What is Canine Cognitive Dysfunction?

Did you know that dogs can develop a condition that is startlingly similar to Alzheimer's Disease in people?  It's true.  It's called Canine Cognitive Dysfunction (CCD) and a large percentage of our best friends will begin to show signs of this condition as early as 6 years old!  

Diagnosis of CCD is difficult.  There are sometimes changes on an MRI, but at other times all the diagnostic tests are normal.  That's why we, as veterinarians, rely so much on you, the pet owner, to identify signs of this condition and begin to intervene as soon as we can.  

You see, just like with Alzheimer's Disease, there is no cure for CCD.  There are lots of supplements, vitamins, botanical products, and even medications that can be used to slow the progression of the disease, but no one knows how to reverse the effects.

This particular disease is one that has caused me very personal heartbreak.  I had to say goodbye to the best-dang-dog-I've-ever-known, Scout, because of it.  

Professor Stout Scout in his prime ...

Professor Stout Scout in his prime ...

I met Professor Stout Scout when I was a technician working at an emergency veterinary clinic in Charleston, SC.  He came in the clinic as a stray and left that same night as my best friend and constant companion.  He went with me to Athens, GA for vet school; to Blacksburg, VA for my internship; and all the way to Davis, CA for my residency.

It was in California that I first started to notice some of the telltale signs of CCD.  Veterinarians use the acronym D-I-S-H to describe these signs.  

Disorientation is common.  

Interactions with their owners or other pets in the household may change

Sleep/Wake cycles are often disturbed

House-training can be lost as well

Scout started to show all these signs, and it seemed to be progressing rather rapidly.  Well, I'm insatiably curious and I had to know if my buddy was starting to show signs of CCD, or if there was something else going on.  Because brain tumors and other diseases can cause these signs too.  So Scout had an MRI and a spinal tap at UC Davis.

Typical structural changes in a dog's brain with CCD on MRI include loss of brain tissue, dilation of the fluid-filled ventricles, and shrinkage of the interthalamic adhesion.

Typical structural changes in a dog's brain with CCD on MRI include loss of brain tissue, dilation of the fluid-filled ventricles, and shrinkage of the interthalamic adhesion.

He must have read the same text books I was studying at the time, because he even had the structural brain changes that happen with CCD.  So, he'd checked all the tick-boxes for me.  I went on a search for something that might help.

I tried everything, and in the end found a cocktail of supplements and vitamins that seemed to slow his decline.  I was able to get another couple of years or so with him, but CCD won in the end.  Scout's quality of life declined, and I finally had to make that difficult, heartrending, and compassionate decision to help him slip off this mortal coil with all of the dignity and peace that I could muster for him.

So, if you think your older pet is starting to show signs of CCD, contact your veterinarian to have a discussion about the signs you're seeing.  We still can't reverse the signs of this disease so early intervention is key...

What is Caudal Cervical Spondylomyelopathy (CCSM)?

This blog post is going to discuss the second form of "Wobbler's Disease" in dogs, Caudal Cervical Spondylomyelopathy or CCSM.

The breeds most commonly affected with CCSM include the Mastiffs and the Great Dane, but almost any large breed dog can be affected.  Typically, this condition is seen in younger dogs as it is a developmental problem (contrasted with the degenerative problem that causes Disc Associated Wobbler's Disease or DAWS).  

Again, to contrast with DAWS, the compression of the spinal cord is due to bony changes rather than discs, tendons, ligaments, or soft tissues.  The parts of the vertebrae that form the bony tunnel of the vertebral canal develop abnormally and are thickened towards the tail-end of the vertebrae.  This bony thickening is most noticable along the lateral (side) walls of the tunnel called the pedicles.  So, the compression is from the side in CCSM, whereas it's mostly top-to-bottom with DAWS.

Once again, there are two different options for therapy, medical management vs surgery.

With medical management, the goal is to control the dog's clinical signs.  But the drugs don't do anything to stop the disease progression.  And, sometimes, the disease can progress very suddenly due to vascular or 'bruising' injuries to the spinal cord!  Othertimes, the progression is slow and due to progressive bony changes at the true joints in the vertebrae, the facets.

Thickening of the facets can often cause progressive signs in CCSM due to worsening spinal cord compression...

Thickening of the facets can often cause progressive signs in CCSM due to worsening spinal cord compression...

Surgery attempts to alleviate the compression and works with medical management to control the clinical signs but also to halt the progression of the disease.  In the ideal situation, surgical decompression even allows us to stop the medications.  

