Joint Effusion (Swelling) in Dogs

Joint effusion is an increase in fluid within the joint space. This increase in joint fluid often leads to a distention of the joint capsule and a swelling of the joint. The general causes of joint effusion include:

• A traumatic injury to a joint
• Chronic degenerative joint disease or osteoarthritis
• Infectious joint disease
• Immune mediated polyarthritis
• Breed specific causes of polyarthritis
• Clotting abnormalities
• Tumors of the joint capsule or bone

What to Watch For

Signs of Joint Effusion (Swelling) in dogs may include:

• Lameness
• External wounds
• Fever
• Anorexia
• Lethargy
• Reluctance to move or stand

Many animals with joint effusion in multiple joints often have a very stiff gait and appear to be “walking on egg shells.”

Diagnosis of Joint Swelling in Dogs

A complete physical examination and accurate history is critical for accurate diagnosis. It is the most important part of the work up in evaluating an animal with joint effusion. Additional tests include radiographs (x-rays) of the affected joint.

Many times a diagnosis can be made on the basis of the physical exam findings, with or without radiographs. If a more systemic illness is suspected, additional diagnostics might include:

• Arthrocentesis of the affected joint or joints
• Complete blood count (CBC)
• Biochemical profile
• Urinalysis
• Chest and abdominal radiographs
• Infectious disease titers
• Immune profile
• CT or magnetic resonance imaging (MRI)
• Synovial or bone biopsy

Treatment of Joint Swelling in Dogs

An accurate diagnosis is needed for proper therapy. Pending a definitive diagnosis, certain treatments may be appropriate:

• Pain relief
• A padded support bandage
• Intravenous fluid support
• Intravenous antibiotics
• Doxycycline or tetracycline
• External wounds may be cleaned and bandaged

Home Care and Prevention

In cases of acute joint swelling, restricted physical activity is always advised. In acute joint swelling, especially if the joint is warm, cold water compresses may be applied to reduce the swelling.

If a wound is noted, it can be cleaned with warm soapy water or hydrogen peroxide. If possible, foreign debris can be removed. Once cleaned, a light wrap may be applied. Contact your veterinarian to see if giving a non-steroidal anti-inflammatory drug such as aspirin, would be indicated to relieve the pain until seeking veterinary care.

More Information on Canine Joint Effusion

Joint effusion may be a sudden (acute) occurrence or a long-standing (chronic) problem. Many times, acute joint swelling is the result of trauma and usually involves only a single joint. External wounds may be noted and the animal is usually lame and painful at the swollen joint. Chronic joint distention may or may not be associated with lameness. The most common cause of chronic distention is degenerative osteoarthritis and may occur in multiple joints. Many animals with this type of joint effusion are more lame after lying down or first thing in the morning. Typically, the lameness improves over the course of the day.

One of the most important observations to make when dealing with joint effusion is if the dog is feeling ill. Animals feeling ill may be lethargic, anorexic, febrile, and they commonly have multiple joints that are affected. Reluctance to walk or even get up is a common complaint. Systemic illness should be expected in ill animals with joint effusion.

Ill animals may often require extensive diagnostic testing before a definitive diagnosis can be made. On the other hand, dogs with acute or chronic joint effusion that are still feeling fairly well are more likely to have conditions that are easier to diagnose. In these dogs a definitive diagnosis can often be achieved by a good history, physical exam and perhaps a radiograph. Rarely, animals with joint effusion will not have obviously distended joints and require arthrocentesis and cytologic evaluation of the joint fluid for diagnosis.

Another important part in evaluating an animal with joint effusion is whether or not there are multiple joints involved (polyarthritis). Animals with polyarthritis may walk very stiffly or have shifting leg lameness. Polyarthritis is a systemic disease that may be acute or chronic and it usually causes an animal to feel ill. Some dogs with polyarthritis have recurrent episodes making diagnosis more difficult. Since there are many causes of joint effusion an accurate diagnosis is crucial for correct treatment.

