Background: Rheumatoid arthritis (RA) is a systemic autoimmune disease that has a great impact on different joints, may result in their destruction and loss of function.Although the shoulder is affected in a large portion of patients with RA, it does not receive much attention during the follow up of RA. The precise diagnosis of shoulder pain in RA is a clinical challenge and benefits from a reliable imaging modality to detect its exact origin. Aim:To determine the diagnostic accuracy of ultrasound (US) in detecting shoulder joint pathologies in RA, considering magnetic resonance imaging (MRI) as the gold standard. Materials and Methods:This cross-sectional, observational study was carried out on 30 RA patients complaining of unilateral or bilateral shoulder pain. Patients were subjected to history taking, clinical shoulder examination, plain X-ray, US examination following a standardized protocol, and MRI. The results were correlated with each other. Results:In comparison with the MRI findings, US showed high accuracy in terms of sensitivity (Sn) and specificity (Sp) in supraspinatus tendinopathy (Sn 96.6%; Sp 93.3%), biceps tenosynovitis (Sn 87.5%; Sp 97.6%), subacromial-subdeltoid bursitis (Sn 72.7%; Sp 95.7%), humeral erosions (Sn 90.5%; Sp 97.3%), and acromioclavicular osteoarthritis (Sn 85.7%; Sp 95.7%). In terms of reliability, the agreement between US and MRI was almost perfect (κ = .9, P < .001). Conclusion:US may have a role as the initial imaging modality in RA patients with shoulder pain, as it is highly sensitive and specific in detecting different pathological abnormalities of the shoulder. K E Y W O R D S MRI, rheumatoid arthritis, shoulder, ultrasound | 2159 ABDELZAHER Et AL.

IntroductionMusculoskeletal ultrasound (MSUS) has been introduced as a valuable simple imaging tool for arthritis. The objective was to assess the role of ultrasound (US) in the differential diagnosis between rheumatoid arthritis (RA) and psoriatic arthritis (PsA) at the wrist and hand joints and tendons.Material and methodsThirty-five patients (20 RA and 15 PsA) with symptomatic involvement of at least one of the hand and/or wrist joints for > 6 weeks were included. Bilateral wrists (distal radioulnar, radiocarpal and midcarpal joints), hands (1st–5th metacarpophalangeal [MCP], 2nd–5th proximal interphalangeal [PIP] and 1st–5th distal interphalangeal [DIP] joints), flexor tendons and extensor compartments at the level of the wrist joint were examined sonographically. Synovial hypertrophy, joint effusion, erosions and tenosynovitis were diagnosed according to Outcome Measures in Rheumatology definitions. The findings were correlated with clinical, laboratory and disease activity indices.ResultsAmong 680 and 510 joints examined in RA and PsA respectively, certain US features such as synovitis and erosions at the DIP were exclusively detected in PsA (p < 0.001). Synovitis was frequently detected at the distal radioulnar joints (DRUJ) in RA in comparison to PsA patients (52.5% vs. 26.7% respectively, p = 0.029). Joint effusion was more frequently detected at radiocarpal and midcarpal joints in RA compared to PsA (p = 0.047, 0.039 respectively), whereas erosions were significantly more frequently detected at radiocarpal joints in RA <i><i>versus</i></i> PsA patients (45% vs. 20% respectively, p = 0.029). Tenosynovitis was significantly more frequently detected at the extensor tendons in RA and at the flexor tendons in PsA patients (p = 0.021, 0.022 respectively).ConclusionsThere are significant differences in the musculoskeletal US findings of the hand and wrist that joints help to distinguish between RA and PsA.

