What is Knee effusion?
Knee effusion or swelling of the knee occurs when excess fluid accumulates in or around the knee joint.
Knee effusion is common with different types of arthritis, infections, and injuries. Arthritis, injury to the ligaments of the knee or infection cause body’s natural reaction is to surround the knee with a protective fluid. The type of fluid that accumulates around the knee depends on the underlying disease.
This is clinical photograph of 55 years old lady who came with complaint of knee pain in left knee.
Causes of Knee Effusion
Osteoarthritis can occur after injury or most commonly with wear and tear of joints with aging. Osteoarthritis causes destruction of the cartilage the cartilage that cushions the ends of the bones. Apart from swelling, there may be pain in the joints.
Osteoarthritis is occurs more in overweight or obese individuals as the body places more weight on the knee joint.
Rheumatoid arthritis is an inflammatory arthritis that leads to progressive joint destruction and painful, stiff, and swollen joints. It can occur both in adults and children.
Infectious arthritis or synovitis can occur as a result of a bacterial, viral, or fungal infection, usually via the bloodstream from another part of the body, such as a person’s skin, nose, throat, ears, or an existing wound.
Common bacterial causes of infectious arthritis include Neisseria gonorrhoeae and Staphylococcus aureus..
With gout, uric acid — a normal chemical in the body — forms crystals that deposit in the joints, causing inflammation and pain.
Gout causes a painful, swollen joint that is very painful. There may also be more than one joint affected with gout.
Knee injuries can cause in painful, swollen joints, and stiffness. Sometimes, the muscles, tendons, and ligaments surrounding the joint are torn or injured. Also, painful, swollen joints may be caused by bursitis, tendinitis, dislocations, strains, sprains, or even fractures.
Pseudogout is a presentation of calcium pyrophosphate deposition disease. It occur is a type of arthritis caused by deposition of calcium pyrophosphate in and around the joints. The term literally means false gout as it resembles gout in symptoms. It can occasionally coexist with gout. It is often used synonymously with all calcium pyrophosphate deposition disease.
Tumours and Cysts in and around knee may cause knee effusion.
Psoriatic arthritis is an inflammatory joint disease that’s linked with psoriasis, a skin condition. About 5% to 23% of people with psoriasis will develop psoriatic arthritis.
Signs and symptoms of Knee Effusion
Pain associated with swelling is the usual complaint. The swelling might be tender to touch and warm due to inflammation. Stiffness of the joint may accompany- it may become difficult to bend or straighten the knee in certain cases.
Lab Investigations in Knee Effusion
Blood tests may be done as directed by clinical examination. Blood tests may indicate inflammatory arthritis. Hyperuricemia might suggest gout. Leucocytes, erythrocyte sedimentation rate, and perhaps the level of C-reactive protein may be raised in infection.
It is also called arthrocentesis, this procedure includes withdrawal of fluid from inside the knee for analysis such as cell count, culture for bacteria, and examination for crystals, such as uric acid or calcium pyrophosphate dihydrate ram crystals found in gout or pseudogout.
Imaging in Knee Effusion
Xrays may be normal or might reveal the underlying pathology such as fracture.It may reveal signs of osteoarthritis.
Magnetic resonance imaging is useful for detecting abnormalities of the bone or knee joint, such as a tear in the ligaments, tendons or cartilage.
Treatment of Knee Effusion
Treatment of fluid in the knee depends on the underlying cause of the swelling. Rest, ice, and analgesics such as NSAIDs are often initial treatment
Definitive treatment for swollen joints depends on the problem or diagnosis.
For example apart from rest and analgesics, antitubercular drugs are presctiFor instance, nonsteroidal anti-inflammatory drugs (NSAIDs) are used in treating swollen joints with OA. NSAIDs may also be used to treat swollen joints from an injury. Along with NSAIDs, applicationbed in case of tuberculosis of knee.
Arthrocentesis may also be used as part of treatment in joints with large effusions.
For inflammatory types of arthritis such as rheumatoid arthritis, psoriatic arthritis treatment may include NSAIDs, steroid medications, and disease-modifying anti-rheumatic drugs (DMARDs) and biologic agents such as tumor necrosis factor inhibitors.
Acute gout is treated with a medicine called colchicine and NSAIDs.
Antibiotics, often intravenous are required for treatment of acute bacterial arthritis and often accompanied by drainage of pus from the joint by open surgery.
Injured ligaments, menisci and fractures may also require surgical stabilization.
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