A grossly obese 26-year-old lady with a body mass index (BMI) of 43, gravida-1, para-1 + 0, type 2 diabetes mellitus, and hypothyroidism. She came to the causality with 12 days history of severe continuous right-sided lower back pain, right side pelvic pain increased with ambulation. Her pain started in a mild way prior to her recent admission for elective cesarean section for twin babies, using spinal epidural anesthesia, got worse and began to radiate to the back of the right thigh, increased with ambulation. There was no history of trauma, fever, chills, urinary, gynecological, or other systemic symptoms. Her physical examination revealed a temperature of 37.1 C, severe tenderness over the lower back, and right side of the pelvic region with intact neurology. Her cesarean section wound in the abdomen has healed. Her lower back and pelvis were stiff with severe pain on movements, standing, or sitting. The straight leg raising test was positive (30-40 ), and the FABER Patrick's test was difficult to evaluate due to intense pain despite the strong analgesia.
The lumbo-sacral spine X-ray was unremarkable, but the pelvis X-ray revealed a 12 mm widening of the symphysis pubis (Figure 1).
She was hospitalized for further examinations and pain control after a clinical diagnosis of perinatal right-sided lumbo-pelvic pain (LPP). Laboratory testing found 6.85 white blood cells (WCC) G/l with 69.2% neutrophils, a 48 mm/h elevated erythrocyte sedimentation rate (ESR) (Figure 2), normal procalcitonin (0.02), and a 68.7 mg/L elevated C- reactive protein (Figure 3).
The lumbar spine magnetic resonance imaging (MRI) was negative, but the pelvic MRI found minor fluid signal amplitude in the right SIJ, which was associated with myositis (Figure 4).
The patient was accused of developing unilateral sacroiliac arthritis and piriformis muscle syndrome. In the context of pain modality and incremental mobilization, we started her treatment with narcotic and non-narcotic analgesics, as well as non-steroidal anti-inflammatory medicines and physiotherapy. Her pain could not be controlled, and she became worse, unable to ambulate or step in or out of bed. Neurosurgery, neurology, rheumatology, anesthesia, obstetrics, and gynecology teams were consulted, but nothing was added to the preliminary diagnosis or the treatment plan. Despite the absence of any symptoms or signs indicating an acute or chronic infection, urine and blood cultures, protein purified derivative (PPD) for tuberculosis, and serology for brucella were required on Day 8. Because it was impossible to place the patient in the prone position on the same day, CT-guided aspiration of the right SIJ was performed in the left lateral position (Figure 5), but no aspirated fluid was obtained; however, SIJ block was performed using 20 mL of 0.25% bupivacaine after which she briefly noticed some relief of her shooting pain.
Although the blood culture, brucella serology, and PPD all came back negative, the urine culture revealed asymptomatic Escherichia coli bacteriuria. The patient was started on IV ceftriaxone 1 g every 12 h and gentamicin 400 mg once a day by the infectious disease (ID) team. She showed steady and progressive clinical improvement just 48 h after intravenous antibiotics (IVAB). Ceftriaxone was given for another 2 weeks, and gentamicin was given for another 10 days. Her pain score (visual analogue scale (VAS) 2 out of 10) improved significantly, as did her walking capacity, bathroom privileges, and blood parameters. Following discharge on Day 26, the patient was sent home with oral ciprofloxacin 750 mg twice daily for 6 weeks. Nevertheless, her MRI on institutional discharge showed no substantial improvement compared to the initial one. She did well with regular ambulation and normal blood parameters at 6-week, 3-month, and 6-month follow-up visits. Her 1-year follow-up MRI was uneventful (Figure 6), while she did have periodic minor right-sided LPP that did not interfere with her daily activities.