Proposal for a simple algorithm to differentiate adult-onset Still’s disease with other fever of unknown origin causes: a longitudinal prospective study

Recent advances and evolving concepts in Still's disease

Still's disease is a rare inflammatory syndrome that encompasses systemic juvenile idiopathic arthritis and adult-onset Still's disease, both of which can exhibit life-threatening complications, including macrophage activation syndrome (MAS), a secondary form of haemophagocytic lymphohistiocytosis. Genetic insights into Still's disease involve both HLA and non-HLA susceptibility genes, suggesting the involvement of adaptive immune cell-mediated immunity. At the same time, phenotypic evidence indicates the involvement of autoinflammatory processes. Evidence also implicates the type I interferon signature, mechanistic target of rapamycin complex 1 signalling and ferritin in the pathogenesis of Still's disease and MAS. Pathological entities associated with Still's disease include lung disease that could be associated with biologic DMARDs and with the occurrence of MAS. Historically, monophasic, recurrent and persistent Still's disease courses were recognized. Newer proposals of alternative Still's disease clusters could enable better dissection of clinical heterogeneity on the basis of immune cell profiles that could represent diverse endotypes or phases of disease activity. Therapeutically, data on IL-1 and IL-6 antagonism and Janus kinase inhibition suggest the importance of early administration in Still's disease. Furthermore, there is evidence that patients who develop MAS can be treated with IFNγ antagonism. Despite these developments, unmet needs remain that can form the basis for the design of future studies leading to improvement of disease management.

The latest advances in the use of biological DMARDs to treat Still's disease

INTRODUCTION

Currently, the therapeutic management of Still's disease, a multisystemic inflammatory rare disorder, is directed to target the inflammatory symptoms and signs of patients. The treatment varies from glucocorticoids to disease-modifying antirheumatic drugs (DMARDs), both conventional synthetic and biological (bDMARDs). Usually, in refractory patients, bDMARDs are administered.

AREAS COVERED

Among bDMARDs, IL-1 and IL-6 inhibitors are frequently used, as data reported from both clinical trials and 'real-life' experiences. Recently, innovative therapeutic strategies have suggested an early administration of bDMARDs to increase the rate of clinical response and drug-free remission. Some new targets have been also proposed targeting IL-18, IFN-γ, and JAK/STAT pathway, which could be applied to Still's disease and its life-threatening evolution.

EXPERT OPINION

Many lines of evidence improved the knowledge about the therapeutic management of Still's disease with bDMARDs. However, many unmet needs may be still highlighted which could provide the basis to arrange further specific research in increasing the rate of clinical response. In fact, Still's disease remains a highly heterogeneous disease suggesting possible diverse underlying pathogenic mechanisms, at least partially, and consequent different therapeutic strategies. A better patient stratification may help in arranging specific studies to improve the long-term outcome of Still's disease.

A Streamlined Diagnostic Process Improved the Outcomes of Patients with Adult-Onset Still's Disease: A Single-Center Retrospective Observational Study

INTRODUCTION

The diagnosis of adult-onset Still's disease (AOSD) is often delayed due to its clinical heterogeneity and lack of pathognomic features. Hence, there is an unmet need for an efficient diagnostic process. The major aim of this study was to compare the differences in disease outcomes between two groups of AOSD patients with and without implementation of the streamlined diagnostic process (SDP).

METHODS

Of 172 febrile patients with skin rash and/or arthralgia, 112 individuals had AOSD. The tentative diagnosis of AOSD or non-AOSD was made with or without the SDP implementation. The selection criteria for AOSD outcomes analysis were as follows: (1) age at study entry older than 20 years, (2) fulfillment of the Yamaguchi criteria for AOSD diagnosis, and (3) a follow-up period longer than 6 months after initiation of therapy. Three outcome parameters were evaluated, including diagnosis lag period, the proportion of "early diagnosis," and the proportion of achieving disease remission after a 6-month therapy.

RESULTS

The SDP was implemented for expediting AOSD diagnosis in 41 (36%) enrolled patients (SDP-implemented group). The diagnosis lag period was significantly shorter in the SDP-implemented group (median 2.0 weeks, interquartile range [IQR] 1.0-2.5 weeks) than in the non-SDP-implemented group (4.0 weeks, IQR 2.0-6.0 weeks, p < 0.001). A significantly higher proportion of "early diagnosis" was also found in the SDP-implemented group (75.6%) compared with the non-SDP-implemented group (33.8%, p < 0.001). We revealed a significantly higher proportion of achieving remission in the SDP-implemented group (85.4%) compared with the non-SDP-implemented group (67.6%, p < 0.05). Logistic regression analysis revealed SDP implementation as a potential predictor of achieving disease remission.

