Infectious Arthritis


Arthritis isn't always something that just comes with the wear and tear as the years go on. Arthritis is the inflammation of the joints - which means swelling and stiffness and frequently pain. This is different from arthralgias (joint pain without swelling). 

Many types of arthritis are caught. They're infectious and can potentially be prevented and treated.

Septic Arthritis

Septic Arthritis occurs when an infection enters a joint.

Our joints are otherwise is sterile, with no microorganisms within. This infection is almost always serious needing immediate medical attention. 

The symptoms include generalized symptoms (fever, chills, tiredness) and specific joint symptoms (pain - especially with movement, warmth, redness, swelling, and the inability to move or fully move the joint). These symptoms should prompt seeking immediate medical attention.

Standard culprits are bacterial: Staph Aureus (including MRSA), Streptococci, Haemophilus influenzae, Neisseria gonorrhea, Salmonella, Brucella, E coli, Pseudomonas, and Serratia.

Rarely, these can be caused by fungal infections (Histoplasma, Blastomyces, Coccidioides, Cryptococcus, and Sporothrix).

Some bugs are more likely than others to lead to multiple joints infected at once. In particular, it is important to identify gonococcal (ie gonorrhea) infections as these can lead to multiple joints infected and rapidly destroy these joint(s).

This is the most common cause in young, sexually active adults and adolescents.

These bugs can enter the joint spaces in a variety of ways.

  • Bloodstream infection (risk for other infected parts of the body)
  • Surgery (especially the placement or adjustment of a prosthetic joint)
  • Penetrating injury into the joint
  • Direct spread from a local abscess, wound, bone, or other nearby infection

Those most at risk are

  • young
  • old,
  • diabetic
  • have a prosthetic joint
  • injured
  • immunocompromised
  • IV drug users.

These infectious are becoming more common as more people have prosthetic joints (which are more prone to infection) and other joint surgeries.

Treatment usually involves a surgical procedure to clean out the joint and antibiotics which can clear the infection. If treatment is delayed, there may be permanent damage to the joint and there can be loss of use.

Lyme Disease

Lyme disease is caused by the bacteria Borrelia burgdorferi. Early in infection, days to weeks after the infection, there may be pain in joints, especially big joints like the knees. Most, 3 in 5, will go on to have intermittent and often painful arthritis if the infection isn't treated.

Fortunately, most who have tick bites don't get Lyme disease; many ticks aren't infected and transmission takes time, meaning the tick has to stay attached long enough for the infection to be transmitted.

Viral Arthritis

There are a number of viruses that cause arthritis. They don't need antibiotics and immediate surgery. There often isn't a specific treatment for these infections, but usually they are not as serious for joints untreated as the bacterial (and fungal) infections.

These include Chikungunya, Ross River Virus Disease, Parvovirus B19, Mumps, Hepatitis A, Hepatitis B, Hepatitis C, Coxsackie and other Enteroviruses viruses, Adenovirus, HTLV-1, HIV, Dengue, and Rubella. For most of these, the arthritis will fade on its own, click on the links to find out more. Hepatitis B, C, and HIV have specific treatment.

Reactive Arthritis

There are also types of arthritis where the immune system attacking another infection gets confused and starts attacking your own joints. This is a case of auto-immunity. The infection is not actually in the joint. This autoimmune response can also affect the eyes and urethra (making it painful to urinate). Medical students are taught to remember this reaction as: "can't see, can't pee, can't climb a tree". Those with HIV and a particular immune system gene (HLA-B27)  are more likely to have this. This arthritis can last weeks to months, with recurring attacks.

These can be caused by reactions to actual infections with often foodborne and sexually transmitted infections: Chlamydia trachomatis, Ureaplasma urealyticum, Salmonella, Shigella, Campylobacter, and Yersinia.

Non-infectious arthritis

Sometimes other types of arthritis - Rheumatoid arthritis, Osteoarthritis, injuries- can be mistaken for infectious arthritis. Crystal-induced arthritis, such as gout or pseudo-gout, is often mistaken for an infection, as it can cause spiking fevers, chills, and fatigue. Joint fluid is examined under a microscope specifically for crystals to ensure a seemingly septic arthritis isn't crystal-induced arthritis.

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