What is Infectious Arthritis?

Infectious arthritis refers to arthritis caused by microorganisms such as bacteria and viruses invading the joint cavity. Patients are mostly children and the elderly with weak physical resistance. The most common cause of joint infections is sepsis. In addition, trauma, surgery, and soft tissue infections near the joints are also important causes.

Basic Information

English name: infectious arthritis
Visiting department: orthopedics

Multiple groups: Children and the elderly
Common causes: Caused by a bacterial or viral infection
Common symptoms: Suffering from joint swelling and heat pain

Causes of infectious arthritis

Acute infectious arthritis

Can be caused by a bacterial or viral infection.

(1) Neisseria gonorrhoeae is a common pathogen in adults . It extends from the surface of the infected mucosa (cervix, rectum, pharynx) to some hand joints, elbows, knees, and ankles. Axial bone joints are less involved.

(2) Non-gonococcal arthritis is mostly caused by Staphylococcus aureus, Streptococcus, and Gram-negative bacteria, such as Enterobacter, Pseudomonas aeruginosa, and Serratia.

(3) Staphylococcus aureus and group B streptococcal infections are more common in newborns and children over 2 years of age.

(4) Joint infections Anaerobic bacteria are often accompanied by facultative or aerobic infections (5% to 10%), such as Staphylococcus aureus, Streptococcus epidermidis, and E. coli.

(5) Most joint infections caused by bites are caused by Gram-negative bacteria such as Streptococcus B, or oral anaerobic bacteria (such as Clostridium, Streptococcus, Bacteroides). Joint infections caused by animal bites are usually Staphylococcus aureus or oral flora.

(6) Joint infections in HIV patients are caused by Staphylococcus aureus, Streptococcus, and Salmonella. HIV patients may have Wrighter syndrome, recurrent arthritis, HIV-related arthritis, and joint pain. The longer an HIV patient survives, the more chances of infection with mycobacteria, fungi, and rare conditional pathogens.

(7) Viruses that cause acute arthritis include parvoviruses B19, HBV, HCV, rubella virus (after acute infection and immunization), and coat virus. Varicella virus, parotid virus (adult), adenovirus, coxsackie virus (A9, B2, B3, B4, B6); Epstein-Barr virus is also associated with joint pain and arthritis, and is more likely to cause polyarthritis than bacteria.

2. Chronic infectious arthritis

Chronic arthritis can be caused by mycobacteria, fungi, and other less pathogenic bacteria. Such as Mycobacterium tuberculosis, Mycobacterium maritime, Mycobacterium kansas, Candida, Bravococcus, Capsular histoplasma, New cryptococcus, Dermatitis, Mycobacterium spp. Aspergillus, Actinomycetes, and Brucella.

Two-thirds of the patients had joint infection within 1 year after joint replacement. This may be due to the introduction of bacteria during the surgical procedure or postoperative bacterial infections such as skin infections, pneumonia, and dental infections.

Clinical manifestations of infectious arthritis

Suffering from joint swelling and heat pain, a large amount of serous, fibrous or purulent exudate accumulated in the joint cavity, the joint capsule swelled, and there was a sense of fluctuation in compression. The limbs are lame, often accompanied by an increase in body temperature; the articular cartilage is destroyed, the subchondral bone is eroded, the bone around the joint bone is hyperplasia, and the synovium is thickened. Tough or dead joints.

Infectious arthritis examination

Laboratory inspection

(1) It can show that the white blood cell count increases, the erythrocyte sedimentation rate increases, and the C-reactive protein increases.

(2) The WBC count in synovial fluid samples of swollen joints with acute infection was> 20000 / l, and the synovial fluid viscosity and sugar content decreased. Gram staining can identify 50% to 75% of joint infections between Gram-negative and Gram-positive bacteria, but it cannot distinguish between Staphylococcus and Streptococcus. Synovial fluid also requires anaerobic and aerobic culture. Synovial fluid has an odor or X-ray shows gas shadows in the joints or around soft tissues, suggesting an anaerobic infection.

2. Bone Scan

Abnormal manifestations can be seen in infectious arthritis, especially the central skeletal joints. The scan showed that the infected synovium had abundant blood flow, increased intake, and accelerated bone metabolism. It showed positive results in both sterile and bacterial arthritis.

Diagnosis of infectious arthritis

The diagnosis of infectious arthritis requires highly suspicious indications, especially the presence of non-joint exogenous infections, as the symptoms of various arthritis are similar. Clinical manifestations and microbiological examination of the infected area are helpful for diagnosis.

Differential diagnosis of infectious arthritis

This disease needs to be distinguished from rheumatoid arthritis. Infectious arthritis itself has the following characteristics, which can help distinguish it from rheumatoid arthritis:

1. Mostly involve a single joint, occasionally more than two, asymmetry.

2. Acute onset, more severe joint pain, and obvious systemic symptoms.

3. Joint cavity puncture can extract pus, and culture can detect pathogenic bacteria.

4. Rheumatoid factor is negative and the immune test is normal.

Infectious arthritis treatment

1. Use sufficient and effective antibiotics throughout the body. When possible, bacterial culture and drug sensitivity tests of joint effusion should be done as much as possible, and the most sensitive antibiotics should be selected according to the results.

2. Inject effective antibiotics directly into the joint cavity. According to the situation every other day or every 3 to 4 days for joint cavity puncture, try to drain the joint cavity fluid, and then inject effective antibiotics.

3. Generally, it is not appropriate to perform incision and drainage for joints. If purulent inflammation is still uncontrollable and the symptoms of systemic poisoning are severe, incision and drainage should be performed.

4. After the acute inflammation subsides, patients should be encouraged to perform opening exercises to prevent intra-articular adhesions and joint ankylosis.

Infectious arthritis prevention

For the prevention of this disease and the following precautions:

1. Preventive treatment is only suitable for patients who have an increased susceptibility to skin infections, genitourinary and respiratory infections. For patients who have undergone microinvasive surgery, preventative treatment is only suitable for highly susceptible patients.

2. Select antibiotics through drug susceptibility tests and apply them continuously for several weeks until infection control.

3. Properly move the joints to prevent adhesions. However, for those with a longer course of disease, due to the severe destruction of articular cartilage and articular bone, inflammation control often turns into osteoarthritis afterwards, and it is difficult to restore function.