[Episodes of unilateral sympathetic hyperfunction, changes in consciousness status and respiratory dysfunction in a...

The Chiari type II malformation, often associated with a myelomeningocele, is characterized by a small posterior fossa and downward displacement of the cerebellum, IV ventricle and brainstem, with elongation and dysgenesis of other structures. It is usually linked to hydrocephaly, anomalies of the corpus callosum and hydrosyringomyelia. In symptomatic cases, the age and form of presentation are very variable and partly dependent on associated anomalies. Respiratory symptoms, the main cause of death in children with myelomeningocele, are frequent. There may be dysfunction of other cranial nerves with dysphagia, bradycardia and weakness of the cervical muscles together with motor and sensory disorders of the arms, signs of involvement of the long pathways and cerebellar dysfunction.

A four year old girl with a myelomeningocele and type II Chiari syndrome causing episodes of congestion, excessive sweating, left mydriasis, impaired consciousness and respiratory alterations with pauses of apnea. Between episodes there was left myosis and ptosis. Surgical decompression was done but the episodes persisted and the girl died eight months after the operation.

We consider that the patient had alternately, on the same side, Horner's syndrome and paroxystic episodes of sympathetic hyperstimulation. However, there are only a few, brief references in the literature to involvement of the sympathetic pathway (both of deficit and of hyperfunction) in patients with Chiari II malformation. We emphasize the evolutionary character of spinal and intracranial anomalies usually present in myelomeningocele, and that treatment is purely palliative.