Hydrocephalus and the Chihuahua

Hydrocephalus is sometimes referred to as water on the brain, and the condition can be either hereditary or acquired later on in life. Certain dog breeds have elevated risk factors for inheriting the hereditary form of the condition, and one such breed is the Chihuahua, which is the second most popular dog breed in the UK overall.

Hydrocephalus is a very serious health condition that can have wide-reaching implications for dogs diagnosed with the disorder, and it can be fatal in some cases too. If you own a Chihuahua or are considering buying one, it is wise to find out what hydrocephalus is, how it is identified, and how it can affect your dog if they inherit the condition.

Read on to learn more about congenital hydrocephalus in the Chihuahua.

What is hydrocephalus?

First of all, it is a good idea to clarify one common misconception about hydrocephalus that comes from its more common name of water on the brain. It’s not actually water that we talk about when referring to the condition but cerebrospinal fluid, the fluid that cushions, protects and lubricates the spinal cord and brain.

In dogs with hydrocephalus, cerebrospinal fluid accumulates in excessive amounts within the skull itself, enlarging the brain’s ventricles and leading to a build up of pressure in the skull as the brain presses into the skull due to this excess fluid.

This can cause headaches and extreme pain, as well as potentially causing other problems such as blindness, problems with walking normally and in some cases, seizures. However, this is not the case for all affected dogs, some of whom will be largely asymptomatic.

What sort of dogs are at risk of hydrocephalus?

When it comes to hereditary hydrocephalus, certain breeds of dog have a heightened predisposition to inheriting the condition and the Chihuahua is just one of them. Boston terriers and pugs are a couple of others, and of course, any dog breed or type may develop the acquired rather than inherited form of the condition.

Because hereditary hydrocephalus is present from birth it often becomes evident in younger dogs, but this is not always the case. Both males and females are equally at risk of inheriting hereditary hydrocephalus.

What are the symptoms of hydrocephalus in the Chihuahua?

The apple-headed Chihuahua’s large, domed skull increases the risk of hydrocephalus, and many Chihuahuas are born with a fontanelle or soft spot on their skulls too, where the bone plates meet but don’t join up completely. This may close over time, but this is not the case for all dogs. Chihuahuas with an exaggerated dome to the skull and a fontanelle are thought to be more at risk of hydrocephalus than others, and so this in itself can be a warning sign to look out for and monitor.

The symptoms of hydrocephalus in the Chihuahua can be quite variable, and some dogs aren’t hugely affected by the condition and may not display any symptoms at all. However, others may manifest with distinct symptoms that may include seizures, a strange walking gait, or loss of vision, and they may not thrive and grow at the expected rate.

Poor condition and an inability to gain weight are other potential symptoms, as is strange behaviours such as circling, staggering, or falling over. Temperament and behavioural problems are often the first signs of hydrocephalus in Chihuahuas, which might include aggression, lethargy and lack of energy, apparent confusion, or an apparent inability to learn and execute basic training commands.

Hereditary hydrocephalus usually presents with symptoms during affected dogs’ first year of life if they inherit the condition, but it can develop later too. Up until the dog’s second birthday is generally considered to be the main window for risk, but it is not unheard of for mature and even elderly dogs to show symptoms for the first time later in life.

It is also important to bear in mind the fact that no obvious symptoms doesn’t necessarily mean the absence of the condition, and some dogs with the condition will have it only mildly and go through their whole lives without displaying symptoms.

Can hydrocephalus in Chihuahuas be treated or cured?

In order to make a formal diagnosis of hydrocephalus in the Chihuahua, your vet will need to conduct a number of tests and examinations on your dog. These might include ultrasound examination of your dog’s brain and potentially, more technical diagnostic imaging tools like an MRI scan, CT scan, or electroencephalogram.

To treat hydrocephalus, your vet may consider a variety of approaches. Easing the pressure in the dog’s skull and brain might be achieved with the use of diuretics, or a surgically placed drainage shunt in acute cases. Medications may be used to reduce inflammation and reduce the incidence rate of seizures, but dogs with hydrocephalus that presents with symptoms need close monitoring and special care for life.

Hydrocephalus can also result in brain damage over time, which cannot be reversed or cured and that may affect your dog’s development, socialisation and ability to learn new skills; however, if the pressure in the dog’s skull can be reduced before brain damage occurs, this can be prevented.

In some cases, hydrocephalus cannot be treated or managed effectively, and may have an acute impact on the dog’s life and health, as well as of course potentially causing brain damage. This means that in some cases, euthanasia is the kindest option.

Even dogs with hydrocephalus that are fine and asymptomatic can potentially pass the condition onto their own offspring, and so Chihuahuas with hydrocephalus should not be bred from. If you are thinking of buying a Chihuahua puppy, talk to the breeder about the health and wellness of the dog’s parents and other close relatives and ask if there have been any presentations of hydrocephalus within the breed line.