Non-gonococcal bacterial arthritis

Introduction to non-gonococcal bacterial arthritis Non-gonococcal bacterial arthritis is a serious disease with a mortality rate of 5% to 10%. 25% to 40% of patients have joint damage and dysfunction. Prognosis is associated with a variety of factors, including the long-term nature of the infection, the nature of the bacteria, the joints involved, the host's resilience, and the application of some therapeutic principles. However, according to the statistics of the Montana State Biomedical Center, non-gonococcal septic arthritis has higher complications, morbidity and mortality than gonococcal arthritis even if it is treated promptly and effectively. basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Mode of infection: non-infectious Complications: Diabetes Anemia Meningitis

The cause of non-gonococcal bacterial arthritis

Bacterial infection (35%):

Among adult patients, Gram-positive cocci are the most common pathogens in non-gonococcal septic arthritis, of which 60% are Staphylococcus aureus, and recent arthritis caused by Gram-negative bacteria and non-A-type streptococcus has become More and more common, with fewer pneumococci. In addition, the discovery of anaerobic bacteria is more common and may be related to improvements in anaerobic culture techniques.

Physical and chemical factors (30%):

Pneumococcal arthritis is quite common before the invention of antibiotics, currently accounting for only 5% of bacterial arthritis, and is common in trauma patients or alcoholics.

Disease factors (35%):

50% of patients have extra-articular infections, such as pneumococcal or meningitis, more common in children, heroin drug users are more common with Pseudomonas aeruginosa and Enterobacter, infection sites are more common in sterno-lock joints, ankle joints and vertebrae Inter-articular joints are considered to be related to the entry of bacteria from the injection site.

Pathogenesis

Gram-positive bacterial arthritis

(1) Staphylococcus aureus arthritis: Most of the Staphylococcus aureus in the joint is resistant to methicillin (methicillin), and patients with intravenous drug injections have golden staphylococcal arthritis It is often resistant to methicillin or benzoxazole penicillin, and about 80% of joint infections in patients with rheumatoid or other chronic arthritis are caused by Staphylococcus aureus.

Other coagulase-negative staphylococci can also cause joint infections, but they are less common and resistant to many antibiotics but sensitive to vancomycin.

The arthritis of Staphylococcus aureus infection is characterized by a short serous period, a long purulent phase, a yellowish white pus, thick, thick, and early destruction of cartilage and bone.

(2) Streptococcal arthritis: another common septic arthritis, recently reported increase in non-A group streptococcosis, characterized by severe disease, infection is difficult to eradicate, hemolytic streptococcus is often healthy Arthritis is caused in individuals, and bacteria often spread from the skin or upper respiratory tract. Streptococcal arthritis is often characterized by single joints. Only 10% to 25% of group A and group B streptococcal arthritis are multi-jointed. Arthritis is characterized by a longer serous phase, a short purulent phase, a thin and pussy pus, and a later joint destruction.

(3) pneumococcal arthritis: quite common before the invention of antibiotics, currently only 5% of bacterial arthritis, common in trauma patients or alcoholics, 50% of patients have extra-articular infections, such as pneumococcal or meningitis More common in children, arthritis generally occurs in the third phase of pneumonia, characterized by a short period of serous, long purulent period, yellow pus, a large amount of fibrin, cartilage destruction, joint stiffness.

2. Gram-negative bacterial arthritis The incidence of this disease has increased to 15% to 20% of non-gonococcal joint infections, more common in newborns, the elderly, traumatized and intravenous drug users.

Children under 2 years old are more common. The pathogens are often Pseudomonas aeruginosa, Escherichia coli, Enterobacter, Klebsiella and Haemophilus influenzae. The children are usually healthy, just because they have lost after 6 months. The mother's antibodies to Haemophilus influenzae have not yet produced an effective level of antibodies, often accompanied by upper respiratory tract infections, otitis media or meningitis.

