Discussion
Psoas abscess is the collection of pus in the iliopsoas muscle
compartment and usually occurs secondary to renal, intestinal, or
skeletal infection. Primary infection leading to psoas abscess is
relatively rare although, it occurs more frequently among children and
young adults and tends to be more common in developing countries (2)
Primary psoas abscess is frequently a single microorganism complication,
including Staphylococcus aureus, and Mycobacterium
tuberculosis , and may also occur due to Brucella spondylodiscitis.
Although CT scan is the modality of choice when a psoas abscess is
suspected, in rare etiologies of psoas abscess like Brucellosis, MRI can
provide more detailed data and is the method of choice in these
circumstances (2).
In our case, according to the prevalence of Brucellosis in Iran as an
endemic region, serology and MRI were sufficient, enabling us to make
the final diagnosis.
Although abscess drainage regardless of the causative microorganism is
the recommended treatment for the psoas abscess in many studies and
guidelines and antibiotics alone are not considered curative unless the
abscess is small (<3mm) (2), a study conducted by Tabrizan et
al. revealed that using Antibiotics alone in iliopsoas abscess
management has a success rate of 78% (5). It is also recommended by
Yacob et al. in a study in 2009 that treatment of Psoas abscesses should
be initiated with antibiotics and small abscesses should be treated with
antibiotics alone (6).
In our case, the abscess was about 34*12*16mm, which was relatively
small. This case highlights that small psoas abscesses could be treated
successfully using oral antibiotics and no drainage.