Dr Priyanka Nagar
Joint effusion, commonly referred to as the accumulation of fluid in or around a joint. It is most commonly caused by an infection, injury and arthritis. The knee is the joints most commonly affected by effusion, although it can occur in the ankle, elbow, shoulder and hip. Joint effusion is associated with swelling, pain and stiffness. The key to diagnosis and management is a thorough history and examination to determine the primary pathology, which includes inflammation, infection or a structural abnormality in the knee.
Keywords : Effusion, knee, arthritis, inflammation, synovitis
The knee is a hinge joint and susceptible to injury from trauma, inflammation, infection and degenerative changes. A knee effusion may result from acute or chronic conditions. The knee contains sac –like structures containing synovial fluid, called bursae, which are located between the skin and bony prominences. Fluid accumulation in the intra-articular space of a joint is called an effusion. Small, asymptomatic effusions can occur in healthy individuals. Larger joint effusion indicates intra-articular pathology. Knee effusion is also termed as ‘water on the knee’.
The knee is more frequently injured than other joints because it is part of a weight bearing limb, and it does not have the stability brought by the joint congruity of the hip and ankle. The lifetime prevalence of knee swelling has been reported as high 27%. It may occur at any age in children, but most commonly in infants and teenagers.
Joint effusion can be broadly classified as either septic (caused by infection) or aseptic (non- infective). Infectious causes are referred to as septic arthritis. Aseptic causes may be categorized as either injuries or arthritis.
- Septic arthritis – Septic arthritis, also known as infectious arthritis, is most commonly caused by bacteria. The joint effusion may be caused by a systemic infection that travelled via bloodstream. The bacteria may be introduced into a joint through a penetrating wound or a medical procedure. Some of the factors that can increase the risk of septic arthritis include:-
- Older age
- Diabetes mellitus
- Recent joint injury
- Intravenous drug use
Fungal, viral and parasitic causes are most commonly associated with a compromised immune system, such as in people with HIV infection, organ transplant recipients, or those undergoing cancer chemotherapy.
- Joint injury – A sports injury is a common cause of joint effusion, especially of the knee. A car accident, serious fall, or blunt force impact can also lead to an effusion. In addition to traumatic injury, joint effusion may result from a repetitive stress injury. This is the type that occurs after repeating a movement again and again, usually in connection with an occupation or sports activity.
Within the context of repetitive stress injuries, effusion occurs most commonly with bursitis (the inflammation of the fluid-filled sac which cushions a joint) and tenosynovitis (inflammation of the tendon sheath where a muscle attaches to a bone).
- Arthritis – Joint effusion is a common feature of arthritis associated with either chronic inflammation or an acute bout of joint inflammation. There are two types of arthritis:-
- Osteoarthritis, also known as “wear and tear” arthritis.
- Autoimmune arthritis, such as rheumatoid arthritis, gout, juvenile idiopathic arthritis and psoriatic arthritis, in which the immune system directly or indirectly attacks joint tissues.
Underlying diseases which may cause effusion include:-
- Knee osteoarthritis
- Rheumatoid arthritis
- Prepatellar bursitis
Signs and Symptoms
Signs and symptoms of knee effusion depend on the cause of excess synovial fluid build-up in the knee joint. These may include:-
- Pain – Ranging from a dull throbbing to sharp, immobilizing pain. Pain when ascending or descending stairs may indicate pathology from the patellofemoral joints. This is the direct result of the increase contact pressures on the patella when a knee is loaded in a flexed position. Night pain is a red flag symptom. The most common cause of night
pain in the adult is a severe degenerative arthritis. However, night pain in a child or a young adult may indicate an underlying pathology such as infection or neoplasm.
- Swelling – Ranging from a mild, generalized puffiness to severe swelling and inflammation. A swelling that occurs immediately after an injury is suggestive of a significant haemarthrosis, i.e. bleeding due to damage to a structure such as bone or ligament. Classically, a swelling that occurs 24-36 hours after injury can be either due to either a sympathetic effusion or a slowly forming haemarthrosis, caused, for example, by a meniscal injury.
