TL;DR: Back leg trembling in cats often signals underlying pain, weakness, or nerve issues and requires a veterinary exam within 24 to 48 hours. Immediate emergency care is necessary if the cat loses leg function or appears in severe distress.
What causes back leg trembling in cats and what does it look like?
Trembling or shaking in a cat's hind legs while standing is a physical sign that something is affecting the cat's motor control, strength, or comfort. It can range from subtle muscle fasciculations to visible tremors that make the cat appear unstable. This symptom often points to underlying issues such as muscle fatigue, nerve dysfunction, electrolyte imbalances, or chronic pain.
Is my cat’s back leg trembling an emergency?
- The urgency level for back leg trembling is currently rated as Medium.
- While rarely an immediate life-and-death crisis, you should schedule a veterinary exam within the next 24 to 48 hours.
- Seek emergency care immediately if the trembling progresses to a complete loss of the use of the legs or if your cat appears to be in significant distress.
How can videos and photos of my cat’s tremors help the veterinarian?
- Capture the trembling on video at home because cats often hide symptoms at the clinic due to adrenaline.
- Provide your veterinarian with an objective look at the frequency and severity of the tremors while the cat is in its natural environment.
- Use visual evidence to help the vet differentiate between neurological twitching and musculoskeletal weakness, significantly speeding up the diagnostic process.
Clinical Context (Merck Veterinary Manual)
Arterial thromboembolism, often secondary to conditions causing left atrial enlargement such as cardiomyopathy, hyperthyroidism, or congenital heart disease, can result in hindlimb paresis or paralysis. Clinical signs include pain, reduced or absent femoral or pedal pulses, cool extremities, and firm, swollen gastrocnemius muscles; however, neurologic abnormalities are commonly misdiagnosed as thromboembolism. Doppler ultrasonography can evaluate blood flow. Although spontaneous clot lysis may occur, analgesics and nursing care are indicated; anticoagulants like heparin may reduce further thrombus formation. Neurologic deficits may improve over weeks to months, but permanent deficits are possible and euthanasia is common.
Chapter: Cardiology
Source: The Merck Veterinary Manual, 11th Edition (Page 1245)