Shoulder rheumatoid arthritis

Clinical History

A 69-year-old woman presented with a 2-year history of left progressive omalgia. She also referred episodes of right wrist pain. The blood test showed leukocytosis with neutophilia, and elevation of acute phase reactant and liver enzymes.
The previous MRI, performed one year before, revealed supraspinatus tendinosis and subacromial bursitis.

Imaging Findings

X-ray showed a soft tissue swelling in the left shoulder and erosion of the distal clavicle. Shoulder MRI was performed demonstrating subacromial-subdeltoid bursal distension with joint effusion and synovial hyperplasia, hyperintense on T2-weighted images and with enhancement after gadolinium injection. Numerous intrabursal loose bodies with low-signal intensity on all pulse sequences were described. Additionally, the patient presented humeral head erosions and rotator cuff tear.

The MRI also confirmed the erosion of the distal clavicle associated to bone marrow oedema in the context of an inflammatory process of the acromioclavicular joint. Supraclavicular and axillary lymph nodes were described.

The patient underwent surgery (bursectomy and intra-articular loose bodies removal), and the histopathologic analysis was consistent with synovial membrane changes compatibles with rheumatoid arthritis and presence of fibrinous bodies ("rice bodies").

Discussion

Rheumatoid arthritis (RA) is a chronic autoimmune multi-systemic inflammatory disease with predominant damage of synovial tissues. It affects around 0.5-1% of the adult population and occurs predominantly in females (2-3:1) between 45-65 years of age [1].

The diagnosis of AR is based on clinical, radiologic and serological findings. In 2010, new classification criteria were published by The American College of Rheumatology and The European League Against Rheumatism to enable an early diagnosis [2].

The clinical symptoms are chronic and fluctuant. They consist principally of polyarthralgia, morning joint stiffness, and other extra-articular manifestations such as fever, fatigue and weight loss. Arthritis symptoms tend to appear first in smaller joints (hands and wrists) in a symmetric proximal distribution. With the progression of the disease, the symptoms spread to other joints [2, 3], such as the shoulder, which is affected in around 91% of patients with long-standing disease [4].

RA is characterized by sinovial hyperplasia and pannus formation, fundamental elements in the pathogenesis of RA [5].

The typical findings in X-ray are soft tissue swelling, symmetrical narrowing of the joint space, osteoporosis and marginal bone erosion due to the pannus [6]. Osteolysis of the distal clavicle may be present [7, 8].

Computed tomography is not frequently used in the evaluation of peripheral disease, since the initial findings are soft-tissue changes and other techniques are superior in detecting them. Therefore, it is basically reserved for evaluation of spinal RA and peri-operative assessment [9].

MRI has a greater sensitivity than radiographs to evaluate the inflammatory disease and can detect bone erosions years before conventional radiography [10]. Synovitis is the earliest finding in patients with AR. MRI allows direct visualization of the pannus, seen as soft tissue mass with low signal intensity on T1-weighted images, high signal on T2-weighted images, and enhancement after gadolinium administration [11, 12]. This technique can also detect bone marrow oedema and effusions, present in early phases of RA [13]. In RA spontaneous tendon ruptures can also occur [8, 12].

Rice bodies may be detected as multiple intra-articular small loose bodies consequence of a non-specific chronic synovial inflammation [9, 12, 13]. They are iso-hypointense in T1, T2 and proton density-weighted images. They can be removed for symptomatic relief.

The life expectancy of patients with RA is reduced by 3 to 12 years, mainly because of cardiovascular diseases [2]. The only treatment that has an effect on the course of the disease are the Disease-modifying antirheumatic drugs (DMARDs). Nonsteroidal antiinflamatory drugs and corticosteroids are also used [9].

Differential Diagnosis List

Final Diagnosis

Rheumatoid arthritis

URL:	https://eurorad.org/case/14322
DOI:	10.1594/EURORAD/CASE.14322
ISSN:	1563-4086