What is Hydrocephalus?

Hydrocephalus is a neurological disorder caused by an abnormal buildup of cerebrospinal fluid in the ventricles (cavities) deep within the brain.

It is a distension of the ventricular system within the brain due to obstruction of flow. CSF production is influenced by osmotic blood pressure and is constant.   Absorption on the other hand is a passive process and is associated with intraventricular vs venous pressure. This increased volume of fluid and pressure leads to shear forces on the white matter and subsequent white matter atrophy.

Common categories of hydrocephalus are congenital  (small breed dogs, and associated with occlusion of the mesencephalic aqueduct, COMs, or others) vs acquired (any breed or age, active disease process to include infection, immune disease, trauma, or neoplasia).

Common Clinical Signs:

  • Dome shaped head
  • Persistent fontanelles
  • Open/movable suture lines
  • Ventrolateral strabismus
  • Behavior changes
  • Seizures
  • Slow to learn
  • Ataxia
  • Circling
  • Loss of vision
  • Vestibular dysfunction


Diagnosis of hydrocephalus can be made with MRI, CT or ultrasound, however determining a cause of the hydrocephalus is achieved with MRI +/- CSF analysis.



Medical management: Lifelong and commonly associated with significant side effects.  These medications include prednisone and omeprazole tapered to the lowest possible dose.

Patient: Sunny – Inflammatory lesion caused decompensation, too little cortex to safely shunt

Due to the lack of cortical tissue and the subdural hemorrhage on the left side, medical management is the best option for Sunny to avoid the potential for cortical collapse associated with surgery.


Surgical management: Includes shunt placement vs. ventriculostomy.  The placement of a shunt is to route CSF from the lateral ventricle to the abdomen and lessen the pressure within the system.   Complications of this procedure include infection, shunt obstruction, over shunting and collapse of the cerebral cortex.  Ventriculostomy shunts CSF from the lateral ventricle to the arachnoid space.  This is like the procedure in people.

Patient: Mayhem – Seizures, Ataxia – Ventriculostomy performed & recovered

Mayhem with a remnant of cortical tissue was a case ideally treated with a ventriculostomy.  He responded well to treatment with improvements in function through persistent seizures.




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