Detection of chlamydial DNA in the inflamed sacroiliac joint of a patient with multiple infections.

Inflammation of the sacroiliac (SI) joint is the hallmark of spondyloarthritis (SpA). Particularly, unilateral sacroiliitis is common in patients with reactive arthritis (ReA) but is sometimes difficult to distinguish from septic arthritis as both conditions can present clinically in a similar way. However, a precise diagnosis is crucial because treatment strategies are rather different. As opposed to septic arthritis, per definition microbes can not be cultured from the inflamed joint in ReA. However, polymerase chain reaction (PCR) has emerged as a sensitive tool to detect microbial structures in the synovial compartment to identify the triggering bacteria and to consequently establish the diagnosis of ReA. We describe the case of a 28-year-old man who was admitted in August 2006 due to acute onset and progressively worsening inflammatory lower back pain (IBP) since 3 weeks. He also reported a tender first MTP joint and groin pain both on the right side for 6 weeks, which had eased over the last 7 days. Three weeks before the acute onset of joint symptoms, the patient-reported symptoms of urethritis with a whitish colored discharge. Fever at any time point was denied. The previous history revealed psoriasis capitis in remission since childhood and recurring IBP since 2001. One year before admission, an HIV-infection was diagnosed. A recent viral load was low (9800 copies/ L) and CD4 count was acceptably high (358 cells/ L), the reason why an antiretroviral therapy had not yet been initiated. On the day of admission, the physical examination showed no peripheral arthritis. However, the motion of the lumbar spine was painful and severely limited, so that Ott’s and Schober’s sign could not be tested, the Mennell’s sign was positive on the right side. Further diagnostic work on the same day yielded an elevated CRP (74 mg/L), leucocyturia, and a bilateral sacroiliitis stage II by conventional radiographs. The sacroiliitis was also confirmed on the CT scan performed later on for joint puncture. HLA-B27 was positive. Interestingly, the magnetic resonance imaging revealed strong gadolinium enhancement only on the right side indicating severe and acute sacroiliitis, and possibly a liquid formation which might indicate pyogenic sacroiliitis (Fig. 1). Neisseria gonorrhoeae was cultured from an urethral swab, whereas DNA amplification from the same specimen for Chlamydia trachomatis was unsuccessful. Two serology testings for C. trachomatis during hospitalization were negative. To rule out bacterial sacroiliitis, a CT-guided puncture from the right SI joint was obtained. Histology revealed sparse synovial material with predominantly spongious bone and slightly increased lymphocytic infiltrations without otherwise clear signs of inflammation. Cultures were sterile. However, the nested PCR from the SI joint puncture material amplifying the C. trachomatis-specific major outer membrane protein (MOMP) was positive (Fig. 2). Because of gonococcal urethritis, the patient was treated by IV ceftriaxone 2 g/d for 10 days but with initiation of the antibiotic experienced worsening and spreading of pain throughout the entire spine. Consecutive treatment with 3 different NSAIDs in sufficient doses (diclofenac, ibuprofen, and etoricoxib) in combination with multiple analgesics (nonopioids and opioids) and intensive physical therapy did not improve his symptoms. Therefore, high-dose IV prednisolone (500 mg/d for 3 consecutive days) was initiated on day 4 of the antibiotic treatment, which led to markedly improved IBP symptoms and motion of the spine. However, one month after being discharged from the hospital, the patient saw his office-based rheumatologist with remitting severe IBP and an increased CRP and was given glucocorticoids again, this time 30 mg/d po. Another month later, IBP was still present; CRP was decreased even though still not normal. Thereafter, the patient was lost to follow-up. This case demonstrates the diagnostic work-up of a young male patient with a SpA and an HIV-infection. Because of his history of psoriasis and recurrent inflammatory back pain with radiologic sacroiliitis (grade II), one part of his manifestations can be classified as HLA-B27 positive psoriatic SpA. There also is a gonococcal (positive gonococcal urethral swab) and possibly a coinfection with Chlamydia, which caused an acute unilateral (reactive) sacroillitis justifying the term posturethritic reactive SpA. As the SI joint PCR was positive for C. trachomatis, this can also be termed Chlamydia-induced sacroiliitis. To our knowledge, this is the From the Departments of *Clinic for Immunology and Rheumatology, †Nephrology, and ‡Radiology, Hannover Medical School (MHH), Hannover, Germany; §Department of Anesthesiology, Pain Clinic, Hannover Medical School (MHH), Hannover, Germany; ¶Rheumatologische Praxis, Hannover, Germany; and Rheumatologikum Hannover, Hannover, Germany. Supported by the German Competence Network Rheumatology (Kompetenznetz Rheuma/BMBF). Correspondence: Markus Rihl, MD, Hannover Medical School (MHH), Department of Clinic for Immunology and Rheumatology, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. E-mail: rihl.markus@mh-hannover.de Copyright © 2009 by Lippincott Williams & Wilkins ISSN: 1076-1608/09/1504-0195 DOI: 10.1097/RHU.0b013e3181a7a9c3 FIGURE 1. Magnetic resonance imaging (STIR) of the pelvis showing strong signal enhancement around the right SI joint. There is additional accentuation of the soft tissue lateral to the iliac bone indicating a liquid, that is, abscess formation (arrows).