Older people, intravenous drug users and chronic diseases are also common, malignant tumors, diabetes, sickle cell anemia, connective tissue diseases and kidney transplantation are more likely to be complicated by Gram-negative bacterial arthritis, most of which originate from the urinary tract or skin. Commonly involved with single joints, Escherichia coli is more common, heroin drug users are more common with Pseudomonas aeruginosa and Enterobacter, the infection site is more common in sterno-lock joints, ankle joints and intervertebral joints, considering bacteria From the injection site, because of no obvious pain, the diagnosis of ankle infection is more difficult, the hip joint active, passive pain, and radiation to the buttocks, ankle joint tenderness, Escherichia coli infection pus Thick, smelly, joint damage is obvious, Pseudomonas aeruginosa infection is common in Pseudomonas aeruginosa sepsis, pus is thin, green or grass green.

Aeromonas hydrophila has been found in patients with leukemia or other immunosuppressive diseases. Genus and Moraxella are present in the normal nasopharynx. They can also cause septic arthritis. The clinical manifestations are painless, bacteria. Slow growth, so it is easy to delay diagnosis, often accompanied by rash, Gram stain like gonococcal, easy to misdiagnose, these bacteria are sensitive to penicillin.

Pasteurella hemorrhagic is a normal strain of cats or other animals. Septic arthritis can occur in patients who are bitten by animals, scratched or have weakened immune mechanisms.

In addition to causing blood-borne septic arthritis, Salmonella can also cause osteomyelitis or aseptic reactive arthritis. Sickle cell disease and systemic lupus erythematosus are most likely to be complicated by Salmonella arthritis. Painless, leukocytosis in the synovial fluid is not obvious, but the immune mechanism is low or the patients with lupus erythematosus complicated with salmonella arthritis, can be a typical single joint acute inflammation, treatment is often unsatisfactory, and it is difficult to determine these patients before Whether there is diarrhea.

3. Anaerobic bacteria and a variety of microbial septic arthritis The recent increase in the incidence of anaerobic arthritis may be due to improvements in bacterial culture techniques, as well as increased understanding of anaerobic infections, large pneumococci, Bacteroides fragilis Various kinds of anaerobic bacteria are the main anaerobic bacteria. Common post-operative wound infections, especially after arthroplasty, can also occur in patients with hypofunction. Septic arthritis of Bacteroides fragilis often occurs in In patients with rheumatoid arthritis, most of the septic arthritis of Clostridium is the direct invasion of bacteria, or the spread of infections in the abdomen and pelvis.

The clinical features are malodorous synovial fluid, X-ray shows gas in the joint, anaerobic bacteria grow slowly, culture for at least 2 weeks, many anaerobic bacteria are resistant to penicillin, so routine antibiotic sensitivity test.

Other micro-aerobic bacteria include Bacillus cereus, carbon dioxide bacteria, Propionibacterium acnes, and Corynebacterium.

Bacterial arthritis of various microorganisms accounts for 2% to 10% of gonococcal arthritis. Almost 50% of anaerobic joint infections are caused by various microorganisms. Common anaerobic and aerobic bacteria coexist. In severe cases, postoperative wound infection or intra-abdominal infection, pelvic infection directly spreads to the hip joint.

Non-gonococcal bacterial arthritis prevention

Eliminate and reduce or avoid the disease factors, improve the living environment, develop good habits, prevent infection, pay attention to food hygiene, and rational diet.

Non-gonococcal bacterial arthritis complications Complications, diabetes, anemia, meningitis

Gram-negative bacterial arthritis in the elderly, intravenous drug users and chronic diseases, easy to be complicated by malignant tumors, diabetes, sickle cell anemia, connective tissue disease, salmonella arthritis most complicated by sickle cell disease and systemic Lupus erythematosus, Gram-negative bacterial arthritis Children under 2 years of age are prone to otitis media or meningitis.

Non-gonococcal bacterial arthritis symptoms common symptoms low fever chills joint pain joint swelling

Typical performance:

1 sudden onset joint pain and swelling,

2 There is obvious intra-articular exudation, active and passive movement is limited,

380%90% of patients only involve a single joint. If multiple joints are invaded, it indicates that the patient is accompanied by severe chronic disease or chronic arthritis, such as rheumatoid arthritis. The common pathogen of polyarticular septic arthritis is Staphylococcus aureus, pneumococcus, group G streptococcus, and Haemophilus influenzae, the mortality rate is twice that of monoarticular septic arthritis.

4 The most common site is the knee joint, which accounts for more than 50% of the adult infected joints. Children's hip infections are more common, especially in newborns.

5 low fever, chilling children are rare.

