Cough syncope and hyperventilation-induced convulsion in Chiari 1.5 malformation

Area of Science:

• Neurology
• Neurosurgery
• Medical Imaging

Background:

• Chiari malformation type I (CM1) involves cerebellar tonsillar herniation below the foramen magnum.
• Cough syncope is a rare but significant symptom in CM1 patients.
• This case involves CM1 with brainstem herniation (CM1.5).

Purpose of the Study:

• To report a case of CM1.5 presenting with recurrent syncope.
• To evaluate the efficacy of decompressive surgery for CM1.5-associated syncope.
• To explore the mechanism of cough syncope in CM1.5.

Main Methods:

• Case report of a 43-year-old male with a 5-year history of cough syncope.
• Neurological examination, cranial and spinal MRI, and EEG with forced hyperventilation were performed.
• The patient underwent foramen magnum decompression surgery.

Main Results:

• MRI confirmed CM1.5 with syringomyelia.
• EEG revealed generalized clonic convulsions during hyperventilation without clear seizure patterns.
• The patient experienced complete resolution of syncope episodes post-surgery with a 1-year follow-up.

Conclusions:

• Decompressive surgery is an effective treatment for cough syncope in CM1.5.
• Cerebrospinal fluid pressure dissociation is a likely mechanism for cough syncope in CM1.5.
• EEG analysis aids in diagnosing seizures and understanding syncope mechanisms.