Postpartum pyogenic sacroiliitis masquerading as sciatic neuropathy

Low back pain is common in women, especially during pregnancy and puerperium. Septic sacroiliitis, a rare cause of back pain in the postpartum period can mimic other common causes of low back pain like muscle strain, urinary tract infection, pelvic inflammatory disease, endometritis and intervertebral disc prolapse. The proximity of the sacroiliac joint to the sacral nerve plexus results in septic sacroiliitis frequently presenting with symptoms mimicking intervertebral disc prolapse. Diagnosis of septic arthritis of the sacroiliac joint during the postpartum period requires a high index of suspicion. Prompt and effective management is required to avoid complications and chronic morbidity. We present a young lady presenting with low backache and left lower limb radiculopathy 3 weeks after delivery. Her case supplements a small cohort of reports in literature emphasising the identification of septic arthritis in the postpartum period, the factors leading to delay in diagnosis and the increased morbidity of this condition.