Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier
WebMD

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine
WebMD

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion
    WebMD

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community
    WebMD

    Community

    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Arthritis Health Center

Font Size
A
A
A

Septic Arthritis

Septic arthritis is also known as infectious arthritis, and is usually caused by bacteria, or fungus. The condition is an inflammation of a joint that's caused by infection. Typically, septic arthritis affects one large joint in the body, such as the knee or hip. Less frequently, septic arthritis can affect multiple joints.

What Causes Septic Arthritis?

Septic arthritis usually is caused by bacteria that spread through the blood stream from another area of the body. It can also be caused by a bacterial infection from an open wound or an opening from a surgical procedure, such as knee surgery.

In adults and children, common bacteria that cause acute septic arthritis include Haemophilus influenza, staphylococcus, and streptococcus. These foreign invaders enter the bloodstream and infect the joint, causing inflammation and pain.

Other infections, such as those caused by viruses and fungi, can also cause arthritis. Viruses include:

Fungi that can cause arthritis include histoplasma, coccidiomyces, and blastomyces. These infections are usually lslower to develop than bacterial infections.

Who's at Risk for Septic Arthritis?

Young children and elderly adults are most likely to develop septic arthritis. People with open wounds are also at a higher risk for septic arthritis. In addition, people with a weakened immune system and those with pre-existing conditions such as cancer, diabetes, intravenous drug abuse, and immune deficiency disorders have a higher risk of septic arthritis. In addition, previously damaged joints have an increased likelihood of becoming infected.

What Are the Symptoms of Septic Arthritis?

Symptoms of septic arthritis usually come on rapidly with intense pain, joint swelling, and fever. Septic arthritis symptoms may include:

  • Chills
  • Fatigue and generalized weakness
  • Fever
  • 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)

How Is Septic Arthritis Diagnosed?

A procedure called arthrocentesis is commonly used to make an accurate diagnosis of septic arthritis. This procedure involves a surgical puncture of the joint to draw a sample of the joint fluid, known as synovial fluid. Normally, this fluid is sterile and acts as a lubricant.

Today on WebMD

Mature woman exercise at home
Hint: Warming up first is crucial.
feet with gout
Quiz yourself.
 
woman in pain
One idea? Eat fish to curb inflammation.
senior couple walking
Can you keep your RA from progressing?
 
xray of knees with osteoarthritis
Slideshow
close up of man wearing dress shoes
Slideshow
 
feet with gout
Quiz
close up of red shoe in shoebox
Slideshow
 
salad
Video
two male hands
ARTICLE
 
Woman massaging her neck
Quiz
5 Lupus Risk Factors
Article