After the surgical treatment of a child with high pressure hydrocephalus, symptoms may recur because of blockage of the shunt system, and surgical revision of the shunt implant may be necessary. In some patients reactive subdural haematoma forms as the result of sudden shrinkage of the brain as the cerebrospinal fluid is drained away by the shunt implant. Subsequent symptoms caused by reactive subdural haematoma may cause diagnostic confusion and, if not detected, may lead to inappropriate treatment, usually an unnecessary revision of the ...