Chiari malformation type I: atypical vestibular presentation with down-beating nystagmus – a case report

Abstract

Arnold-Chiari malformation type I (CM-I) is a neurological disorder characterized by the caudal displacement of the cerebellar tonsils through the foramen magnum into the cervical spinal canal. The most common clinical manifestations include occipital headache and neck pain. However, vertigo is an uncommon presentation and may lead to diagnostic confusion with other vestibular disorders. A 39-year-old female presented with a ten-year history of occipitocervical pain accompanied by recurrent episodes of dizziness. Her symptoms clinically resembled cervicogenic dizziness for which she received treatment with minimal improvement. Further evaluation at a specialized center included videonystagmography, which demonstrated down-beating nystagmus. Magnetic resonance imaging (MRI) of the brain with craniovertebral junction assessment subsequently revealed herniation of the cerebellar tonsils consistent with chiari malformation type I. This case highlights an atypical presentation of CM-I in which vestibular symptoms predominated, while the classic symptom of persistent occipital headache was less prominent. Such atypical manifestations can delay diagnosis and appropriate management. Comprehensive neuro-otological evaluation, including vestibular testing and neuroimaging, plays a crucial role in identifying central causes of vertigo. CM-I should be considered in the differential diagnosis of patients presenting with unexplained vertigo or vestibular symptoms, particularly when associated with occipitocervical pain. Early recognition and appropriate imaging are essential for timely diagnosis and management. Following diagnosis, the patient was planned for foramen magnum decompression surgery.