By Dr. Joanne Fernandez-Lopez
What causes a dogs’s back legs to suddenly give out? Many dogs may play and run without missing a step. Then, your pet may start limping, not weight bearing or even dragging both back legs. You may think your dog may be sore and will be back to normal pretty soon. However, when there is sudden weakness of the back legs and your dog still is unable to move, this is a symptom that should be evaluated and treated immediately by your veterinarian. Following are some possible causes for a dog’s back legs suddenly giving out.
Intervertebral Disc Disease
When your dog’s back legs suddenly give out or show paralysis, there are numerous potential causes. One of them is intervertebral disc disease or IVDD. This is when the cartilaginous disc in the backbones herniates and pushes the spinal cord. This places pressure on nerves preventing hind limb motor function.
Now, the faster a veterinarian evaluates your pet with this condition, the better the prognosis. When there are mild cases of IVDD, meaning they are able to walk a bit, medical treatment like anti-inflammatory medication, muscle relaxers and rest may improve the condition.
But when there is no motor function at all and surgery is not performed within 12 hours, prognosis decreases to 5 percent. Surgical correction consists of removing the herniated disc causing the pressure on the spinal cord. Your pet will also need post-operative nursing care for pain management and monitoring until it regains ability to walk well.
If surgery is performed, your pet will have a prognosis of 80-90 percent for recovery of motor function. The approximate cost of surgical correction with hospitalization may be between $2,500 to 4,500.
Hip and Knee Problems
Other possible causes of sudden weakness are hip and knee orthopedic issues such as hip dysplasia and cruciate ligament injury. An orthopedic examination and x-rays of the hips and knees will localize one or both of these conditions.
Fortunately, medications and rest can provide temporary relieve until planned surgical intervention. This will not require emergency surgery like severe conditions of IVDD unless it involves complicated fractures with a history of trauma.
Do not worry; your veterinarian will determine the best treatment option at that moment.
Other Possible Causes
Another less common cause is degenerative myelopathy. This is an inherited degenerative disorder that causes progressive weakness. Initially, affected dogs may start dragging their nails. Later on, will show difficulty jumping and loose balance while walking. Occasionally, this symptom may progress to the front legs.
Diagnosis is based on exclusion of other disorders that may mimic it, but, a genetic test for the SOD1 gene may assist in diagnosis. Unfortunately, for this condition there are no proven effective therapies and supportive palliative care is provided to maintain quality of life.
Other less common conditions may include neoplasia (cancer of bone or spinal cord) and infection or inflammation of the spinal cord (myelitis).
At the Vet’s Office
Your veterinarian will ask you if your pet has any history of trauma, concurrent medical issues, current medications, exposure to any potential toxins, travel, vaccine history and so on.
Then, the veterinarian will proceed with an orthopedic and neurological examination to localize lesion and differentiate bone-related lesions versus nerve deficits.
To reach a diagnosis, this may be by exclusion of the other discussed causes. Xrays may show gross lesions in the bone like osteosarcomas. Still, most of the time other advanced imaging like myelogram, CT scans, or MRI are required.
Diagnostics like bloodwork and imaging will be recommended during this visit. The average costs between diagnosis and treatment may roughly range between $400-4,500. Please, contact your veterinarian immediately if you notice any sudden instability in the back legs.
About the author
Dr. Joanne Fernandez-Lopez is an emergency veterinarian on staff in the Emergency and Critical Care Department at Florida veterinary Referral Center (FVRC).
Originally from Puerto Rico, Dr. Joanne Fernandez-Lopez graduated from North Carolina State University – College of Veterinary Medicine in Raleigh, NC. Prior to joining FVRC, Dr. Fernandez-Lopez worked in small animal general practice and as a relief doctor in South East Florida. Her professional interests include dermatology, surgery, internal medicine, preventive medicine, reptile medicine and practice management.
In her free time, Dr. Fernandez-Lopez enjoys relaxing at the beach, paddle boarding, kayaking, and surfing. She has a small Tibetan spaniel mix named Carlitos.