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Dr. Kara
Dr. Kara, Veterinarian
Category: Dog Veterinary
Satisfied Customers: 16538
Experience:  Over 20 years of experience as a veterinarian.
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My 8 year old, overweight pomeranian mix has severe luxating

Customer Question

My 8 year old, overweight pomeranian mix has severe luxating patellas. Her left is fixed out of place and she has compensated by turning her leg in. She gets around ok but suddenly this evening, she stopped being able to support her weight and was scooching around by pulling herself with her front legs. She is not acting like she is in pain at all. If I support her weight with a towel, she tries to walk with all 4 legs. We just returned from the emergency vet with a neurological appointment in the morning. The ER vet suggested that we may be looking at the end of our dog's time with us. We brought her home with tramadol but are wondering if it makes sense to pay $3k for an MRI. What do you think?
Submitted: 1 year ago.
Category: Dog Veterinary
Expert:  Dr. Kara replied 1 year ago.

Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that Lily has suddenly lost the ability to support her weight on her rear legs.

Did the veterinarian at emergency give you any idea on why she is unable to support herself?

Does she seem to be able to feel her rear feet toes?

Is she able to urinate and defecate normally?

Unfortunately Pomeranians as a breed are prone to a problem with their intervertebral discs, which are the spongy cushions between the individual vertebrae in their back and neck. These spongy discs can move or rupture and place pressure upon the spinal cord which can lead to pain, and in severe cases paralysis. I suspect that this is the trouble with Lily.

Radiographs can sometimes be diagnostic but often early on in the disease process, because the discs are soft tissue not bone, everything will look normal. An MRI is the best way of diagnosing disc disease.

If the dog is painful but has no evidence of paralysis we can try strict rest, anti-inflammatories and pain medications for several weeks to allow healing. In that case an MRI isn't absolutely necessary.

If there is evidence of weakness or paralysis then surgery by a board certified veterinary neurologist, as soon as possible, is indicated. An MRI is indicated at that point as it will identify which discs are affected and thus direct the surgeon.

Surgery is no guarantee that she would regain function, but it is her best chance. Surgery and the aftercare needed can be thousands of dollars.

If you know surgery is not something that you could or would have done for Lily then an MRI isn't absolutely necessary. It would confirm the diagnosis, but not change medical therapy. They can try anti-inflammatories and see if she comes along. But once dogs lose feeling their prognosis for return to function becomes very guarded, thus the veterinarian's comment about possibly this being the end of her time with you.

So in short if surgery is not an option then I don't think an MRI is absolutely needed.

Please let me know if you have any further questions.

Customer: replied 1 year ago.
Lily seems to not be in pain. She just has significant weakness in her hind end. She can move both back legs but cannot support her weight. Does that change your comments at all?
Expert:  Dr. Kara replied 1 year ago.

Some dogs have enough pressure on their spinal cord to cause loss of pain sensation too, although usually they lose the ability to move their rear legs at all with that amount of pressure.

There are other possible reasons for rear leg weakness.

FCE, fibrocatilagenous emboli, is a condition where a chunk of cartilage breaks off and lodges in the blood vessels that supply the spinal nerve roots. It is very painful initially as blood supply to tissue is blocked off. The pain only lasts a short time, less than a few hours to a day, but the weakness from the nerve damage it causes it can last for weeks or in rare cases is permanent.

Large breed dogs like Rotties and German Shepherds are prone to a disease process that affects the rear legs called lumbosacral stenosis (LSS), but it can occur in small breeds too.
It can have many of the same symptoms as a FCE as it causes neurologic symptoms too. It is caused by weak spinal ligaments that allow the bones in the spinal column to move and place pressure on the spinal cord or it can be due to inflammation of the ligaments inside the spinal cord canal causing pressure on the spinal cord leading to loss of function, just like a FCE.

FCE are initially painful but after that it's just a matter of regaining function.
LSS can be painful on and off until the spinal column is stabilized and the pressure is taken off the spinal cord permanently.

Another possibility if she seems not painful is a condition called ascending myelopathy. This is a progressive degeneration of the spinal nerves that begins with incoordination of the rear legs then progresses to loss of urine and stool control (continence). This seems very unlikely with her as her symptoms came on very suddenly according to your history. But perhaps the symptoms in her rear leg that you attributed to a luxating patella were actually due to myelopathy.

An MRI will show a FCE, lumbosacral stenosis, and intervertebral disc disease.

Myelopathy can only be definitively diagnosed with a biopsy of the affected spinal cord (so only after death) but there is a blood test that looks for genetic markers for the disease. If you want to test her for the disease there is a blood test available which is pretty accurate. Here is a link to a website which will give you information about how to get her tested: