Acute intramuscular infection secondary to haematogenous spread of the microorganism into the body of a skeletal muscle, most commonly caused by Staph. aureusAetiologyRisk factorsPWIDsDiabetes meletusImmunosuppressedCausative organisms90% staphlococcalSome site specific e.g. GNB in perineumImmunosuppressed - psudomonas, beta haemolytic strep. enterococcusIn tropical climates - MSSA infection in immune competant patients and childrenClostridium infection possible in contaminated woundsClinical presentationPain and swelling of the affected area (usually lower extremities)FeverInvestigationsImaging - US, CT, MRIPus discharge culture and sensitivityManagementAntibiotics and surgery (debridement)