TL;DR: Sudden hind leg lameness in cats often stems from physical injury and typically requires a vet visit within 24 hours, though cold limbs or extreme pain signify a life-threatening emergency.
What causes sudden hind leg lameness in cats?
Sudden hind leg lameness occurs when a cat unexpectedly stops putting weight on one of its back legs or moves with a noticeable limp. When this happens immediately after play, it is often the result of a physical injury. Common causes include soft tissue strains, ligament tears (similar to an ACL injury in humans), or even a small fracture from a jump or sudden turn. In some instances, it may also indicate a neurological or vascular issue that was exacerbated by activity.
Is my cat's sudden lameness a veterinary emergency?
- The urgency level for this situation is Medium.
- If your cat is still eating, drinking, and not in extreme distress, you should schedule a veterinary appointment within 24 hours.
- If the leg is hanging limply, feels cold to the touch, or if your cat is vocalizing in intense pain, seek immediate emergency care as this may indicate a blood clot (Aortic Thromboembolism).
Why should I provide a photo or video of my cat's lameness to the vet?
- Capturing a short video of your cat's movement or a photo of how they are resting their leg is vital for your veterinarian.
- Cats often "mask" their pain due to the stress of a clinic visit; visual evidence from home ensures the vet sees the true behavior.
- Showing the vet exactly how your cat was limping helps them identify the specific joint involved and the severity of the lameness for a faster diagnosis.
Clinical Context (Merck Veterinary Manual)
Following sudden hindlimb lameness in cats after play, a thorough physical examination is crucial to identify the underlying cause. Assessment should proceed from distal to proximal, noting any swelling, pain, instability, crepitation, reduced range of motion, or muscle atrophy. Serial examinations before and after exercise may be necessary for subtle lameness. Imaging techniques such as radiography, ultrasonography, CT, or MRI can aid in diagnosis. One potential cause to consider is arterial thromboembolism, particularly in cats with pre-existing conditions like cardiomyopathy or hyperthyroidism, which can manifest as pain, paresis, or paralysis of the hindlimbs, accompanied by reduced or absent arterial pulses, cool extremities, and firm, swollen gastrocnemius muscles.
Chapter: Orthopedics, Neurology, Anesthesia
Source: The Merck Veterinary Manual, 11th Edition (Page 1193)