A theoretical model of benign external hydrocephalus that predicts a predisposition towards extra-axial hemorrhage after minor head trauma

Prospective measurement of the width of cerebrospinal fluid spaces by cranial ultrasound in neurologically healthy children aged 0-19 months

BACKGROUND

Ultrasound (US) is often the first method used to look for brain or cerebrospinal fluid (CSF) space pathologies. Knowledge of normal CSF width values is essential. Most of the available US normative values were established over 20 years ago, were obtained with older equipment, and cover only part of the age spectrum that can be examined by cranial US. This prospective study aimed to determine the normative values of the widths of the subarachnoid and internal CSF spaces (craniocortical, minimal and maximal interhemispheric, interventricular, and frontal horn) for high-resolution linear US probes in neurologically healthy infants and children aged 0-19 months and assess whether subdural fluid collections can be delineated.

METHODS

Two radiologists measured the width of the CSF spaces with a conventional linear probe and an ultralight hockey-stick probe in neurologically healthy children not referred for cranial or spinal US.

RESULTS

This study included 359 neurologically healthy children (nboys = 178, 49.6%; ngirls = 181, 50.4%) with a median age of 46.0 days and a range of 1-599 days. We constructed prediction plots, including the 5th, 50th, and 95th percentiles, and an interactive spreadsheet to calculate normative values for individual patients. The measurements of the two probes and the left and right sides did not differ, eliminating the need for separate normative values. No subdural fluid collection was detected.

CONCLUSION

Normative values for the widths of the subarachnoid space and the internal CSF spaces are useful for evaluating intracranial pathology, especially when determining whether an increase in the subarachnoid space width is abnormal.

Benign enlargement of the subarachnoid spaces and subdural collections-when to evaluate for abuse

In infants without a history of trauma, subdural haemorrhages should raise the concern for an abusive head injury, particularly when they are associated with bridging vein clotting/rupture or with septations. However, non-haemorrhagic, fluid-appearing subdural collections (also called hygromas) may also be the result of abuse. Subdural collections have also been uncommonly observed in patients with benign enlargement of the subarachnoid spaces (BESS) and a few large-scale studies accurately investigate the incidence and the significance. Currently, there is a wide variation of practices in children with BESS and subdural collections. Due to the social risks associated with abuse evaluation and the perceived risk of radiation exposure, there might be a reluctance to fully evaluate these children in some centres. The diagnosis of physical abuse cannot be substantiated nor safely excluded in infants with BESS and subdural collection(s), without investigation for concomitant traumatic findings. The exact prevalence of occult injuries and abuse in these infants is unknown. In macrocephalic infants with subdural collections and imaging features of BESS, thorough investigations for abuse are warranted and paediatricians should consider performing full skeletal surveys even when fundoscopy, social work consult, and detailed clinical evaluation are unremarkable.

Prevalence of Visible Subdural Spaces in Benign Enlargement of Subarachnoid Spaces in Infancy: A Retrospective Analysis Utilizing Magnetic Resonance Imaging

OBJECTIVE

Benign Enlargement of the Subarachnoid Spaces in Infancy (BESSI) is a common finding during workup for progressive macrocephaly. BESSI has been associated with slightly higher prevalence of subdural (SD) spaces and a risk for developing subdural hematoma. This study utilizes fast brain magnetic resonance imaging (MRI) to investigate the prevalence of visible SD spaces in BESSI.

METHODS

A retrospective review was performed for all pediatric patients who underwent brain MRI for macrocephaly. Patients with a diagnosis of BESSI were included in the study. A total of 109 patients met the inclusion criteria. Patient demographics were collected, and images were reviewed for size of subarachnoid, visible SD spaces, and ventricle size. Descriptive and inferential statistics were performed.

RESULTS

The average age was 8 ± 4.6 months, 64 (59%) were male, and 55 patients had no previous medical history (50%). Sixty-seven percent of all patients were identified to have visible SD spaces. Eleven patients had confirmed SD hematomas; 1 patient was deemed to have abusive head trauma. Visible SD spaces were associated with younger age (6.9 months). Thirty-one patients with visible SD spaces had follow-up MRI, with complete resolution by 33 months.

CONCLUSIONS

BESSI is a self-limiting pathology that has been associated with visible SD spaces and potential risk for SD hemorrhages. We report a high prevalence of visible SD spaces within BESSI through utilization of fast brain MRI. These spaces may contribute to the higher rate of incidental subdural hematoma in this population.

Re-evaluation of medical findings in alleged shaken baby syndrome and abusive head trauma in Norwegian courts fails to support abuse diagnoses

AIM

The criteria for diagnosing abusive head trauma (AHT) are not well defined and this condition might be diagnosed on failing premises. Our aim was to review criminal AHT cases in Norwegian courts by scrutinising the underlying medical documentation.

METHODS

Cases were identified in the data registry for Norwegian courts from 2004 to 2015. Documentation was obtained from relevant health institutions. The medical co-authors first made independent evaluations of the documentation for each child, followed by a consensus evaluation.

RESULTS

A total of 17 children (11 boys) were identified, all diagnosed as AHT by court appointed experts, 15 were infants (mean age 2.6 months). A high proportion (41.2%) was born to immigrant parents and 31.3% were premature. The medical findings could be explained by alternative diagnoses in 16 of the 17 children; 8 boys (7 infants - mean age 2.9 months) had clinical and radiological characteristics compatible with external hydrocephalus complicated by chronic subdural haematoma. Six children (five infants with mean age 2.1 months) had a female preponderance and findings compatible with hypoxic ischaemic insults.

CONCLUSION

The medical condition in most children had not necessarily been caused by shaking or direct impact, as was originally concluded by the court experts.

Is external hydrocephalus a possible differential diagnosis when child abuse is suspected?

BACKGROUND

Criteria for diagnosing abusive head trauma (AHT) or "shaken baby syndrome" are not well defined; consequently, these conditions might be diagnosed on failing premises.

METHODS

The authors have collected a total of 28 infants, from the US (20) and Norway (8), suspected of having been violently shaken, and their caregivers had been suspected, investigated, prosecuted or convicted of having performed this action. Among 26 symptomatic infants, there were 18 boys (69%) and 8 girls (31%)-mean age 5.1 month, without age difference between genders.

RESULTS

Twenty-one of 26 symptomatic children (81%) had a head circumference at or above the 90 percentile, and 18 had a head circumference at or above the 97 percentile. After macrocephaly, seizure was the most frequent initial symptom in 13 (50%) of the symptomatic infants. Seventeen (65%) of the symptomatic infants had bilateral retinal haemorrhages, and two had unilateral retinal haemorrhages. All infants had neuroimaging compatible with chronic subdural haematomas/hygromas as well as radiological characteristics compatible with benign external hydrocephalus (BEH).

