SEPTIC ARTHRITIS�

Issah J. kiswagala

(M.B.B.S)

INTRODUCTION

• Septic arthritis, also known as infectious arthritis, may represent a direct invasion of joint space by various microorganisms, most commonly caused by bacteria. 
• Bacteria are the most significant pathogens in septic arthritis because of their rapidly destructive nature.  It can also be caused by a virus or fungus.
• Typically, septic arthritis affects one large joint in the body, such as the knee or hip. Less frequently, septic arthritis can affect multiple joints.

EPIDEMIOLOGY

• Approximately 20,000 cases of septic arthritis occur in the United States each year, with a similar incidence occurring in Europe.
• Because of the increasing use of prosthetic joints, infection associated with these devices has become the most common and challenging type of septic arthritis encountered by most clinicians.
• Septic arthritis is also becoming increasingly common among people who are immunosuppressed and elderly persons.
• 56% of patients with septic arthritis are male.

AETIOLOGY/RISK FACTORS

Organisms may invade the joint by direct inoculation, by contiguous spread from infected peri-articular tissue, or via the bloodstream (the most common route). So,

• People with open wounds are also at a higher risk for septic arthritis.
• Weakened immune system.
• Pre-existing conditions such as cancer, diabetes, intravenous drug abuse, and immune deficiency disorders have a higher risk of septic arthritis.
• In adults and children, common bacteria that cause acute septic arthritis include staphylococcus and streptococcus. These foreign invaders enter the bloodstream and infect the joint, causing inflammation and pain.

CLINICAL PRESENTATION

• Patients with an infected joint typically present with the triad of fever, pain and impaired range of motion. These symptoms may evolve over a few days to a few weeks. Fever is usually low-grade with rigors. Other presentations are
• Chills
• Fatigue and generalized weakness
• Inability to move the limb with the infected joint
• Severe pain in the affected joint, especially with movement
• Swelling (increased fluid within the joint)
• Warmth (the joint is red and warm to touch because of increased blood flow)

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DIFFERENTIAL DIAGNOSIS

• Drug-induced arthritis
• Reactive arthritis
• Vasculitis
• Peri-articular osteomyelitis 

INVESTIGATIONS

• Complete blood count
• Perform joint aspiration under the most sterile conditions for stains and/or cultures 
• Plain radiography is of limited value in evaluating a joint for infection^, peri-articular soft-tissue swelling is the most common finding.
• CT scan and MRI

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TREATMENT

• Medical management of infective arthritis focuses on adequate and timely drainage of the infected synovial fluid, administration of appropriate antimicrobial therapy, and immobilization of the joint to control pain.
• Antibiotics usually need to be administered parenterally (IV) for at least 2 weeks.
• Synovial Fluid Drainage : use a needle aspirate initially 2-3 times a day, repeating joint taps frequently enough to prevent significant re-accumulation of fluid.
• Surgical drainage is opted if infected joints are difficult to aspirate or Adjacent soft tissue is infected.
• Joint Immobilization and Physical Therapy:  If the patient's condition responds adequately after 5 days of treatment, begin gentle mobilization of the infected joint.

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PROGNOSIS

• The primary morbidity of septic arthritis is significant dysfunction of the joint, even if treated properly.
• 50% of adults with septic arthritis have significant sequelae of decreased range of motion or chronic pain after infection.
• The mortality rate depends primarily on the causative organism.

COMPLICATIONS

• Dysfunctional joints,
• Osteomyelitis, and
• Sepsis