A relationship between extracapsular involvement and response to steroid treatment in polymyalgia rheumatica: too soon to conclude?

Case Report and Literature Review of an Atypical Polymyalgia Rheumatica and Its Management

Polymyalgia rheumatica (PMR) is a systemic inflammatory disease of the elderly population that increases in incidence as age advances. It is characterised by the sudden or sub-acute onset of symptoms affecting the shoulder and pelvic girdles, often accompanied by constitutional symptoms. Due to the lack of consensual diagnostic criteria and specific laboratory or radiological investigations for PMR, its diagnosis can be very challenging, particularly because it can be mimicked or masked by other geriatric syndromes. PMR responds well to glucocorticoid treatment, but if left untreated, can lead to morbidity and poor quality of life. We present the case of an 87-year-old male who presented with a one-week history of localised pain in the left hip joint, later involving the contralateral hip. Previously able to ambulate unaided, his mobility was now severely impaired. Due to his Alzheimer's dementia and multiple comorbid geriatric conditions, extensive investigations were undertaken before a diagnosis of atypical PMR was reached. Treatment with a low dose of prednisolone led to a full recovery. This case highlights the inconsistency between an atypical presentation and the classic presentation of PMR and draws attention to the possibility of missed diagnosis in older, frail patients. Atypical symptomatology on top of cognitive impairment and language barriers can be easily overlooked and left untreated and could lead to severe adverse outcomes. Accurate diagnosis is crucial, as PMR is readily diagnosed, but the treatment with glucocorticoids, though generally straightforward, can pose challenges, particularly when dealing with polypharmacy and multiple coexisting health conditions.

Paroxetine alleviates T lymphocyte activation and infiltration to joints of collagen-induced arthritis

T cell infiltration to synovial tissue is an early pathogenic mechanism of rheumatoid arthritis (RA). In the present work, we reveal that G protein coupled receptor kinase 2 (GRK2) is abundantly expressed in T cells of collagen-induced arthritis (CIA). A GRK2 inhibitor, paroxetine protects the joints from inflammation and destruction, primarily through inhibition of both CD4+ helper T (Th) cell and CD8+ cytotoxic T (Tc) cell migration to synovial tissue. Meanwhile, paroxetine restores the balance of Th/Tc, effector Th (Theff)/ naïve Th (Thnaive) and effector Tc (Tceff)/ naïve Tc (Tcnaive) to equilibrium by elevating the frequency of Thnaive, Tcnaive and regulatory Th cells; reducing the increased Theff, activated Th and Tceff, having a similar effect as methotrexate (MTX). In addition, both serum and synovial IL-1β, TNF-α and CX3CL1 expression was effectively inhibited in treated rats. In vitro assay confirmed that paroxetine inhibits CX3CL1-induced T cell migration through blocking the activity of GRK2. Among three MAPK families, paroxetine was found to be able to decrease the phosphorylation of ERK. This study elucidates that paroxetine attenuates the symptoms of CIA rats due to its inhibitory effect on T cell activation and infiltration to synovial tissue via suppression of ERK pathway.