What are the other Names for this Condition? (Also known as/Synonyms)

• Pyogenic Arthritis
• Suppurative Arthritis

What is Septic Arthritis? (Definition/Background Information)

• Septic Arthritis is an infection of a joint caused by invasion of the joint by microorganisms, such as bacteria, fungi, etc. The condition more commonly affects children and elderly individuals
• Staphylococcus aureus is the most common causative organism of Septic Arthritis. The condition causes joint pain, swelling and redness of the affected joint along with restricted range of motion
• Diagnosis of Septic Arthritis is made by physical examination of  the joint and aspiration of joint fluid, which is then examined in the laboratory
• Antibiotics are the mainstay of treatment for Septic Arthritis. Sometimes, in severe cases, aspiration of joint fluid is required
• The prognosis of Septic Arthritis with appropriate treatment is generally very good. However, it varies according to the microorganism causing the condition

Who gets Septic Arthritis? (Age and Sex Distribution)

• Septic Arthritis can affect individuals of any age group, but is more common in children and elderly adults
• Both males and females can be affected
• Individuals of all races and ethnic groups are at risk

What are the Risk Factors for Septic Arthritis? (Predisposing Factors)

The risk factors associated with Septic Arthritis may include:

• Untreated and persistent bacterial infection in other parts of the body
• Artificial joint implants
• An open wound over or close to the joint
• Recent surgeries involving the joint
• Medical conditions like uncontrolled Diabetes mellitus, which weaken the body’s immune system
• Drugs and medication that decrease the immune response of the body
• Intravenous drug use

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Septic Arthritis? (Etiology)

Septic Arthritis can be caused by a bacteria, virus, or fungus. However, bacterial infection accounts for most of the cases of Septic Arthritis. The bacteria commonly involved include the following:

• Staphylococcus aureus is the most common causative agent
• Streptococci is the second most common cause; most common bacteria in children
• Hemophilus influenza- only seen in unvaccinated children; the incidence has reduced due to a widespread vaccination against this bacterium
• Mycobacterium tuberculosis - causes chronic Septic Arthritis and usually involves the spine
• Neisseria gonorrhea - it is common in individuals who are sexually-active with multiple partners
• Pseudomonas aeruginosa - following a puncture wound, which is at or near to the joint area

Fungal and viral infections account for a small number of cases; mostly these are slow, progressive, and chronic.

What are the Signs and Symptoms of Septic Arthritis?

Signs and symptoms associated with Septic Arthritis include:

• Fever in children, seen with high temperature with/without chills; fever in adults is usually of a low temperature
• Joint pain
• Swelling, warmth, and redness of the affected joint
• Mostly involves a single joint, but occasionally may involve multiple joints, as seen in infection with Staphylococcus or Gonococcus
• Limited range of motion of the affected joint; restriction of joint movement

How is Septic Arthritis Diagnosed?

The diagnosis of Septic Arthritis may involve:

• Physical examination with evaluation of medical history
• Blood work-up to look for an increase in the total white blood cell (WBC) count and the differential count (DC). Neutrophils are increased out of proportion in case of acute arthritis; lymphocytes are increased in chronic arthritis
• Erythrocyte sedimentation rate (ESR): The collected blood sample is centrifuged and allowed to settle down. The sedimentation of the red blood cells at the end of one hour is noted. It is significant when it is over 40 mm/ hour. In Septic Arthritis, ESR is increased
• C-reactive protein (CRP): It is a non-specific marker of infection and is usually elevated
• Arthrocentesis: A surgical procedure wherein a needle is inserted into the affected joint space under sterile conditions and the joint fluid (synovial fluid) is aspirated. It is then examined for the presence of white blood cells. Gram staining and culture of the joint fluid is done to detect the organism causing the infection. In case of chronic infections, organisms may not be present in the joint fluid
• X-ray of the affected joint and adjacent bones to look for any structural damage
• Magnetic resonance imaging (MRI) scan for a better view of the joint and to determine damage to the soft tissue around the joint

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Septic Arthritis?

Septic Arthritis usually resolves completely with appropriate treatment.

• When not treated appropriately, it can involve the adjacent bone causing osteomyelitis and also may cause irreversible joint damage
• The infection can spread to the blood causing septicemia
• Chronic infection can lead to osteoarthritis

How is Septic Arthritis Treated?

Septic Arthritis can be completely treated. The treatment measures may involve the following:

• Antibiotics that is specific and sensitive to the causative organism. The antibiotics are either prescribed orally or given intravenously depending upon the severity of the infection
• Drainage of the pus and infected joint fluid
• In case of irreversible joint damage, a joint replacement surgery may be necessary

How can Septic Arthritis be Prevented?

Preventive measures for Septic Arthritis include:

• Avoiding intravenous drug abuse and needle sharing
• Appropriate management and control of medical conditions that suppress the immune system
• Childhood vaccination against Hemophilus influenza
• Appropriate wound care
• Controlling diabetes
• Avoiding excessive alcohol consumption
• Treating infections in other parts of the body early

What is the Prognosis of Septic Arthritis? (Outcomes/Resolutions)

• The prognosis of Septic Arthritis is generally very good
• It usually resolves completely with adequate treatment

Additional and Relevant Useful Information for Septic Arthritis:

• During the course of treatment, engaging the affected joint in less straining activities is generally recommended
• Non-steroidal anti inflammatory drugs (NSAIDs), such as ibuprofen or aspirin, can be used to reduce the joint pain
• Hot compresses can also be used to reduce pain