CONCLUSIONS

Implementing an SDP for expediting diagnosis could improve outcomes for AOSD patients. This diagnostic process increased the early diagnosis rate and led to a higher disease remission rate. However, the beneficial effects of SDP implementation need further external validation.

Derivation and validation of adult Still Activity Score (SAS)

OBJECTIVES

Adult-onset Still's disease (AOSD) is a multi-systemic, autoinflammatory disorder. Several activity scores have been proposed but none of them have been adopted universally. Our aim was to create a clinician-friendly activity scoring system by using simple clinical and laboratory parameters.

METHODS

AODS patients, according to Yamaguchi criteria, were included in this cross-sectional, multicenter study. Derivation and validation cohorts were constituted. Demographic, clinical, and laboratory evaluation at the study visit; patients' and physicians' global assessments of disease activity (both VAS/Likert scale) were recorded. To develop the score, an ordinal logistic regression model was used to determine independent predictors of physicians' global assessments of disease activity. Clinically and statistically significant variables were weighted according to regression coefficients. Then, performance of the score was tested on the validation cohort.

RESULTS

A total of 197 consecutive AOSD patients (125 in derivation, 72 in validation cohorts) were included. Final Still Activity Score was fever (2 points), arthralgia (2 points, plus 1 point if arthritis was present in≥2 joints), neutrophilia≥65% (1 point) and ferritin≥350ng/mL (1 point) (maximum of 7 points). The SAS yielded an AUC value of 0.98 (0.96-1.00) in the derivation cohort and 0.91 (95%CI: 0.85-0.98) in the validation cohort to discriminate high AOSD activity from moderate-inactive AOSD. The correlation of SAS with PGA was 83% for the derivation cohort and 76% for the validation cohort.

CONCLUSIONS

SAS has shown a good test performance to distinguish active AOSD patients from others. SAS may be a useful method for evaluating the disease activity of AOSD patients in daily practice.

Rheumatic disorders among patients with fever of unknown origin: A systematic review and meta-analysis

OBJECTIVES

To conduct a systematic literature review and meta-analysis to estimate the proportion of fever of unknown origin (FUO) and inflammation of unknown origin (IUO) cases that are due to rheumatic disorders and the relative frequency of specific entities associated with FUO/IUO.

METHODS

We searched PubMed and EMBASE between January 1, 2002, and December 31, 2021, for studies with ≥50 patients reporting on causes of FUO/IUO. The primary outcome was the proportion of FUO/IUO patients with rheumatic disease. Secondary outcomes include the association between study and patient characteristics and the proportion of rheumatic disease in addition to the relative frequency of rheumatic disorders within this group. Proportion estimates were calculated using random-effects models.

RESULTS

The included studies represented 16884 patients with FUO/IUO. Rheumatic disease explained 22.2% (95%CI 19.6 - 25.0%) of cases. Adult-onset Still's disease (22.8% [95%CI 18.4-27.9%]), giant cell arteritis (11.4% [95%CI 8.0-16.3%]), and systemic lupus erythematosus (11.1% [95%CI 9.0-13.8%]) were the most frequent disorders. The proportion of rheumatic disorders was significantly higher in high-income countries (25.9% [95%CI 21.5 - 30.8%]) versus middle-income countries (19.5% [95%CI 16.7 - 22.7%]) and in prospective studies (27.0% [95%CI 21.9-32.8%]) versus retrospective studies (20.6% [95%CI 18.1-24.0%]). Multivariable meta-regression analysis demonstrated that rheumatic disease was associated with the fever duration (0.011 [95%CI 0.003-0.021]; P=0.01) and with the fraction of patients with IUO (1.05 [95%CI 0.41-1.68]; P=0.002).

CONCLUSION

Rheumatic disorders are a common cause of FUO/IUO. The care of patients with FUO/IUO should involve physicians who are familiar with the diagnostic workup of rheumatic disease.

The role of lactate dehydrogenase-to-albumin ratio in clinical evaluation of adult-onset Still's disease

OBJECTIVES

The aim of the study is to evaluate the importance of lactate dehydrogenase-to-albumin ratio (LAR) in patients with adult-onset Still's disease (AOSD) and to investigate the relationship between this ratio and clinical laboratory variables.