CONCLUSIONS

BEH with subdural haematomas/hygromas in infants may sometimes be misdiagnosed as abusive head trauma. Based on the authors' experience and findings of the study, the following measures are suggested to avoid this diagnostic pitfall: medical experts in infant abuse cases should be trained in recognising clinical and radiological BEH features, clinicians with neuro-paediatric experience should always be included in the expert teams and reliable information about the head circumference development from birth should always be available.

Subdural hematoma prevalence and long-term developmental outcomes in patients with benign expansion of the subarachnoid spaces

OBJECTIVE

Benign expansion of the subarachnoid spaces (BESS) is a condition seen in macrocephalic infants. BESS is associated with mild developmental delays which tend to resolve within a few years. It is accepted that patients with BESS are at increased risk of spontaneous subdural hematomas (SDHs), although the exact pathophysiology is not well understood. The prevalence of spontaneous SDH in BESS patients is poorly defined, with only a few large single-center series published. In this study the authors aimed to better define BESS prevalence and developmental outcomes through the longitudinal review of a large cohort of BESS patients.

METHODS

A large retrospective review was performed at a single institution from 1995 to 2020 for patients 2 years of age or younger with a diagnosis of BESS by neurology or neurosurgery and head circumference > 85th percentile. Demographic data, head circumference, presence of developmental delay, occurrence of SDH, and need for surgery were extracted from patient charts. The subarachnoid space (SAS) size was measured from the available MR images, and the sizes of those who did and did not develop SDH were compared.

RESULTS

Free text search revealed BESS mentioned within the medical records of 1410 of 2.6 million patients. After exclusion criteria, 480 patients remained eligible for the study. Thirty-two percent (n = 154) of patients were diagnosed with developmental delay, most commonly gross motor delay (53%). Gross motor delay resolved in 86% of patients at a mean age of 22.2 months. The prevalence of spontaneous SDH in this BESS population over a period of 25 years was 8.1%. There was no significant association between SAS size and SDH formation.

CONCLUSIONS

This study represents results for one of the largest cohorts of patients with BESS at a single institution. Gross motor delay was the most common developmental delay diagnosed, and a majority of patients had resolution of their delay. These data support that children with BESS have a higher prevalence of SDH than the general pediatric population, although SAS size was not significantly associated with SDH development.

Chronic subdural hemorrhage predisposes to development of cerebral venous thrombosis and associated retinal hemorrhages and subdural rebleeds in infants

For infants presenting with subdural hemorrhage, retinal hemorrhage, and neurological decline the "consensus" opinion is that this constellation represents child abuse and that cerebral venous sinus thrombosis and cortical vein thrombosis is a false mimic. This article contends that this conclusion is false for a subset of infants with no evidence of spinal, external head, or body injury and is the result of a poor radiologic evidence base and misinterpreted data. Underdiagnosis of thrombosis is the result of rapid clot dissolution and radiologic under recognition. A pre-existing/chronic subdural hemorrhage predisposes to development of venous sinus thrombosis/cortical vein thrombosis, triggered by minor trauma or an acute life-threatening event such as dysphagic choking, variably leading to retinal and subdural hemorrhages and neurologic decline. These conclusions are based on analysis of the neuroradiologic imaging findings in 11 infants, all featuring undiagnosed cortical vein or venous sinus thrombosis. Subtle neuroradiologic signs of and the mechanisms of thrombosis are discussed. Subarachnoid hemorrhage from leaking thrombosed cortical veins may be confused with acute subdural hemorrhage and probably contributes to the development of retinal hemorrhage ala Terson's syndrome. Chronic subdural hemorrhage rebleeding from minor trauma likely occurs more readily than bleeding from traumatic bridging vein rupture. Radiologists must meet the challenge of stringent evaluation of neuro imaging studies; any infant with a pre-existing subdural hemorrhage presenting with neurologic decline must be assumed to have venous sinus or cortical vein thrombosis until proven otherwise.

External Hydrocephalus as a Cause of Infant Subdural Hematoma: Epidemiological and Radiological Investigations of Infants Suspected of Being Abused

BACKGROUND

Acute subdural hematoma (ASDH) and chronic subdural hematoma (CSDH) in infants have been regarded as highly specific for abuse. Other causes of CSDH have not been investigated in a large population.

PURPOSE

The purpose of this study was to investigate to what extent external hydrocephalus is present in infants with ASDH and CSDH undergoing evaluation for abuse.

MATERIAL AND METHODS

Eighty-five infants suspected of being abused, with ASDH (n = 16) or CSDH (n = 69), were reviewed regarding age, risk factor profiles, craniocortical width (CCW), sinocortical width (SCW), frontal interhemispheric width (IHW), subarachnoid space width (SSW), and head circumference (HC). In infants with unilateral subdural hematoma (SDH), correlations between contralateral SSW and ipsilateral CCW and SDH width were investigated.

RESULTS

Infants with CSDH had significantly lower mortality, were more often premature and male, and had significantly higher CCW, SCW, IHW, and SSW than infants with ASDH (P < 0.05). Ipsilateral CCW (R = 0.92, P < 0.001) and SDH width (R = 0.81, P < 0.01) correlated with contralateral SSW. Increased HC was more prevalent in infants with CSDH (71%) than in infants with ASDH (14%) (P < 0.01). Forty-two infants, all with CSDH, had at least one of CCW, SCW, or IHW ≥95^th percentile. Twenty infants, all with CSDH, had CCW, SCW, and IHW >5 mm, in addition to increased HC.

CONCLUSION

A substantial proportion of infants with CSDH who had been suspected of being abused had findings suggesting external hydrocephalus.

Infantile Macrocephaly: Complicated Familial Benign Enlargement of Subarachnoid Space in Twins of Suspected Nonaccidental Injury

A 3-month-old first of dizygotic male twins, born at 34 + 5 weeks gestational age, presented with a 4-week history of increasing head circumference and vomiting. He had a tense anterior fontanelle and a head circumference above the 97th percentile. Magnetic resonance imaging showed large bilateral subdural collection with hemosiderin deposits suggestive of hemorrhage. Nine days of bilateral subdural drainage reduced the collection size and blood load. On postoperative day 16, magnetic resonance imaging confirmed persistent but smaller subdural collections, unmasking the underlying subarachnoid space enlargement. On day 18, a right subdural-peritoneal valveless shunt was inserted as definitive treatment. As part of a nonaccidental injury investigation, Twin 2 was also found to have macrocephaly secondary to benign enlargement of subarachnoid space, which was managed conservatively. Benign enlargement of subarachnoid space has an assumed autosomal/multifactorial inheritance and predisposes to subdural hemorrhage. Ultimately, no safeguarding issues were raised. Both twins continued to be neurologically stable at 2-year follow-up with head circumferences between the 98th and 99th percentiles.

