TL;DR: Hind leg trembling in dogs is often caused by fatigue, aging, or excitement and is usually not an emergency unless accompanied by pain or mobility loss. Capturing a video of the episode is the most effective way to help your veterinarian reach an accurate diagnosis.
What causes my dog's back legs to shake and what does it mean?
It can be distressing to see your canine companion's back legs shaking, but this is a common symptom with many possible causes. In many cases, localized trembling in the hindquarters is related to muscle fatigue, excitement, or the natural aging process. Unlike a seizure, your dog will remain fully conscious, alert, and responsive to your voice while the trembling occurs.
Is hind leg trembling in dogs considered a medical emergency?
- The urgency level for isolated hind leg trembling is typically Low.
- If your dog is eating well, drinking, and moving without a significant limp, you likely do not need an emergency visit.
- Seek immediate veterinary care if the shaking is accompanied by a sudden inability to walk, extreme lethargy, or signs of severe pain.
How can a video or photo of my dog's shaking help a veterinarian?
- Capturing a clear video while the trembling is occurring is vital because tremors often stop by the time you arrive at the clinic.
- Seeing the specific rhythm and frequency of the movement helps the vet distinguish between neurological issues, orthopedic discomfort, or simple muscle weakness.
- Providing visual evidence ensures a more accurate path to treatment and a more efficient triage process.
Clinical Context (Merck Veterinary Manual)
Trembling or weakness in the hind legs of dogs can stem from several causes. Distal denervating disease can manifest as intermittent flexing of the hip and stifle of one pelvic limb, progressing to a dance-like motion in both hind legs, and eventually mild paraparesis, decreased proprioception, and gastrocnemius muscle atrophy; thoracic limbs are not affected and the condition is usually not severely debilitating or painful. Neosporosis or toxoplasmosis, especially in puppies, can cause paraparesis and a bunny-hopping gait, progressing to extensor rigidity and muscle atrophy in the pelvic limbs; without treatment, this can ascend to the thoracic limbs, causing dysphagia and fatal respiratory paralysis. In cases of suspected neosporosis or toxoplasmosis, serum CK concentration is often increased, and CSF analysis may reveal increased protein and leukocytes; diagnosis can be aided by serum or CSF antibody tests or muscle biopsy. Early treatment with clindamycin (15-20 mg/kg, IM, PO, bid) or trimethoprim/sulfadiazine (15 mg/kg, bid) and pyrimethamine (1 mg/kg/day) may be effective for neosporosis or toxoplasmosis.
Chapter: Neurology
Source: The Merck Veterinary Manual, 11th Edition (Page 1241)