METHODS

The study design was retrospective cross-sectional. The demographic and clinical data, laboratory results and imaging findings were documented. Univariate and multinomial logistic regression analyses were performed to find the predictors, which could be useful to define the ferritin level and organ involvement. Receiver-operating characteristic (ROC) analysis was used to clarify the diagnostic ability of the LAR for ferritin level and organ involvement.

RESULTS

Fifty-eight patients with AOSD were evaluated. When patients were divided into two groups according to the serum ferritin level with a cut-off of 1500 ng/dL, lymphocyte count and albumin level were significantly less in patients who had higher ferritin levels (P = .015 and P = .005). In multinominal logistic regression analysis, AST, LDH and LAR were found as predictors for ferritin levels. When we compared LAR between patients with and without organ involvement, higher LAR was found in patients with HM, SM, serositis and MAS. Also, LAR was significantly higher in patients with higher ferritin levels (≥1500 ng/dL) than those without (P < .001). In ROC analysis, the cut-off point of LAR predicting the ferritin level was determined as 80.75 with 83.7% sensitivity and 80.0% specificity (AUC = 0.89, 95% CI 0.79-0.98, P < .001).

CONCLUSION

LAR can be a valuable inflammatory marker to determine AOSD patients with organ involvement and higher ferritin level.

Adult-onset Still's disease in focus: Clinical manifestations, diagnosis, treatment, and unmet needs in the era of targeted therapies

BACKGROUND

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology, characterized by a clinical triad of high spiking fever, arthralgia (± arthritis), and evanescent skin rash. Management of AOSD poses several challenges, including difficulty in diagnosis and limited therapeutic options. In this review, we examined whether AOSD and systemic juvenile idiopathic arthritis (SJIA) represent a continuum of the same disease. We also explored the latest available evidence related to prevalence, clinical and laboratory manifestations, complications, diagnostic challenges, novel biomarkers, and treatment options in the era of biologics and identified the unmet needs of patients with AOSD.

METHODS

A comprehensive systematic literature search was performed in the Embase and MEDLINE (via PubMed) literature databases. The search was limited to human studies published in English from inception up to March 2020. Additionally, abstracts presented at various conferences were screened and hand searches were performed. Publications were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 123 publications were identified through the literature search, majority of which were case series and retrospective observational studies. AOSD and SJIA are widely considered part of the same disease spectrum owing to similarities in their clinical and biological features. The clinical presentation of AOSD is highly variable, accompanied by a broad spectrum of disease manifestations. Recent evidence suggests that the AOSD disease course can be classified into two distinct categories: "systemic" and "articular." Furthermore, AOSD patients may experience various life-threatening complications, such as macrophage activation syndrome - reported in as high as 23% of AOSD patients and considered to be the most severe complication characterized by a high mortality rate. The ambiguity in presentation and lack of serologic markers make the diagnosis of AOSD difficult, often leading to a delay in diagnosis. Given these limitations, the Yamaguchi and Fautrel criteria are the most widely used diagnostic tools in clinical practice. It has been observed that a clinical diagnosis of AOSD is generally reached by exclusion while investigating a patient with fever of unknown origin. Recent advances have demonstrated a major role of proinflammatory cytokines, such as interleukin (IL)-1, IL-6, IL-18, and IL-37, and other biomarkers in the pathogenesis and management of AOSD. Owing to the rarity of the disease, there are very limited clinical trials evaluating management strategies for AOSD. The current AOSD treatment paradigm includes non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids initially, conventional synthetic disease-modifying anti-rheumatic drugs in steroid-refractory patients, and biologics in those resistant to conventional treatment. Only a few country-specific guidelines for the management of AOSD have been published, and a treat-to-target approach, as previously recommended for SJIA, is still lacking. Canakinumab is the only FDA-approved biologic for the treatment of AOSD.

CONCLUSION

Emerging evidence supports that AOSD and SJIA represent a continuum of the same disease entity. Despite advancements in the understanding of AOSD, it continues to pose a substantial burden on patients and the healthcare systems, and substantial unmet needs exist across key domains such as the pathway to diagnosis, use of biomarkers in clinical practice, and standardized treatment strategies. Further research and collaboration is crucial for optimizing the diagnosis and management of AOSD patients.

