Spectrum of the syndrome of the isolated fourth ventricle in posthemorrhagic hydrocephalus of the premature infant.

Ten patients who were premature born and had intracranial/intraventricular hemorrhage and developed hydrocephalus in early life were treated with ventriculoperitoneal shunts because of progression of the hydrocephalus. The hydrocephalus remained well controlled but in a follow-up period of 2 months to 7 years after shunt placement the patients developed an isolated fourth ventricle that required treatment. The presenting symptoms varied: increasing head size, fontanelle fullness, irritability difficulty with swallowing, vomiting, hypoactivity, headaches and lethargy. One patient presented with full cardiorespiratory arrest and expired. The remainder on neuroimaging studies revealed an extremely large fourth ventricle creating a mass effect and very small (slit-like) lateral ventricles, indicating a functioning lateral ventricle-peritoneal shunt. These patients were treated with the placement of a fourth ventricle shunt catheter and connection to the existing shunt, with resolution of symptoms. Premature infants with hydrocephalus need to be followed and assessed for findings of the syndrome of the isolated fourth ventricle in an attempt to prevent sudden neurological deterioration.