Macrocephaly and subdural collections

Enlarged subarachnoid spaces are a common finding in infants and young children imaged for macrocephaly or an enlarging head circumference, and benign enlargement of the subarachnoid spaces is often diagnosed. Infrequently, presumed "spontaneous" subdural hemorrhages or subdural collections might complicate these enlarged subarachnoid spaces. Children with large bilateral subdural collections might also present for imaging with macrocephaly. Each scenario potentially raises concerns for prior injury because subdural hemorrhage is a frequent finding in children with abusive head trauma.

Subarachnomegaly-venous congestion of infancy

PURPOSE

Multiple names within the literature refer to a clinical picture affecting infants and consisting of a large or fast growing head circumference with enlarged cortical subarachnoid spaces (CSAS) while cranial sutures are open. This myriad of terms demonstrates the confusion about the entity, that may even group together different etiological processes. In this review, we aim to shed light on this matter in an effort to restate the defining features of the clinical picture and sum the evidence and current understanding of its pathophysiology and related imaging findings.

METHODS

Extensive and updated review of the literature with special focus on defining features, clinical history with long term evaluation and pathophysiological process.

RESULTS

Functional and molecular CSF studies as well as clinical evidence challenges the common pathophysiological theory based on non-functional arachnoid villi. Conversely, there is increasing evidence supporting cerebro-venous system abnormalities as the main pathophysiological factor. Additionally, long term cohorts studies show that it may have subtle but irreversible neurodevelopmental consequences.

CONCLUSION

Subarachnomegaly is an age-related condition of the infancy with radiological enlargement of CSAS and often self limiting course. However, considering the evidence on pathophysiology as outlined herein and long term outcome reports, further research effort is needed to assess the consequences of venous outflow impairment and enlarged CSAS and how this relates to imaging findings and neurodevelopment test results later in life.

Examining perinatal subdural haematoma as an aetiology of extra-axial hygroma and chronic subdural haematoma

AIM

Benign external hydrocephalus (BEH), hygroma and chronic subdural haematoma are extra-axial fluid collections in infants. MRI studies have shown that almost half of all new-borns have perinatal subdural blood, generally referred to as subdural haematoma (SDH) or perinatal SDH. Epidemiologically there are striking similarities between chronic SDH and BEH in infants.

METHODS

Discussion of pathophysiological mechanisms for BEH and chronic SDH, based on existing literature.

RESULTS

Perinatal SDH is common, and we hypothesise that this condition in some infants develop into extra-axial fluid collections, known as hygroma, BEH or chronic subdural haematoma. The mechanism seems to be an intradural bleeding that creates an obstructive layer preventing normal CSF absorption. The site where the bleeding originates from and those areas enveloped in blood from the primary damaged area are prone to later rebleeds, seen as 'acute on chronic' haematomas. With steady production of CSF and the blockage, increased intracranial pressure drives the accelerated skull growth seen in many of these children.

CONCLUSION

Perinatal SDH hampers CSF absorption, possibly leading to BEH and chronic SDH, with a high risk of false accusations of abuse. Close monitoring of head circumference could prove vital in detecting children with this condition.

Macrocephaly: Solving the Diagnostic Dilemma

Macrocephaly is a relatively common clinical condition affecting up to 5% of the pediatric population. It is defined as an abnormally large head with an occipitofrontal circumference greater than 2 standard deviations above the mean for a given age and sex. Megalencephaly refers exclusively to brain overgrowth exceeding twice the standard deviation. Macrocephaly can be isolated and benign or may be the first indication of an underlying congenital, genetic, or acquired disorder, whereas megalencephaly is more often syndromic. Megalencephaly can be divided into 2 subtypes: metabolic and developmental, caused by genetic defects in cellular metabolism and alterations in signaling pathways, respectively. Neuroimaging plays an important role in the evaluation of macrocephaly, especially in the metabolic subtype which may not be overtly apparent clinically. This article outlines the diverse etiologies of macrocephaly, delineates their clinical and radiographic features, and suggests a clinicoradiological algorithm for evaluation.

Benign extracerebral fluid collection complicated by subdural hematoma and fluid collection: clinical characteristics and management

INTRODUCTION

Benign extracerebral fluid collection (bECFC) can be complicated by subdural hematoma (SDH) or subdural fluid collection (SDFC). The etiology, natural history, and management strategy for SDH/SDFC in bECFC are not fully understood. We retrospectively reviewed the cases of bECFC patients complicated with SDH/SDFC and tried (1) to confirm the fact that bECFC children are vulnerable to SDH/SDFC, (2) to investigate the clinical significance of 'trauma history' witnessed by a caregiver, and (3) to determine optimal management for them.

METHOD

Among 213 bECFC patients identified from January 2000 to August 2015, 20 patients (male:female = 14:6; median age, 6.5 months; range 1-16 months) complicated by SDH/SDFC documented with brain imaging were evaluated for their clinical manifestations, radiologic features, and management outcomes. The median follow-up period was 9.5 months. They were divided into two groups (traumatic group versus non-traumatic group) according to whether objective radiologic evidence of head injury was present or not, and the two groups were analyzed for any clinical differences between them. We also evaluated the clinical significance of witnessed traumatic events by caregivers as an additional independent variable in the analysis.

RESULTS

The incidence of SDH/SDFC in bECFC patients was 9.4% (20/213) in our data. In a comparative analysis, the traumatic group is more likely to have 'acute' stage SDH, whereas the non-traumatic group is more likely to have 'chronic' stage SDH. The trauma history witnessed by caregivers did not show clinical significance in the data analysis when included as an independent variable. The prognosis of SDH/SDFC in bECFC patients was favorable without surgery in most of patients regardless of whether the patient has evidence of head trauma or not.

CONCLUSION

Benign ECFC is vulnerable to SDH/SDFC development. For the bECFC patients complicated by SDH/SDFC, the trauma history witnessed by a caregiver did not show any clinical significance. A 'wait and watch' strategy is sufficient for the management of SDH/SDFC in bECFC patients.

Enlarged subarachnoid spaces and intracranial hemorrhage in children with accidental head trauma

OBJECTIVE Benign external hydrocephalus (BEH) is an enlargement of the subarachnoid spaces (SASs) that can be seen in young children. It is controversial whether children with BEH are predisposed to developing subdural hemorrhage (SDH) with or without trauma. This issue is clinically relevant as a finding of unexplained SDH raises concerns about child abuse and often prompts child protection and law enforcement investigations. METHODS This retrospective study included children (1-24 months of age) who underwent head CT scanning after an accidental fall of less than 6 feet. Head CT scans were reviewed, cranial findings were documented, and the SAS was measured and qualitatively evaluated. Enlarged SAS was defined as an extraaxial space (EAS) greater than 4 mm on CT scans. Clinical measurements of head circumference (HC) were noted, and the head circumference percentile was calculated. The relationship between enlarged SAS and HC percentile, and enlarged SAS and intracranial hemorrhage (ICH), were investigated using bivariate analysis. RESULTS Of the 110 children included in this sample, 23 had EASs greater than 4 mm. The mean patient age was 6.8 months (median 6.0 months). Thirty-four patients (30.9%) had ICHs, including subarachnoid/subpial (6.2%), subdural (6.2%), epidural (5.0%), and unspecified extraaxial hemorrhage (16.5%). Enlarged SAS was positively associated with subarachnoid/subpial hemorrhage; there was no association between enlarged SASs and either SDH or epidural hemorrhage. A larger SAS was positively associated with larger HC percentile; however, HC percentile was not independently associated with ICH. CONCLUSIONS Enlarged SAS was not associated with SDH, but was associated with other ICHs. The authors' findings do not support the theory that BEH predisposes children to SDH with minor accidental trauma.

