Acute septic arthritis

Introduction to acute septic arthritis Septic arthritis is an infection caused by purulent bacteria at the joints. More than 85% of the common pathogens are Staphylococcus aureus. Most of the infection routes are blood-borne, and a few are direct spread of infection. The disease is common in children around 10 years old. Most often occurs in the hip and knee joints. Single-shot joints. The joint of the hip joint is often missed due to deep relationship or obscuration due to infection symptoms in other parts of the body. Therefore, the therapeutic effect of the disease emphasizes early diagnosis, and early treatment is the key to ensuring that joint function does not cause obstacles and loss. basic knowledge The proportion of illness: 0.001% Susceptible population: more children occur Mode of infection: non-infectious Complications: suppurative osteomyelitis

Acute septic arthritis

The path of bacteria invading the joint may be blood-borne, traumatic or spread by adjacent infected lesions. After the bacteria invade the joint, there is synovitis, joint exudate, joint swelling and pain. After the disease develops, the effusion is made up of the slurry. Sexually converted to serous fibrin, and finally purulent, when the joint is involved, the lesion gradually invades the cartilage and bone, and finally the joint stiffness occurs. After the joint is purulent, the joint capsule and the skin can be worn out to form the sinus, or Spread to adjacent bone, causing suppurative osteomyelitis, in addition, due to joint capsule relaxation and muscle spasm, can also cause pathological dislocation, joint deformity, loss of function.

Acute septic arthritis prevention

The key to the prevention of this disease is to prevent joint infections.

Suppurative arthritis is caused by purulent bacterial infection in the joints. It is an acute onset, with symptoms of systemic infection, high fever and chills. It is different from the "arthritis" and "rheumatoid arthritis" that ordinary people say. And attention, especially deep hip infection due to deep relationship, or masked by other parts of the body, and missed diagnosis or delay diagnosis, resulting in loss of joint function and obstacles, early diagnosis of this disease, early high-dose antibiotic treatment, etc. , can restore joint function without causing functional obstacles.

Acute septic arthritis complications Complications of suppurative osteomyelitis

Common complications of this disease include joint stiffness, suppurative osteomyelitis, pathological dislocation, joint deformity, and loss of function.

Symptoms of acute septic arthritis Common symptoms High heat convulsions, chills, joint swelling, joint fluid, increased dead bone

The main symptoms of acute septic arthritis are poisoning. The patients have chills and fever, and the systemic symptoms are serious. Children with cerebral palsy due to high fever may have acute inflammatory symptoms such as redness, swelling and obvious tenderness. The joint fluid increases and fluctuates. The patient often places the knee joint in a semi-bend position, which relaxes the joint capsule to relieve tension, long-term flexion, joint flexion contracture, joint pain and pain, and protective muscle spasm.

Examination of acute septic arthritis

Diagnosis is mainly based on medical history, clinical symptoms and signs. In patients with suspected blood-borne septic arthritis, blood and joint fluid bacterial culture and drug sensitivity tests should be performed.

X-ray examination is not helpful in the early stage, only joint swelling; only later may have bone decalcification, joint space stenosis due to cartilage and bone destruction, joint bone or fiber toughness and deformity may occur in the late stage, with new bone Proliferation, but less dead bone formation.

(1) Laboratory inspection

1, blood routine: the total number of white blood cells increased, neutrophils increased.

2, ESR increased.

3. Blood culture can be positive.

4, joint synovial fluid examination: is the key to diagnosis, should be carried out as soon as possible. 1 synovial fluid is serous or purulent, the total number of white fine sputum is often greater than 50 × 10 ⁹ / L, even up to 100 × 10 ⁹ - 200 × 10 ⁹ / L, neutrophils greater than 80%. 2 Gram staining can find bacteria. Bacterial culture is positive. If it is negative, it should be re-cultured with parallel oxygenation bacteria and tested for drug susceptibility.

5, arthroscopy: can directly observe the structure of the joint cavity, taking synovial fluid or tissue examination.

(2) X-ray examination

The soft tissue around the joint is swollen and the bones are loose. After the joint space is narrowed, the bone shield is destroyed, and the reaction is found to have hyperplasia. Late joints are fibrotic or bony fusion, dead bone formation, joint dislocation or dislocation. In the X-ray examination, the joint capsule was swollen in the early stage due to the increase of joint fluid, the gap was widened, and the bone end gradually decalcified. If the articular cartilage is damaged, the joint space is narrowed. Sometimes it can be said to have osteophyte spondylolisthesis or pathological dislocation. In the later stage, the bone under the joint surface is reactive hyperplasia, osteosclerosis, and increased density. Finally, the articular cartilage is completely dissolved, the joint space disappears, and it is bony or fibrous, or the disease is dislocated. Its X-ray performance is:

1. When there is suppurative inflammation in the early joints, the soft tissues around the joints often have congestion and edema, which is characterized by soft tissue thicker than the healthy side and unclear level. The joint capsule expands due to fluid accumulation in the joint, and the fat layer is curved. Occasionally, the joint space is slightly widened, and it should be compared with the healthy side, so that it will not be missed.

2. Joint space stenosis Synovial bacteria first caused by synovitis after entering the joint. The exudate contains a large amount of neutrophils. A large amount of lytic protease released after leukocyte death, quickly dissolving articular cartilage. According to the degree of destruction of articular cartilage, joint space stenosis often occurs shortly after onset, or even disappears completely.

3. Articular surface changes After the articular cartilage is destroyed, the subchondral bone can be further destroyed. It first appeared in the mutual contact part of the articular surface, that is, the weight bearing part. It is characterized by blurred and irregular joint surfaces. Then a larger damage zone is formed, forming a dead bone. Due to the repairing effect of the body, the density around the damaged area increases due to bone hyperplasia, and the edge of the joint has lip-like bone hyperplasia. When the trabecular bone penetrates the joint space to join the bilateral articular surface, it is called osteogenic rigidity.

4. Articular cartilage and bone destruction can cause dislocation or subluxation in adolescents and adults. It is often due to the destruction of articular cartilage to form a strong bone, and children often suffer from bone destruction and absorption, causing pathological dislocation.

Diagnosis and diagnosis of acute septic arthritis

Diagnostic criteria

Diagnosis is mainly based on medical history, clinical symptoms and signs. In patients with suspected blood-borne septic arthritis, blood and joint fluid bacterial culture and drug sensitivity test should be performed. X-ray examination does not help much in the early stage, only joint swelling is seen; There may be decalcification of the bone, joint space stenosis due to cartilage and bone destruction, joint bone or fiber toughness and deformity may occur in the late stage, and there is new bone hyperplasia, but less dead bone formation.

Differential diagnosis

There are many types of arthritis. The symptoms of acute septic arthritis are often similar to those of some diseases. It is easy to be misdiagnosed, resulting in wrong treatment, unsatisfactory results, and even worsening of the disease. Therefore, acute septic arthritis should be differentiated from the following diseases. :

(1) Acute blood-borne osteomyelitis: The main lesions and tenderness of osteomyelitis are at the metaphysis, not at the joints, and the early effects of joint activities are not significant. The joint fluid puncture and stratified puncture can be clearly diagnosed.

(2) joint tuberculosis: slow onset, often low fever in the afternoon, night sweats, cheeks flushing and other systemic symptoms, local skin temperature is slightly higher, but the joint is swollen and not red.

(3) rheumatoid arthritis: multiple migratory pain, serum anti-"O" is positive, joint fluid without pus cells and pathogenic bacteria, can be identified.

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