Unlike DAWS which can suffer a 'domino effect' following surgery, this isn't common with CCSM decompression.  But, just like DAWS, there are several surgical options for pets with CCSM.  Some include decompression by removing bone from the top and sides of the vertebral canal.  Others involve a distraction-fusion technique to allow the bone to resorb on its own and alleviate the compression.

Diagnosis of this disease often requires an MRI or a CT scan combined with a myelogram.  In the end, the diagnosis will play an integral role in deciding which medical or surgical option is right for each individual patient.

What is Chiari Malformation (COMS)?

Chiari malformation is the term used in human medicine that equates in veterinary medicine to Caudal Occipital Malformation Syndrome, COMS.  The most commonly affected breed with COMS is the Cavalier King Charles Spaniel.  With the advent of MRI we are finding this condition in several other breeds as well such as the Chihuahua, Yorkshire Terrier, and other small breeds of dogs.  

COMS is a condition where the base of the skull in the dog is abnormally shaped.  This leads to a more 'rounded skull' and, in turn, causes the part of the brain at the base of the skull (the cerebellum) to be 'crowded'.  Because this skull defect is present at birth and through the growth phase of the puppy, once the dog reaches adulthood, the skull changes are static and don't change.  But the after-effects are progressive.

This is a sagittal MRI of a dog with COMS.  You can see the cerebellum at the base of the skull has slipped out of the base of the skull into the 1st vertebrae of the neck in what is termed a cerebellar herniation.  The SM secondary to the COMS is present as the white area in the spinal cord just behind the cerebellum.

This is a sagittal MRI of a dog with COMS.  You can see the cerebellum at the base of the skull has slipped out of the base of the skull into the 1st vertebrae of the neck in what is termed a cerebellar herniation.  The SM secondary to the COMS is present as the white area in the spinal cord just behind the cerebellum.

You see, COMS is associated with another condition that takes place in the spinal cord 'downstream' from the skull in the dog's neck.  This condition is called syringohydromyelia or SM.  SM is a progressive degenerative condition in the spinal cord that can happen anytime the flow of spinal fluid is disrupted.  

Scoliosis, or a left-right bending malformation f the spinal cord can also happen in cases of COMS and SM

Scoliosis, or a left-right bending malformation f the spinal cord can also happen in cases of COMS and SM

Most people know that the spinal cord has a left and right side that correspond directly to the left and right sides of the body.  If you damage the left side of the spinal cord, the signs associated with that damage will be seen on the left side of the body.  However, did you know that the spinal cord also has a 'front' and 'back' that carry specific types of information?  

The part of the spinal cord that is towards the chest of a person or animal carries information from the brain to the body, instructions on how to move.  The part of the spinal cord towards the back of the person or animal carries information from the body to the brain, sensory information if you will.

Interestingly enough, SM almost always forms in the sensory part of the spinal cord.  So it leads to abnormal sensations rather than weakness or abnormal movments.  That means that dogs with SM manifest some very odd and quite varied behaviors secondary to the abnormal sensations that their spinal cord is causing them to feel.  Imagine, that every time you got excited your toes began to itch and burn, your ear began to feel hot, or your arm became numb and tingly...

The most striking manifestation of this abnormal sensation is called 'phantom scratching'.  In this situation, dogs will begin to scratch 'at' their ear, but just a little bit off to the side.  Almost as if they were scratching the air!

Diagnosis of COMS and SM requires an MRI.  No other tests are able to definitively diagnose this condition.  There are other tests that have been used to support the diagnosis though, including BAER hearing tests, CT scans, ultrasound, and even infrared imaging.  

Treatment for COMS is sometimes medical, and sometimes surgical.  There are several drugs that can be used to help control the condition, and surgery can be very successful (depending on how one defines 'success').

What is an EEG?

EEG is the acronym for electroencephalography.  

Which is definitely a word that needs an acronym ....

Electroencephalography is a method of using electrodes that can sense the flow of electricity within biological tissues to look at brain function.  The brain, spinal cord, heart, and some other special tissues in the body use electrical signals to communicate rapidly between the cells that make up those particular tissues.  With these special electrodes, we can watch this electrical current and deduce information from them with regard to certain diseases.  

The machine shows us the electrical activity as several lines on a screen.  In animals and people, EEG is primarily used to evaluate an individual for seizures or, sometimes, sleep disorders.  

