Imaging Indications in Polymyalgia Rheumatica
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REVIEW Imaging indications in polymyalgia rheumatica With the recent improvement in technology, various imaging modalities are increasingly being used in the diagnosis and monitoring of musculoskeletal diseases. Although polymyalgia rheumatica (PMR) is traditionally considered a ‘clinical diagnosis’ the utility of imaging for diagnosis, assessment of disease severity and treatment response in PMR is increasingly recognized. Imaging not only adds to the diagnosis by detecting PMR-specific features, but also helps to make alternative diagnoses. Recently published classification criteria emphasize the importance of ultrasonography, an easily available imaging modality in the diagnosis of PMR. Herein we discuss the role and limitations of ultrasonography, MRI and fludeoxyglucose-PET scanning in the management of PMR, particularly in the diagnosis, and distinguishing it from its numerous mimics. KEYWOD R S: FDG-PET n imaging n MRI n polymyalgia rheumatica n ultrasonograpgy Pravin Patil1, Tochi Adizie1, Shaifali Jain1 The diagnosis of polymyalgia rheumatica (PMR), in the diagnosis of PMR and distinguishing it & Bhaskar Dasgupta*1,2 characterized by proximal pain and stiffness, is from its mimics. In light of the classification 1Southend University Hospital, often uncertain owing to PMR mimics, such as criteria, we also report validation findings from Prittlewell Chase, Westcliff-on-Sea, rheumatoid arthritis (RA), spondyloarthritides, a shoulder ultrasound study of consecutive Essex, SS0 0RY, UK 2Essex University, Colchester, UK inflammatory myopathies connective tissue patients referred from general practice for *Author for correspondence: diseases and vasculitis – all of which can present evaluation of suspected PMR. Synovitis, effusion, Tel.: +44 1702221048 with the polymyalgic syndrome in the elderly. tenosynovitis and erosions referred in this paper Fax: +44 1702385909 [email protected] Inflammatory markers are often discordant with are defined according to the Outcome Measures disease activity and imaging techniques show in Rheumatology (OMERACT) definitions for promise in diagnosis and disease monitoring, musculoskeletal (MSK) ultrasound [3]. improving our understanding of PMR and its overlap with inflammatory arthritis and large Diagnostic challenges in PMR vessel vasculitis (LVV). In this article, we discuss The polymyalgic syndrome of proximal pain imaging techniques, primarily ultrasonography and stiffness, with or without elevation of (US), but also MRI and fludeoxyglucose inflammatory markers, is shared by several medical (FDG)-PET, in the assessment of PMR. Current conditions affecting older people. Inflammatory guidelines recommend a stepwise approach to arthritides frequently present with pain and PMR and we add the imaging requirements to morning stiffness. Elderly-onset RA involves facilitate the various diagnostic steps (FIGURE 1). large joints (most notably the shoulders) in 40% Imaging adds to PMR diagnosis by either of patients [4]. In a cohort study of 116 patients identifying abnormalities associated with with raised erythrocyte sedimentation rate (ESR) alternative diagnoses or detecting PMR-specific referred for shoulder girdle pain and followed-up features. MRI studies have shown synovitis and for 12 months by Caporali et al., 35% eventually periarticular inflammation in PMR and confirm received the diagnosis of RA and 56% retained that there is no actual muscle inflammation a firm diagnosis of PMR at 1 year [5]. Peripheral [1], while FDG-PET scans show vascular arthritis was present in nearly 80% of patients inflammation, synovitis, bursitis and enthesitis with RA but also in 26% of patients with PMR, in a significant portion of PMR patients [1] . indicating poor positive predictive value of this Recently published PMR classification criteria sign [5]. Similarly, Pease et al. reported that recognize PMR-associated ultrasound lesions in 23% of patients with PMR also have peripheral the shoulders and hips as criteria items for the synovitis [6]. However, it is clear that persistent scoring algorithm for the classification as PMR[2] . synovitis in multiple joints and the need for a We review the current understanding of the role prolonged high-dose corticosteroid therapy should of ultrasound, MRI and PET-CT and imaging prompt reconsideration of the diagnosis of PMR. part of 10.2217/IJR.12.77 © 2013 Future Medicine Ltd Int. J. Clin. Rheumatol. (2013) 8(1), 39–48 ISSN 1758-4272 39 REVIEW Patil, Adizie, Jain & Dasgupta 40 Presenting Clinical feature DiagnosisInvestigation complaint Age more than 50 years, Polymyalgia rheumatica Ultrasonography shoulders, hips shoulder and thigh symptoms, and temporal artery symmetrical FDG-PET scan Predominant