The sonographic signs of the peritoneal pseudocyst obstructing the ventriculo-peritoneal shunt in children.

The installation of the ventriculo-peritoneal shunt (VPS) is on the rise in the pediatric age. Its obstruction is a major cause for further deterioration of the already present hydrocephalus. Distal VPS obstruction may be due to a pseudocyst, an infected pseudocyst or an abscess-formation within the peritoneal cavity. These pathologies are identified through an abdominal radiograph and ultrasonography. The sonographic signs are described and its differential diagnosis is discussed in relation to 6 diagnosed cases. One VPS was obstructed by Ascaris lumbricoides clinging to its tip within an abscess.