TL;DR: Sudden hind leg paralysis in dogs is a critical medical emergency that requires immediate veterinary intervention to preserve spinal function and mobility.
What causes sudden hind leg paralysis in dogs?
Sudden paralysis of the back legs occurs when a dog abruptly loses the ability to move their hind limbs or support their own weight. This condition is often caused by a neurological issue where the communication between the brain and the spinal cord is interrupted. Common causes include Intervertebral Disc Disease (IVDD), Fibrocartilaginous Embolism (FCE or 'spinal stroke'), or acute spinal trauma.
Is sudden hind leg paralysis a veterinary emergency?
- Sudden paralysis is a high-urgency medical emergency where the window for successful treatment, especially surgery, is very narrow.
- If your dog has lost 'deep pain sensation' (the ability to feel a firm squeeze on their toes), the prognosis worsens with every hour that passes.
- You should contact an emergency veterinarian immediately, as rapid intervention can be the difference between permanent paralysis and a full recovery.
Why should I provide a photo or video to help with my dog's triage?
- Providing a short video of your dog's movement allows triage professionals to see if the dog is 'knuckling' or if there is total flaccidity in the limbs.
- Visuals help the veterinary team differentiate between a severe orthopedic injury and a neurological crisis.
- Advance information allows the clinic to prepare necessary diagnostic tools, such as an MRI or CT scan, before you even arrive.
Clinical Context (Merck Veterinary Manual)
Acute, painful paraparesis with an inability to flex or extend the hock may indicate arterial thromboembolism, commonly occurring at the distal aortic trifurcation and causing ischemia of the pelvic limb muscles and nerves. Underlying conditions may include myocardial disease, hyperadrenocorticism, hypothyroidism, renal disease, cancer, and heart disease. Clinical signs include loss of flexor and potentially patellar reflexes, decreased sensation distal to the hock, firm and painful gastrocnemius and cranial tibial muscles, and potentially cyanotic nails with weak or absent femoral pulses. Diagnosis is typically based on clinical features, with elevated serum creatine kinase (CK) levels often present; Doppler ultrasonography can aid in evaluating blood flow in the distal aorta and femoral arteries. Severe thoracolumbar spinal cord injury may cause paraplegia with increased extensor tone in the thoracic limbs (Schiff-Sherrington phenomenon). In cases of suspected spinal trauma, advanced imaging such as CT is indicated, as radiographs may not reveal all spinal fractures.
Chapter: Neurology
Source: The Merck Veterinary Manual, 11th Edition (Page 1240)