SYMPTOM
Hind leg paralysis in cats
Sudden inability to move one or both hind legs, sometimes accompanied by cold paws or vocalisation.
Aortic Thromboembolism
One of the most recognised causes of acute hind leg paralysis in cats involves the formation of a blood clot that lodges at the aortic trifurcation, the point where the aorta divides to supply the hind limbs. This thromboembolic event abruptly interrupts blood flow to one or both hind legs, producing sudden onset paralysis, pain, and characteristic changes including cold limbs, absent pulses, and pale or bluish nail beds. The condition is frequently associated with underlying heart disease, though the cardiac condition may have been clinically silent prior to the embolic event; hyperthyroidism and some tumours are less common underlying causes. Affected cats are typically in severe pain and often cry out. In one series of 127 cats, 91 per cent were breathing rapidly, around two thirds had a low body temperature and had lost all movement in the affected legs, and 44 per cent had congestive heart failure. The outlook is guarded: in a study of 250 cats in UK general practice, 61 per cent were euthanised at presentation. Cats with only one leg affected, or with some movement retained, tend to fare better.
Spinal Cord Disease
Conditions affecting the thoracolumbar or lumbosacral spinal cord can produce hind leg paralysis through compression, inflammation, or vascular compromise of the neural tissue. In a large pathology-based study, inflammatory and infectious disease, most often feline infectious peritonitis, was the commonest category of feline spinal cord disease, followed by tumours such as lymphoma. Intervertebral disc disease, fibrocartilaginous embolism and other forms of myelitis are less common but recognised, and all can present with varying degrees of hind limb dysfunction. The onset may be acute or progressive depending on the specific condition, and the degree of sensory and motor loss can vary from subtle weakness to complete paralysis with loss of deep pain perception.
Traumatic
Injuries to the spine, pelvis, or hind limbs from falls, vehicular trauma, or other physical impacts can produce acute hind leg paralysis. Spinal fractures or luxations may directly damage the spinal cord, while pelvic fractures may affect the nerves supplying the hind limbs. The history of trauma is not always known, particularly in outdoor cats, and the full extent of injuries may not be apparent from the outside.
Peripheral Neuropathy
Conditions affecting the peripheral nerves supplying the hind limbs can produce weakness progressing to paralysis. Diabetic neuropathy is a recognised cause of hind limb weakness in cats, often producing a characteristic plantigrade stance where the cat walks on its hocks rather than its toes. Other neuropathies, whether metabolic, toxic, or immune-mediated, can similarly affect hind limb function, though the onset is typically more gradual than vascular or traumatic causes.
Neoplastic
Tumours affecting the spinal cord, spinal canal, or the nerves supplying the hind limbs can produce progressive hind leg dysfunction. Lymphoma is the most commonly reported spinal tumour in cats and may produce a gradual onset of weakness that progresses to paralysis over days to weeks. The progression tends to be steady or stepwise, and the paralysis may initially affect one limb before involving both.
Why timing matters
Early observation
The onset characteristics of hind leg paralysis carry significant diagnostic meaning. A sudden, acute onset, where a cat that was walking normally moments ago is suddenly unable to use its hind legs and appears distressed, presents a different picture from a gradual onset over days or weeks. Acute presentations are more commonly associated with vascular events or acute spinal cord injury, while gradual onset may suggest progressive conditions such as tumours, chronic disc disease, or metabolic neuropathies. In the first hours the picture can change quickly. With a clot, the legs are without blood supply from the moment of onset, the pain is severe, and heart failure, when present, can make breathing progressively harder. With spinal cord compression or trauma, the presence or absence of conscious pain sensation is the most important indicator of whether walking may return. Cold legs with pale pads point towards a blocked blood supply and warm legs with pink pads point more towards the spinal cord, but the two can only be separated with confidence in an examination.
Later presentation
As time passes following the onset of hind leg paralysis, changes in the cat's condition, whether improving, stable, or deteriorating, provide important prognostic context. Some causes can show gradual improvement as swelling resolves or new blood flow develops around a clot, while others worsen as the underlying condition advances. Improvement after a clot does not mean the event has passed: the return of blood flow to starved muscle can release potassium into the bloodstream and disturb the heart rhythm, and parts of the limb may be permanently damaged. Secondary complications including pressure sores from immobility, urinary retention or incontinence, and muscle atrophy may develop over days to weeks. The cat's overall demeanour, appetite, and engagement with its environment during this period can also reflect the degree of pain and systemic impact.
The trajectory following hind leg paralysis varies dramatically with the underlying cause. After a thromboembolic event, cats that survive the first days may regain at least partial use of the legs over roughly two to six weeks as the clot breaks down or new blood flow develops. Many cats do not reach that point, as a large share are euthanised at presentation because of pain, heart failure or a poor outlook. The risk of a further clot remains while the heart disease persists, and survival after discharge is often measured in months, shorter when congestive heart failure is present. Spinal cord compression from disc disease may fluctuate or progressively worsen without intervention. Neoplastic causes tend to show steady or stepwise decline. Traumatic causes have variable outcomes depending on the severity of neural damage. Whether the paralysis is complete or partial, whether deep pain sensation is preserved, and whether there is any voluntary motor function all influence the expected trajectory.