Causes of Joint Swelling in Dogs

Joint effusion is caused by an increase in fluid within the joint space. The amount of fluid within the joint can vary greatly, from a visually imperceptible amount to a very distended joint. In all cases of joint effusion, the fluid in the joint is abnormal in either cell type or viscosity (thickness). In many cases, the evaluation of the joint fluid is needed to determine the cause of the effusion. Joint fluid analysis may suggest a specific disease. Many times a simple history may identify the cause of the effusion. Traumatic injury, history of degenerative osteoarthritis, breed and age of the dog, and a travel history are all important in the assessment of joint effusion. The general causes of joint effusion include:

• Trauma: A traumatic injury to a joint usually causes an acute joint swelling and lameness. The injury may be a soft tissue injury with joint swelling the result of inflammation or bleeding into the joint. Fractures of the bones involving the joint can also lead to severe joint effusion and pain. If a wound penetrates the skin and enters the joint, a bacterial (or septic) infection can result, leading to joint swelling, fever and pain.
• Chronic degenerative joint disease or osteoarthritis: Commonly known as just “arthritis,” it is generally seen in older animals with a history of intermittent or chronic lameness. The joint swelling can result from an increase in joint fluid due to chronic inflammation or an actual increase in bone size due to bony proliferation around the joint. Joint viscosity decreases as chronic intermittent inflammation causes an increase in joint size with time. Typically, the joint swelling develops very slowly; however, a minor traumatic injury to a previously arthritic joint may cause an acute severe effusion.
• Infectious joint disease: There are many causes of infectious joint disease that can cause a joint effusion. Septic bacterial infections can either be from an external wound or be spread by the blood from another area of the body. Typically only one joint is affected. Other types of effusions caused by infectious agents usually involve multiple joints and may be associated with other symptoms. Tick borne diseases including Lyme disease, Rocky Mountain spotted fever, and ehrlichiosis are more commonly being diagnosed within certain geographic areas. Dogs with these diseases are usually quite ill from additional metabolic dysfunction that might include bleeding problems, vasculitis (inflammation of blood vessels), kidney disease, and neurologic impairment.
• Immune mediated polyarthritis: Numerous immune disorders may cause joint effusion. Many times this will be associated with other signs of illness. Immune mediated polyarthritis may cause either an erosive (causing bony destruction of the articular bone) or non-erosive arthritis. Causes of erosive polyarthritis include: rheumatoid arthritis and erosive polyarthritis of greyhounds. Non-erosive causes of polyarthritis include: systemic lupus erythematosus (SLE), idiopathic (unknown cause), drug and vaccine reactions, and polyarthritis secondary to other chronic inflammatory, infectious or cancerous conditions.
• Certain breeds are associated with breed specific polyarthropathies (disease and effusion of multiple joints): Greyhounds, usually under two years, may develop an erosive (bone deforming) polyarthritis (multiple joint inflammation) of their distal extremities. The Shar Pei breed may develop a disease called “Shar Pei fever,” categorized by fevers and swellings of the hock and carpal joints. Over time, severe kidney disease (renal amyloidosis) may develop. Akitas, Boxers, Weimaraners, Bernese Mountain dogs, German shorthair pointers and beagles have been known to develop a polyarthritis or a polyarthritis/meningitis (inflammation of the spinal cord) syndrome that affects young dogs.
• Clotting abnormalities: Occasionally animals with clotting abnormalities have acute bleeding into a joint. This is called hemarthosis. Most of the time, this is related to a minor traumatic injury that under normal circumstances would not cause a problem, but when a tendency to bleed is also present, a bloody joint effusion may form. Some causes of clotting problems include: thrombocytopenia, hemophilia, rodenticide intoxication, and von Willebrand’s disease.
• Tumors of the joint capsule or bone: Tumors that involve the joint capsule most commonly a synovial cell carcinoma can cause joint effusion. A single joint is affected and it generally occurs in middle-aged to older dogs. Other tumors of the bone around the joint space can occasionally cause effusion and joint swelling.

