Hydrocephalus in dogs, also known as “water on the brain,” occurs when cerebrospinal fluid builds up in the brain. The fluid accumulates in the ventricles (fluid-filled areas) of the brain and puts pressure on the brain tissue. This can cause a range of neurological problems and even be life-threatening if left untreated.
There are two types of hydrocephalus in dogs:
- Congenital: Present at birth. This is usually caused by a defect in the development of the brain or spine that blocks the flow of cerebrospinal fluid.
- Acquired: Develops at some point after birth. This is usually caused by an injury, tumor, or infection that blocks the flow of cerebrospinal fluid.
The symptoms of hydrocephalus typically appear gradually and include:
- Lethargy or decreased activity level. Your dog may seem less playful or not want to go for walks.
- Vision problems or blindness. The pressure on the brain can affect the optic nerve.
- Loss of balance or coordination. Your dog may wobble, stumble or even have seizures.
- An abnormally large head. Especially in puppies, the head may become dome-shaped.
- Irritability or aggression. The pain and pressure in the brain can alter your dog’s behavior and temperament.
To diagnose hydrocephalus, your vet will perform a physical exam, order blood tests and imaging scans like MRI or CT to view the brain. The only treatment for hydrocephalus is surgery to drain and divert the excess fluid and relieve pressure on the brain. Without treatment, hydrocephalus is usually fatal. The prognosis depends on the underlying cause and severity. Early diagnosis and treatment provide the best outcome.
If your dog shows symptoms of hydrocephalus, take them to the vet immediately for an accurate diagnosis and treatment. With prompt surgery and follow-up care, dogs with hydrocephalus can live happily for many years. But the condition does require ongoing monitoring to ensure excess fluid does not build up again.
Symptoms of Hydrocephalus in Dogs
If your dog is showing any of these symptoms, it may indicate hydrocephalus. Take your dog to the vet as soon as possible for an accurate diagnosis and treatment.
- Your dog may have trouble balancing or walking steadily. Hydrocephalus can cause pressure on the brain that leads to lack of coordination, stumbling or falling over. You may notice your dog walking in circles or seeming unsteady on their feet.
- Changes in behavior or personality. Excess fluid may put pressure on your dog’s brain, potentially causing irritability, aggression, depression or other behavioral changes. Your usually friendly dog may become snappy or want to be left alone.
- Difficulty controlling bladder or bowels. The pressure on your dog’s brain can impact nerves that control waste elimination, leading to frequent urination, difficulty holding urine, or loss of bowel control.
- Vision problems or blindness. Fluid buildup in the brain can put pressure on the optic nerve, causing vision loss, blurred vision, unequal pupil size, or blindness. Your dog may bump into objects or seem hesitant in unfamiliar places.
- Seizures or convulsions. In some dogs, the increased pressure on the brain from hydrocephalus can trigger epileptic seizures, spasms, or convulsions. Seek emergency vet care immediately if your dog is experiencing seizures.
- Vomiting or nausea. Excess fluid in the brain may lead to a buildup of pressure that causes vomiting, gagging, or loss of appetite in some dogs. The vomiting is often unrelated to eating.
- Headache or head pressing. Dogs can’t tell us when they have a headache, but may press their head against walls or furniture for relief from the pain. Head pressing is often a sign of an underlying condition like hydrocephalus that requires vet care.
- Bulging or misshapen skull (in puppies). In young dogs with open fontanels (soft spots), the skull bones have not yet fused, so the head may appear dome-shaped or misshapen as fluid builds up. The soft spot may also bulge. This is an emergency situation, as permanent brain damage can occur quickly in puppies. Seek vet care immediately.
Causes of Hydrocephalus in Dogs
Hydrocephalus in dogs occurs when excess cerebrospinal fluid (CSF) accumulates in the brain. There are a few reasons why this may happen to your canine companion.
1. Congenital defects
Some puppies are born with congenital defects that obstruct the flow of CSF, like an abnormal development of the skull, spine or brain. This is known as congenital hydrocephalus and is present at birth. Certain dog breeds are more prone to congenital hydrocephalus, including Boston Terriers, Chihuahuas, Maltese, Poodles, and Yorkshire Terriers.
2. Obstructions or tumors
An obstruction in the ventricles of the brain or along the flow pathway of CSF can cause hydrocephalus to develop in dogs of any age. This could be caused by a tumor, cyst, blood clot or other mass blocking the flow. In some cases, surgery may be recommended to remove the obstruction and restore normal CSF circulation.
3. Inflammation or infection
Inflammation of the meninges (the membranes surrounding the brain and spinal cord) or an infection like meningitis can also trigger excess fluid buildup and lead to hydrocephalus. In these cases, medications like steroids, antibiotics or antifungal drugs may be used to reduce inflammation or treat the infection, which can then relieve pressure on the brain.
4. Head trauma
Serious head injuries or trauma can cause blood or scarring to block the flow of CSF and create hydrocephalus. Surgery to repair any damage or relieve pressure may be required, especially if symptoms appear shortly after a head trauma.
As dogs age, the brain and skull naturally lose some volume, and the production of CSF remains the same or increases. This mismatch can lead to a gradual buildup of fluid and hydrocephalus in senior dogs. Medications or surgical procedures may help provide relief in these age-related cases.
With prompt diagnosis and treatment, many dogs with hydrocephalus can live comfortably for years. Be sure to monitor your dog closely for any symptoms and take them for regular vet checkups, especially if they are at higher risk due to their age, breed or medical history.
Treating and Managing Hydrocephalus in Dogs
Once diagnosed, hydrocephalus needs to be properly managed to relieve pressure on the brain, improve neurological function, and increase life expectancy. Unfortunately, there is no cure for hydrocephalus, but with consistent treatment and monitoring, dogs can live comfortably for many years.
Treatment options for hydrocephalus typically include either medical management or surgical intervention. The specific course of treatment will depend on the severity of the condition, the dog’s age, and the owner’s preferences.
For less severe cases of hydrocephalus, especially in very young puppies, vets may first try medical management with diuretics and corticosteroids to reduce fluid buildup and relieve pressure. Medications need to be carefully monitored to find the right balance, as too high a dose can cause dehydration and low blood pressure. With medication, regular rechecks and MRI scans are needed to monitor the condition.
For persistent or worsening hydrocephalus, surgery to divert excess fluid from the brain may be recommended. The most common procedures are ventriculoperitoneal shunting (VPS) and endoscopic third ventriculostomy (ETV).
VPS involves placing a shunt system to drain fluid from the brain to the abdomen where it can be absorbed. Shunts require frequent monitoring to ensure proper function but can be very effective at controlling fluid buildup.
ETV uses an endoscope to create an opening in the third ventricle, allowing fluid to bypass the obstruction and flow out of the brain. This avoids the need for a shunt but has a higher failure rate and may need to be repeated.
After surgery, dogs will need frequent vet checkups, especially in the first few months, to monitor for any complications or shunt malfunction. With proper aftercare and management, many dogs can go on to live full, active lives with well-controlled hydrocephalus. The key is diligent monitoring and a willingness to make adjustments to treatment as needed to give your dog the best chance at a good quality of life.