Conditions commonly associated
Hypertrophic Cardiomyopathy in Cats
Thickened heart muscle can lead to an enlarged left atrium in which blood moves slowly and a clot can form. A clot that breaks away can lodge where the aorta divides and block circulation to the hind legs, causing sudden paralysis, severe pain and cold limbs. The heart disease has often gone unnoticed before this happens.
Arthritis in Cats
Severe arthritis affecting the hips, spine, or hind limb joints can occasionally cause such marked pain and stiffness that a cat may be reluctant or unable to bear weight on the hind legs, though true paralysis from arthritis alone is uncommon. This presentation tends to develop more gradually than the sudden onset seen with vascular or acute spinal events.
Aortic Thromboembolism in Cats
A blood clot lodging where the aorta divides cuts off blood flow to the hind legs, most often both at once, causing sudden paralysis, severe pain, cold legs and pale or bluish paw pads. A clot lodging further along can affect a single leg.
The page on this condition is being checked again and is offline for now.
Restrictive Cardiomyopathy in Cats
Sudden loss of use of the hind legs can follow a blood clot forming within an enlarged heart chamber and lodging where the aorta divides, a recognised complication of this condition.
Fibrocartilaginous Embolism (FCE)
When a fragment of disc material enters a spinal blood vessel and blocks flow to part of the spinal cord, the sudden loss of blood supply can cause paralysis in the hind limbs, typically appearing within minutes of an episode that may begin with vocalisation. Unlike a clot at the division of the aorta, the legs stay warm, the signs often affect one side more than the other, the pain usually settles after the first hours, and the weakness tends to stop worsening after 24 to 48 hours. In cats it affects the neck region more often than the lower back, so the front legs can also be involved.
The page on this condition is being checked again and is offline for now.
Intervertebral Disc Disease (IVDD)
Pressure on the spinal cord from displaced disc material can interrupt the nerve signals that control movement in the hind legs, and in severe cases this compression can progress to complete paralysis, particularly when the affected disc lies in the mid to lower back.
Feline Infectious Peritonitis (FIP)
The dry form of FIP can inflame the spinal cord and its membranes, and in a large pathology study it was the most common disease found in the feline spinal cord. The weakness it causes tends to develop over days to weeks, often alongside fever, weight loss or other neurological signs, and can involve all four legs rather than the hind legs alone.
The page on this condition is being checked again and is offline for now.
Lymphoma in Cats
Lymphoma is the most commonly reported tumour affecting the feline spinal cord and spinal canal. It tends to cause hind leg weakness that worsens over days to weeks, and it is more likely in cats infected with feline leukaemia virus.
Diabetes Mellitus in Cats
Diabetic neuropathy can weaken the hind legs, typically producing a gradual change to a stance in which the cat walks on its hocks. It causes weakness rather than sudden paralysis, and it can improve when blood glucose is brought under control.
When to explore further
Sudden onset hind leg paralysis accompanied by vocalisations of distress, cold or cool hind limbs, and firm or painful calf muscles is the typical pattern of a clot blocking blood flow where the aorta divides. Other features of this form are pale or bluish paw pads, rapid or open-mouthed breathing, and a body that feels cool to the touch. The leg muscles and nerves are without blood supply from the moment the clot lodges, and the pain is severe from the outset.
When hind leg paralysis develops gradually over days to weeks, starting with subtle incoordination or weakness that progresses to inability to walk, the progressive nature of the onset may suggest a condition that is expanding or worsening rather than a single acute event.
Whether a paralysed cat can still feel its hind feet is one of the most important indicators of outlook after spinal cord injury, but it cannot be reliably judged at home. A leg can pull away from a pinch as a spinal reflex even when the cat has no conscious sensation; the examination looks instead for a conscious response such as turning the head or crying out. A cat in pain from a clot or a spinal injury may also bite when its legs are handled.
Hind leg paralysis accompanied by loss of bladder or bowel control adds an additional dimension to the presentation, as the nerves controlling these functions travel in close proximity to those supplying the hind limbs, and their involvement may indicate a broader area of neural compromise.
When a previously healthy indoor cat with no known trauma history develops acute hind leg paralysis, the absence of an obvious external cause may direct attention towards internal vascular or neurological processes rather than traumatic injury.
Hind leg paralysis together with rapid breathing, breathing with the mouth open, or visible effort at the belly with each breath suggests that heart disease may also be causing fluid to build up in or around the lungs. Congestive heart failure was present in 44 per cent of cats with arterial thromboembolism in one series, and breathing difficulty from it can worsen over hours.
Observing the specific characteristics of the hind leg paralysis, whether both legs are equally affected, whether the limbs feel warm or cold, whether the paw pads look pink or pale and bluish, how fast the cat is breathing, and whether there is any voluntary movement however slight, can provide meaningful information about the nature and location of the problem. Noting the exact circumstances and speed of onset, any preceding changes in behaviour or activity, and the cat's overall condition before the event occurred helps build a complete picture of the clinical timeline. The time the cat was last seen moving normally belongs in that picture, because damage from blocked blood flow or spinal cord compression continues to accumulate from onset. Several of the features that separate the causes, including pulses in the legs, conscious pain sensation and heart sounds, can only be assessed in an examination.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS