Arnold‐Chiari malformation type 1 as an unusual cause of acute respiratory failure: A case report

The authors urge clinicians to consider the possibility of Arnold-Chiari Malformation type 1 with other central causes especially in cases where acute respiratory failure is unexplainable.

BACKGROUND

Chiari malformations are a group of heterogeneous disorders; Chiari I malformation is characterized by a form of structural defect in the cerebellum and the cranial base. The case report highlights the possibility of underlying neurological disease in cases where acute type 2 respiratory failure is unexplainable.

Historically, Hans von Chiari described certain hindbrain abnormalities as postmortem findings in infants; these came to be known as Chiari malformations. Four types of Chiari malformations are described in the literature: types I, II, III, and IV.1, 2 (Chiari malformation types II, III, and IV are distinct from type I and are not discussed in this article). Chiari I malformation is the most common, having been estimated to occur in 1 in 1000 births.1

Arnold-Chiari type I malformation (type I ACM or CM-I) is characterized by cerebellar tonsils herniation and downwardly displaced below the level of the foramen magnum. Typically, tonsils lying 5 mm or more (normally 3 mm) below the foramen magnum on neuroimaging are consistent with an ACM. However, there is no known direct correlation between clinical severity and the tonsils position.

The actual nature of CM-I has not been fully understood.2 In most cases, CM-I does not become symptomatic until adolescence or adulthood3-5 and the mean age at presentation is approximately 18 years.6 Also, symptom onset is often insidious. Usually, symptoms of type I ACM develop as a result of the following mechanisms: cerebellum, medulla, and upper spinal cord compression, and disruption of cerebral spinal fluid (CSF) flow through the foramen magnum. Medulla and spinal cord compression may result in spinal cord injury and lower cranial nerve and nuclear dysfunction. Also, the cerebellum compression may result in various neurological symptoms such as dysequilibrium, dysmetria, ataxia, and nystagmus. Disruption of the CSF flow through foramen magnum probably leads to the most common symptom, which is pain.

Other Information

Published in: Clinical Case Reports
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: http://dx.doi.org/10.1002/ccr3.3043