Arnold-Chiari Syndrome (Type I)

Arnold-Chiari syndrome is a rare malformation of the brain that is generally present from birth. This type of brain malformation may be associated with other anomalies including hydrocephalus, myelomeningocele, syringomyelia and spina bifida. There are 3 types of Arnold-Chiari malformation (types I, II and III). The clinical symptoms of all 3 types include torticollis, opisthotonus, headache, vertigo, vocal cord paralysis, apnea, nystagmus, dysphagia and ataxia. The Chiari I malformation is considered to be congenital, although there have been reported cases of an acquired form. The incidence of this malformation has been found to be ∼0.56% via magnetic resonance imaging (MRI) studies. The malformation is characterized by a displacement of the cerebellar tonsils, medulla and the fourth ventricle into the spinal canal. The diagnosis can be difficult because not all patients present the classical symptoms of herniated tonsils. However, this anomaly may be diagnosed with MRI. Here we describe a case study of a 22-year-old female patient in a neurology clinic complaining of both headache and vertigo. We determined via MRI that there was a hernia of the cerebellar tonsillar located inferiorly to the foramen magnum. On the other hand the width of the fourth ventricle and the parenchyma tissue of the cerebellum were normal. This type of malformation may prove to be the cause of headache and vertigo in some people. MRI may therefore be a useful tool to aid in the accurate diagnosis of their symptoms.