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Chiari II malformation with obstructive hydrocephalus and spinal dysraphism

Case contributed by Doaa Khedr Mohamed Khedr
Diagnosis certain

Presentation

Abnormal antenatal obstetric US with hydrocephalus underwent cesarean section. At birth, the patient presented with lower back swelling.

Patient Data

Age: 6 weeks
Gender: Female

Evidence of supratentorial hydrocephalus with a markedly narrowed fourth ventricle. Patent aqueduct of Sylvius with flow void.

Small-sized posterior fossa with low insertion of the tentorium, low torcula, and abnormal course of the straight sinus.

Evidence of downward herniation of cerebellum and brainstem through the foramen magnum. A tectal peaking sign of inferior colliculus is seen on the sagittal view as well as a cerebellar wrapping sign around the brain stem.

Thinning of the corpus callosum along with retrograde CSF permeation are noted.

An obstructive CSF flow curve (zigzag appearance) with very slow flow through the aqueduct of Sylvius.

Small-sized posterior fossa and downward herniation of cerebellar tonsils and brainstem through the foramen magnum.

Large spina bifida in the lumbar region with myelomeningocele and tethered cord (spinal dysraphism).

Two levels of syringohydromyelia in cervical and lumbar regions.

Case Discussion

Chiari II malformation is a complex congenital anomaly with posterior fossa and spinal cord abnormalities.

Obstructive hydrocephalus is one of the key signs of Chiari malformation. It results secondary to downward displacement of posterior fossa structure with the collapsed/trapped fourth ventricle.

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