Psoas Abscess

A psoas abscess is a painful collection of pus that forms in the psoas muscle, a large muscle located in the lower back and pelvis. This condition affects the musculoskeletal system and can cause symptoms like fever, lower back pain, and difficulty walking or moving the hip. The abscess develops when bacteria or other germs infect the muscle, often spreading from nearby areas or through the bloodstream. Because the psoas muscle is close to important organs and nerves, the infection can cause significant discomfort and limit mobility. Early recognition is important as the abscess can grow and lead to serious complications if untreated.

Psoas abscess is a localized collection of purulent material within the psoas muscle compartment, typically caused by bacterial infection. It can be classified as primary, resulting from hematogenous spread often involving Staphylococcus aureus, or secondary, due to direct extension from adjacent infections such as vertebral osteomyelitis, Crohn’s disease, or intra-abdominal abscesses. The condition is characterized by inflammation, muscle spasm, and systemic signs of infection including fever and leukocytosis. Clinically, patients present with the psoas sign (pain on hip extension) and may have a limp or difficulty walking. The abscess poses a risk of spreading infection to surrounding structures and causing sepsis if not promptly diagnosed and managed.