The diagnostic yield of ultrasound of the head in healthy infants presenting with the clinical diagnosis of benign macrocrania

AIM

To investigate the frequency of sonographic findings that required neurosurgical consultation for all referred outpatients suspected to have benign macrocrania (BMC).

MATERIALS AND METHODS

A retrospective review was performed from September 2011 until June 2015 for all outpatients referred to the ultrasound (US) department for BMC. Electronic medical records, US images, and reports were reviewed in conjunction with follow-up imaging. Each review consisted of gender, specialty of referring physician, first head circumference, head circumference at or closest to the time of the head US, the last head circumference, and any neurological issue prior to the US, at the time of US, or following the US, and clinical outcomes. Statistical analysis employed the Kruskal-Wallis rank sum test and Fischer's exact test (chi square test of independence) that compared normal/BMC patients from the patients requiring a neurosurgical consultation.

RESULTS

One hundred and thirty (40.9%) had a normal head US, 181 patients (56.9%) had sonographic findings of BMC, and seven (2.2%) patients had an abnormal head US that required a neurosurgical consultation. Of the 181 patients with BMC, 23 underwent follow-up imaging with 22 patients having unchanged BMC or a normal head US and one patient developing mild ventriculomegaly that was stable on follow-up imaging. Three of the seven patients (1%) aged 1.8, 2.3, and 13.1 months with abnormal head US requiring neurosurgical consultation, had mild ventriculomegaly that was stable on follow-up imaging. Four of the seven patients (1.2%) that required neurosurgical consultation needed a neurosurgical procedure. Between the two US subgroups (normal and BMC), no statistical significance was noted regarding age of patient at US, head circumference at clinical and radiological presentation (p>0.05) except for the first head circumference clinically documented which demonstrated statistical significance (p<0.03).

CONCLUSION

Short interval surveillance including head circumference and assessment for the development of bulging anterior fontanelle and neurological abnormalities may be more cost effective than US in the initial evaluation of patients clinically suspected to have BMC.

Macrocephaly in infancy: benign enlargement of the subarachnoid spaces and subdural collections

OBJECTIVE Benign enlargement of the subarachnoid spaces (BESS) is a common finding on imaging studies indicated by macrocephaly in infancy. This finding has been associated with the presence of subdural fluid collections that are sometimes construed as suggestive of abusive head injury. The prevalence of BESS among infants with macrocephaly and the prevalence of subdural collections among infants with BESS are both poorly defined. The goal of this study was to determine the relative frequencies of BESS, hydrocephalus, and subdural collections in a large consecutive series of imaging studies performed for macrocephaly and to determine the prevalence of subdural fluid collections among patients with BESS. METHODS A text search of radiology requisitions identified studies performed for macrocephaly in patients ≤ 2 years of age. Studies of patients with hydrocephalus or acute trauma were excluded. Studies that demonstrated hydrocephalus or chronic subdural hematoma not previously recognized but responsible for macrocephaly were noted but not investigated further. The remaining studies were reviewed for the presence of incidental subdural collections and for measurement of the depth of the subarachnoid space. A 3-point scale was used to grade BESS: Grade 0, < 5 mm; Grade 1, 5-9 mm; and Grade 2, ≥ 10 mm. RESULTS After exclusions, there were 538 studies, including 7 cases of hydrocephalus (1.3%) and 1 large, bilateral chronic subdural hematoma (0.2%). There were incidental subdural collections in 21 cases (3.9%). Two hundred sixty-five studies (49.2%) exhibited Grade 1 BESS, and 46 studies (8.6%) exhibited Grade 2 BESS. The prevalence of incidental subdural collections among studies with BESS was 18 of 311 (5.8%). The presence of BESS was associated with a greater prevalence of subdural collections, and higher grades of BESS were associated with increasing prevalence of subdural collections. After controlling for imaging modality, the odds ratio of the association of BESS with subdural collections was 3.68 (95% CI 1.12-12.1, p = 0.0115). There was no association of race, sex, or insurance status with subdural collections. Patients with BESS had larger head circumference Z-scores, but there was no association of head circumference or age with subdural collections. Interrater reliability in the diagnosis and grading of BESS was only fair. CONCLUSIONS The current study confirms the association of BESS with incidental subdural collections and suggests that greater depth of the subarachnoid space is associated with increased prevalence of such collections. These observations support the theory that infants with BESS have a predisposition to subdural collections on an anatomical basis. Incidental subdural collections in the setting of BESS are not necessarily indicative of abusive head injury.

The significance of macrocephaly or enlarging head circumference in infants with the triad: further evidence of mimics of shaken baby syndrome

Infants with the triad (neurologic dysfunction, subdural hematoma [SDH], and retinal hemorrhage) are often diagnosed as victims of shaken baby syndrome. Medical conditions/predisposing factors to developing the triad are often dismissed: short falls, birth-related SDH that enlarges, macrocephaly, sinus/cortical vein thrombosis, and others. Six infants with the triad are described in which child abuse was diagnosed, but parents denied wrongdoing. All 6 had either macrocephaly or enlarging head circumference, which suggested medical explanations. Three infants incurred short falls, 1 had a difficult delivery in which there was likely a rebleed of a birth-related SDH, 1 had a spontaneous SDH associated with increased extra-axial fluid spaces, and 1 had a sinus thrombosis. Following legal proceedings, all 6 infants were returned to their parents, and there has been no child maltreatment in follow-up, suggesting child abuse never happened. The results indicate that alternative medical explanations for causing the triad should be considered and that macrocephaly or an enlarging head circumference raises the possibility of a medical explanation.

Recent progress and future issues in the management of abusive head trauma

Head trauma is the leading cause of death in child abuse cases and one of the important issues in the care of abused children. Since the Child Abuse Prevention Law was enforced in 2000 in Japan, various measures have been taken to prevent child abuse over the following decade. Accordingly, medical research on abusive head trauma (AHT) has advanced, leading to significant progress in the medical diagnosis of AHT. This progress has been brought about by (1) the widespread establishment of child protection teams (CPTs) at core hospitals, (2) the progress in neuroradiological imaging and ophthalmoscopic technologies, and (3) the introduction of postmortem imaging. However, the pathological condition of patients with AHT, particularly that of the diffuse brain swelling type, still remains poorly understood. As a result, no clear treatment strategies for AHT have been developed and no treatment outcomes have been improved to date. The development of new treatment strategies for AHT and the construction of a comprehensive database that supports clinical studies are required in the future.

