A study performed at the University of Missouri School of Medicine published recently in the Journal of Neurosurgery: Pediatrics revealed the prevalence of Chiari I malformation (CM-I) in children and adolescents with autism and discussed the difficulty of recognizing CM-I the co-existence of these two disorders.
The authors evaluated the brain MRI scans of 125 pediatric patients younger than 18 years of age seen at the Thompson Center for Autism and Developmental Disorders. The Chiari I malformation was found in 5 children, their ages ranging from 3 years 9 months to 5 years. The amount of cerebellar tonsillar herniation varied from 8 to 19 mm. All five patients presented with symptoms of autism spectrum disorder (ASD) and CM-I and underwent posterior fossa decompression by surgeons at the Division of Neurological Surgery consisting of “suboccipital craniectomy, a C-1 or a C-1 and C-2 laminectomy, and duraplasty with bovine pericardium or Type I collagen allograft.”
Outcome in these 5 autistic children with CM-I was uniformly positive:
“All patients showed symptom improvement and/or resolution of presenting symptoms, which included headache, dysphasia, speech, and irritability.”
Recognizing the presence of CM-I in children with autism can be difficult. As noted in the study, symptoms of ASD include “impairments in social interaction, communication difficulties, and the presence of restricted, repetitive, and stereotyped patterns of behavior.” Frequently these impairments make it difficult to recognize other associated disorders such as CM-I. Thus, recognizing the symptoms and findings of CM-I in autistic children of is of utmost importance. Common symptoms include “headaches, ocular disturbances, sleep apnea, lower cranial nerve compression, dysphagia, dysarthria, disequilibrium with vertigo, and motor or sensory findings caused by syringomyelia or scoliosis.”
“Features such as head holding, head banging, and difficulty in flexion and extension of the neck suggest the likelihood of headaches and neck pain. Swallowing difficulties and dysarthria may reflect lower cranial nerve dysfunction, while difficulties in balance and ambulation may reflect cerebellar or spinal cord compromise.”
The authors note the “current frequency of CM-I in the pediatric and adult population is thought to be about 1%–3.6%,” a 4% prevalence roughly similar to that in the general population.
Should routine MRI screening be performed in all children with ASD? The authors do not recommend this:
“Nevertheless, it is difficult to recommend performing cranial imaging in all patients with ASD to evaluate for CM-I, as the patient may be asymptomatic and such a practice does not represent a cost-effective form of health care delivery.”
However, they emphasize alertness on the part of evaluating physician and “clear communication” among treating specialists:
“It is therefore imperative that the physician is alert to the history given by the child’s parents or caretakers, as well as the observed clinical findings, and corroborates these aspects with the sensible utilization of further testing and subsequent management.”
“Awareness of the coexistence of symptomatic CM-I and ASD necessitates clear communication between primary care physicians, autism specialists, pediatric neurologists, and pediatric neurosurgeons.”
John Oró, MD
January 31, 2015