Diagnosis
Usually progressive groin pain, inability to straight leg raise, often with fevers. The diagnosis is made on CT.
Epidemiologic Risk
Either trauma (usually a groin pull) or occasionally tracking down (or up to) from the disc/spine at the insertion site.
microbiology
Occasionally mixed infection from a gi source, like an appendiceal abscess, or gu infection.
On occasion Coccidiomycosis and Tuberculosis.
Treatment
Drain the pus, either in IR or the OR, then treat whatever grows until it is all gone.
Pearls
The "groin pull" can be relatively mild. I saw one that was due to putting a suitcase in an overhead bin. But to get an infection of muscle, you need trauma, which leads to a bleed/clot, which is what gets infected.
Curious Cases
Relevant links to my Medscape blog
Last Update: 01/11/19.