Subdural hemorrhages associated with antithrombotic therapy in infants with cerebral atrophy

Low-molecular-weight heparins, such as enoxaparin, are often used to treat thrombosis in infants. We present 4 infants with diffuse brain injury who developed cerebral venous sinus thrombosis or deep vein thrombosis and were treated with enoxaparin. These infants subsequently developed subdural hemorrhages, and enoxaparin was stopped. In 3 cases, the subdural hemorrhages were found on routine surveillance brain MRI, and in 1 case imaging was urgently obtained because of focal seizures. Two patients needed urgent neurosurgical intervention, and all subdural hemorrhages improved or resolved on follow-up imaging. Each infant developed severe neurologic deficits, probably from the coexisting diffuse brain injury rather than from the subdural hemorrhages themselves. The risk of intracranial hemorrhage from enoxaparin may be accentuated in patients with diffuse brain injury, and careful consideration should be given before treatment in this population.

Benign external hydrocephalus in infants. A single centre experience and literature review

External hydrocephalus (EH) is a benign clinical entity in which macrocephaly is associated with an increase in volume of the subarachnoid space, especially overlying both frontal lobes, and a normal or only slight increase in volume of the lateral ventricles. Several pathogenic hypotheses have been proposed but the most accredited theory seems to be delayed maturation of the arachnoid villi. There is a consensus that this is a benign entity, correlated to a familial predisposition and, in some cases, inheritance. CT and MRI are very important to make a diagnosis but also to establish the prognosis in patients who encounter the rare complications such as subdural haematomas. In conclusion, CT and MRI can provide a highly accurate diagnosis in these patients, allowing a preliminary assessment of the prognosis, particularly regarding the enlarged subarachnoid space limits and the "cortical vein" sign which can predict a further complication. These results are obtained with the same examination performed in a standard CT or MRI study of the brain and no injection of contrast medium is needed.

Prevalence of subdural collections in children with macrocrania

BACKGROUND AND PURPOSE

The relationship between enlarged subarachnoid spaces and subdural collections is poorly understood and creates challenges for clinicians investigating the etiology of subdural collections. The purpose of this study was to determine the prevalence of subdural collections on cross sectional imaging in children with macrocephaly correlating with subarachnoid space enlargement.

MATERIALS AND METHODS

The radiology information system of a large pediatric medical center was reviewed for "macrocrania" and "macrocephaly" on reports of cranial MRI/CT examinations in children <24 months of age, over a 24-month period. Head circumference was obtained from the clinical record. Studies were reviewed blindly for subdural collection presence and subarachnoid space size. Children with prior cranial surgery, parenchymal abnormalities, hydrocephalus, or conditions predisposing to parenchymal volume loss were excluded. Chart review was performed on those with subdural collections.

RESULTS

Imaging from 177 children with enlarged head circumference was reviewed. Nine were excluded, for a final cohort of 168 subjects (108 with enlarged subarachnoid space). Subdural collections were identified in 6 (3.6%), all with enlarged subarachnoid space (6/108, 5.6%). In 4, subdural collections were small, homogeneous, and nonhemorrhagic. In 2, the collections were complex (septations or hemorrhage). Two children were reported as victims of child abuse (both with complex collections). No definitive etiology was established in the other cases.

CONCLUSIONS

The prevalence of subdural collections in imaged children with macrocrania was 3.6%, all occurring in children with enlarged subarachnoid space. Our results suggest that enlarged subarachnoid space can be associated with some subdural collections in this cohort. Despite this, we believe that unexpected subdural collections in children should receive close clinical evaluation for underlying causes, including abusive head trauma.

Subdural hemorrhage in pediatric patients with enlargement of the subarachnoid spaces

OBJECT

Enlargement of the subarachnoid spaces has been theorized as a risk factor for the development of subdural hemorrhage (SDH). As the finding of unexplained SDH in children often raises suspicion for nonaccidental trauma, the possibility of increased risk of SDH in children with enlargement of the subarachnoid spaces has important clinical, social, and legal implications. Therefore, the authors evaluated the frequency of SDH in a cohort of children with enlargement of the subarachnoid spaces.

METHODS

The authors identified children younger than 2 years of age who were diagnosed with enlargement of the subarachnoid spaces on MRI or CT scanning in a large primary care network between July 2001 and January 2008. The authors excluded children who had enlargement of the subarachnoid spaces diagnosed on imaging performed for trauma or developmental delay, as well as children with a history of prematurity, diagnosis of intracranial pathology, or metabolic or genetic disorders. Chart review recovered the following data: patient demographics, head circumference, history of head trauma, and head imaging results. For the subset of children with SDH, information regarding evaluation for other injuries, including skeletal survey, ophthalmological examination, and child protection team evaluation, was abstracted.

RESULTS

There were 177 children with enlargement of the subarachnoid spaces who met the inclusion criteria. Subdural hemorrhage was identified in 4 (2.3%) of the 177 children. All of the children with SDH underwent evaluations for suspected nonaccidental trauma, which included consultation by the child protection team, skeletal survey, and ophthalmological examination. Additional injuries (healing rib fractures) were identified in 1 of 4 patients. None of the 4 children had retinal hemorrhages. Only the child with rib fractures was reported to child protective services due to concerns for abuse.

CONCLUSIONS

Only a small minority of the patients with enlargement of the subarachnoid spaces had SDH. Evidence of additional injuries concerning for physical abuse were identified in a quarter of the children with enlargement of the subarachnoid spaces and SDH, suggesting that an evaluation for suspected nonaccidental trauma including occult injury screening should be performed in cases of SDH with enlargement of the subarachnoid spaces. In the absence of additional injuries, however, the presence of an unexplained SDH in the setting of enlargement of the subarachnoid spaces may be insufficient to support a diagnosis of nonaccidental trauma.

Predisposition to subdural hemorrhage in X-linked myotubular myopathy

X-linked myotubular myopathy is a severe congenital myopathy that can involve multiple organs. We report on a 10-month-old boy who manifested X-linked myotubular myopathy with subdural hemorrhage. The diagnosis of X-linked myotubular myopathy was based on typical muscle pathology and MTM1 missense mutation. The patient had undergone no traumatic episodes or bleeding diathesis. Axial growth acceleration is known to occur in X-linked myotubular myopathy, potentially leading to dolichocephaly. In our patient, an enlarged subdural space apparently stretched the bridging veins, increasing susceptibility to subdural hemorrhage. Patients who manifest X-linked myotubular myopathy with typical dolichocephaly are at increased risk for subdural hemorrhage.

Diffusion tensor imaging findings in young children with benign external hydrocephalus differ from the normal population

PURPOSE

To compare a pediatric population diagnosed with benign external hydrocephalus (BEH) to normal age-matched controls using diffusion tensor imaging (DTI) techniques.