Carpal tunnel syndrome (CTS) represents about 90% of all entrapment neuropathies and is caused by entrapment of the median nerve while passing in the carpal tunnel. US has revealed equal effectiveness as magnetic resonance imaging (MRI) in diagnosis of CTS; however further attention should be given in case of equivocal results from nerve conduction studies (NCS) and/or before endoscopic surgical intervention. This study was conducted to evaluate the role of US in diagnosis and treatment of CTS which was done by endoscopic release. This is a prospective study including patients having CTS who were treated by endoscopic release between December 2017 and December 2018. All cases were evaluated by electrophysiological studies and US at the preoperative period. US was used to measure the cross sectional area (CSA) of the median nerve. Patients underwent endoscopic carpal tunnel release and were called for follow up after 1, 3, and 6 months for clinical and US assessment of the median nerve. Forty cases were included with mean age of 27.85 years. Numbness was the predominant symptom (92.5%) followed by wrist pain (85%). The mean diameter of median nerve showed a significant decrease at different time points (P < 0.001). The sensitivity of US in diagnosis of CTS was 87.5% in the preoperative assessment as compared to electrophysiological study. The sensitivity of US in detecting the improvement of CTS as compared to clinical examination increased from 28% at 1 month postoperative, 53.4% at 3 months to 92.1% at 6 months. Ultrasonography is a sensitive non-invasive diagnostic tool in diagnosis of CTS preoperative and diagnosis of improvement of the patients postoperatively especially at 6 months.

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In this work, the interesting dynamics of coupled nonlinear memristor-based oscillators in ring configuration are explored. The mathematical models are derived to describe the possible cases of employing identical or different nonlinearities. Analytical and numerical techniques, involving perturbation methods, normal forms, phase portraits, and Lyapunov exponents are used to investigate various types of dynamical behaviors along with their stability regions in parameters space. The effects of time-delayed coupling on the proposed system are numerically studied. It is demonstrated that the coupled oscillators show rich dynamics including periodic orbits, quasiperiodicity, two-dimensional, and three-dimensional tori.

Background:Rheumatoid arthritis (RA) is a chronic inflammatory disease that results in progressive destruction of structural components of the joints1.It commonly affects the shoulder leading to pain, tenderness and decreased range of motion2.Increased shoulder pain has been found to correlate strongly with disease severity3, however there is little information available in the literature regarding shoulder pathologies in asymptomatic RA patients.Objectives:To determine the prevalence of pathologies in asymptomatic shoulders in rheumatoid arthritis patients and role of ultrasound to detect it.Methods:A cross-sectional study including two groups, first group included 36 RA patients, meeting the ACR/EULAR classification criteria for RA with no shoulder complaints. The second group included 36 healthy control subjects of similar age groups and sex, with no shoulder complaints. They were recruited from rheumatology outpatient clinic in Mansoura University Hospital. Only asymptomatic shoulders of both groups were examined clinically by inspection, palpation and special tests, then examined by ultrasound using Toshiba Xario 200 machine with 13 MHz superficial probe including biceps tendon, subscapularis tendon, supraspinatus tendon, subacromial subdeltoid (SASD) bursa, infraspinatus tendon, posterior glenohumeral joint for effusion or synovitis, acromioclavicular joint and humeral head for erosions. Findings of both groups were compared to each other.Results:Asymptomatic shoulders in RA patients showed significant number of pathologies in 72% of the examined patients in comparison with healthy subjects (17%). According to frequency, humeral erosions were detected in 12 patients (33%), acromioclavicular osteoarthritis in 8 patients (22%), biceps tenosynovitis, supraspinatus tendinopathy, glenohumeral effusion in 6 patients (17%), subscapularis tendinopathy in 4 patients (11.%), SASD bursitis in 2 patients (6%), Infraspinatus tendinopathy in 1 patient (3%).The healthy group showed less number of pathologies including supraspinatus tendinopathy 3 (8%), acromioclavicular osteoarthritis 2 (6%), humeral erosions 1 (3%).Conclusion:A significant high rate of different pathologies can be present in shoulders of RA patients despite negative history and normal physical examination. Ultrasound can be used for early detection and better management before irreversible joint destruction.References:[1]Weishaupt D, Schweitzer ME (2004) MR imaging of septic arthritis and rheumatoid arthritis of the shoulder. Magn Reson Imaging Clin N Am 12:111–124[2]Varache S, Cornec D, Morvan J, et al. Diagnostic accuracy of acr/eular 2010 criteria for rheumatoid arthritis in a 2-year cohort. The Journal of rheumatology. 2011; 38(7): 1250-1257.[3]Van de Sande MA, De Groot JH, Rozing PM. Clinical implications of rotator cuff degeneration in the rheumatic shoulder. Arthritis care & research. 2008; 59(3): 317-324.Disclosure of Interests:None declared