TL;DR: Sudden hind limb weakness in cats is a life-threatening medical emergency often caused by a blood clot and requires immediate veterinary intervention to manage pain and restore circulation.
What is sudden hind limb weakness in my cat?
Sudden hind limb weakness, or paralysis, occurs when a cat unexpectedly loses the ability to use or support weight on their rear legs. This can manifest as dragging the limbs, wobbling, or a total inability to get up. It is often a sign of a severe underlying vascular or neurological issue rather than a simple muscle strain.
Is sudden hind limb weakness in my cat a medical emergency?
- Urgency Level: High. This is a critical medical emergency that requires immediate attention.
- The most frequent cause is Feline Aortic Thromboembolism (FATE), also known as a saddle thrombus.
- This occurs when a blood clot lodges at the base of the aorta, cutting off blood supply to the legs.
- It is extremely painful and requires immediate veterinary intervention to manage pain and attempt to restore circulation.
- Do not wait for an appointment; go to an emergency clinic immediately.
How can a photo or video help the vet triage my cat?
- If it is safe to do so while preparing for transport, capture a short video of your cat attempting to move to provide invaluable information for the veterinary team.
- Take a photo of your cat's paw pads; in cases of a blood clot, the pads may appear pale or bluish compared to the front paws.
- These visual aids allow the triage nurse to quickly assess the severity and prioritize your cat for immediate stabilization upon arrival.
Clinical Context (Merck Veterinary Manual)
Posterior paresis or paralysis in cats can stem from various causes, including feline infectious peritonitis (FIP) involving the central nervous system, feline leukemia virus-associated myelopathy, or saddle thrombus secondary to an underlying disease such as cardiomyopathy. FIP-related spinal cord involvement may present with spinal hyperesthesia, parapareisis or tetraparesis, hyperglobulinemia, and a mixed pleocytosis with increased protein concentration on CSF analysis; prognosis is poor. FeLV-associated myelopathy leads to progressive pelvic limb weakness and ataxia, progressing to paraplegia, diffuse spinal pain, and abnormal behavior. Saddle thrombus manifests as focal muscle necrosis and degeneration of the sciatic nerve and its branches distal to the mid-thigh, diagnosed via Doppler ultrasonography to evaluate blood flow. Emergency management of saddle thrombus includes analgesics, nursing care, treatment of underlying disease, and anticoagulants to reduce further thrombus formation; neurologic deficits may improve over weeks to months, but permanent deficits are possible, and the prognosis is guarded.
Chapter: Cardiology
Source: The Merck Veterinary Manual, 11th Edition (Page 1245)