Headache in Chiari Malformation Type I: The Importance of Differential Diagnosis

Chiari Malformation Type I (CM1) syndrome is characterized by a congenital anomaly of the cranial base bones, craniovertebral junction (CVJ), and obstruction of the foramen magnum by the cerebellar tonsils. This can lead to compression of anatomically normal neural structures, disruption of cerebrospinal fluid circulation at the CVJ, and the presence or absence of associated syringomyelia and idiopathic scoliosis. These changes result in various neurological symptoms, including headaches, which are often mistakenly attributed to primary headache disorders. Among 102 patients who underwent neurosurgical treatment at the Surgical Clinic of AMU and the Republican Neurosurgery Hospital between 2016 and 2024, 97 reported headaches. Of these, 37 cases (36.3%) presented with nonspecific headaches not characteristic of CM1. Headaches in CM1 can be typical or atypical. Prolonged and unusual headache characteristics that do not correspond to classic primary headaches necessitate neuroimaging to rule out intracranial pathology, including CM1.