Sacroiliitis associated with pyelonephritis in pregnancy

Sacroiliitis is a rare infection and an unusual cause of back pain during pregnancy. Because pregnancy and infections commonly associated with pregnancy are risk factors, this diagnosis should be considered in the gravida with sacroiliac pain.

A 17-year-old woman at 24 weeks' gestation, with a history of illicit drug use, presented to a local emergency room with back and buttock pain. Bacteriuria and pyuria were diagnosed, and cefazolin was initiated. Blood cultures grew Staphylococcus aureus and Escherichia coli. Despite prolonged antibiotic therapy for possible endocarditis, she had persistent debilitating lower back and buttock pain. Radiographic studies detected sacroiliitis, and broadened antibiotic therapy effected cure.

When sacroiliitis is suspected, diagnostic imaging with either computed axial tomography, or, preferably, magnetic resonance imaging may be helpful. Antibiotic therapy should be tailored to the specific organism involved and continued for 3-6 weeks.