Hello and welcome to the zero to finals podcast. My name is Tom and in this episode I'm going to be

talking to you about septic arthritis. And you can find written notes on this topic at

zero to finals.com slash infectious diseases or in the infectious diseases section of the second edition of the

Zero to Finals Medicine book. So let's get straight into it. Septic arthritis refers to infection

in a joint. Infection in a joint is a medical emergency. The infection can rapidly destroy the

joint and cause systemic illness, including sepsis.

It has a mortality rate, meaning the risk of death, of around 10%.

Infection may occur in a native joint, meaning an original joint, or in a prosthetic joint replacement.

Infection in a prosthetic joint is a big problem and happens in around 1% of joint replacements.

Extensive measures are taken to prevent it such as perioperative prophylactic antibiotics.

Infection is more likely to occur in revision surgery rather than in the initial

joint replacement. Let's talk about the presentation. Septic arthritis usually only affects a single

joint, often a knee. It presents with a rapid onset of a hot, red, swollen and painful joint,

stiffness and reduced range of motion in the joint,

and systemic symptoms such as fever, lethargy and sepsis.

Let's talk about the common bacteria.

Staphylococcus aureus is the most common causative organism.

Other bacteria include Nyseria gonorrhea or gonococcus in sexually active individuals,

Group A streptococcus, most commonly streptococcus pyogenes, hemophilus influenza, and Escherichia coli, or E. coli.

Atomtip for you, in a young patient presenting with a single, acutely swollen joint,

consider gonocococcal septic arthritis until proven otherwise.

The gram stain reveals a gram-negative diploccus.

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