The formation of an abscess in the iliopsoas muscle is defined as psoas abscess 3
. Some cases could only be diagnosed in postmortem bodies. However, the use of CT increases the diagnosis of psoas abscess 4
. In our study, we report a psoas abscess in an IDU diagnosed on CT. Psoas abscesses can be classified as primary and secondary abscesses according to the etiology. Primary psoas abscess occurs by hematogenous or lymphatic seeding from a distant location 5,6,
and the risk factors can be diabetes mellitus, intravenous drug use, HIV infection, renal failure, and immunosuppression 3,4
. Besides, it was found to be more likely in children and young adults 4-6
. Secondary psoas abscess occurs by contiguous spread and trauma 5
.The main organism causing primary psoas abscess is staphylococcus aureus, and methicillin-resistant staphylococcus aureus can also be demonstrated. 7
The symptoms include back or flank pain, fever, inguinal mass, limp, anorexia, and weight loss 3-5,6. Nearly 91% of the cases suffer from pain located in the back or flank and radiated to the hip or the posterior aspect of the thigh 4,5,6-8. This finding also made our diagnosis easier. The second most common symptom is fever with a prevalence of 75%, and psoas abscess can be the etiology in the patients with fever of unknown origin 8.
Intravenous drug use is rare in this country and patients and their relatives often conceal this situation. Also this is a matter, which accepted as a taboo and may not be investigated in deep by doctors. Besides, IDUs are in danger for the conditions associated with the direct effects of the agents and infection transmission. In addition, those infections seen in IDU patients may be mostly presented in occult and atypical formations. Psoas abscess is one of the well-known occult focuses for IDU patients. Usually, cases of psoas abscess may not admit to emergency departments with classical signs, on the other hand, they may be under investigation for different prediagnoses. She experienced the worsening of left hip pain, which was initially misdiagnosed in a previous hospital admission. An ED physician facing with an IDU-related abscess must be guarded for the associated complications and coexisting infections, such as necrotizing soft-tissue infection, septic arthritis, osteomyelitis, and epidural abscess. These complications were reported in 15-19% of the patients with IDU-related abscess 9,10.
In conclusion, diagnosis of psoas abscess is rare and difficult in ED. Emergency medicine specialists, when encountered with unexplained fever, lumbar pain and pain radiating to inner leg, should keep in mind the psoas abscess. To ensure the diagnosis, also should question related drug use, DM, risk factors such as immune suppression.