TL;DR: Sudden hind limb weakness or paralysis in dogs is a high-priority emergency requiring immediate veterinary intervention. Contact an emergency vet if your dog collapses, drags their legs, or cannot support their weight to prevent permanent nerve damage.
What causes sudden weakness or collapse in my dog's back legs?
- Sudden weakness or paralysis occurs when the neurological or musculoskeletal systems fail.
- Common signs include wobbliness (ataxia), dragging of the paws, or a complete inability to stand.
- Underlying causes often include Intervertebral Disc Disease (IVDD), Fibrocartilaginous Embolism (FCE), or acute spinal trauma.
Is sudden hind limb weakness in my dog a veterinary emergency?
- Yes, any sudden loss of limb function is a high-urgency veterinary emergency.
- The window for successful treatment of spinal cord compression can be very narrow.
- Seek emergency care immediately if your dog cannot support weight, appears to be in pain, or has a "drunken" gait to avoid permanent damage.
How can a video or photo of my dog help the veterinary triage team?
- A brief video of your dog attempting to move shows the vet the exact nature of the weakness.
- It captures specific coordination or motor function loss that may be hidden by stress once the dog is at the clinic.
- Visual evidence helps the triage team accurately prioritize your pet's care upon arrival.
Clinical Context (Merck Veterinary Manual)
Sudden back leg weakness in dogs can stem from several causes. Arterial thromboembolism, often secondary to myocardial disease or underlying disorders like hyperadrenocorticism, hypothyroidism, renal disease, cancer, and heart disease, can cause acute, painful paraparesis and an inability to flex or extend the hock, along with decreased sensation distal to the hock and weak or absent femoral pulses. Fibrocartilaginous embolism, primarily seen in adult, large, and giant breed dogs, involves occlusion of spinal cord vessels by fragments from intervertebral discs, leading to an abrupt onset of gait dysfunction, often asymmetric, and rarely progressing past 12 hours. Acute idiopathic polyradiculoneuritis can manifest as a short-strided gait in the pelvic limbs progressing to flaccid tetraparesis or tetraplegia within 1-2 days, potentially with facial and laryngeal weakness.
Chapter: Cardiology, Neurology
Source: The Merck Veterinary Manual, 11th Edition (Page 1245)