CASE REPORT
ILIOPSOAS ABSCESS SECONDARY TO PYELONEPHRITIS WITH SUBSEQUENT UNILATERAL SACROILIITIS PRESENTING AS LOW BACK PAIN IN A YOUNG ADULT: A CASE REPORT

UDK: 616.748-002.3-076-085.281

www.doi.org/10.67214/cgpgnv67

Vranishkoski T.1,2, Ciriviri J.1,2, Talevski D.1,2, Jovanova A.1,2

1 Department of Orthopaedics and Traumatology, City General Hospital “8th September” – Skopje, North Macedonia

2 Faculty of Medical Sciences, Goce Delchev University – Shtip, North Macedonia

Abstract

Introduction: Iliopsoas abscess is a rare but potentially life-threatening condition. Secondary iliopsoas abscess following pyelonephritis is rarely reported, and contiguous spread to the sacroiliac joint resulting in sacroiliitis is an uncommon complication. Early detection is crucial, as initial symptoms may mimic low back pain, hip or gluteal discomfort, or genitourinary tract infection, often leading to delayed diagnosis.

Case Presentation: We report a case of a young adult who presented with severe low back pain radiating to the right lower extremity. Pyelonephritis was initially diagnosed based on CT imaging and laboratory tests, including blood tests and urinalysis.Almost two months after symptom onset, MRI revealed a unilateral iliopsoas abscess with contiguous involvement of the sacroiliac joint, resulting in secondary sacroiliitis. Methicillin-resistant Staphylococcus aureus (MRSA) was identified as the causative organism. The patient underwent percutaneous core biopsy and culture-guided antimicrobial therapy, leading to complete recovery.

Conclusion: This case underscores the importance of considering retroperitoneal and sacroiliac infections in patients with persistent, immobilizing low back pain, even when laboratory abnormalities are transient. Prompt imaging and timely management are essential to prevent morbidity and mortality associated with iliopsoas abscess and secondary sacroiliitis.

Keywords: Iliopsoas abscess; Low back pain; MRSA; Pyelonephritis; Sacroiliitis.

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