The patient, who underwent bilateral hip arthroplasty at the age of 57 and 59 years, was referred to the Emergency Department because of osteomyalgia and fever (38.3°) for 12 days. Clinical examination revealed a palpable mass in the left iliac fossa.
The patient, a 71-year-old woman, was referred to the Emergency Department in September 2009 because of fever and osteomyalgia and was admitted to the Infectious Diseases Department. She had a history of right hip arthroplasty due to fracture at the age of 57 years and left hip arthroplasty due to coxarthosis at the age of 59 years. Clinical examination revealed a palpable, non-tender mass with firm rubbery consistency and a diameter of 10 cm in the left iliac fossa. Laboratory tests revealed high inflammatory indexes: C-reactive protein 154.66 mg/L (4-11) without leukocytosis; white cells 9.73x10^3/µL (1.00-3.00). Abdominal ultrasonography (fig.1) showed two abscess-like lesions, with no vascular color-Doppler signal, adjacent to the iliac wings on both sides, at the psoas insertion. Abdominal CT investigation (fig.2) confirmed the collections, and revealed further lesions with the same features adjacent to the left gluteus maximus and to the left obturator internus. Endocarditis was excluded by blood culture and transthoracic echocardiogram. An ultrasound-guided drainage procedure was performed by placing a drainage catheter into the largest collection in the left iliac fossa. Pus-like fluid was drained, but cytological and microbiological laboratory tests (also for mycobacteria) and the search for neoplastic cells were negative. A guillotine needle biopsy performed on the collection walls did not any neoplastic tissue. A pelvic MRI scan (T1, T2, Fat Sat sequences) (fig.3) was performed and showed the inflammation of the iliopsoas bursa and gluteus maximus bursa bilaterally and of the left obturator internus bursa.
The etiopathogenetic hypothesis is that the mechanical damage to the iliopsoas bursae and, to a lesser extent, to the gluteus maximus and left obturator internus bursae, caused by deambulation, led to chronic inflammation. In the case shown here, hip arthroplasty is likely to have produced a direct communication between the bursae and hip joints causing bursal distension due to increased synovial fluid. Indeed, the iliopsoas bursa ( Fig 4. a,b ) communicates with the hip joint in 15% of cases only. Communication occurs commonly after hip arthoplasty procedures because of interruption of the bursal wall, but it can also arise as a result of increased synovial fluid pressure due to inflammation or trauma. To establish a correct diagnosis, the locations and features of the collections should be considered: multiple bilateral lesions allow exclusion of conditions presenting with unilateral swelling in the inguinal region (hernia, neoplasm, joint inflammation). In the case presented, the absence of neoplastic cells, fungi and anaerobic bacteria suggested aseptic bursitis. Anatomical knowledge is essential for interpreting the collections as swollen bursae related to various muscular structures, and for relating the pathologic findings to the history of previous bilateral hip arthoplasty procedures.
Aseptic ileopsoas bursitis
The patient is a 71-year-old female with a history of bilateral hip joint replacements performed at the ages of 57 and 59, respectively. She presented with a 12-day history of persistent fever (with a maximum temperature of approximately 38.3°C) and musculoskeletal pain. Ultrasound imaging shows a relatively large, well-defined hypoechoic area in the iliac fossa. Under color Doppler, there is no significant blood flow signal in this region. Both CT and MRI scans reveal multiple fluid-density or T2 hyperintense lesions in the bilateral iliopsoas region and adjacent bursae near the hip joints, which are more prominent on the left side. Their shapes are consistent with the anatomical location of the bursae, and some appear to communicate with the replaced hip joint. There is no obvious evidence of a tumor-like occupying lesion or bone destruction, nor is there any apparent fracture line. The imaging characteristics suggest the presence of fluid accumulation in the involved bursae due to repeated friction or inflammation.
Based on a comprehensive assessment of the clinical presentation (long-term hip prostheses, chronic bone or muscle aches, low-grade fever), imaging findings of multiple symmetrical bursal effusions without obvious signs of infection or tumor, and negative results from pathogen testing, the most likely diagnosis is:
Aseptic (Chronic) Bursitis, i.e., bilateral iliopsoas bursae and related bursae inflamed due to mechanical irritation and communication with the joint effusion but without infection.
If suspicious signs of infection emerge or the condition continues to worsen, repeating pathogen culture or performing a biopsy under ultrasound or CT guidance may be necessary to exclude rare pathogens or other potential etiologies.
During the acute inflammatory phase or when bursal effusion is evident, reducing excessive load on the hip joint is crucial. After pain and inflammation improve, a gradual exercise program can be implemented, as follows:
The above rehabilitation plan follows the FITT-VP principle (frequency, intensity, time, type, progression, and individualization) and should ideally be carried out under the supervision of a specialized rehabilitation department or an experienced physical therapist to ensure safety and effectiveness.
This report is based solely on the available medical history and imaging data for reference. It cannot replace an in-person consultation or a professional doctor’s opinion. If the patient’s condition changes significantly or a definitive diagnosis and treatment are required, please visit a reputable medical institution for further evaluation and individualized treatment.
Aseptic ileopsoas bursitis
