Accidental Discovery of Pregnancy-associated Septic Sacroilitis on Ultrasound

Abstract

Pain in the sacroiliac joint and lower back is common during pregnancy and postpartum periods. However, pregnancy related septic sacroilitis is very rare. A 37-year-old pregnant woman had a sudden severe lower back pain two days in advance of the delivery. However, she delivered a healthy baby under cesarean section in good condition. Laboratory tests revealed elevated erythrocyte sedimentation and C-reactive protein, but her initial magnetic resonance imaging of lumbar spine and abdominal pelvis computed tomography were normal. Therefore, she was considered having a general acute back pain that many postpartum patients can have. Conservative treatment was received until she was referred to pain clinic. While we were planning pain management under ultrasound guided, we encounterd mass-like lesion on her left sacroiliac joint accidentally. Sacroiliac MRI was taken immediately and It revealed septic sacroilitis. Pregnant with high ESR, CPR with severe localized sacroiliac joint pain should be suspected of pregnancy related septic sacroilitis.