Development of symptomatic Chiari malformation in a child with craniofacial dysmorphism.

We present the case of a 28-month-old child with craniofacial anomalies who presented for evaluation of apnea. The patient had associated symptoms referable to a Chiari malformation and MRI scanning of the head and cervical spine revealed some, but not all, of the anatomical features classically associated with the Chiari II malformation. The child has mid-face hypoplasia and it appeared that his posterior fossa hypertension was partially caused by anterior compression of the brain stem as a result of the malformation at the base of the skull. The patient responded dramatically to posterior fossa decompression. Evidence from this and other cases from the literature suggests that different pathophysiological mechanisms may cause the classic Chiari malformation and/or other anatomical abnormalities in the continuum between Chiari I and II.