peripheral joint symptoms Rheumatoid arthritis and Ultrasonography Inflammatory other inflammatory arthritis Radiograph – Morning stiffness – Joint swelling Peripheral hand/foot edema Remitting, seronegative, symmetrical Ultrasonography synovitis with pitting edema syndrome Predominant constitutional symptoms, FDG-PET scan, CT/MR angiogram, Large vessel vasculitis very high CRP, limb claudication symptoms ultrasonography shoulders, hips and temporal artery Lower back pain and stiffness Late-onset spondyloarthropathy MRI spine and sacro-iliac joints with fat-suppressed views Autoantibodies, creatine kinase Weakness of muscles Inflammatory myopathy Proximal pain or stiffness Electromyelography, MRI and Int. J. Clin. Rheumatol. muscle biopsy Noninflammatory pain in shoulder, Osteoarthritis and Articular Radiographs, blood/synovial acromioclavicular joints, cervical spine septic arthritis fluid cultures and hips Adhesive capsulitis Ultrasonography Periarticular Capsular restriction and so on Rotator cuff lesions and atrophy Radiographs (2013) Elevated sedimentation rate, CRP Concomitant sepsis (e.g.,urinary Blood, urine cultures, fluid relevant history and tests (e.g., urinalysis) infection, occult and deep sepsis microscopy and culture, and 8 hip, muscle and body cavity MRI/CT (1) abscesses, osteomylitis and so on) Noninflammatory/ Microscopic hematuria Bacterial endocarditis Trans-thoracic/esophageal echo infective/neoplastic/ fever and murmur and blood cultures neuro/endocrine Serum and urine electrophoresis, Neoplasia (e.g., myeloma) Weight loss and associated features CT chest, abdomen and pelvis, and FDG-PET Tender spots and long-standing history Fibromyalgia, chronic pain Diagnosis of exclusions, syndromes and depression sleep disturbance, tender points and fatigue Nonarticular Generalized aches and lack of sun exposure Metabolic bone disease Bone profile, vitamin D and and endocrinopahy thyroid/parathyroid tests Rigidity, shuffle, stare and Parkinsonism Assessment by neurologist gradual onset Dopamine transporter scan Figure 1. Recommendation on approach for the evaluation of proximal pain and stiffness. CRP: C-reactive protein; CT: Computed tomograpy: FDG: Fludeoxyglucose; MR: Magnetic resonance. Reproduced with permission from [34]. future science group Imaging in polymyalgia indications rheumatica R EVIEW REVIEW Patil, Adizie, Jain & Dasgupta Imaging indications in polymyalgia rheumatica REVIEW Late-onset spondyloarthropathy with its features allows contralateral examination and does not of oligoarthritis, constitutional symptoms and pose limitations due to metal artifacts, which can high ESR may easily mimic PMR [7]. be problematic in MRI. The presentation of PMR can be atypical and Ultrasound has been used in the diagnosis varied. Patients with dominant constitutional of PMR patients, especially in patients with the symptoms (such as anemia, weight loss and low typical symptoms with normal ESR [11] . Typical grade fever) may mimic infection or neoplasia but findings on ultrasound include subdeltoid bursitis also systemic inflammation such as LVV. Due (FIGURE 2) and tenosynovitis of long head of biceps to overlapping clinical features, the distinction tendon (FIGURES 3 & 4) at the shoulders [16,17] and, between isolated PMR and giant cell arteritis less frequently, synovitis of the glenohumoral (GCA)-associated polymyalgia can be difficult. joint. In the hips, ultrasound often reveals GCA can present with polymyalgia in 40–50% synovitis (FIGURE 5) and trochanteric bursitis [18,19] . of patients and studies have shown that patients Interspinous bursitis can also be found on PET initially diagnosed with isolated PMR have US scanning in PMR [20]. and histological features of GCA [8]. Evidence, In a series by Lange et al., these ultrasound however, is still lacking to support the use of findings were found in 40.9% of PMR patients temporal artery US in every PMR patient, as we and 65.5% of elderly-onset rheumatoid arthritis do not know whether this subclinical vascular (EORA) patients. The latter being characterized inflammation has any long-term consequences. by more severe inflammation on ultrasound [21] . Presentation of PMR with predominant Bursitis and long head biceps tenosynovitis are constitutional symptoms could also represent a more frequently bilateral in PMR patients [17] . In paraneoplastic phenomenon [9]. a series of 24 patients studied by Cantini et al., As no gold standard test has been established US bilateral bursitis had 92.9% sensitivity, 99.1% for the diagnosis of PMR, clinicians rely heavily specificity and 98.1% positive predictive value for on inflammatory markers in confirming clinical PMR [17] . diagnosis of PMR. However, the presence of With regards to hip symptoms, Cantini PMR with normal inflammatory markers is well