When is enlargement of the subarachnoid spaces not benign? A genetic perspective

Subdural Hemorrhage as an Early Presentation in a Case of Sotos Syndrome

Subdural hemorrhages (SDHs) in the pediatric population are associated with a high mortality and morbidity and may present in the context of abusive head trauma. Diagnostic investigations for such cases often include evaluation for rare genetic and metabolic disorders that can have associated SDH. Sotos syndrome is an overgrowth syndrome associated with macrocephaly and increased subarachnoid spaces and rarely with neurovascular complications. Here, we report two cases of Sotos syndrome, one with SDH during infancy who underwent repeated evaluation for suspected child abuse prior to the Sotos syndrome diagnosis and the other with enlarged extra-axial cerebrospinal fluid spaces, demonstrating a possible mechanism for SDH development in this setting. These cases suggest that some individuals with Sotos syndrome may be at elevated risk of developing SDH in infancy and that Sotos syndrome should be on the differential diagnosis during a medical genetics evaluation in cases of unexplained SDH, especially in the setting of macrocephaly.

Neurodevelopmental profile in children with benign external hydrocephalus syndrome. A pilot cohort study

PURPOSE

The management of children with benign external hydrocephalus (BEH) remains controversial. Most BEH children do well in the long-term, but a substantial number have temporary or permanent psychomotor delays. The study aims to assess the prevalence and pattern of neurodevelopmental delay in a cohort of children with BEH.

METHODS

We conducted a cohort study of 42 BEH children (30 boys and 12 girls, aged 6 to 38 months). A pediatric neurosurgeon performed a first clinical evaluation to confirm/reject the diagnosis according to the clinical features and neuroimaging studies. Two trained evaluators assessed the child's psychomotor development using the third edition of the Bayley Scales of Infant and Toddler Development (Bayley-III). Developmental delay was defined as a scaled score < 7 according to the simple scale and/or a composite score < 85.

RESULTS

Eighteen children (43%) presented statistically lower scores in the gross motor and composite motor of the Bayley-III scales compared to their healthy peers.

CONCLUSION

In BEH, it is important to establish a diagnostic algorithm that helps to discriminate BEH patients that have self-limiting delays from those at risk of a persistent delay that should be referred for additional studies and/or interventions that might improve the natural evolution of a disease with high impact on the children and adult's quality of life.

Transmantle and transvenous pressure gradients in cerebrospinal fluid disorders

Hydrocephalus is the symptomatic endpoint of a variety of disease processes. Simple hydrodynamic models have failed to explain the entire spectrum of cerebrospinal fluid (CSF) disorders. Physical principles argue that for ventricles to expand, they must be driven by a force, Fishman's transmantle pressure gradient (TMPG). However, the literature to date, reviewed herein, is heterogenous and fails to consistently measure a TMPG. The venous system, like CSF, traverses the cerebral mantle, and thus analogous transparenchymal and transvenous pressure gradients have been described, reliant on the differential haemodynamics of the deep and superficial venous systems. Interpreting CSF disorders through these models provides new insights into the possible pathophysiological mechanisms underlying these diseases. However, until more sophisticated testing is performed, these models should remain heuristics.

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.

Evaluation of fetal subarachnoid space using transabdominal ultrasonography and normal values during pregnancy

Objectives

To determine the feasibility of evaluating the subarachnoid space by measuring two novel sonographic parameters in axial section using transabdominal ultrasound, in addition to the parameters previously defined in coronal section, and to construct a normal range for the subarachnoid space width in singleton healthy fetuses.

Methods

Healthy pregnant women between 20 and 29 weeks were scanned using transabdominal ultrasound. Four variables were measured for the evaluation of subarachnoid space width; sinocortical width and anterior craniocortical width in coronal plane, and lateral and posterior craniocortical width in axial plane.

