Infectious (Pyogenic) Arthritis

What is Infectious (Pyogenic) Arthritis?

Infectious arthritis, also called septic arthritis or pyogenic arthritis, is a serious infectious disease of the joints, characterized by pain, fever, chills, redness and swelling of one or more joints, as well as loss of mobility of affected joints. This condition requires emergency medical care.

Infectious arthritis occurs in all age groups, including newborns and children. In adults, the disease usually affects the hands or joints that carry a particular weight load – most often the knee. In approximately 20% of adult patients, symptoms of the disease appear in more than one joint. Children with polyarthritis develop on the background of the infection and usually affect the shoulder, knee and hip joints.

The following patients are at increased risk for infectious arthritis:
– patients with chronic rheumatoid arthritis.
– Patients with serious systemic infections, including gonorrhea and HIV infection.
– Men and women of homosexual sexual orientation are at an increased risk of gonorrheal arthritis compared with heterosexuals.
– patients with certain types of oncology.
– drug addicts and alcohol dependent patients.
– Patients with diabetes, sickle cell anemia or systemic lupus erythematosus.
– patients who have recently undergone trauma or surgery on the joints
– patients receiving intra-articular injections.

Causes of Infectious (Pyogenic) Arthritis

In general, infectious arthritis is caused by bacterial, viral, or fungal infections that enter the joint through the bloodstream. The causative agents of the disease can get into the joint, bypassing the blood flow through intra-articular injections or with surgical intervention, as well as from the source of infection in the patient’s body. Pathogens also vary according to age group. Newborns are most often infected with gonococcal infection from a mother with gonorrhea. Children may become infected with infectious arthritis as a result of hospital procedures, usually as a result of inserting a catheter. In children under two years old, haemophilius influencae or staphylococcus aureus usually act as pathogens. In older children and adults, streptococcus pyogenes and streptococcus viridans are added to staphylococcus aureus. Staphylococcus epidermidis involvement in the process usually occurs as a result of surgical procedures. Infectious arthritis in sexually active adolescents and adults is usually a consequence of infection with Neisseria gonorrhoeae. The cause of infectious arthritis in older people is often Gram-negative bacteria, including Salmonella and Pseudomonas. Usually, infectious arthritis begins suddenly, but sometimes the symptoms increase during the period from 3 days to 2 weeks – the affected joint swells up and becomes painful when moving. Infectious arthritis of the hip joint may be manifested by pain in the groin area, which is much worse when trying to walk. The joint painfully reacts to touch, it may or may not be hot to the touch, depending on how deep the source of infection is. In most cases, the patient has a fever and chills, but sometimes the temperature can be raised very slightly. Children may experience nausea and vomiting. Septic arthritis is regarded as a serious threat to the health and even the life of the patient, since bone tissue and cartilage destruction can occur, and there is also a great risk of developing septic shock, which can be fatal. Staphylococcus aureus is capable of destroying cartilage in 1-2 days. The destruction of cartilage and bone tissue subsequently leads to displacement (subluxation) of the joints and bones. If the infection is caused by bacteria, it can spread to the blood and surrounding tissues, causing abscesses or even blood infection. The most common complication of infectious arthritis is osteoarthritis.

Pathogenesis during Infectious (Pyogenic) Arthritis

Infectious arthritis is associated with the direct entry into the joint tissues of infectious agents in trauma due to their lymphoma or hematogenous drift during septic conditions (actually infectious, septic arthritis) or the formation and deposition of inflammatory (postinfectious arthritis) tissue in the joint tissues. A special group consists of reactive arthritis, which reveals an obvious connection with a specific infection, but neither the pathogen itself, nor its toxins in the joint cavity are detected. The mechanism of development of these arthritis is not well understood.

The division of arthritis associated with infection into infectious, post-infectious, and reactive is quite arbitrary, since even with modern advanced technology, it is not always possible to identify microbial pathogens and their toxins in the joint.

Symptoms of Infectious (Pyogenic) Arthritis

Local signs of acute purulent arthritis – pain in the joint, sharp pain when moving in it, increasing swelling with a change in the contours of the joint, redness and local increase in skin temperature, impaired function of the limb, taking a forced position.