- Stiffness – When the knee joint contains excess fluid, it may become difficult or painful to bend or straighten. It limits the joint’s range of motion or entirely immobilizing a joint.
- Redness and warmth – It is associated with localized inflammation.
- Bruising – Joint effusion caused by an injury may be accompanied by bruising and bleeding in the joint space. Bruising may be seen as bluish lesion.
- Red flags – Red flags include fever, non-weight bearing, loss of distal pulses and loss of sensation distal to the knee. These red flags typically need immediate evaluation.
- Disability – The degree of difficulty the patient experiences with mobilization indicates the disability the patient is suffering as a result of their knee pain.
- Joint effusion associated with severe arthritis may lead to progressive muscle loss, a condition referred to as arthrogenic muscle inhibition.
The diagnosis of a joint effusion may involve a physical examination, imaging tests and lab evaluation of joint fluids.
- Physical examination
- When palpating the knee, it is particularly important to appreciate the anatomical structures that are being palpated. Muscle wasting is also appreciated better while palpating.
- With arthritis, the lubricating tissues between the joints, called the synovium, will feel boggy.
- Joint infections tend to develop rapidly and cause excessive pain and redness.
- Acute swelling accompanied by the inability to bear weight may suggest a torn ligament or fracture of the knee.
- Synovial fluid aspiration
Arthrocentesis and subsequent synovial fluid analysis should be done in all cases of unexplained knee effusion. The synovial fluid aspirate should be analyzed for:-
- Complete blood count (CBC) with differential [ white blood cells (WBC), polymorphonuclear leukocytes].
- Crystal examination of synovial fluid
- Culture and gram staining of synovial fluid
▪Glucose – Low level of synovial fluid glucose is suggestive of an infected joint, but low glucose levels are present in only about 50% of patients with septic joints and can also occur in rheumatoidarthritis.
Synovial fluid will usually be clear and have the viscosity of an egg white. Any changes in its appearance, texture and cellular composition can provide clues as to underlying cause of joint effusion. For example:-
- Septic arthritis – Joint fluid appears cloudy or purulent. Cell count with WBC greater than 50,000 is considered diagnostic for septic arthritis.
- Non-inflammatory synovial fluid – Synovial fluid is considered to be non- inflammatory if it contains WBC less than 2000/ml. The most common cause of non-inflammatory effusion of the knee is osteoarthritis. Aspiration of dark brown serosanguinous fluid should raise the possibility of pigmented villonodular synovitis.
- Inflammatory synovial fluid – Inflammatory arthritis can be caused by infection, autoimmune disease and crystal induced arthritis. Synovial fluid white blood cells are greater than 2000 cells/ml. Yellow-green fluid may suggest an infection. Golden fluid is commonly associated with gout. Bloody or pink fluid is the classic sign of a joint injury.
- X-ray – An X-ray is useful for identifying bone fractures or dislocation of joint when there is a history of trauma. May show signs of osteoarthritis.
- Ultrasonography – Ultrasonography uses sound waves to visualize bone and connective tissues. It can be used to confirm arthritis or the inflammation of tendons or ligaments.
- MRI – Magnetic Resonance Imaging detects abnormalities of the bone or knee joint, such as a tear in the ligaments, tendons or cartilage.
- Risks of delaying treatment beyond 24 to 48 hours include a permanent limitation in joint function and subchondral bone loss.
- Bacterial invasion can lead to permanent damage to articular cartilage.
Treatment of fluid in the knee depends on the underlying cause of the swelling which may include:-
- Anti-inflammatory drugs
- Antibiotics in case of an infection
- Joint aspiration to relieve pressure temporarily
- Arthroscopy, to help repair damage in knee
- Physical therapy to improve flexibility and build strength in the muscles around the joint.
Self-care management includes:-
- Lose weight, if needed, to reduce stress on the hip and lower extremities.
- Avoid heavy weight lifting or deep squats.
- Use an elastic knee support or elbow brace when engaging in sports or manual labor.
- Rest when you have pain and swelling.
- Use resistance training to strengthen muscles in and around the joint.
