Acquired Chiari I malformation and syringomyelia after valveless lumboperitoneal shunt in infancy.

The authors present the case of a 13-year-old boy who experienced frequent disabling episodes of typical postural induced headaches, which revealed a Chiari I malformation, syringomyelia and cervical spinal cord edema. This boy had received a valveless lumboperitoneal (LP) shunt at the age of 18 months for macrocephaly. At this time, cranial CT scan showed moderate enlargement of the subarachnoid spaces without hydrocephalus or tonsillar herniation. The LP shunt was clamped but the patient experienced signs of brain stem dysfunction and increased intracranial pressure. Finally, an adjustable valve (110 mm Hg) was inserted and all the symptoms resolved. Although some authors consider LP shunt as a safe and effective procedure even in the pediatric population, our case reminds us that these shunts, especially when valveless, may expose the patient to the risk of symptomatic acquired Chiari I malformation and syringomyelia consecutive to a chronic spinal CSF leakage.