Paralysis is a loss of muscle movement and feeling in a part of the body. It may be partial (paresis) or complete (paralysis) and can occur anywhere on the body. This article focuses on paralysis of the rear (hind) legs in cats.
Several components of the body are involved in movement. These consist of, the brain and the spinal cord (central nervous system) and nerves which connect the central nervous system to the rest of the body. The spinal cord is located within the spine. Anything affecting one or more of these systems can potentially result in paralysis.
Brain - The brain controls movement of the skeletal muscles. A region of the brain known as the motor cortex sends a signal to the spinal cord and from there to the nerves.
Spinal cord, nerves and muscles: The brain sends an electrical signal down the spinal cord, and from there to branching nerves. These nerves release a chemical known as acetylcholine which is picked up by the receptors within the muscles, causing them to contract (and move).
What are the most common causes of paralysis in cats?
- Aortic thromboembolism (saddle thrombosis) - A blood clot which forms in the left atrium of the heart (this most commonly occurs in cats with hypertrophic cardiomyopathy) and then moves down the aorta (which is located along the back), until the junction at the rear legs (known as the saddle), where it splits into the two 'iliac arteries', of the right and left leg. If the blockage occurs before the saddle, both legs will be affected, if the blockage occurs in the iliac artery of the left or right leg then only that leg will be affected.
- Tick poisoning - A common problem, especially along the east coast of Australia, is tick paralysis. A neurotoxin (a toxin affecting the nervous system) is injected into the cat (via the tick's mouth parts).
- Stroke - A stroke occurs when the brain is deprived of oxygen. It can occur due to a blocked artery (ischemic stroke) or a leaking/burst blood vessel (hemorrhagic stroke). Deprived of oxygen, the brain cells begin to die affecting the functions controlled by that area of the brain.
- Trauma - Most cases of trauma in cats are from car accidents, falls from a height and abuse (being beaten or kicked). A broken pelvis is very common in cats who have been hit by cars or fallen from a height.
- Cancer - Tumours of the spine or brain.
- Slipped disc (intervertebral disc herniation) - The spine is made up of vertebrae and discs, spongy cushions between each vertebra which act as a shock absorber and allowing movement and flexibility within the spine. Occasionally a disc may bulge or rupture, putting pressure on the spinal cord, leading to pain and in some cases paralysis.
- Viral infection - In particular, Feline Infectious Peritonitis.
- Toxoplasmosis - Infection caused by an intracellular parasite known as Toxoplasma gondii.
What are the symptoms of paralysis in cats?
Symptoms vary depending on the underlying cause of paralysis and may include:
- Limb weakness or complete paralysis (inability to move the limbs). If weakness has occurred, your cat may walk as if he is intoxicated, have difficulty jumping or standing.
- Urinary and/or fecal incontinence.
- Inability to feel pain in the hind leg(s) or feet.
- If trauma has occurred such as a car accident or fall, the tail may also be paralysed, resulting in limpness. You may notice bleeding and/or other signs of trauma. Cats who have been hit by a car often have severely damaged feet and claws.
- Cold rear limbs.
- Blue-tinged paw pads, which are easier to see in cats with light coloured skin.
- Weak or absent pulse in the groin.
- Hunched appearance, with the head lowered.
- Pain when touched.
- Reluctance to move.
- Dilated pupils (tick paralysis).
- Difficulty swallowing.
- Dilated pupils.
FIP has two forms, wet or dry. Symptoms vary depending on the type of FIP your cat has. 75% of cats have the wet form of FIP, with symptoms including:
- Swollen abdomen.
- Difficulty breathing.
- Weight loss.
- Persistent fever.
- Head tilt.
- Inability to get up.
- Fixed pupils.
- Facial paralysis.
Most cats infected with toxoplasmosis display no symptoms at all. When they are present, they are usually mild such as loss of appetite and lethargy.
- Pain. Crying out when touched, reluctance to move.
- Loss of appetite.
Transporting your cat to the vet:
A paralysed cat is a medical emergency and requires urgent attention. Be extremely careful handling a cat who is paralysed. Use a towel to carefully lift and place the cat on a flat surface (such as a board or heavy piece of cardboard) for transportation. If possible, call ahead to let your veterinarian know you are on the way.
How is the cause of paralysis diagnosed?
Your veterinarian will perform a complete physical examination and neurological assessment. He will obtain a medical history from you including if the cat has had access to outside, has he had any recent traumas such as a car accident or fall, does he have any heart conditions, anything else you have noticed? He will look for presenting symptoms such as:
In the case of trauma, there may be obvious signs of injury such as bleeding, pain when touched, broken skin.
A cat with aortic thromboembolism will have a weak or absent pulse in the groin.
Paralysis tick poisoning is extremely common in Australia, with my local (small) veterinarian seeing around 30 cases in dogs and cats every month. If you live in a tick-prone area, this may increase your veterinarian's index of suspicion. A thorough examination of your cat from the nose all along to the tail will be performed. However, the absence of a tick does not necessarily exclude the possibility of a paralysis tick as it is possible the tick has already fed and dropped off the cat (as happened with our own cat).
Diagnostic tests will vary depending on the possible cause of paralysis and may include:
Biochemical profile, complete blood count, and urinalysis to evaluate the overall health of your cat.
X-ray or ultrasound to evaluate the heart, spine and pelvis look for tumours.
A myelogram will be necessary for a definitive diagnosis of a slipped disc. This involves injecting a contrast material into the spinal canal followed by an x-ray to see where the spinal cord is being compressed.
Ultrasound to evaluate the heart for hypertrophic cardiomyopathy.
If the wet form of FIP is suspected, a sample of fluid from the abdomen may be taken for analysis.
Blood test to check for coronavirus antibodies, the virus responsible for FIP or antibodies to the t. gondii.
How is paralysis treated?
Treatment of rear leg paralysis depends on the underlying cause and may include:
- Antiserum to reverse the effects of the tick toxin.
- Supportive care such as cage rest, oxygen therapy while your cat recovers.
- IV fluids to treat dehydration.
Surgery to remove the tumour, which is usually followed up with chemotherapy.
Mild cases may be treated with cage rest and anti-inflammatory medications. More severe cases may require surgery to relieve pressure on the spinal cord and remove any material.
Most cats infected with toxoplasmosis will display mild symptoms if any at all and treatment isn't necessary. In severe cases, antibiotics will be prescribed to kill the parasite.
- Surgery to repair broken pelvis or back.
- Painkillers to relieve discomfort while he recuperates.
The option to perform surgery depends on the severity of the trauma and the long-term quality of life your cat may experience. In some cases, euthanasia may be the kindest option.
This can be tricky to treat and many pet owners elect to euthanise their cat. If treatment does go ahead, your cat will be put on pain medication to relieve discomfort and medications designed to dissolve the clot and prevent new clots forming.
Sadly the prognosis for FIP is grave and euthanasia is usually necessary.
Most cats are discharged once they are stable and have regained the ability to urinate and defecate on their own. It is common for your cat to be put on cage rest while he recovers. This may be keeping him confined to a small room or a cage. Cats adapt well to this setup, particularly as they are usually not feeling well. Always follow your veterinarian's instructions carefully and if you notice any changes, contact him immediately. It can take several weeks or even months for your cat to fully recover, depending on the severity of the condition.
In some cases, rehabilitation may be necessary to help your cat to regain strength in the rear legs.