METHODS

We retrospectively identified 17 BEH patients by specific clinical and neuroimaging criteria. Fractional anisotropy (FA) and mean diffusivity (MD) values obtained from DTI scans were compared to a population of age-matched controls and group differences were examined by mixed model analysis. A longitudinal comparison was completed on a subset that underwent multiple scans (n = 8).

RESULTS

In the genu of the corpus callosum (gCC), six of 15 BEH children had an FA value above the upper limit of 95% prediction interval, nine of 15 BEH children had MD values below the lower limit of 95% prediction interval. A similar trend applied to the other regions of interest (ROIs): splenium of the corpus callosum (sCC), ALIC, and PLIC. Statistical analysis demonstrated significant differences in FA within the gCC, sCC, and PLIC and in MD within the sCC between BEH patients and controls given (P = 0.05). No statistical differences were identified at any ROIs at the later scans.

CONCLUSIONS

We found a significant increase in FA and decrease in MD in children with BEH compared with normal children in specific white matter (WM) ROIs, notably in the gCC and sCC; furthermore, in longitudinal comparison, DTI parameters normalized over time. The current study further demonstrates the ability of DTI to distinguish between subtle diffusion changes in periventricular white matter and establishes preliminary objective radiographic parameters for watchful observation of patients with BEH.

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.

Subdural hematoma in infants without accidental or nonaccidental injury: benign external hydrocephalus, a risk factor

Benign external hydrocephalus (BEH) is considered a self-limiting condition in infants. Subdural hematoma (SDH) in infants without a history of trauma indicates nonaccidental injury (NAI). The authors studied whether SDH can complicate BEH without apparent trauma. Out of 45 children younger than 3 years with nontraumatic SDH, 9 (7 boys) with mean age 6 months had BEH as risk factor. Symptoms included increasing head size (8), fussiness, and irritability (3). Three had up-gaze restriction, 1 axial hypotonia, and 6 normal examination. Neuroimaging showed prominent extra-axial spaces; SDH was bilateral (6), subacute (5). Other etiological workup for SDH was negative except NAI in 1. Two required evacuation of SDH and subdural-peritoneal shunt; others managed conservatively. Development was normal in 8 on follow-up. On follow-up imaging of 8, SDH completely resolved in 3, markedly reduced in 3, and remained stable in 2. BEH is a risk factor for SDH in infants, thus not always benign.

Benign external hydrocephalus: a review, with emphasis on management

Benign external hydrocephalus in infants, characterized by macrocephaly and typical neuroimaging findings, is considered as a self-limiting condition and is therefore rarely treated. This review concerns all aspects of this condition: etiology, neuroimaging, symptoms and clinical findings, treatment, and outcome, with emphasis on management. The review is based on a systematic search in the Pubmed and Web of Science databases. The search covered various forms of hydrocephalus, extracerebral fluid, and macrocephaly. Studies reporting small children with idiopathic external hydrocephalus were included, mostly focusing on the studies reporting a long-term outcome. A total of 147 studies are included, the majority however with a limited methodological quality. Several theories regarding pathophysiology and various symptoms, signs, and clinical findings underscore the heterogeneity of the condition. Neuroimaging is important in the differentiation between external hydrocephalus and similar conditions. A transient delay of psychomotor development is commonly seen during childhood. A long-term outcome is scarcely reported, and the results are varying. Although most children with external hydrocephalus seem to do well both initially and in the long term, a substantial number of patients show temporary or permanent psychomotor delay. To verify that this truly is a benign condition, we suggest that future research on external hydrocephalus should focus on the long-term effects of surgical treatment as opposed to conservative management.

Imaging of nonaccidental injury and the mimics: issues and controversies in the era of evidence-based medicine

Because of the controversy involving the determination of child abuse, or nonaccidental injury (NAI), radiologists must be familiar with the issues, literature, and principles of evidence-based medicine to understand the role of imaging. Children with suspected NAI must receive protective evaluation along with a timely and complete clinical and imaging work-up. Imaging findings cannot stand alone and must be correlated with clinical findings, laboratory testing, and pathologic and forensic examinations. Only the child protection investigation may provide the basis for inflicted injury in the context of supportive clinical, imaging, biomechanical, or pathology findings.

Long-term health status in benign external hydrocephalus

PURPOSE

Benign external hydrocephalus (BEH) is characterized by excess cerebrospinal fluid in the frontal subarachnoid spaces in infants evaluated for macrocephaly. We sought to describe the natural history of this disorder, specifically its clinical presentation, disease course and long-term health status impact using the validated, disease-specific Hydrocephalus Outcome Questionnaire (HOQ).

METHODS

An inception cohort of children >5 and <18 years old, with a history of BEH was assembled by ICD-9 and a key word search of medical and radiology records. Review confirmed the diagnosis of BEH, excluded major medical comorbidities and assessed presentation, radiographic features and head size/growth velocity. The HOQ was administered by mail.

RESULTS

We identified 99 patients, 5-12 years old (55% males). Twenty were born prematurely, 12 with <33 weeks gestation. Children presented at an average age of 9 ± 4.8 months (mean ± SD). The presenting complaint was macrocephaly in 65 cases. Other presenting findings were positional head shape deformity and torticollis; 10% had a family history of macrocephaly. Developmental delay was present in 21% of patients (4% verbal, 20% gross motor, 4% fine motor delay). Four patients had small subdural hematomas, none with suspicion of a non-accidental trauma. During clinical reassessment over a mean follow-up of 13 months, the average head percentile was stable and none of the patients developed new subdural hematomas. Gross motor delay resolved in 15/20 and fine motor delay in 4/4 patients. Verbal delay resolved in 2/4 patients, but interestingly, was newly detected in 6 other children. None of the patients required cerebrospinal fluid shunting. The response rate to the HOQ was 25% (median age 7 years, 74% females). The average overall HOQ score was 0.75 ± 0.24 versus 0.68 ± 0.19 for a previously published cohort of shunted hydrocephalic children.

CONCLUSIONS

BEH patients in this series generally saw resolution of presenting motor developmental delays; however, new verbal delays were detected in a non-trivial number of patients. Quality of life measurements suggest some reduction in health status, but less so than is seen with shunted hydrocephalus.

Subdural hematoma in infants: can it occur spontaneously? Data from a prospective series and critical review of the literature

BACKGROUND

Subdural hematomas (SDH) in infants often result from nonaccidental head injury (NAHI), which is diagnosed based on the absence of history of trauma and the presence of associated lesions. When these are lacking, the possibility of spontaneous SDH in infant (SSDHI) is raised, but this entity is hotly debated; in particular, the lack of positive diagnostic criteria has hampered its recognition. The role of arachnoidomegaly, idiopathic macrocephaly, and dehydration in the pathogenesis of SSDHI is also much discussed.

PURPOSE

We decided to analyze apparent cases of SSDHI from our prospective databank.

