CASE REPORT Infectious Sacroiliitis in a Patient With a History of IV Drug Use Victor Huang, MD; Marc Olshan, MD; Bryan McCarty, MD; Zhanna Roit, MD A 29-year-old man presented for evaluation of unabating left-sided low back pain that radiated to his left buttock and groin. Case Hg; and temperature, 98.2°F. Oxygen satu- A 29-year-old man presented to the ED ration was 98% on room air. with a 3-day history of constant left-sid- The patient was a well-developed young ed low back pain that radiated to his left man in no apparent distress. Dermatologi- buttock and groin. The patient stated the cal examination showed bilateral track pain worsened with movement, making it marks in the antecubital fossa. The mus- difficult for him to walk. He reported lift- culoskeletal (MSK) examination demon- ing heavy boxes at work, but denied any strated left gluteal tenderness to palpation trauma. The patient also denied recent fe- and decreased active and passive range vers, chills, chest pain, dyspnea, abdomi- of motion of the left hip, especially with nal pain, urinary or fecal incontinence, internal rotation and flexion. He had no weakness, numbness, or saddle anesthe- midline tenderness, and the lower extrem- sia. Regarding his medical history, he had ities had normal pulses and no motor or an appendectomy as a child, but reported sensory deficits. no other surgeries or medical issues. His The patient’s pain improved with IV flu- social history was significant for narcotic ids, diazepam, and ketorolac, and he was and inhalant use and daily tobacco use. able to ambulate with assistance. He was The patient also reported taking heroin in- clinically diagnosed with sciatica, and travenously (IV) 6 months prior. discharged home with prescriptions for Vital signs at presentation were: heart diazepam and ibuprofen. He was also in- rate (HR), 92 beats/min; respiratory rate, 15 structed to follow-up with an orthopedist breaths/min; blood pressure, 118/80 mm within 7 days from discharge. Dr Huang is an emergency physician, department of emergency medicine, North Shore University Hospital, Hofstra Northwell School of Medi- cine, Manhasset, New York. Dr Olshan is an emergency physician, department of emergency medicine, North Shore University Hospital, Hof- stra Northwell School of Medicine, Manhasset, New York. Dr McCarty is an emergency physician, department of emergency medicine, North Shore University Hospital, Hofstra Northwell School of Medicine, Manhasset, New York; and Primary Care Sports Medicine, Hofstra Northwell School of Medicine, Hempstead, New York. Dr Roit is an emergency physician, department of emergency medicine, North Shore University Hospital, Hofstra Northwell School of Medicine, Manhasset, New York. Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article. DOI: 10.12788/emed.2017.0034 264 EMERGENCY MEDICINE I JUNE 2017 www.emed-journal.com The patient returned to the ED the fol- lowing day with similar complaints of unabating left-sided pain and difficulty ambulating. His vital signs were notable for an elevated HR of 106 beats/min. Phys- ical examination findings were unchanged from his presentation the previous day, and an X-ray of the lumbar spine showed no abnormalities. After receiving IV analgesics, the pa- tient’s pain improved and his tachycardia resolved. He was discharged home with instructions to continue taking diazepam, and was also given prescriptions for pred- nisone and oxycodone/acetaminophen. He was instructed to follow-up with an orthopedist within 24 hours. Over the next 9 days, the patient was Figure. Magnetic resonance imaging of the patient’s pelvis in the axial plane demon- seen twice by an orthopedist, who ordered strating signal enhancement of the left sacroiliac joint (white arrow) and adjacent mar- imaging of the lumbar spine, including a row, with surrounding fluid and soft tissue edema, consistent with infectious sacroiliitis. repeat X-ray and contrast-enhanced mag- netic resonance imaging (MRI), both of cyte sedimentation rate (ESR), 19 mm/h; which were unremarkable. The patient C-reactive protein (CRP), 2.45 mg/L; white completed the prescribed course of di- blood cell count (WBC), 13.6 K/uL with clofenac, oxycodone/acetaminophen, and normal differential; and lactate level, 2.6 prednisone, but experienced only minimal mg/dL. The toxicology screen was posi- pain relief. The orthopedist prescribed the tive for opioids. The basic metabolic pan- diclofenac to supplement the medication el, chest X-ray, and urinalysis were all un- regimen that he was already on. remarkable. An electrocardiogram showed At the second follow-up visit, the ortho- sinus tachycardia. pedist ordered an MRI of the patient’s left The patient was admitted to the hospi- hip, which demonstrated inflammation of tal, and infectious disease services was the left sacroiliac joint (SIJ) with effusion, contacted. While awaiting transport to the and a 1-cm by 1-cm collection adjacent to