Etiology and routes of infection
Suppurative joint inflammation is caused by pyogenic microflora. In the overwhelming majority of cases, Staphylococcus predominates, while Streptococcus, Pneumococcus, Enterobacteriaceae, and Gonococcus are less common.
Infection can enter the joint through two main pathways:
- Primary: direct microbial contamination through an open joint wound.
- Secondary: pathogen penetration from an external source. This can be a hematogenous route (transport of microflora via the bloodstream from distant purulent foci—often suspected in the absence of trauma) or a contact route (spread of pus from adjacent inflamed tissues).
Dynamics of development and localization
The nature of the inflammatory process can be serous, fibrinous, purulent, or putrid. The disease does not stand still; pus spreads progressively, going through several stages:
- Synovitis: rapid exudation, edema, hyperemia, and leukocyte infiltration of the synovial membrane.
- Phlegmon of the joint capsule: inflammation extends beyond the synovial membrane, melting the entire capsule.
- Pararticular phlegmon: pus spreads to the surrounding soft tissues.
- Purulent streaks: formation of deep accumulations of pus in intermuscular and interosseous spaces.
- Osteoarthritis: destruction involves the articular cartilage and the spongy substance of the epiphyses.
In terms of frequency of involvement, the knee joint (gonitis) ranks first, the hip joint (coxitis) second, and the shoulder joint (omarthritis) third.
Clinical presentation
The disease manifests acutely, presenting with a combination of local and general symptoms.
Local manifestations:
- Severe, sharp pain in the affected area.
- Contracture: forced (semi-flexed) limb posture and restriction of movement. The degree of restriction directly reflects the severity of inflammation.
- Defiguration of the joint: alteration of its contours, easily noticeable when compared to the healthy limb.
- Skin hyperemia, local hyperthermia, tension, and tissue infiltration.
- Palpation reveals fluctuation (indicating fluid accumulation or the development of pararticular phlegmon), and in the knee joint, the patellar tapotement (ballottement) sign.
General symptoms (purulent intoxication):
- Hectic fever, chills, and sweating.
- Weakness, malaise, and altered mental status.
- Progressive anemia.
Diagnostics of acute purulent arthritis
In addition to taking a medical history and performing a physical examination, a combination of instrumental and laboratory methods is used to establish a diagnosis:
- Joint puncture (key method): allows visual evaluation of the effusion (serous, purulent, purulent-hemorrhagic) and microbiological examination. Fluid culture determines the pathogen type and its antibiotic susceptibility.
- Blood test: confirms systemic purulent inflammation (revealing leukocytosis, neutrophilia, high ESR, dysproteinemia).
- X-ray examination: images show widening of the joint space and osteoporosis in the epiphyseal ends of the bones.
Principles of treatment and prevention
Therapy must be comprehensive.
Local treatment:
- Daily therapeutic punctures until exudate accumulation ceases (evacuation of pus, washing with antiseptics, administration of antibiotics).
- Immobilization (plaster splint or brace).
- Physiotherapy (UHF therapy, quartz irradiation, electrophoresis).
- After inflammation subsides—functional restoration (exercise therapy, massage).
General treatment:
- Antibiotic therapy (according to culture results).
- Detoxification and transfusion therapy (blood, plasma, protein solutions).
- Immunotherapy and a diet rich in proteins and vitamins.
Surgical treatment (Arthrotomy): Indicated when punctures are ineffective. The joint is opened, pus and fibrin films are removed, after which drains are installed for active continuous-wash debridement. If pararticular phlegmon has developed, it requires mandatory opening and drainage according to general rules of purulent surgery.
Prevention consists of thorough primary surgical debridement (PSD) of joint wounds, adherence to asepsis during orthopedic surgeries, and timely treatment of purulent processes in adjacent tissues.
The stages of process development are easy to remember using the "inside-out" principle: first, the membrane becomes inflamed (synovitis), then the entire capsule (capsular phlegmon), after which pus extends beyond the joint (pararticular phlegmon and streaks), and finally, the bones are destroyed (osteoarthritis).
Class and exam questions
Which joints are most frequently affected by purulent arthritis?
The knee joint is most frequently affected (gonitis), while the hip (coxitis) and shoulder (omarthritis) joints are involved somewhat less frequently.
What does the fluctuation sign indicate during a joint examination?
The presence of fluctuation directly indicates the accumulation of fluid (effusion) in the joint cavity or the development of pararticular phlegmon in the surrounding tissues.
When is surgical opening (arthrotomy) used in purulent arthritis?
Arthrotomy is indicated when conservative methods—therapeutic punctures with cavity washing and antibiotic administration against the background of systemic therapy—are ineffective.
What else to study on this topic
- Topography and spread pathways of purulent streaks in shoulder arthritis (axillary, subdeltoid, subpectoral, etc.).
- Diagram of the localization of purulent streaks on the lower leg in progressive purulent gonitis.
- Technique for performing therapeutic punctures of various joints (hip, knee, ankle, shoulder).
- Features of continuous-wash joint drainage after arthrotomy (placement of microirrigators and irrigation regimen).
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Other topics from the section "CHAPTER 11. SURGICAL INFECTION (PURULENT-INFLAMMATORY DISEASES)"
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