Hemarthrosis is defined by the presence of blood within the joint cavity, a space normally filled with synovial fluid. Joints are complex structures where bones meet, cushioned by cartilage and stabilized by ligaments and tendons. When bleeding occurs into this closed space, the accumulation of blood creates pressure and irritation that disrupts normal joint function. The blood itself can damage delicate joint tissues, requiring prompt medical attention to prevent long-term complications.
Recognizing the Signs and Symptoms
The primary sign of hemarthrosis is the rapid onset of significant joint swelling, often developing within a few hours. This swelling, known as an effusion, results from the blood filling the joint capsule, causing a feeling of fullness or tension. The pressure buildup leads to severe and sudden pain, frequently accompanied by warmth or heat radiating from the affected area.
The mechanical pressure from the pooled blood also causes stiffness and a limited range of motion. The joint may become difficult to fully extend or flex, and a person may refuse to bear weight on the affected limb. Bruising or discoloration around the joint can also become visible as the blood moves into the surrounding soft tissues.
Primary Causes of Joint Bleeding
The causes of hemarthrosis are broadly categorized into those resulting from acute injury and those originating from systemic medical conditions. Traumatic injury is the most common reason for joint bleeding, typically involving damage to blood vessels within the joint structure. Acute events include tears of major ligaments, such as the anterior cruciate ligament, intra-articular fractures, or severe blunt force trauma.
Bleeding can also occur as a complication following orthopedic procedures, such as arthroscopic surgery or joint replacement. The physical disruption of tissues during the operation can lead to excessive post-operative bleeding into the joint space. This traumatic form of hemarthrosis is characterized by a rapid accumulation of blood and a swift increase in symptoms.
A second major category involves non-traumatic or systemic causes, where bleeding is due to an underlying condition that compromises the body’s clotting ability. The most recognized example is hemophilia, an inherited bleeding disorder characterized by a deficiency in specific blood clotting factors, such as Factor VIII or Factor IX. Individuals with severe hemophilia are prone to spontaneous joint bleeds.
Acquired bleeding issues can also lead to hemarthrosis, most commonly from the therapeutic use of anticoagulant medications, often referred to as blood thinners. These drugs, like warfarin, prevent dangerous blood clots but increase the risk of bleeding into enclosed spaces, including joints. Other systemic causes include advanced liver disease, which impairs clotting factor production, or inflammatory arthropathies.
Confirmation and Treatment Protocols
When hemarthrosis is suspected, initial steps involve a thorough physical examination and a review of the patient’s medical history for recent trauma or bleeding disorders. Imaging begins with plain X-rays to check for bone fractures or joint space abnormalities, common causes of traumatic bleeding. Magnetic resonance imaging (MRI) further evaluates soft tissue structures like ligaments, tendons, and cartilage for signs of injury not visible on an X-ray.
The definitive diagnostic procedure is arthrocentesis, which involves inserting a sterile needle into the joint space to aspirate the fluid. The fluid is examined for visual confirmation of blood, which may appear red, pink, or brownish. This procedure is both diagnostic and therapeutic, as removing the accumulated blood helps to relieve painful pressure within the joint capsule.
Immediate management typically follows the RICE protocol: Rest, Ice, Compression, and Elevation of the affected joint. Pain control is addressed, but nonsteroidal anti-inflammatory drugs (NSAIDs) are often avoided because they can interfere with clotting and potentially worsen the bleeding. Physical therapy is necessary for recovery to restore the joint’s strength and range of motion after the acute bleeding is controlled.
The most important part of treatment is addressing the underlying cause to prevent recurrence and limit long-term damage. For patients with hemophilia, this involves immediate infusion of the deficient clotting factor to stop the hemorrhage and restore normal clotting function. For traumatic causes, treatment focuses on stabilizing the injury, such as surgically repairing a torn ligament or fracture. Untreated or recurrent hemarthrosis leads to significant long-term complications, as iron in the blood causes chronic inflammation and progressive destruction of the cartilage, resulting in permanent joint damage and chronic arthritis.