Hind-leg weakness in a rabbit is any time the animal doesn't have its usual strength in its back legs. This can be anything from minor stumbling while hopping around to complete paralysis in which there is no movement in the hind legs and no response to stimuli. There are many different reasons for hind leg weakness. Determining the cause will help lead to the correct treatment.
Any sudden impact, pulling or twisting on the hind legs or back can lead to a traumatic injury. If you witness this sort of trauma and the rabbit immediately shows signs of hind-leg weakness, the rabbit should be taken to a veterinarian immediately. If there is complete paralysis, there likely is little that can be done to improve the rabbit's quality of life. If the rabbit still has sensation in its toes and bowel control, it probably can recover if given six to eight weeks in a small cage to confine its movements. Corticosteroids may be used initially to control swelling.
Arthritis, vertebral disc deterioration and spondylosis are degenerative diseases that can cause hind-leg weakness. The weakness usually starts with minor symptoms and progressively worsens. Glucosamine and chondroitin are supplements used to help with joint problems in the hips. Other drugs may be prescribed to reduce inflammation that causes pressure on the spinal chord. You may also be shown some simple physiotherapy you can do with the rabbit to improve its range of motion. Acupuncture and skeletal manipulation are also becoming more popular alternatives, but it may be difficult to find a vet who is able to use these treatments on a rabbit.
Pathogens such as parasites or bacterial infections can also cause hind-leg weakness. For an infection, the treatment would include giving the rabbit antibiotics. You may need to have the rabbit stay at the vet hospital to have the antibiotics given intravenously. Unfortunately, the two most common parasites in rabbits that could cause hind-leg weakness, and encephalitozoon cuniculi and baylisascaris procyonis have no known cure. However, fenbendazole and ponazuril have shown promise in treating E. cuniculi, according to Dr. Dana Krempels on the University of Miami website. The usual treatment for B. procyonis is to give the patient corticosteroids immediately to help reduce the damage caused by the parasites.
A rabbit that is allowed to roam freely in a yard or other large area could come into contact with toxins that could cause hind-leg weakness. A proper treatment can't be done until it is determined which toxin is in the rabbit.
A cancerous tumour on the spine also can cause a rabbit to lose movement in its hind legs. Treatment could include removal of the tumour, chemotherapy, radiation or some combination of the three treatments.
Numerous diseases can cause general weakness that can be confused with hind-leg weakness. These can include cancer, anaemia, heart disease, liver disease, kidney disease, malnutrition and an imbalanced diet. Other conditions that can cause pain, such as ulcerated feet or an intestinal blockage, can limit the rabbit's mobility.