Arnold Chiari syndrome is a rare congenital disease of unknown prevalence and whose origin is still under study. It is encompassed within the posterior cranial malformations, showing a wide spectrum of symptomatology that can range from severe headache, dizziness, and paresthesia to complete asymptomatology. (Rodríguez-Blanque et al, 2023)
Chiari malformations (CM) represent a group of anomalies characterized by descent of the cerebellar tonsils or vermis into the cervical spinal canal. These malformations can be associated with abnormalities such as hydrocephalus, spina bifida, hydromyelia, syringomyelia, curvature of the spine (kyphosis and scoliosis) and tethered cord syndrome. (Mancarella et al, 2019)
Arnold-Chiari malformation (ACM), a defect that involves downward displacement of the hindbrain and herniation of the cerebellar vermis, tonsils, pons, medulla, and fourth ventricle through the foramen magnum. (Fons and Jnah, 2021)
Chiari malformation type 1 (CM-1) is a variation of hindbrain development that can sometimes occur in asymptomatic individuals. The natural history of mild symptomatic and asymptomatic CM-1 in adults (inlcuding headaches and nausea) is relatively benign and nonprogressive; the decision to perform surgical decompression should be based on severity and duration of a patient's symptoms at presentation. (Langridge et al, 2017)
Migraine and tension-type headache are common clinical problems, occurring even at a young age. When patients report headache as a symptom, it is necessary to exclude a secondary headache induced by an organic disease. A Chiari malformation is one organic cause that should not be overlooked. A thorough clinical screening is always recommended, including a complete neurological, mental status and physical examination. However, when the symptom pattern suggests a Chiari malformation, neuroimaging is warranted to identify correctly the pathologic condition and the most appropriate therapeutic approach. (Grazzi and Andrasik, 2012)
Headache is a common symptom in patients with Chiari I malformation (CMI), characterized by 5 mm or greater cerebellar tonsillar herniation below foramen magnum. Radiologists should be aware of the different types of headaches reported by CMI patients and which headache patterns are distinctive features of the diagnosis. A methodical imaging strategy is required to fully assess a CMI patient to exclude secondary causes of tonsillar herniation such as intracranial hypotension or associated conditions such as syrinx. Both anatomic and physiologic imaging can help determine if headaches are CMI associated and assist clinicians in therapeutic decision making. (Bezuidenhout et al, 2019)
Sleep-disordered breathing (SDB) is a frequent symptomatic feature of pediatric Chiari I, reported in at least 24% of patients presenting to neurosurgeons. Diagnosis requires polysomnography, which should be pursued in young or symptomatic patients or those with prominent imaging findings. (Marino et al, 2023)
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