Poster 9: Piriformis Muscle Syndrome Caused by Acute Septic Sacroiliitis: A Case Report

Article Outline

• Disclosures
• Patients or Programs
• Program Description
• Setting
• Results
• Discussion
• Conclusions
• Copyright

Keywords: Sciatica, Sacroiliac joint, Septic arthritis

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Disclosures 

F. Tian, None.

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Patients or Programs 

A 64-year-old woman with acute septic sacroiliitis resulting in piriformis syndrome and sciatica.

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Program Description 

The patient was admitted for asthma exacerbation. During the hospitalization she developed low back pain and left hip pain. Initial radiograph showed no abnormalities of her lumbosacral spine, pelvis or hips. She was given naproxen for pain control without relief. Four days later she developed a cough and fever and experienced excruciating pain of her left buttock, radiating to her left ankle.

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Setting 

Tertiary hospital.

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Results 

Her range of motion of left hip and spine was limited due to the pain. She had tender point at the sciatic notch and around her left piriformis muscle by palpation of the gluteal region, and by a digital pelvic examination. The Patrick test and FADIR maneuver caused exacerbation of her pain. Her sputum and blood cultures grew Staphylococcus aureus. Her pelvic computed tomography (CT) scan showed periarticular erosions at the left sacroiliac (SI) joint and piriformis muscle thickening. A bone scan also showed increased uptake in the left SI joint. She was diagnosed with septic sacroiliitis and piriformis syndrome, which caused her sciatica. After treatment with intravenous daptomycin for 6 weeks, CT scan showed resolution of the acute SI pathology. With physical therapy she regained full range of motion and was ambulatory with a cane.

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Discussion 

Septic sacroiliitis is a rare joint infection in middle-aged and elderly patients. To our knowledge, this is the first reported case of piriformis syndrome caused by acute septic sacroiliitis. The diagnosis is often initially overlooked because of its rarity, nonspecific symptoms, or inadequate physical examination. The pathophysiology is hematogenous spread of bacteria from a distant source. Our patient developed pulmonary infection and bacteremia, which could lead to septic sacroiliitis and piriformis muscle inflammation. CT or magnetic resonance imaging is very useful to assess SI joint infections and surrounding tissue pathology.

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Conclusions 

Bacterial septic sacroiliitis, a rare infectious arthritis, can cause piriformis muscle syndrome and result in sciatica. Clinicians should be aware of the diagnosis and the proper treatment without delay for favorable outcomes.