Result

The data of 154 patients were recorded. SCW could be measured in 87.6 % (135) of fetuses, while the same figure was 77.9 % (120), 96.1 % (151) and 98.1 % (148) for anterior, lateral and posterolateral CCW, respectively. The SCW and anterior CCW did not display a significant correlation with gestational age and head circumference. The mean of SCW was 1.55 ± 0.41 mm with a range of 0.85–3.87 mm. The mean anterior CCW was 1.63 ± 0.39 mm with a range of 0.85–2.82 mm. A linear regression line was plotted between gestational age and lateral CCW (r = 0.707; p < 0.0001) and posterolateral CCW (r = 0.437; p < 0.0001), and nomograms for these parameters are constructed.

Conclusion

This study presents a novel approach for the in utero evaluation of the subarachnoid space with two measurements in axial plane using transabdominal ultrasound. The nomograms will be helpful when there is a suspicion of subarachnoid space dilatation during routine cranial scan.

The value of head circumference measurements after 36 months of age: a clinical report and review of practice patterns

OBJECT The cranium is documented to grow from birth through adolescence. The standard of practice in primary care is measuring head circumference and plotting growth using curves that stop at 36 months. The authors report the importance of their experience with measuring head circumference in the child and same-sex parent beyond 36 months. METHODS In the University of Florida genetics and pediatric neurosurgery clinics, head circumference is measured and plotted on growth charts through 18 years of age. Circumference and rate of growth over time are compared with those of the same-sex parent. A diagnostic workup is initiated if there is a discrepancy with the patient's head circumference or if there is significant change in the growth rate of the cranium. RESULTS Between January 2004 and December 2007, the lead author examined 190 patients referred by pediatricians and/or pediatric subspecialists because of the concerns regarding head size of the child. Neuroimaging was performed in 70% of the patients prior to referral. None of the patients had their head size compared with that of their same-sex parent prior to referral. On assessing referring physician responses as to why the same-sex parents, head measurements were not pursued prior to imaging or referral to the specialists, the results were: 1) only have head circumference sheets to 36 months of age (n = 28); 2) the American Academy of Pediatrics does not recommend it (n = 3); and 3) the head stops growing at 36 months of age (n = 2). CONCLUSIONS Pediatricians and pediatric subspecialists need instruction on head circumference measurement in children from infancy through adolescence, and when indicated, in comparison with the head size of the same-sex parent. This measurement may be an effective and inexpensive assessment tool.

Development of Infants With Idiopathic External Hydrocephalus

External hydrocephalus in an infant is a condition in which the rate of growth of head circumference exceeds the expectations of the Nellhouse curve together with increased size of the subarachnoid spaces. Developmental milestones of 20 infants (aged 0-16 months) with external hydrocephalus were studied by the Mullen Scales of Early Learning. The areas of development that were studied were visual reception, fine motor, expressive language, receptive language, and total Mullen score. There were no significant differences between the study group and the general population in all 5 scores. The only prominent feature of our external hydrocephalus patients was hypotonia (transient in 9 [45%] and persistent in 2 [10%]). Although the term external hydrocephalus describes a roentgenographic presentation, the term benign enlargement of subarachnoid space is preferred in infants similar to our group by better describing the benign nature of the phenomenon in appropriately selected infants.

Incidental findings on brain and spine imaging in children

In recent years, the utilization of diagnostic imaging of the brain and spine in children has increased dramatically, leading to a corresponding increase in the detection of incidental findings of the central nervous system. Patients with unexpected findings on imaging are often referred for subspecialty evaluation. Even with rational use of diagnostic imaging and subspecialty consultation, the diagnostic process will always generate unexpected findings that must be explained and managed. Familiarity with the most common findings that are discovered incidentally on diagnostic imaging of the brain and spine will assist the pediatrician in providing counseling to families and in making recommendations in conjunction with a neurosurgeon, when needed, regarding additional treatments and prognosis.