More Information on Diagnosing Swollen Joints in Dogs

A complete history and physical exam is vital in the evaluation of an dog with joint effusion. A history of trauma or current illness should be noted. Some causes of joint effusion are more common in certain geographic locations (tick borne diseases), so a travel history should be recorded. Determining if single or multiple joints are affected is an important part of the physical exam. Additional tests include:

• A radiograph of the affected joint may reveal a fracture, tumor, degenerative joint disease or erosive bony destruction. Distention of the joint can often be visualized. Most of the time, sedation is required for taking x-rays of joints, as they are difficult to position and are usually painful. Radiographs are a very useful tool for evaluating joint effusion.
• Arthrocentesis, or the sampling of joint fluid, is an excellent way of determining the cause of the effusion. Effusions caused by trauma, infectious diseases, immune disorders or degenerative conditions all have characteristic cytology (a microscopic evaluation of cell types). White blood cells, red blood cells, and even occasional organisms can be identified. The numbers of white blood cells are counted, and the types of white cells (specifically: neutrophils, lymphocytes, monocytes, macrophages, and eosinophils) are proportionately recorded. If polyarthritis (more than one joint affected) is suspected, multiple joints can be sampled to confirm the diagnosis. The joint fluid is also cultured to check for any bacterial agent that might be responsibly for the effusion. The cytology of the joint fluid can often give a definite diagnosis alone, but other times the results need to be interpreted considering additional diagnostics.
• A CBC is an important test to include when infection or polyarthritis is suspected. With an infection, the white cells might be elevated. Platelets are blood cells that help with clotting, and their numbers are typically estimated or counted on a CBC. Low platelet counts (thrombocytopenia) could cause hemarthrosis or be related to other causes of polyarthritis. Since polyarthritis is a systemic disease, the red cell count should be checked for anemia and a white cell count evaluated. Both tick borne and immune mediated diseases are systemic illnesses that often have changes in red and white blood cell counts.
• A biochemical profile is important in evaluating liver and kidney status. Many causes of polyarthritis, specifically immune and infectious, can be associated with liver or kidney disease.
• A urinalysis is needed to evaluate kidney function. Occasionally, protein loss through the urine may occur due to various immune diseases or infectious agents. Protein loss may be quantified by a urine protein creatinine ratio. The amount of protein loss may correlate with specific diseases.
• Chest and abdominal radiographs are sometimes needed if there is a concern of cancer, immune or infectious diseases.
• Infectious disease titers may be drawn to test for Lyme disease, ehrlichia, and Rocky Mountain spotted fever. If an animal has been vaccinated for Lyme disease, a western blot should be done to separate a vaccine-induced titer from true infection.
• Immune panels to include a rheumatoid factor and an ANA may be done if immune mediated polyarthritis is suspected. These tests should be interpreted with caution, as false positives and false negatives are common findings.
• CT or MRI scans may be done in cases of single joint effusion where a subtle lesion is suspected as having caused the joint effusion. These tests are usually done at referral or specialty clinics.
• Synovial or bone biopsies may be done if a tumor of the joint capsule or bone is present. Definitive diagnosis can only be made through a biopsy.

More Information on Treating Swollen Joints in Dogs

One or more of the diagnostic tests described above may be recommended by your veterinarian. In the meantime, treatment of the symptoms might be needed, especially if the problem is severe. The following nonspecific (symptomatic) treatments may be applicable to some, but not all pets with joint effusion. These treatments may reduce severity of symptoms or provide relief for your pet. However, nonspecific therapy is not a substitute for treatment of the underlying disease responsible for your pet’s condition.

Pain relief may need to be provided. No medication should be given without first speaking to your veterinarian. Some medications that are often used for pain relief include non-steroidal anti-inflammatory drugs and narcotics. Controlling the pain is important in making your pet comfortable until veterinary care can be obtained.

If trauma or a fracture is suspected a bandage may be applied. Decreasing the range of motion in the joint and providing support may make your pet more comfortable and less painful.
Occasionally joint effusion is associated with more severe systemic illness and intravenous fluid support may be needed to stabilize your pet pending test results. Fluid therapy prevents dehydration and may be needed if an animal is in shock.

Once appropriate diagnostic tests have been submitted and infectious disease is suspected, antibiotics might be started. Starting antibiotics prior to getting the appropriate samples may prevent accurate diagnosis. Once tests are pending, starting antibiotics might be appropriate.