Swelling is a warning that something is wrong with your dog's leg. Regardless of whether your dog shows sign of pain or distress, a swollen leg requires his veterinarian's attention. Some causes of swelling, such as a sprain or a strained muscle, may require only minor medical treatment. However, other causes may require surgery or drug therapy to correct them. Left untreated, some causes of swelling can cause permanent injury or even death.
The term peripheral edema describes the buildup of the body's fluids in one or more of a dog's limbs. A focal or localized edema may be caused by traumatic injury to the limb or from a toxin being introduced, such as from an insect bite. Diffuse or generalized edema may be caused by disease, such as congestive heart failure or kidney disease. It can be caused by tying a bandage too tightly or by abnormal growth of tissues in the lymphatic system, part of the circulatory system, which keeps the body's fluids in balance and removes impurities. Peripheral edema is diagnosed by a needle biopsy or by aspirating the fluid, drawing the fluid from the area. An electrocardiogram may be used to diagnose related heart conditions. Amputation may be required in the case of prolonged or severe edema.
Swelling Caused by Infection
Infections that cause swelling are typically localized, such as that created by an abscess. Abscessed wounds, often from an overlooked bite or a puncture wound, can cause severe and painful localized swelling. These wounds can often be identified by a dimple or scab on the surface of the swelling. Abscesses require veterinary attention, as they must be lanced and drained and may need further skilled treatment.
Swelling Caused by an Injury
An injury to your dog's leg bone or muscle may cause swelling. Many traumatic injuries result in swelling, due to damage caused to the soft tissue in the area of the injury. This damage may disrupt the flow of the lymphatic system through the area, resulting in the temporary accumulation of fluids in the tissue. Injuries such as strains and sprains can cause swelling and typically require little treatment other than rest and treatment with pain relievers and anti-inflammatory drugs. Other injuries may be more complex, requiring surgery to repair the damage that causes the swelling. However, swelling may continue during the recovery period after surgery until the dog's wounds are healed. In such cases, the dog may benefit from pain relievers and anti-inflammatory drugs, as with strains and sprains. Best to seek veterinary advice.
Osteoarthritis, commonly called arthritis, can cause painful swelling of a dog's joints. Swelling can either be caused by fluid in the joints or by bones themselves developing abnormal growth. The proper treatment for the swelling is determined by various tests, including blood tests, urinalysis and biopsies of abnormal growths in the joint. The treatment of the swelling varies and is based on the underlying cause. As with other forms of swelling, arthritic swelling can be aided by anti-inflammatory drugs and painkillers. Some breeds of dogs are more prone to joint swelling than others, including Labrador retrievers, poodles and English bulldogs. Chinese Shar-Peis are prone to a syndrome variously called swollen hock syndrome, familial Shar-Pei fever and Shar-Pei recurrent fever syndrome. Dogs with this syndrome will develop excessive swelling in the wrinkles surrounding their hocks when fever episodes occur. These fevers are of sudden onset and may or may not respond to anti-inflammatory drugs. No treatment exists for the swelling, which disappears when the fever passes.
Hygromas and Swelling
Hygromas usually appear on a dog's elbows, although they may appear on his hips or hocks as well. These hard swollen areas consist of hard, fluid-filled capsules under the dog's skin. Hygromas are caused by trauma, usually from the dog repeatedly sleeping on hard surfaces. Large dogs are more frequently affected by hygromas than are small dogs. They can be treated by placing soft bedding on the hard sleeping surface. Other treatments, including removing the fluid using a needle and surgically removing the hygroma, tend to be ineffective.