A to Z: Joint Effusionenparentshttps://kidshealth.org/EN/images/headers/P-khAZDictionary-enHD-AR1.jpgLearn more about this type of joint swelling that can caused by infections, injuries, and arthritis.Joint effusion, joint swelling, swollen joints, water on the knee, joints, effusion, swelling, infection, inflammation, lymph system, lymph, blood, anatomical vessels, blood vessels, arteries, veins, synovial fluid, synovial cavity, lymph vessels, joint injuries, knee injuries, broken bones, ligament tears, tendon tears01/05/201503/21/201909/02/20191e1e309b-68eb-489d-a5f8-107a3ad7d9b3https://kidshealth.org/ws/RadyChildrens/en/parents/az-joint-effusion.html/<p><a href="https://kidshealth.org/ws/RadyChildrens/en/parents/dictionary/"><img class="right" title="Parents image" src="https://kidshealth.org/EN/images/buttons/P-atoZDictionary-enBT.jpg" alt="A to Z Dictionary 500 Go" name="5093-P_ATOZDICTIONARY2_ENBT.JPG" /></a></p> <p><strong>May also be called: Joint Swelling; Swollen Joints</strong></p> <p>Joint effusion (ih-FYOO-zuhn) is swelling in a <a href="https://kidshealth.org/ws/RadyChildrens/en/parents/bones-muscles-joints.html/">joint</a> due to fluid moving into the soft tissues surrounding the joint.</p> <h3>More to Know</h3> <p>The body makes many different fluids, including <a href="https://kidshealth.org/ws/RadyChildrens/en/parents/blood.html/">blood</a>, lymph (part of the body's <a href="https://kidshealth.org/ws/RadyChildrens/en/parents/immune.html/">immune system</a>), and synovial fluid, which helps lubricate joints. Effusion is swelling that happens when fluid leaks out of a vein, artery, lymph vessel, or synovial membrane into the surrounding tissue. This causes the tissue to expand, or swell.</p> <p>When effusion happens in a joint &mdash; commonly the knee &mdash; excess fluid can pool in a part of the joint called the synovial cavity. It then leaks out into the soft tissue around the joint. This can happen as a result of injury, infection, or arthritis:</p> <ul class="kh_longline_list"> <li><strong>Injuries</strong> to joints can rupture blood vessels or lymph vessels, causing blood or lymph to build up under the skin. Effusion following an injury can sometimes be a sign of a broken bone or a tear in a ligament or tendon. Joint effusion caused by an injury often is accompanied by&nbsp;joint pain.</li> <li>In effusions due to <strong>infection</strong>, <a href="https://kidshealth.org/ws/RadyChildrens/en/parents/germs.html/">germs</a> (bacteria, viruses, or fungi) move from an injury&nbsp;into the bloodstream. When they reach a joint, they can escape to the bloodstream and cause pain, fever, redness, and warmth.</li> <li>Effusion caused by <strong>arthritis</strong> can happen in autoimmune diseases such as <a href="https://kidshealth.org/ws/RadyChildrens/en/parents/jra.html/">juvenile idiopathic arthritis</a> where general inflammation in the body also affects the joints and can cause both redness and warmth.</li> </ul> <p>Joint effusions also can happen in diseases such as gout, where crystals deposit in the joint, or in cancerous and noncancerous tumors.</p> <p>Treatment for joint effusion depends on the cause and often includes resting the joint and applying ice packs to reduce swelling. In some cases, fluid may be removed from the joint to reduce swelling and increase the joint's range of motion. This fluid can be checked for signs of infection, crystals, and other substances to help find out the cause of the effusion.</p> <h3>Keep in Mind</h3> <p>Effusion is a symptom of an injury or other condition affecting a joint. In almost all cases, if the underlying condition is identified and treated, the effusion will go away. Joint effusion that happens for no apparent reason or with a fever should be checked by a doctor as soon as possible.</p> <p><em>All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.</em></p>
ArthritisKids can get a kind of arthritis that causes joint pain. Find out more in this article for kids.https://kidshealth.org/ws/RadyChildrens/en/kids/juv-rheum-arthritis.html/8d74d9e3-5b65-49cb-86b1-f03a78d98bb9
Bones, Muscles, and JointsOur bones, muscles, and joints form our musculoskeletal system and enable us to do everyday physical activities.https://kidshealth.org/ws/RadyChildrens/en/teens/bones-muscles-joints.html/d55a922b-e87a-49e0-82ae-0c5a0773cee9
Immune SystemThe immune system is made up of special cells, proteins, tissues, and organs that defend people against germs and microorganisms.https://kidshealth.org/ws/RadyChildrens/en/teens/immune.html/45385c22-09f4-4e2e-98d9-8be5155bedc5
Joint Aspiration (Arthrocentesis)A joint aspiration (arthrocentesis) involves withdrawing (aspirating) a sample of fluid from a joint using a needle and syringe.https://kidshealth.org/ws/RadyChildrens/en/parents/arthrocentesis.html/ba9a6aa6-5cd2-4b4a-b792-33c86d1c42df
Juvenile Idiopathic ArthritisIn juvenile idiopathic arthritis (also called juvenile rheumatoid arthritis)), a person can develop swollen, warm, and painful joints. Learn more.https://kidshealth.org/ws/RadyChildrens/en/parents/jra.html/64ceaa10-23cf-4f1c-b6e0-21bd7cb07b97
Juvenile Idiopathic Arthritis (JIA)Learn about juvenile idiopathic arthritis, a specific kind of arthritis that usually occurs in kids and teens younger than 17.https://kidshealth.org/ws/RadyChildrens/en/teens/juv-rheumatoid-arthritis.html/f118a90b-88e2-491c-bad2-24a8ef6e2144
Knee InjuriesHealthy knees are needed for many activities and sports and getting hurt can mean some time sitting on the sidelines.https://kidshealth.org/ws/RadyChildrens/en/teens/knee-injuries.html/0e348562-5958-4a91-96ad-c8affb5fff4f
Toxic SynovitisRead about this temporary inflammation of the hip joint that affects young children.https://kidshealth.org/ws/RadyChildrens/en/parents/toxic-synovitis.html/23ff7c0f-65da-4356-bddc-81a13e3661a6
Word! JointsJoints are the places in your body where bones meet.https://kidshealth.org/ws/RadyChildrens/en/kids/word-joints.html/e5dc48ce-c070-41a8-991c-d7042af651d9
Word! Juvenile Rheumatoid ArthritisJuvenile rheumatoid arthritis is an autoimmune disease that makes it hard for kids to move their joints.https://kidshealth.org/ws/RadyChildrens/en/kids/jra.html/61cfa834-47b2-4a68-bf2a-ab89462bd8af
Your Immune SystemThe immune system keeps you healthy. How does it work? Find out in this article for kids.https://kidshealth.org/ws/RadyChildrens/en/kids/immune.html/6b9fad76-c866-450e-81d9-1e625343744f
kh:age-allAgesOrAgeAgnostickh:clinicalDesignation-plasticSurgerykh:genre-dictionarykh:primaryClinicalDesignation-orthopedicsNonSportsMedJhttps://kidshealth.org/ws/RadyChildrens/en/parents/dictionary/j/63c52edc-57aa-4d0b-bcf5-4d2db9e3725fOrthopedics A to Zhttps://kidshealth.org/ws/RadyChildrens/en/parents/dictionary/az-ortho/9fdd6bbc-254a-4dff-be33-c4c6c66c3f6ehttps://kidshealth.org/EN/images/buttons/P-atoZDictionary-enBT.jpg