Arnold-Chiari malformation is a developmental defect that primarily affects Chihuahuas, Papillons, Cavalier King Charles Spaniels, Brussels Griffons, Pomeranians, Maltese, and Yorkshire Terriers. This condition develops during the embryonic period and involves the displacement of hindbrain structures into the spinal canal, leading to spinal cord compression and neurological symptoms.
What is Chiari Malformation (CM) and why does my dog have Chiari Malformation (CM)?
Chiari malformation (CM) is a genetic and congenital neurological disorder characterized by abnormal bone growth at the back of the skull, essentially making the skull too small for the brain.
The pressure created in this tight space affects the flow of cerebrospinal fluid. This can result in the formation of fluid-filled cysts in the spinal cord, a secondary condition known as syringomyelia (SM) . Unfortunately, as the cysts enlarge over time, they eventually damage the center of the spinal cord.
So how do we ensure the purity of the breed is free from genetic diseases?
The transmission of these traits to future generations can be stopped by selective breeding = excluding dogs that carry this gene from breeding.
Excluding dogs carrying the gene from their mother or father's side is crucial (in fact, the entire breeding line from which the gene originated) because it reduces the risk of the genetic disease being passed on to offspring. This prevents the further spread of unfavorable genetic traits in the dog population.
Selective breeding is not only about caring for dogs' health , but also about preserving genetic diversity within the population. Through controlled crossbreeding , desirable breed characteristics can be preserved while eliminating the risk of inheriting genetic diseases .
Are there other disorders associated with Arnold-Chiari Malformation?
Arnold-Chiari malformation often occurs in conjunction with other developmental disorders, such as myelomeningocele, hydrocephalus, syringomyelia, and dwarfism. Initial symptoms may be confused with allergies or ear infections, and if ignored, the condition can progress and lead to paralysis.
Clinical symptoms of syringomyelia:
- Phantom scratching
- Scratching around the ears, neck or back of the head
- Rubbing the muzzle
- Sensitivity
- Pain episodes
- Changes in behavior
- Weakness in the limbs or lack of coordination
- Scoliosis
- Catching invisible flies
- Temporary vision problems
We will explain the rest of the symptoms below.
Is it possible to cure Arnold-Chiari Malformation and MS?
Well, no . As we wrote above, this disease is: congenital (formed already in the embryo), genetic – passed down from generation to generation (each subsequent generation produces increasingly stronger and faster symptoms).
Early diagnosis can slow the progression of the disease, effectively relieving the pain with medication, and pet parents can be better prepared for what awaits their pet and themselves. However, no one is truly prepared for the progression of the disease, and in many cases, no one expects the worst. Many owners of dogs with Arnold-Chiari Malformation and MS eventually decide to alleviate their canine friend's pain because, at a certain point, medication stops working and the range of soothing medications shrinks rapidly after a sudden and drastic worsening.
"Treatment" for Arnold-Chiari malformation may also involve neurosurgery. Early detection and appropriate treatment can, in some cases, help prevent serious consequences for the dog's health. However, neurologists advise against this type of surgery, which carries a series of complications – from persistent and debilitating seizures to even more severe, unbearable pain. Not every patient survives such surgery unscathed, and there is no way to reverse the damage already done or what will happen afterward.
What does such an operation look like?
Such surgery in the case of Arnold-Chiari Malformation involves surgical removal of the compressing part of the brain and enlargement of the spinal canal to prevent repeated compression of the spinal cord. In some cases, symptomatic treatment is also necessary, such as the use of painkillers or antispasmodic or antiepileptic drugs.
In the case of Arnold-Chiari malformation, proper post-operative management is also crucial. Thorough rehabilitation is required to restore the dog's normal function. Rehabilitation may include exercise, hydrotherapy, and manual therapy.
It is also recommended for dogs that are only on medication to attend a specialized facility that offers aquatic rehabilitation for animals, however, if you decide to take this step, you must do a thorough research because the rehabilitator will need to be able to understand the disease and will need to have an idea of how they can help your pet cope with pain through rehabilitation.
In addition to neurological symptoms, Arnold-Chiari malformation can also present with breathing and swallowing difficulties. In some cases, the syndrome may be asymptomatic or symptoms may be very mild, and the diagnosis is made incidentally during an imaging test performed for another reason.
Although Arnold-Chiari malformation is a congenital condition, symptoms don't always appear immediately after birth. In some cases, symptoms don't appear until later in life, and diagnosis is difficult due to the ambiguity of the symptoms.
What do I need to pay attention to?
It's important for dog owners to be alert to alarming symptoms and not ignore them. Diagnosing Arnold-Chiari malformation too late can lead to a deterioration of the dog's health and an increased risk of neurological complications.
Owners of dogs of breeds particularly susceptible to Arnold-Chiari malformation should be aware of the risk and undergo regular diagnostic testing for early detection. If Arnold-Chiari malformation is suspected, immediately contact a veterinarian specializing in neurology , who will conduct a thorough examination and determine appropriate treatment.
To sum up:
Early symptoms of MD can be easily confused with other conditions, making accurate diagnosis and treatment difficult. These symptoms include scratching around the eyes, head, and ears, as well as itching of the neck. Headbanging and rubbing against objects are also common, often mistaken for allergies or behavioral issues.
Early symptoms may also include vocalization, pain when picked up, or poor response to touch around the occiput. Dogs with the malformation often experience discomfort with the collar and have a poor bite and undersized jaw.
The last known symptom of malformation is paralysis, but this symptom often appears only in the later stages of the disease, as dogs with malformation are often confused with other diseases, and diagnosis is difficult. Unfortunately, because paralysis is often confused with epilepsy, dogs often receive inadequate treatment, and their health deteriorates until it may be too late to save them. Therefore, the sooner we diagnose malformation and begin treatment, the greater the chances of improving our pet's well-being – unfortunately, there is nothing else we can do. These diseases are incurable and, in most cases, shorten the lifespan and reduce the quality of life for your pet, as well as yours.