Diagnosis of Infectious (Pyogenic) Arthritis

The diagnosis of “septic arthritis” is made only on the basis of laboratory tests performed, a thorough medical examination of the affected joint and a careful study of the patient’s medical record. It is important to keep in mind that similar symptoms – joint pain and fever – may be caused by other causes, such as other types of arthritis, gout, rheumatic fever, Lyme disease (borreliosis), etc. In some cases, the doctor has to consult a specialist – orthopedist or rheumatologist, to eliminate the error in the diagnosis.

Anamnesis for infectious arthritis
The patient’s medical history will allow the doctor to determine if the patient belongs to one of the risk groups. Cases of sudden joint pain are also important information. Medical examination The doctor will assess the degree of swelling and tenderness of the affected joint, its temperature and other signs of the infection process. In some cases, the location may be the key to the correct diagnosis, for example, the defeat of the sternoclavicular or pelvic joints often occurs in drug-dependent patients. Laboratory tests Laboratory tests are needed to confirm the diagnosis of infectious arthritis. The doctor will puncture the joint, this procedure is a puncture with a syringe to extract a sample of synovial fluid. Synovial fluid is a lubricant produced by the tissues surrounding the joint. The sample is sent in a sealed syringe for sowing. Synovial fluid from the affected joint usually contains flakes of pus and looks dull. Cell counting usually reveals a high white blood cell count; level above 100,000 cells / mm cube. or a neutrophilic proportion of more than 90% indicates septic arthritis. For preliminary identification of the causative agent of infection is used so-called. Gram staining (all bacteria are divided into two types: Gram-stained and Gram-non-stained – Gram-positive and Gram-negative. These groups of bacteria are differently sensitive to antibiotics. Synovial fluid is sown for final identification. If the synovial fluid does not grow, the doctor may prescribe a biopsy and sowing of the synovial tissue around the joint Other tests, such as urine, blood or mucus culture from the cervix, may be prescribed only in addition to puncture.

Hardware diagnosis of infectious arthritis
Hardware diagnostics is ineffective in the early stages of infectious arthritis. X-rays do not reveal the destruction of bones or cartilage within 10-14 days from the onset of symptoms. Obtaining any images only sometimes can be effective if the focus of infection is located in a deep-seated joint.

Treatment of Infectious (Pyogenic) Arthritis

Infectious arthritis usually requires several days of inpatient treatment, followed by medication and physiotherapy sessions for several weeks or months.

In case of delayed treatment there is a risk of serious damage to the joints and other complications, therefore, intravenous administration of antibiotics should be started immediately, even before the exact determination of the infectious agent. After determining the causative agent of infection, the doctor may prescribe a drug that acts specifically on these bacteria or virus.

Non-steroidal anti-inflammatory drugs are usually prescribed for viral infections. The course of treatment with intravenous antibiotics is approximately 2 weeks (or until the inflammation disappears). After that, the patient may be prescribed a 2 or 4 week course of antibiotics in tablets (capsules).

Surgical intervention
In some cases, surgical drainage of the infected joint is necessary. This applies to patients who are immune to treatment with antibiotics, or to those with lesions of the hip or other joints that are difficult to puncture, and also if infectious arthritis is caused by a firearm or other penetrating wound. Patients with severe lesions of bones and cartilage may need reconstructive surgery, but the operation is possible only after the complete disappearance of the infection.

Medical observation and concomitant therapy
During inpatient treatment, the patient is under close supervision, and the doctor must send a sample of synovial fluid to the crop daily to monitor the patient’s response to the administration of antibiotics. Infectious arthritis is often accompanied by severe pain. Painkillers are prescribed to the patient, it is also possible to apply compresses on the affected joint. In some cases, immobilization is recommended — putting a splint on an arm or leg to protect the joint from accidental movements. After immobilization, to speed up recovery, the patient must perform a special set of exercises for expanding the range of motion (of course, without bringing it to painful sensations).

Prognosis of infectious arthritis
The favorable prognosis depends on whether immediate treatment with antibiotics and drainage of the infected joint has been initiated. Approximately 70% of patients avoid irreversible destruction of the joints, but many patients develop osteoarthritis or partial deformity of the joints. In children with infected hip joints, destruction of the bone growth zone is possible. If treatment was not started in time, the mortality rate from the complications of infectious arthritis is 5% -30% due to septic shock and respiratory failure.

Prevention of Infectious (Pyogenic) Arthritis

Some types of infectious arthritis can be prevented by choosing the appropriate lifestyle: refusing to inject drugs, abstaining from sexual relations or monogamous sexual relations, immediate examination and treatment for suspected gonorrhea.