- For acute pain and swelling, application of splints, cold or ice-packs, partial or non- weight bearing braces should be used.
Homoeopathy is one of the holistic systems of medicine. The selection of remedy is based upon the theory of individualization and symptoms similarity by using holistic approach. The aim of homoeopathy is not only to treat synovitis but to address its underlying cause and individual susceptibility. There are following remedies which are helpful in the treatment of knee effusion:-
- Apis mellifica – This remedy is very useful in synovitis of knee joint. There are sharp, stinging, lancinating pains shooting through the joint and aggravation from the slightest motion. Extreme sensitiveness to touch and general soreness is marked. The skin around joints are rosy, light red colour. Joint pain gets better when cold is applied and worse from hot applications. Sensation of stiffness and as of something torn off in the interior of the body. Apis does not affect the joint itself, but helps the tissues around the joint, like the synovium, ligaments and tendons.
- Rhustox – Rhustox affects fibrous tissue markedly, joints, tendons, sheaths etc. producing pain and stiffness. Hot, painful swelling of joints. Tearing pains in tendons, ligaments and fasciae. Tenderness about knee joint. Symptoms become worse from sitting, after rising from a sitting position and first motion. He feels better after continuous motion and from a change of position. Ailments from strains and over-lifting. Septic arthritis. Warmth relieves the pain and there is aggravation from cold, damp weather as well as from approaching storms. The person is restless and often paces because of the pain, especially at night.
- Bryonia alba – It is a medicine used to treat swelling in the knees due to rheumatic joint complaint. Knees are stiff and painful. The knee joints are red, swollen, hot with stitching and tearing pain; worse on least movement. Red and shining swelling of the knees, with violent shootings, especially on walking.
- Kali iodatum – This remedy is indicated in cases of rheumatism of knees with effusion. Severe bone pains, worse at night and in damp weather. There is spongy swelling of the joint, a feeling of heat inside the joint.
- Causticum – Causticum mainly manifests its action in chronic rheumatic, arthritic and paralytic affections. There are tearing, drawing pains in the muscular and fibrous tissues with deformities about the joint. The affected joints feel stiff, burning sensation in joints and tension in knees. Pain is worse from cold and relieved by warmth, especially heat of bed.
- Iodium – Inflammatory swelling of the knee with tearing pains and suppuration. White swelling of the knee. The affected joint is swollen, bright red, hot with burning and pricking sensation, aggravated by touch and pressure.
- Ledum palustre – This remedy is of rheumatic nature, rheumatic and gouty. It is suitable in old prolonged cases of inflammation of the knee joint, of rheumatic knee joint. The gouty joints become suddenly inflamed and are relieved by cold. Rheumatic and gouty extremities with pain and swelling; pain worse from motion, at night and warmth of bed and better from cold applications.
- Pulstilla – This remedy is useful for gouty, rheumatic or blenorrhagic synovitis. The knee joints are swollen with tearing and drawing pains, shifting from one joint to other. There is a feeling of deep soreness, as of subcutaneous ulceration.
- Mercurius – This remedy suits syphilitic or strunous synovitis, with tendency to complete destruction of the joint. The general symptoms will indicate the remedy, such as aggravation at night, profuse sweating, feeling of coldness and chilliness, restlessness, a threatening suppuration and the characteristic cachexia.
- Arnica Montana – It is used to treat a swollen knee that develops as a result of an injury or trauma. Sore, lame, bruised feeling all over the body, as if beaten; traumatic affections of muscles. A sensation of dislocation with a tenderness of the knee joint may also be present.
An adequate history and examination is essential in managing the patient with an acutely swollen knee. The best outcome for a patient can be achieved with a coordinated therapy plan between multispeciality and inter-professional teams. As far as therapeutic medication is concerned, homoeopathy is one of the ways through which a state of complete health can be regained by removing all the sign and symptoms from which the patient is suffering.
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Dr. Priyanka Nagar
MD Scholar, Department of Practice of Medicine
Dr. MPK Homoeopathic Medical College, Hospital and Research Centre, Jaipur, Rajasthan, India