Infantile hydrocephalus: a review of epidemiology, classification and causes

Hydrocephalus is a common but complex condition caused by physical or functional obstruction of CSF flow that leads to progressive ventricular dilatation. Though hydrocephalus was recently estimated to affect 1.1 in 1000 infants, there have been few systematic assessments of the causes of hydrocephalus in this age group, which makes it a challenging condition to approach as a scientist or as a clinician. Here, we review contemporary literature on the epidemiology, classification and pathogenesis of infantile hydrocephalus. We describe the major environmental and genetic causes of hydrocephalus, with the goal of providing a framework to assess infants with hydrocephalus and guide future research.

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.

Intracranial pressure measurement in infants presenting with progressive macrocephaly and enlarged subarachnoid spaces

INTRODUCTION

For subarachnomegaly in infants with enlarged external and internal CSF spaces clear treatment decisions, such as observation or ventriculo-peritoneal (VP) shunting, are still lacking. The aim of this study is to measure intracranial pressure (ICP) in these patients to elucidate treatment necessity.

MATERIALS AND METHODS

Seven children presenting with macrocephaly, moderately enlarged ventricles, and subarachnoid spaces on magnetic resonance imaging (MRI) without neurological deficits or other CSF-associated pathological conditions were enrolled. Continuous ICP recording was conducted using an external ventricular drain. Data recordings during overnight measurements were analyzed offline to calculate baseline, mean ICP values, and a histogram distribution.

RESULTS

Mean age at enrollment was 9.4 months (2-22 months). ICP monitoring was conducted for 2.7 ± 1.1 nights (range 2-5 nights) and revealed baseline values above 10 mmHg in three patients, who went on to receive a VP shunt. One patient with average values over 10 mmHg also underwent VP shunting. Three patients displayed both baseline and average ICP values of less than 10 mmHg. Observational management was chosen for this subgroup. Comparing shunted versus the non-shunted group in a histogram analysis the percentages of recorded ICP values above 8, 10, and 15 mmHg were significantly different (p < 0.05).

CONCLUSION

Subarachnomegaly in infants remains a dilemma to the treating neurosurgeon. Risks and benefits of observational management options need to be weighed against those of VP shunting. Continuous ICP monitoring may help to identify patients who may potentially benefit from the surgical treatment option.

Neuroimaging findings in patient series with mucopolysaccharidosis

INTRODUCTION

Mucopolysaccharidoses (MPS) are a group of inherited disorders due to lysosomal enzyme deficiencies. The aims of this study are to describe the neuroimaging findings in children evaluated in our hospital with this diagnosis, looking for a possible correlation of these alterations with the type of MPS and clinical severity, and finally to compare these findings with those previously reported.

MATERIAL AND METHODS

We retrospectively analysed the medical records of 19 patients who had been diagnosed with MPS between 1992 and 2010: 7 had type I (5 with Hurler syndrome and 2 with Hurler-Scheie syndrome), 10 had type II or Hunter syndrome (4 with the severe form and 6 with the mild form), 1 had type III or Sanfilippo syndrome and 1 had type VI or Maroteaux-Lamy syndrome. We assessed the brain neuroimaging studies: computed axial tomography (CAT) in 5 patients, and magnetic resonance imaging (MRI) in 15.

RESULTS

We observed a broad spectrum of neuroimaging anomalies. In CAT: mega cisterna magna (3/5, 60%). In brain MRI: dilated Virchow-Robin perivascular spaces (11/15, 73%), white matter abnormalities (11/15, 73%), and ventriculomegaly (5/15, 33%).

CONCLUSIONS

Abnormal findings in neuroimaging studies are frequent in MPS (dilated Virchow-Robin perivascular spaces, white matter abnormalities and ventriculomegaly). Thus, given these abnormalities we should be aware of this possible diagnosis, particularly when typical signs and symptoms are present. However, we did not find a correlation between these findings and either any specific type of MPS or clinical severity.

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.

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.

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.