Hydrocephalus is an uncommon neurological disorder in dogs and cats. While it is more common in dogs than in cats, it is still considered rare.
What is Hydrocephalus?
The word hydrocephalus translates to “water on the brain.” This condition occurs when cerebrospinal fluid (CSF) cannot drain properly causing an increase in pressure on the brain. CSF is the fluid that surrounds the brain and spinal cord, providing nutrients and protection. A buildup of CSF can occur in the brain when the flow or absorption of the fluid is blocked or too much is produced by the body. The swelling and increased pressure in the brain and skull can lead to permanent, irreversible brain damage and death.
There are two types of hydrocephalus:
- Nonobstructive hydrocephalus results in increased production or decreased absorption of CSF.
- With Obstructive hydrocephalus, CSF accumulates in the ventricles of the brain due to an obstruction in the brain's circulatory pattern, causing high intracranial pressure (within the skull). The increased pressure in the skull presses on sensitive brain tissues and can cause irreversible brain damage.
Hydrocephalus is also classified as congenital or secondary.
- The congenital form of hydrocephalus is a genetic disease or birth defect. It is most often associated with a dome-shaped skull, a large fontanel (soft spot) on top of the skull, and eyes that appear to gaze downward. Congenital hydrocephalus is more common in small breeds (Chihuahua, Maltese, Toy Poodles, Yorkshire Terrier) and brachycephalic breeds (Boston Terrier, Pekingese, Cavalier King Charles Spaniel) of canines and in Siamese cats. Dogs and cats with dome-shaped heads are more at risk than other breeds. Breeding animals with hydrocephalus in their lines should not be bred.
- Secondary or acquired hydrocephalus occurs when the flow of CSF is blocked or altered by infection, tumor or swelling. The most common cause of this condition is a brain tumor. However, viral, parasitic, and fungal infections have resulted in acquired hydrocephalus. Immune dysfunctions are another probable cause.
How is hydrocephalus diagnosed?
The following clinical signs/symptoms may point to hydrocephalus:
- Large/open fontanel (soft spot in the skull): An open fontanel does not mean the dog/cat will have hydrocephalus; however, most dogs and cats diagnosed with hydrocephalus will have open fontanels. It is not uncommon for fontanels in toy dog breeds to remain open.
- A large dome-shaped head
- Stunted growth, difficulty gaining weight
- Wetting or soiling in the house, difficulty in housetraining
- Excess vocalization
- Crossed or bulging eyes
- Squinting, decreased vision or blindness
- Changes in behavior such as aggression, hyperexcitability, pacing and restlessness
- Gait abnormalities, such as spastic or high-step walking, lack of coordination, loss of balance, falling over
- Abnormal breathing
- Regular circling
- Pressing head against a hard surface, such as a wall
In puppies and kittens, clinical signs usually begin to show before 6 months of age. Ultrasound through the fontanel can reveal dilated or enlarged brain ventricles. If the puppy’s or kitten’s fontanel is closed, or in the case of adult dogs and cats, cranial radiographs (X-rays), Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) can also be used to diagnose hydrocephalus. CT and MRI require general anesthesia as the animal must be perfectly still for the test. Hydrocephalus is more difficult to diagnose in adult dogs and cats, as these signs can also point to other conditions. Some animals may have mild hydrocephalus with no signs; however, trauma, hemorrhage or infection can make the condition worse and result in clinical signs.
Provide your vet with a thorough and detailed history of the animal’s health, including any information you have about its birth and parentage, observation of any symptoms, and possible incidents, including minor falls. Diagnostic procedures should include a complete physical examination, complete blood profile, complete chemistry profile, complete blood count, an electrolyte panel, and a urinalysis. Once other conditions are ruled out, a spinal tap and electroencephalogram (EEG) can also be used for a definitive diagnosis. CT and MRI are the diagnostic gold standard.
How is hydrocephalus treated?
Treatment depends on the type and cause of the hydrocephalus as well as its severity. In most cases, hydrocephalus is managed and not cured. The goal of treatment is to reduce CSF production and systemic inflammation. Conventional treatment uses corticosteroids such as prednisone. Steroids should be given only in the short term (no longer than 2-4 weeks).
Diuretics such as furosemide, acetazolamide, and omeprazole work to reduce CSF production. Medication must be used with caution, as long-term use of any diuretic can cause electrolyte depletion and place stress on the kidneys. Electrolyte loss will occur faster when diuretics are used in combination with steroids. Your veterinarian will determine dosage.
Surgery is an option that is often considered a last resort because it is expensive and has potential complications. The goal of surgery is to provide drainage of the CSF from the brain to another site for absorption. This procedure is not performed by all veterinarians and may require referral to a surgical specialist. Surgery to place a tube that runs from the open spaces in the brain to the abdomen (ventriculoperitoneal shunt - VPS) can be performed and success rates with this procedure can be as high as 80%. One downside to using this surgical procedure is that shunts can become obstructed because of protein build up. This situation can lead to a return of elevated intracranial pressure. Blockage at the shunt site may require a second surgery. It is best to use a shunt with a valve system, as the valve can control the drainage flow of CSF. A flow rate that is too slow can result in infection, and a flow rate that is too high can result in headache, vomiting, nausea, changes in vision, and protein build up. Other potential complications of the surgery include inflammation/infection of the shunt site and systemic infection.
Traditional Chinese Veterinary Medicine for hydrocephalus
From a Traditional Chinese Veterinary Medicine (TCVM) perspective, animals with congenital hydrocephalus have an underlying Kidney Jing Deficiency that results in reduced Spleen Qi and increased damp in the brain. Both Kidney Jing and Spleen Qi deficiency affect the liver. Most congenital problems are often traced to a lack of kidney jing. The kidney controls the bones, and bone marrow, and the brain is considered the “marrow sea.”
Food therapy and Chinese herbs are recommended along with dry needle (DN) acupuncture to support a dog or cat with hydrocephalus. A TCVM practitioner can prescribe herbs that are specific to an animal’s symptoms.
- Examples of foods and supplements that support spleen qi include beef, chicken, sardines, egg, sweet potato, carrots, squash, and microalgae (chlorella and spirulina).
- Foods and supplements to support kidney jing include liver, kidneys, fish, kelp, reishi mushrooms, Vitamin D, fermented raw goat milk, bone, bone marrow and bone broth, almonds, black sesame seeds (grind first) and bee pollen.
- Foods to drain damp include eel, mackerel, quail, blueberries, celery, mushrooms, and dandelion greens.
What is the prognosis for hydrocephalus?
Prognosis will vary depending on the cause. For example, hydrocephalus caused by an infection can be resolved if the infection is resolved. Congenital hydrocephalus cannot be totally cured but can be managed. Alternative TCVM treatments are available and place less stress on the body. Most dogs and cats with mild to moderate hydrocephalus can live high quality lives with treatment. Procedures, such as MRI and CT, can be costly but will provide a definitive diagnosis. The type of treatment will depend on you, as the pet parent, in consultation with your veterinarian.
My pup, Forrest, was born with congenital hydrocephalus. We support him using TCVM food therapy and supplements. Although his gait is a little funny and he has a few odd behaviors, he enjoys an incredible life on the farm.