Infectious Arthritis vs Reactive Arthritis

Introduction:

Arthritis is a disorder caused by inflammation of the joints that involves a diverse range of subtypes, each with its distinctive triggers and characteristics. The two types that are commonly seen occur commonly and are associated with infections are infectious arthritis and reactive arthritis. The term 'reactive arthritis' was first used in 1969 to elucidate the development of sterile inflammatory arthritis after a remote infection, usually in the gastrointestinal or urogenital tract. Understanding the differences between these two conditions is essential for accurate diagnosis and effective management. This article explores the differences between infectious arthritis and reactive arthritis, throwing light on their causes, symptoms, and treatment approaches.

What Is Infectious Arthritis?

Infectious arthritis, also known as septic arthritis, is a serious and potentially debilitating condition caused by invading microorganisms like bacteria, viruses, or fungi, into the joint space. This invasion triggers an inflammatory response, which further leads to the rapid onset of symptoms. The most common causative agents for infectious arthritis include bacteria like Staphylococcus aureus and Streptococcus species. Infection-causing germs might also enter the body during surgery or via open wounds or an injection.

What Is Reactive Arthritis?

Reactive arthritis, earlier known as Reiter's syndrome, is an inflammatory arthritis that develops in response to an infection in another part of the body. Unlike infectious arthritis, the causative infection might not be present in the joints. However, it can initiate an immune response, triggering joint inflammation. Common infections associated with reactive arthritis include gastrointestinal infections caused by bacteria like Shigella, Salmonella, and Campylobacter, as well as genitourinary infections, often triggered by Chlamydia trachomatis.

What Are the Common Infectious Agents?

Common infectious agents of reactive arthritis:

• Salmonella species.

• Chlamydia trachomatis.

• Shigella species.

• Yersinia enterocolitica.

• Campylobacter jejuni.

Common infectious agents of septic arthritis:

• Staphylococcus aureus.

• Pseudomonas aeruginosa.

• Streptococcus species.

• Neisseria gonorrhea.

What Are the Causes of Infectious Arthritis and Reactive Arthritis?

The causes of infectious arthritis include:

• The most common cause of infectious arthritis is the direct introduction of bacteria into the joint space. This can take place through the bloodstream, generally from an existing infection somewhere else in the body, or through direct contamination due to trauma or surgery.

• Viruses and fungi can also lead to infectious arthritis. However, it is a less common cause. Viruses like hepatitis C, human immunodeficiency virus (HIV), and parvovirus B19, as well as fungi like Candida, may invade the joints, triggering an inflammatory response.

The causes of reactive arthritis include:

• Reactive arthritis is typically an infection, and the body's immune system reacts to the infection by mistakenly attacking healthy joint tissues.

• Certain genetic factors might increase an individual's susceptibility to developing reactive arthritis following an infection.

What Are the Symptoms of Infectious Arthritis and Reactive Arthritis?

The symptoms of infectious arthritis include:

• Symptoms develop rapidly, often over a few days.

• Severe pain in the affected joint, making it red, swollen, and warm to the touch.

• Systemic symptoms might accompany joint symptoms, indicating a broader inflammatory response.

Reactive arthritis presents with a distinctive set of symptoms, including:

• Arthritis or joint pain, swelling, and stiffness, typically affecting the lower extremities, such as the knees and ankles.

• Urethritis or inflammation of the urethra leading to pain during urination.

• Conjunctivitis orinflammation of the eye's outer membrane causes redness and irritation.

What Is the Difference in Diagnosis and Treatment?

The diagnosis and treatment of infectious arthritis include:

• Joint Aspiration: An essential diagnostic step involves the aspiration of fluid from the affected joint to detect the causative organism.

• Imaging: X-rays and other imaging studies usually help to evaluate the extent of joint damage.

• Antibiotic Therapy: Early and aggressive antibiotic treatment is essential to eradicate the infectious agent. In severe cases, surgical drainage might be required. Treatment of septic arthritis involves antimicrobial therapy and joint fluid drainage, such as daily needle aspiration.

The diagnosis and treatment of reactive arthritis include:

• Clinical History: A proper examination of the patient's medical history involves recent infections and helps establish a link between the infection and the onset of arthritis.

• Laboratory Tests: Blood tests might reveal markers of inflammation, and specific tests can detect the presence of the triggering infection.

• Treatment of Underlying Infection: Addressing the underlying infection is paramount. Antibiotics are administered for bacterial infections, while antiviral or antifungal medications may be necessary for other causative agents.

• Anti-inflammatory Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) and, in more severe cases, disease-modifying antirheumatic drugs (DMARDs) might be used to manage symptoms and control inflammation.

• Antibiotics: Treatment with antibiotics to manage Chlamydia infection is essential. However, the use of either short or prolonged antibiotic courses in established arthritis is not effective for the cure of arthritis. The long-term outcome of reactive arthritis is generally good.

What Are the Common Distinguishing Factors?

While both infectious arthritis and reactive arthritis involve joint inflammation associated with infections, the following aspects help to distinguish between the two:

• Site of Infection: In infectious arthritis, the infection affects the joint directly, while in reactive arthritis, the infection is usually in a distant part of the body.

• Onset of Symptoms: Infectious arthritis shows a rapid onset, with severe joint symptoms emerging quickly. Reactive arthritis might have a more gradual onset, with symptoms developing after the resolution of the initial infection.

• Identification of Causative Organism: Joint aspiration in infectious arthritis directly identifies the causative organism in the joint fluid. In reactive arthritis, the focus is on identifying the triggering infection in other body parts.

Conclusion:

Infectious arthritis and reactive arthritis, though both associated with infections represent distinct entities with unique characteristics and diagnostic considerations. Accurate diagnosis and prompt intervention are important for effective management and the prevention of long-term joint damage. A collaborative approach involving healthcare professionals, like rheumatologists (doctors specializing in inflammatory or rheumatic disease), infectious disease specialists, and primary care physicians, is essential for comprehensive care and optimal outcomes. As the understanding of these conditions advances, so does the ability to customize the treatment strategies, giving hope for better outcomes and an improved quality of life for those affected by these forms of arthritis.