Imaging and health metrics in Incidental Cerebellar Tonsillar Ectopia: Findings from the Adolescent Brain Cognitive Development Study (ABCD)

Purpose. Incidental cerebellar tonsillar ectopia (ICTE) that meets the radiographic criterion for Chiari malformation type I (CMI) is an increasingly common finding in the clinical setting, but its significance is unclear. The present study examined posterior cranial fossa (PCF) morphometrics and a broad range of health instruments of pediatric ICTE cases and matched controls extracted from the Adolescent Brain Cognitive Development (ABCD) dataset. Methods. 106 subjects with ICTE and 106 matched controls without ICTE were identified from 11,411 anatomical MRI of healthy screened pediatric subjects from the ABCD project. Subjects were matched by sex, age, body mass index, race, and ethnicity. Twenty-two brain morphometrics and 22 health instruments were compared between the two groups to identify unrecognized CMI symptoms and assess the general health impact of ICTE. Results. Twelve and 15 measures were significantly different between the ICTE and control groups for females and males, respectively. Notably, for females, the anterior CSF space was significantly smaller (p = 0.00005) for the ICTE group than controls. For males, the clivus bone length was significantly shorter (p = 0.0002) for the ICTE group compared to controls. No significant differences were found among the 22 health instruments between the two groups. Conclusion. This study demonstrated that pediatric ICTE subjects have similar PCF morphometrics to adult CMI. ICTE alone did not appear to cause any unrecognized CMI symptoms and had no impact on the subjects' current mental, physical, or behavioral health. Still, given their cranial and brain morphology, these cases may be at risk for adult-onset symptomatic CMI.

Pyramidal and Proprioceptive Dysfunctions as the Main Neurologic Features In Symptomatic Type I Chiari Malformation Patients

Objective Broader access to magnetic resonance imaging (MRI) has increased the diagnosis of tonsillar ectopia, with most of these patients being asymptomatic. The early diagnosis and treatment of type I Chiari malformation (CM I) patients has impact on the prognosis. This study supplements information about the neurologic exam of symptomatic patients with CM I. Methods The sample was composed of 32 symptomatic patients with CM I diagnosed by a combination of tonsil herniation of more than 5 mm below the magnum foramen (observed in the sagittal T2 MRI) and at least one of the following alterations: intractable occipital headache, ataxia, upper or lower motor neuron impairment, sensitivity deficits (superficial and deep) or lower cranial nerves disorders. Results Occipital headache was the most frequent symptom (53.12%). During the physical exam, the most common dysfunctions were those from the pyramidal system (96.87%), followed by posterior cord syndrome (87.5%). Discussion In this study, patients became symptomatic around the fifth decade of life, which is compatible with previous descriptions. Patients with more than 2 years of evolution have worse responses to treatment. Occipital headache, symptoms in the upper limbs, gait and proprioceptive disorders are common findings in patients with CM I. Conclusion Deep tendinous reflexes and proprioception disorders were the main neurologic features found in symptomatic CM I patients.

Epidemiology of Symptomatic Chiari Malformation in Tatarstan: Regional and Ethnic Differences in Prevalence

BACKGROUNDEpidemiology can assess the effect of Chiari I malformation (CM1) on the neurological health of a population and evaluate factors influencing CM1 development.OBJECTIVETo analyze the regional and ethnic differences in the prevalence of CM1.METHODSThe population of the Republic of Tatarstan (RT) in the Russian Federation was evaluated for patients with CM1 symptoms over an 11-yr period. Typical symptoms of CM1 were found in 868 patients. Data from neurological examination and magnetic resonance imaging (MRI) measurement of posterior cranial fossa structures were analyzed.RESULTSMRI evidence of CM1, defined as cerebellar tonsils lying at least 5 mm inferior to the foramen magnum, was found in 67% of symptomatic patients. Another 33% of symptomatic patients had 2 to 4 mm of tonsillar ectopia, which we defined as “borderline Chiari malformation type 1 (bCM1).” The period prevalence in the entire RT for symptomatic CM1 was 20:100 000; for bCM1 was 10:100 000; and for CM1 and bCM1 together was 30:100 000. Prevalence of patients with CM1 symptoms was greater in the northern than southern districts of Tatarstan, due to a high prevalence (413:100 000) of CM1 in the Baltasy region in one of the northern districts.CONCLUSIONOne-third of patients with typical symptoms of CM1 had less than 5 mm of tonsillar ectopia (bCM1). Assessments of the health impact of CM1-type symptoms on a patient population should include the bCM1 patient group. A regional disease cluster of patients with Chiari malformation was found in Baltasy district of RT and needs further study.

Traumatic Transient Herniation Concomitant with Tonsillar Hemorrhagic Contusion in a Child

Downward displacement of cerebellar tonsils more than 5 mm below the foramen magnum is named as Chiari type I malformation and named benign tonsillar ectopia if herniation is less than 3 mm. It does not just depend on congenital causes. There are also some reasons for acquired Chiari Type 1 and benign tonsillar ectopia/herniation. Trauma is one of them. Trauma may increase tonsillar ectopia or may be the cause of new-onset Chiari type 1. The relationship between the tonsil contusion and its position is unclear. We present a case of pediatric age group with tonsillar herniation with a hemorrhagic contusion. Only 1 case has been presented so far in the literature. A case with unilateral tonsil contusion has not been presented to date. We will discuss the possible reasons for taking the place of the tonsils to the above level of the foramen magnum in the follow-up period, by looking at the literature.