Hand ultrasound patterns in rheumatoid and psoriatic arthritis: the role of ultrasound in the differential diagnosis

Prospective double-blind study on the value of musculoskeletal ultrasound by dermatologists as a screening instrument for psoriatic arthritis

OBJECTIVES

This study evaluated musculoskeletal ultrasound (MSUS) use by dermatologists previously trained on a novel handheld, chip-based ultrasound device (HHUD) to screen for early PsA.

METHODS

Twelve dermatologists were recruited to screen psoriasis patients for PsA using the novel HHUD in one major hospital in Bonn (Germany) and six private practices in surrounding regions. Patient screening was based on medical history, clinical examination, and the GEPARD questionnaire paired with an MSUS examination of up to three painful joints. All screened patients were then referred to rheumatologists, who determined the final diagnosis. The screening effect of MSUS was assessed according to its sensitivity and specificity before and after its application.

RESULTS

Between 1 October 2020 and 26 May 2021, a total of 140 psoriasis patients with arthralgia participated in this study. PsA was diagnosed in 19 (13.6%) cases. Before applying MSUS, dermatologists' screening sensitivity and specificity were recorded as 88.2% and 54.4%, respectively, while after applying MSUS the sensitivity and specificity changed to 70.6% and 90.4%, respectively. MSUS led to a change of PsA suspicion in 46 cases, with PsA no longer being suspected in 45 of them.

CONCLUSION

This study was able to demonstrate that PsA screening using MSUS by previously trained dermatologists can lead to more precise PsA detection and potentially decreased rheumatologist referral rates.

ACR Appropriateness Criteria® Chronic Extremity Joint Pain-Suspected Inflammatory Arthritis, Crystalline Arthritis, or Erosive Osteoarthritis: 2022 Update

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity because there is significant overlap of imaging findings among the various types of arthritis. This document provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The role of trauma and isomorphic reaction in the pathogenesis of psoriatic arthritis

The role of biomechanical stress and trauma in the initiation of inflammation of the joints and periarticular structures in psoriatic arthritis (PA) is currently not fully understood. Soft tissues and joints are the target for constant biomechanical stress and microtrauma, leading to inflammation. There is an opinion that this inflammation in PA is due to an analogue of the skin isomorphic reaction that develops in the skin of psoriatic patients in response to trauma. Some authors have called this reaction the deep Koebner phenomenon. It is assumed that the early, preclinical phase of psoriatic arthritis may be based on inflammation of the enthesis as a response to microtrauma, and explained by the proximity of the entheses and the articular membranes. Detection of early changes in entheses in psoriatic patients, including those who do not have complaints from the musculoskeletal system, is of great importance for the early diagnosis of psoriatic arthritis. In the literature review, the sources for the period 20102021 were studied, devoted to the role of the isomorphic reaction and microtraumatization in the pathogenesis of PA, as well as the role of various imaging methods for the early diagnosis of enthesitis in psoriatic patients.

Ultrasound detected synovitis, tenosynovitis and erosions in hand and wrist joints: a comparative study between rheumatoid and psoriatic arthritis

Objectives

Musculoskeletal 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 methods

Thirty-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 (1^st–5^th metacarpophalangeal [MCP], 2ⁿd–5^th proximal interphalangeal [PIP] and 1^st–5^th 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.

Results

Among 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 versus 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).

Conclusions

There are significant differences in the musculoskeletal US findings of the hand and wrist that joints help to distinguish between RA and PsA.

A standardized sonographic analysis of nails in psoriatic arthritis and healthy controls: Feasibility, reliability, diagnostic performance, and demographic and clinical associations

OBJECTIVES

Subunits of the nail can be evaluated by nail ultrasonography (NUSG). The purposes of this study are to document NUSG properties (both nail-based and participant-based evaluations) in patients with psoriatic arthritis (PsA) and healthy controls and to explore the final scorings.

METHODS

After the literature review and a pilot study, a consensus was reached to evaluate 12 nails and 5 parameters by NUSG: nail plate impairment (NPI), nail plate thickness (NPT), nail bed thickness (NBT), nail thickness (NT), and Doppler activity (DA); further, scorings for each parameter (NPIs, NPTs, NBTs, NTs, and DAs) were calculated. Group comparisons and diagnostic performances (with ROC curve analysis) were applied to both parameters and scorings. Final scorings to predict PsA diagnosis among the NUSG scorings were reached by regression analysis. Feasibility, reliability, and clinical associations of the scores were also performed.

RESULTS

Sixty-four patients with PsA and 26 controls (3240 baseline images) were assessed. The most affected nails, PsA/control comparisons, and the ROC analysis varied among the nails, within the higher values of PsA; therefore, 12 nails remained in the scorings. Participant-based scorings showed better content and diagnostic performances than the nail-based. Diagnostic performances, feasibility, reliability, and regression analysis of the scorings documented that NPIs, NTs, and DAs were the best. Some demographics, employee status, hemoglobin, and disease activity of the participants were associated with them.

CONCLUSIONS

The NUSG Index (NUSGI) including NPIs, NTs, and DAs is a feasible, reliable, and discriminative method to predict PsA diagnosis, with its rich content. Clinicaltrials.gov-ID: NCT04718428.

Imaging in the diagnosis and management of peripheral psoriatic arthritis

Psoriatic arthritis is a heterogenous disease affecting peripheral and axial joints, tendons, ligaments, and their insertions, in addition to the skin and the nails. The complexity of the involved structures has puzzled clinicians trying to understand the underlying pathology that leads to symptoms in order to choose the appropriate medications with different modes of actions. Imaging, mainly ultrasound and magnetic resonance imaging, allows of accurate detection of inflammatory changes in the musculoskeletal structures, which helps to avoid false positive and negative assessments. The linking of different anatomical structures' involvement using imaging also provides insights into the pathogenesis of psoriatic arthritis. In this review, ultrasound and magnetic resonance imaging will be discussed in depth with regard to their use in the field of peripheral psoriatic arthritis, with a focus on the literature from the last 4 years and recent advances.

Ultrasound Imaging in Psoriatic Arthritis: What Have We Learnt in the Last Five Years?

Psoriatic arthritis (PsA) is a complex heterogeneous disease with multiple inter-related pathologies such as synovitis, enthesitis, tendinopathy, and dactylitis. Clinical assessment is limited in its detail to assess pathology, thus in recent years, ultrasound (US) has become more popular, given its high sensitivity to detect inflammatory arthritis and ability to inform clinical decisions. Although a qualitative technique, US findings can be graded semi-quantitatively for grayscale (GS) and power Doppler (PD). Synovitis is frequently present in inflammatory arthritis pathologies, and in PsA, recent evidence shows a propensity for tendon and entheseal lesions. The presence of flexor tenosynovitis and flexor tendon insertional enthesopathy at accessory pulleys is supportive of the “Deep Koebner” concept. Peri-tendinous inflammation—mutual to PsA or rheumatoid arthritis (RA), is associated with soft tissue oedema with PD signal frequently at the flexor tendon compartments in PsA. Research on enthesitis in PsA/PsO has improved understanding in subclinical and clinical PsA, explored associations with progression to PsA, and investigated links to prognosis assessment. Dactylitis is a pathognomonic PsA lesion where US has enhanced knowledge of the disease course and pathology of lesions such as: flexor tenosynovitis; synovitis; and soft tissue oedema. Increased US sensitivity has also brought innovation including promising automated ultrasound scanning techniques. So, what have we learnt in recent years and what are the unmet needs to focus future research initiatives in this disabling disease? This narrative review article assesses the neoteric evidence, bringing into context the knowledge gained and highlighting potential areas of research.