Adult Chiari Type I Malformation Presenting as Emergent Acute Respiratory Insufficiency: A Case Report and Literature Review.

Chiari type I malformation (CM-1) is a condition that is often asymptomatic, though when symptoms occur, they commonly involve occipital headaches. Acute respiratory insufficiency as the presenting symptom requiring emergent surgical intervention is extremely rare. We present the case of a 51-year-old female who developed sudden-onset respiratory insufficiency due to CM-1 and syringomyelia affecting the brainstem, necessitating urgent surgical intervention. The patient, with a history of mild tetraparesis, arrived at the emergency department with an acute loss of consciousness, severe respiratory acidosis, and acidemia. Imaging revealed tonsillar herniation at the foramen magnum, significant compression of the bulbomedullary junction, and an extensive syringomyelic cavity extending from the cervical to the dorsal spine. The patient underwent a comprehensive evaluation, with no alternative causes found for the clinical presentation. An emergent posterior fossa decompressive craniectomy and C1 laminectomy were performed, leading to a satisfactory clinical recovery. This case highlights the importance of prompt surgical intervention in rare presentations of CM-1, which can lead to significant improvement in symptoms and favorable outcomes.