.

Birth injury of the cranium and central nervous system

Birth injury of the scalp, skull and central nervous system (CNS) is a well-recognized complication of a difficult delivery. The rate of birth trauma has dropped precipitously and now accounts for less than 2% of neonatal deaths. Despite this dramatic decrease in birth-trauma mortality significant injuries still occur. A variety of risk factors clearly predispose certain infants to birth-related injury. Recent neuroradiology studies indicate that intracranial hemorrhage, even in asymptomatic infants, is not rare. Pathologists' (neuropathologists and forensic pathologists) appreciation of the spectrum of birth injuries and their sequelae is critical in order to be able to distinguish these from inflicted injuries and post-mortem changes.