MATERIALS AND METHODS

We selected cases of SDH in infants without systemic disease, history of trauma, and suspicion of NAHI. All cases had fundoscopy and were evaluated for possible NAHI. Head growth curves were reconstructed in order to differentiate idiopathic from symptomatic macrocrania.

RESULTS

Sixteen patients, 14 males and two females, were diagnosed with SSDHI. Twelve patients had idiopathic macrocrania, seven of these being previously diagnosed with arachnoidomegaly on imaging. Five had risk factors for dehydration, including two with severe enteritis. Two patients had mild or moderate retinal hemorrhage, considered not indicative of NAHI. Thirteen patients underwent cerebrospinal fluid drainage. The outcome was favorable in almost all cases; one child has sequels, which were attributable to obstetrical difficulties.

CONCLUSION

SSDHI exists but is rare and cannot be diagnosed unless NAHI has been questioned thoroughly. The absence of traumatic features is not sufficient, and positive elements like macrocrania, arachnoidomegaly, or severe dehydration are necessary for the diagnosis of SSDHI.

Infant craniospinal ultrasonography: beyond hemorrhage and hydrocephalus

Ultrasonography is widely used for screening for neonatal intracranial hemorrhage, hydrocephalus, and cord tethering in young infants. Proper interpretation of infant cranial and spinal ultrasound examinations requires not only familiarity with the appearances of these disorders, but also recognition of imaging artifacts capable of mimicking pathology and awareness of developmental variants and conditions that occupy a borderline position along the spectrum from normal to abnormal. This article will review the current understanding of the ultrasonographic characteristics and clinical relevance of these imaging artifacts, developmental variants, and quasi-pathologic conditions to avoid diagnostic pitfalls and guide appropriate patient management.

Natural history of traumatic meningeal bleeding in infants: semiquantitative analysis of serial CT scans in corroborated cases

BACKGROUND

The natural history of posttraumatic meningeal bleeding in infants is poorly documented, and the differences between inflicted head injury (IHI) and accidental trauma (AT) are debated. Autopsy findings have suggested that anoxia also plays a role in bleeding; however, these findings may not reflect what occurs in live trauma patients.

PURPOSE

We studied the natural history of traumatic meningeal bleeding in infants using serial computed tomography (CT) scans in corroborated IHI and AT.

MATERIALS AND METHODS

From our prospective series, we selected corroborated cases (confessed IHI or AT having occurred in public), who underwent at least three CT scans in the acute phase. We performed a semiquantitative analysis of meningeal bleeding using a four-tier scale (absent, faint, frank, and thick) derived from the Fisher grading for aneurysmal bleeding in four regions of interest (convexity, falx cerebri, sagittal sinus, and tentorium cerebelli).

RESULTS

We studied 20 cases: ten IHI and ten AT. Bleeding was maximal at the convexity initially, then increased along the falx and sagittal sinus, and then along the tentorium. Decrease and disappearance of blood was variable according to the site and the initial quantity of blood. We found no difference between IHI and AT.

CONCLUSION

Our findings suggest that the primary site of meningeal bleeding in infantile head trauma is the convexity of the brain; blood cells then migrate toward the midline following the flow of cerebrospinal fluid circulation and inferiorly following gravity. The pattern of bleeding in traumatic cases appears similar in IHI and AT but different from anoxic lesions.

Dynamics of subdural hygroma following decompressive craniectomy: a comparative study

Object

This retrospective comparative cohort study was aimed at discovering the risk factors associated with subdural hygroma (SDG) following decompressive craniectomy (DC) to relieve intracranial hypertension in severe head injury.

Methods

Sixty-eight of 104 patients who had undergone DC during a 48-month period and survived > 30 days were eligible for this study. To assess the dynamics of subdural fluid collections, the authors compared CT scanning data from and the characteristics of 39 patients who had SDGs with the data in 29 patients who did not have hygromas. Variables significant in the appearance, evolution, and resolution of this complication were analyzed in a 36-week longitudinal study.

Results

The earliest imaging evidence of SDG was seen during the 1st week after DC. The SDG volume peaked between Weeks 3 and 4 post-DC and was gradually resolved by the 17th week. Among the mechanisms of injury, motor vehicle accidents were most often linked to the development of an SDG after DC (p < 0.0007), and falls were least often associated (p < 0.005). Moreover, patients with diffuse brain injury were more prone to this complication (p < 0.0299) than those with an evacuated mass (p < 0.0001). There were no statistically significant differences between patients with and without hygromas in terms of age, sex, Glasgow Coma Scale score, intraventricular and subarachnoid hemorrhage, levels of intracranial pressure and cerebral perfusion pressure, timing of decompression, and the need for CSF diversion. More than 90% of the SDGs were ipsilateral to the side of the craniectomy, and 3 (8%) of 39 SDGs showed evidence of internal bleeding at ~ 8 weeks postinjury. Surgical evacuation was needed in 4 patients with SDGs.

Conclusions

High dynamic accidents and patients with diffuse injury were more prone to SDGs. Close to 8% of SDGs converted themselves into subdural hematomas at ~ 2 months postinjury. Although SDGs developed in 39 (~ 60%) of 68 post-DC patients, surgical evacuation was needed in only 4.

Benign extracerebral fluid collections in infancy: clinical presentation and long-term follow-up

OBJECT

Benign extracerebral fluid collections are common in infants, but there are unanswered questions regarding presentation and long-term outcome. This study was undertaken to establish head size at birth, head size at presentation, head growth over time, history of presentation, indications for surgery, and long-term results.

METHODS

Cases of benign extracerebral fluid collections in infancy were retrospectively reviewed. Data pertaining to clinical presentation, progress, and long-term follow-up were evaluated. Patients were divided into two groups on the basis of the presence or absence of increased signal intensity of fluid in the extracerebral space on T1-weighted magnetic resonance images. Group 1 consisted of 39 patients who had benign extracerebral fluid collections without any subdural collections. Group 2 consisted of nine patients who had a chronic subdural hematoma or hygroma without a history of trauma and had generous subarachnoid spaces and/or a history of premature birth. Patients were observed for an average of 49 months.

RESULTS

Group 1 included 39 patients (ages at presentation 3-12 months); the most common presentation in this group was macrocephaly (28 cases). Of those Group 1 cases in which data regarding gestational age at birth were available, 15 births were either severely or mildly premature and 14 were full term. Of those Group 1 patients with adequate data, 14 had an occipitofrontal circumference (OFC) in the 50th to 98th percentile at birth and two had OFCs greater than the 98th percentile. Measurements obtained at 24 months of age were available for 18 Group 1 patients: OFC was at approximately the 98th percentile in eight (all eight born at full term) and more than 1 cm larger than the 98th percentile in 10. Head growth in Group 1 patients continued to decrease, approaching the 98th percentile after 24 months of age. Only three of the 39 patients in Group 1 required shunt placement. Of the 33 Group 1 patients for whom long-term follow-up was available, 30 were developing normally, and three had mild developmental delays. Group 2 included nine patients (ages at presentation 3-7 months); the most common presentations were large head (three patients) and seizures (three patients). Data concerning gestational age at birth were available in eight Group 2 cases: birth was severely premature in four and gestation was full term in four. Five Group 2 patients were treated surgically-two with subduroperitoneal (SDP) shunt placement, two with subdural punctures, and one with subdural punctures and SDP shunt placement. Adequate follow-up information was available in eight of nine Group 2 cases; all eight patients were found to be developing normally.

