Or “Water on the brain”, is a condition in its congenital form (meaning it may be acquired it close to birth) affects the toy breeds and the “brachycephalics” dogs with very short noses, like the boxer, pug etc.  Congenital Hydrocephalus symptoms usually appear within a year of being born.  However acquired Hydrocephalus can affect any breed at any age.  It is a build of fluid inside the skull causing swelling of the brain.

It can be causes by a number of things such as Parainfluenza virus, brain hemorrhages or tumours, vitamin A deficiencies, prenatal infections, etc.

Diagnostic tests are needed to confirm the diagnosis.  It may require surgery or may be treated on an outpatient basis.