Seizures look like 'spikes' followed by 'waves' as you can see here...

Seizures look like 'spikes' followed by 'waves' as you can see here...

We also use it for patients that are in status epilepticus.  This is a condition when a seizure lasts longer than 20 minutes or there are multiple seizures without a return to consciousness in between.  Left untreated, this can cause permanent brain damage!

We've actually had two patients at LOVN this year that were in status epilepticus when they came in, but weren't having any outward signs.  This is called non-convulsive status epilepticus and without our EEG we wouldn't have been able to recognize it.  What's more, we were able to treat both of these patients with medications and use the EEG to monitor the effect of the drugs.

When patients are having such prolonged seizures, we often have to put them under general anesthesia to stop the seizures.  Then we have to decide when to try and wake them up.  Without the EEG this would just be a guess.  But with our EEG we can monitor the read-out for continued seizures even though the patient is completely asleep.  So, now, we don't have to guess when it's safe to wake a patient up.  We know...

Brain tumors in dogs and cats

Dogs and cats can develop brain tumors similar to those found in people.  These tumors can cause a variety of clinical signs depending on where they are and what structures are affected.  Diagnosis often requires an MRI of the brain and sometimes we use spinal fluid tests as well.

Just because a dog or cat has a brain tumor, it doesn't mean that they can't be treated.  While some cancers are treated with chemotherapy, we have surgical options for some others.  The overall prognosis will depend on what type of tumor it is, where it is, and what treatment option is chosen.

Chemotherapy in animals is not very similar to what happens in people.  Because of the doses and drugs that we use, dogs and cats very rarely have significant side effects from the medications.  After all, our goal is ALWAYS to maintain your pet's quality of life for as long as we possibly can.

We've recently added a new device to our surgical suite that allows us to more readily and completely remove cancer cells at surgery.  It's called a Cavitronic Ultrasonic Aspirator, or CUSA.  This device uses ultrasound waves to disrupt the adhesions between the cancer cells which literally liquifies the tumor.  It then irrigates the area with saline and aspirates the cancer cells back out!

At LOVN we are skilled and experienced in all of the surgical approaches to the brain.  We have the technology and expertise to give your pet the very best care and outcome.  A recent case that we performed a transfrontal craniotomy on (see the illustration above) allowed us to use the CUSA for surgical removal of her meningioma.  With this device we are able to get so much of the tumor that we expect her to be disease free for close to two years!

What is Wobbler's Disease?

Wobbler's disease is a term used to describe two different pathological processes in the neck of dogs.  One form happens in younger large breed dogs, and the Great Dane and Mastiff are the most common breeds.  The other form happens in older dogs, and the Doberman Pinscher is the most common breed.  It also occurs in horses, but we'll save that for another blog post on another day!  

The medical term for the condition in younger dogs is Caudal Cervical Spondylomyelopathy.  In this disease, the spinal cord is compressed by increased thickness of the bones in the vertebrae themselves.  Typically, this is towards the base of the neck, and it is slowly progressive.  While low doses of steroids can help control the disease; this type of medical management does not address the underlying cause and the signs often progress in spite of the drugs.  Surgery to remove the compressive bone is often curative but is a complicated procedure and carries some degree of risk.

In older dogs, Wobbler's disease is more aptly termed Disc Associated Wobbler's Syndrome, or DAWS.  In these patients the spinal cord compression is caused by bulging of the intervertebral disc and thickening of other supportive ligaments in the vertebrae at the base of the neck.  Medical management for this condition also makes use of low-dose steroids.  Just like the condition in younger dogs though, medications do not treat the underlying cause and the clinical signs often progress.  Surgical options exist for these pets as well, but have often been plagued with complications.  Particularly, a problem known as the 'Domino Effect'.  We'll discuss this condition and the surgical options in more detail in a later post.

Because both of these conditions occur in the neck and are progressive, dogs can become completely paralyzed if not treated.  Classically, these pets have a 'two-engine' gait where the forelimbs take short and choppy strides and the hindlimbs have a longer, loping gait.  

If you think your pet might have Wobbler's disease, contact your veterinarian.  Oftentimes an MRI is necessary to make the diagnosis, but there are treatment options and help is out there!

This is a video illustrating the gait disturbance we typically see and outlining the story of a dog with Wobbler's Disease that had a disc replacement surgery!  If you're interested in learning more about disc replacement therapy and the Adamo Spinal Disc click here.