inpatient floor, the patient admitted to IV the left psoas muscle; these findings were drug use 4 weeks prior to his initial pre- concerning for septic arthritis (Figure). sentation—not the 6 months he initially Based on the MRI study, a computed to- reported at the first ED visit. mography (CT)-guided arthrocentesis of The blood cultures grew Candida parap- the left SIJ was performed by an interven- silosis, and culture from the SIJ arthrocen- tional radiologist. tesis grew Pseudomonas aeruginosa. The Following the arthrocentesis, the ortho- infectious disease physician switched the pedist referred the patient to the ED. At patient’s antibiotic therapy to IV cefepime this presentation, the emergency physi- and fluconazole. The patient also was seen cian (EP) ordered blood cultures, blood by an orthopedist, who determined that work, urinalysis, and a urinary toxicology no surgical intervention was required. screen, and started the patient on IV cef- Follow-up laboratory studies showed triaxone and vancomycin. The laboratory inflammatory markers peaking at the fol- studies were significant for the following lowing levels: ESR, 36 mm/h; CRP, 4.84 elevated inflammatory markers: erythro- mg/L; and WBC, 32.1 K/uL with 90% www.emed-journal.com JUNE 2017 I EMERGENCY MEDICINE 265 INFECTIOUS SACROILIITIS neutrophils. These markers normalized disease has progressed, with a mean time throughout his hospital stay. The patient to diagnosis of 43.3 days.2 was also tested for hepatitis and human Infectious arthritis of any joint has a prev- immunodeficiency virus, both of which alence of 2 to 10 per 100,000 people. In 50% were negative. A transesophageal echo- of cases, the knee is the joint most common- cardiogram showed no obvious masses or ly affected, followed by the hip, shoulder, vegetations. and elbow.3 Regardless of location, infec- The patient had an uncomplicated hos- tious arthritis is associated with significant pital course, and was discharged home on morbidity and mortality due to sepsis and hospital day 6 with a 4-week prescription irreversible loss of joint function.4 of oral fluconazole and levofloxacin, and Risk factors for ISI include IV drug use, instructed to follow-up with both infec- pregnancy, trauma, endocarditis, and im- tious disease and the orthopedist. To ad- munosuppression.1 The decision to initiate dress his history of IV drug use, he also was the workup for ISI can be difficult to make given follow-up with pain management. because the condition may present with- One month later, the patient returned a out signs of an infectious etiology, such as fourth time to the ED for evaluation of bi- toxic appearance, inflammatory changes lateral lower extremity pain and swelling. surrounding the joint, or even fever—only He stated that he had been mostly bed- 41% of affected patients in one case series bound at home since his discharge from were febrile.2 The workup is often time- the hospital due to continued pain with consuming, invasive, and expensive. weight-bearing. Although delayed diagnosis and treat- The patient’s vital signs were normal. ment of septic arthritis is associated with The EP ordered a duplex ultrasound significant adverse effects, there is unfor- study, which showed extensive bilateral tunately no consensus to guide the workup lower extremity deep vein thrombosis. He for ISI. As opposed to Kocher’s criteria for was started on subcutaneous therapeutic the differentiation of septic hip arthritis enoxaparin and admitted to the inpatient from transient synovitis in pediatric pa- hospital. During admission, a left lower tients or well-known red-flags for further lobe pulmonary artery embolism was evaluation of low back pain, physicians found on chest CT angiography, though he are left without much guidance when con- had no cardiac or respiratory symptoms. sidering laboratory workup or imaging de- He was discharged home with a 3-month cisions to evaluate for ISI. prescription for oral rivaroxaban. At a 4-month follow-up visit, the pa- Sacroiliac Joint tient reported minimal residual disability As previously noted, the SIJ is not com- after completing the course of treatment. monly affected by infection. It is a diarthro- During the follow-up, the patient denied dial, L-shaped joint comprised of the pos- using IV heroin; he was referred to a pain terior ilium and sacrum, and is a near-rigid management specialist, who placed the structure with very limited movement that patient on methadone. provides stability to the axial skeleton.5 The SIJ is often overlooked as a secondary cause Discussion of low back pain in younger patients with Infectious sacroiliitis (ISI) is a rare form of rheumatologic conditions (eg, ankylosing infectious arthritis affecting the SIJ, with spondylitis, Reiter syndrome), pregnancy- an incidence of 1 to 2 reported cases per associated ligamentous laxity, and osteo- year.1 The literature on ISI currently con- arthritis in elderly patients.