Examination of non-gonococcal bacterial arthritis

1. Bacterial culture and examination of synovial fluid The first and most important method for definitive diagnosis is joint puncture and synovial fluid culture. Under aseptic conditions, the synovial fluid should be removed as much as possible and placed directly in the broth and On the solid medium, it can also be inoculated into aerobic and anaerobic blood culture bottles. It is suspected that the synovial fluid of Neisseria or Haemophilus should be placed on chocolate agar and in a 5% to 10% carbon dioxide environment. Medium incubation, hip and shoulder joint angiography can be used to determine the exudation of the joint and help determine the puncture site. Fluorescence and CT are used to guide the puncture of the sacral or ankle joint, etc., if necessary, with arthroscopy or Surgical incision to obtain a synovial fluid that can be diagnosed, but a large amount of lidocaine can not contact the synovial fluid, so as not to interfere with bacterial growth, synovial fluid culture is almost positive, the positive rate of Gram staining is different, golden yellow grapes The positive rate of cocci is 75%, and the positive rate of Gram-negative bacteria is only 50%. Acridine orange staining is better than Gram stain for Gram-negative bacteria.

The number of white blood cells in the synovial fluid, classification and determination of glucose are helpful for diagnosis. Generally, the total number of white blood cells is greater than 50×109/L, neutrophils are greater than 80%, and about 30% of the early synovial fluid leukocytes are less than the total. The number of white blood cells of rheumatoid arthritis or rheumatoid arthritis is also often increased in 50×109/L. It is necessary to identify that the number of white blood cells of Gram-negative bacterial arthritis can be as low as 10×109/L.

After fasting for 2 to 4 hours, if the glucose level in the synovial fluid is lower than 50% of the blood glucose measured at the same time, it suggests bacterial arthritis. If the glucose is particularly low, it is 0-25 mg per 100 ml, suggesting septic arthritis.

Gas liquid chromatography (GLC) can be used as an auxiliary diagnosis. The metabolites of bacteria, including fatty acids, are volatile and can be analyzed by GLC.

Lactic acid and succinic acid levels are elevated, and the determination of lactate and lactic dehydrogenase (LDH) is helpful in the diagnosis of patients who have used antibiotics and negative synovial fluid culture. When lactate or LDH levels are low, To help rule out bacterial arthritis, the increase in lactate levels is associated with increased white blood cells in the synovial fluid, decreased pH, and conversion of glucose to lactic acid under anaerobic conditions.

The identification of bacterial antigens in synovial fluid is a more specialized diagnostic method. Countercurrent immunoelectrophoresis (CIE), latex particle agglutination and synergistic agglutination can all help to diagnose, especially with encapsulated antigens, such as influenza bloodthirsty. The diagnosis of bacilli and pneumococci is more helpful.

2. Blood culture is almost 50% positive for blood culture. Sometimes the synovial fluid culture is negative, while blood culture is positive. In addition, the infection outside the joint should also be Gram stain and culture. For example, urinary tract infection may cause Gram-negative arthritis, a skin infection is often the entrance to Gram-positive cocci.

3. Peripheral blood 67% of patients with leukocytosis, but no specificity.

4. ESR has increased erythrocyte sedimentation rate in almost all patients.

5. C-reactive protein (CRP) is positive, but no specific diagnostic significance.

6. X-ray examination: no obvious infection changes in early X-ray films, only revealing intra-articular exudation and fat pad displacement, and can also exclude adjacent osteomyelitis, osteoporosis can be seen after one week, and joint space is narrowed afterwards, joints The shape changes, these changes depend on the toxicity of the bacteria. Gas formation in the joints suggests the possibility of infection with Escherichia coli or anaerobic bacteria. Joints that are difficult to see can be used for arthrography, fluoroscopy or CT, in addition to radionuclide Photography is helpful in the diagnosis of early septic arthritis.

Diagnosis and identification of non-gonococcal bacterial arthritis

According to the clinical manifestations, the bacterial culture and examination of the synovial fluid can be diagnosed by the characteristics of the auxiliary examination.

It should be differentiated from osteomyelitis and tuberculous arthritis. Agglutination of latex particles and synergistic agglutination, especially with encapsulated antigens, can help identify the diagnosis of Haemophilus influenzae and pneumococci.

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