CONCLUSIONS

Group 1 patients usually had a normal head size at birth, they rarely required shunt placement, their head growth eventually leveled off toward the 98th percentile line, and their outcomes were generally good. Although five of nine Group 2 patients required subdural punctures and/or SDP shunt placement, that group of patients also developed well. Infants with nontraumatic subdural hematomas or hygromas, presumably associated with benign extracerebral fluid collections, can often experience significant resolutions of the hematoma or hygroma within several months without surgical treatment.

Nonaccidental head trauma in infants

BACKGROUND

Nonaccidental head trauma in infants is the leading cause of infant death from injury.

RESULTS AND DISCUSSION

Clinical features that suggest inflicted head trauma include the triad of the so-called shaken baby syndrome, consisting of retinal hemorrhage, subdural, and/or subarachnoid hemorrhage in an infant with little signs of external trauma. Studies have shown that, in general, the average short fall in the home is extremely unlikely to produce either subdural or retinal hemorrhage, although focal injuries such as skull fractures and epidural hemorrhage may be seen. Acceleration/deceleration, especially of the rotational type, is believed to be the most probable mechanism of injury in cases of nonaccidental head trauma. Damage to the cervicomedullary junction and the respiratory centers, with subsequent hypoxia and intracerebral edema, has also been implicated. After the initial trauma and hemorrhage, loss of cerebral autoregulation, breakdown of the blood-brain barrier, and disruption of ionic homeostasis occur, leading to brain edema and cytotoxicity. Cellular damage can involve large volumes of tissue, without respecting vascular territories.

CONCLUSION

Overall, a satisfactory biomechanical model is lacking, and the criminal nature of abusive injury makes it difficult to perform systematic, controlled studies. Unfortunately, outcomes are poor, and the rate of repeated abusive episodes is high. Future research should focus on the development of a satisfactory research model and on prevention strategies.

Imaging of the central nervous system in suspected or alleged nonaccidental injury, including the mimics

Because of the widely acknowledged controversy in nonaccidental injury, the radiologist involved in such cases must be thoroughly familiar with the imaging, clinical, surgical, pathological, biomechanical, and forensic literature from all perspectives and with the principles of evidence-based medicine. Children with suspected nonaccidental injury versus accidental injury must not only receive protective evaluation but also require a timely and complete clinical and imaging workup to evaluate pattern of injury and timing issues and to consider the mimics of abuse. All imaging findings must be correlated with clinical findings (including current and past medical record) and with laboratory and pathological findings (eg, surgical, autopsy). The medical and imaging evidence, particularly when there is only central nervous system injury, cannot reliably diagnose intentional injury. Only the child protection investigation may provide the basis for inflicted injury in the context of supportive medical, imaging, biomechanical, or pathological findings.

Inflicted traumatic brain injury: advances in evaluation and collaborative diagnosis

The determination that a traumatic brain injury is not accidental requires data collection from multiple domains: historical, clinical, laboratory, radiographic, environmental and psychosocial. These essential, yet disparate, types of information must be synthesized in a collaborative and interdisciplinary process to formulate a medical opinion with regard to the cause of an injury, and the final opinion has tremendous consequences for children and families. Medically directed child protection teams have emerged as the standard of care in many children's hospitals and child abuse pediatrics is now a recognized medical subspecialty with board certification available in the next several years. Not only do the child and family benefit from this coordinated effort, but there are also great benefits for the members of the child protection team: more clearly defined responsibilities, redirected focus on treatment for the surgeon, and increased confidence that the opinion is based upon consensus and current scientific knowledge. By this process and its division of labor, the child abuse pediatrician assumes responsibility for ensuring that a final medical opinion is arrived at, and then advocates for appropriate disposition for the child. The child abuse pediatrician is responsible for establishing institutional standards for family evaluation, collecting all necessary medical data and directing a consensus-based decision making process that is based upon current medical knowledge, medical literature and experience. The child abuse pediatrician also assumes the role of primary communication conduit for investigational agencies and the courts. The neurosurgeon is a key member of the child protection team and relies on the team to obtain necessary historical information to address consistency of the mechanism with the sustained injuries and has an integral role in determining the team's final opinion. An interdisciplinary response to inflicted traumatic brain injury is the cornerstone for establishing a rigorous standard of care; it also fosters education across medical subspecialties where controversy has been a significant part of the landscape. Valid and useful clinical research that describes head injury as accidental or inflicted can only be performed in the context of an interdisciplinary, medically directed child protection team that strives for objectivity and precision in the determination of the manner of an injury.

Diagnostic method for differentiating external hydrocephalus from simple subdural hygroma

Object

The various terms used to describe subdural fluid collection—“external hydrocephalus,” “subdural hygroma,” “subdural effusion,” “benign subdural collection,” and “extraventricular obstructive hydrocephalus”—reflect the confusion surrounding the diagnoses of these diseases. Differentiating external hydrocephalus from simple subdural hygroma may be difficult, but the former appears to be a distinct clinical entity separate from the latter. In this report, the authors present a diagnostic method for differentiating external hydrocephalus from simple subdural hygroma, based on their clinical experience in treating subdural fluid collection after mild head trauma.

Methods

Twenty patients with subdural fluid collection after mild head trauma were included in this study. Ventricle size was measured using a modified frontal horn index (mFHI); that is, the largest width of the frontal horns divided by the bicortical distance in the same plane, instead of the inner table distance. Bur hole trephination was performed on the appearance of a subdural fluid collection thicker than 15 mm on computed tomography (CT), persistent (longer than 4 weeks) or increasing in size, and accompanied by neurological symptoms (confusion or memory impairment). During the procedure, subdural pressure was measured using a manometer before opening the dura mater. Subdural pressure varied among the patients, ranging from 3 to 27.5 cm H2O. Four patients with a subdural pressure greater than 15 cm H2O had hydrocephalus after surgery (p < 0.05). Hydrocephalus developed in a pediatric patient (2 years old) with a subdural pressure of 12 cm H2O. All of the patients in whom hydrocephalus developed after bur hole trephination had had enlarged ventricles (mFHI > 33%) on preoperative CT scans.

Conclusions

Monitoring subdural pressure may be a valuable tool for differentiating subdural hygroma from external hydrocephalus in patients with mild head trauma. Additionally, the mFHI reflects the nature of the subdural collection more accurately than the standard frontal horn index.