Purpose of review: To discuss and summarize recent findings in peripheral neuropathy (PN) related to connective tissue diseases (CTD) including its prevalence, clinical manifestations, pathogenesis, diagnosis and treatment. Recent findings: Although PN is a common complication in CTD and has been well studied, recent research has shown that PN is more diverse and frequent in different subtypes of CTD than was expected. The incidence of PN in Sjögren’s syndrome and rheumatoid arthritis (RA) varies according to different disease subtypes, and the pathogenesis of neuropathic pain in different subtypes of eosinophilic granulomatosis with polyangiitis (EGPA) may also differ. Neurogenic inflammation, autoantibody-mediated changes, ischemia of the vascular wall and metabolic mechanisms have been shown to contribute to the pathogenesis of PN in CTD. Moreover, allergic inflammation has been recently identified as a possible new mechanism producing peripheral neuropathic pain associated with MPO-ANCA negative EGPA patients. Glucocorticoids are routinely used to relieve pain caused by PN. However, these steroids may cause hyperalgesia, exacerbate neuropathic pain, and activate the early phase of pain induction and produce hyperalgesia. Recently, neuroactive steroids, such as progesterone, tetrahydroprogesterone and testosterone, have been shown to exert protective effects for several PN symptoms, and in particular neuropathic pain. Neuroactive steroids will be an interesting topic for future research into PN in CTD. Summary: It is essential for the diagnosis and treatment of PN in CTD to be updated. Timely diagnosis, appropriate treatments, and multidisciplinary care are essential to minimize morbidity and decrease the risk of permanent neurologic deficits. Further studies are needed to guide diagnosis and treatment.

Background: Cogan's syndrome (CS) is a rare autoimmune disorder characterized by non-syphilitic interstitial keratitis (IK) and Menière-like cochlear vestibular symptoms, which may also have systemic effects. Corticosteroids are first-line treatment. DMARDs and biologics have been used to treat ocular and systemic symptoms of CS. Case presentation: This is a case of a 35-year-old female who reported hearing loss, eye redness and photophobia. Her condition progressed to a sudden sensorineural hearing loss, tinnitus, and constant vertigo accompanied by cephalea. CS was diagnosed after excluding other diseases. The patient still developed bilateral sensorineural hearing loss after receiving hormone, methotrexate, cyclophosphamide, and a variety of biological agents. Joint symptoms were relieved after treatment with a JAK inhibitor (tofacitinib), and hearing did not deteriorate further. Conclusions: CS should be involved in the differential diagnosis of keratitis. Early identification and intervention of this autoimmune disease can minimize disability and irreversible damage.

Background We conducted to examine the prevalence of frailty among different arthritis populations and to elucidate the associations between frailty and all-cause and cause-specific mortality among rheumatoid arthritis (RA) in the American adults. Method National Health and Nutrition Examination Survey (NHANES) database spanning 1999 to 2018 was collected, supplemented with pertinent mortality records from the U.S. National Death Index (NDI) up to December 31, 2019. The Frailty Index defined by Searle was adopted. Different types of arthritis include: RA, Osteoarthritis (OA), Psoriatic Arthritis (PsA), and others. Statistical methods mainly included maximum selected rank statistics, univariate and multivariate COX regression models, and Restricted Cubic Spline (RCS). Results The frailty indices of different arthritis populations were 0.24, 0.21, 0.21, and 0.20, respectively. The cut-off value for the frailty index was 0.3. Compared to those with a lower frailty index, participants with a higher frailty index exhibited higher risks of all-cause mortality (HR = 2.11, 95% CI 1.70–2.62), heart disease mortality (HR = 2.38, 95% CI 1.53–3.70), lower respiratory disease mortality (HR = 3.79, 95% CI 1.62–8.88), and influenza and pneumonia mortality (HR = 6.08, 95% CI 2.12–17.42). Frailty-associated all-cause mortality risks increased with age among different age groups. Conclusion Frailty was particularly pronounced among RA patients. Relatively high frailty index could predict higher all-cause and cause-specific mortality among RA adults in America, and the all-cause mortality related to frailty increased with age. Frailty index could be utilized as a prognostic marker in RA management. Timely interventions are paramount for optimizing patient outcomes.