The role of platelet to mean platelet volume ratio in the identification of adult-onset still's disease from sepsis

OBJECTIVES

Inflammatory factors exert a significant role in the development of adult-onset Still's disease (AOSD) and sepsis. Although platelet counts and platelet parameters have long served as indicators for inflammatory diseases, their role in the differential diagnosis between adult-onset stilĺs disease and sepsis remains unclear. We designed this retrospective study to explore whether the platelet to mean platelet volume (MPV) ratio (PMR) can help to distinguish AOSD from sepsis.

METHODS

A total of 110 AOSD patients and 84 sepsis patients were enrolled in the study. Seventy-three AOSD patients and 56 sepsis patients between January 2010 and June 2017 were enrolled in the test cohort to analyze PMR values, which was then validated in the validation cohort (37 AOSD patients and 28 sepsis patients between June 2017 and December 2019).

RESULTS

The values of PMR were significantly higher in AOSD patients than in sepsis patients (test cohort, validation cohort, and entire cohort), In the test cohort, logistic regression analysis showed that PMR was an independent risk factor of AOSD (odds ratios [OR]: 9.22, 95% confidence interval [CI] 2.15-39.46, p=0.003). Further receiver operating characteristic curve (ROC) analysis showed that the area under the ROC curve was 0.735 (95% CI 0.631-0.839, p<0.001) for PMR alone and 0.925 (95% CI 0.869-0.980, p<0.001) for the combination of PMR and serum ferritin. Consistently, the validation cohort exhibited analogous results.

CONCLUSIONS

PMR could be used as a single indicator or a complementary indicator to distinguish AOSD from sepsis.

Schnitzler Syndrome in a 27-Year-Old Man: Diagnostic and Therapeutic Dilemma in Adult Auto-Inflammatory Syndromes A Case Report and Literature Review

A 32-year-old-man, with a history of chronic urticaria from the age of 27, diagnosed with an adult-onset Still’s disease and received a low dose of glucocorticoids, methotrexate and tocilizumab. Despite the long-term combined treatments, he suffered from chronic urticaria, low-grade fever and bone pain. He was found to have high inflammatory markers, hypogammaglobulinemia, monoclonal IgM – kappa light chain in serum and increased radiotracer uptake in the whole bone scintigraphy. No pathological variants for monogenic autoinflammatory diseases were present in the genome exome sequencing. These investigations confirmed the diagnosis of Schnitzler syndrome, which is an exception before the age of 35. Switching from tocilizumab to interleukin 1 receptor inhibitor, anakinra led to a full clinical response and normalisation of inflammatory markers. Patients with a history of fever and chronic urticaria are routinely tested for monoclonal gammopathy in the context of malignancy, but it should also be considered as a sign of the autoinflammatory syndrome. The Schnitzler syndrome and the adult-onset Still’s disease share common features, so the diagnosis requires a thorough investigation to establish an optimal treatment. In the diagnostic algorithm, monoclonal gammopathy is usually considered red flag for malignancy but might be overlooked as a criterion of Schnitzler syndrome, particularly in young adults. We confirm that the interleukin 1 inhibitor should be the first line of therapy in Schnitzler syndrome, and in the presented case we found it more effective than the interleukin 6 blockade. The main goal of this paper is to increase awareness of Schnitzler syndrome among health care professionals. We aim to present features which can be helpful in differential diagnosis.

Combination value of biomarkers in discriminating adult onset Still's disease and sepsis

BACKGROUND

Lymphocyte and plateletcrit (PCT) as proportions of routine complete blood count tests, have been studied as simple biomarkers for inflammatory diseases. The aim of our study was to investigate whether blood routine parameters, especially platelet parameters could be a useful tool to distinguish Adult onset Still's disease (AOSD) from sepsis.

METHODS

We retrospectively reviewed 58 patients with AOSD and 55 sepsis patients diagnosed at the First Affiliated Hospital of Nanjing Medical University between January, 2015 to December 2018. Laboratory data including ferritin, blood routine parameters and C‑reactive protein (CRP) level were collected, and the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte (PLR) were calculated.

RESULTS

The results showed that AOSD patients showed higher ferritin, lymphocyte and PCT (all P < 0.01) and these factors are independent risk factors for predicting AOSD. In receiver operating characteristic (ROC) curve analysis of LY, PCT and ferritin for distinguish of AOSD, the area under the curve (AUC) was 0.676 (0.576-0.777); 0.706 (95% CI = 0.596-0.816); 0.715 (0.617-0.814). Meanwhile, the AUC of the combination of lymphocyte, PCT and ferritin was 0.836 (0.737-0.909) with sensitivity 67.3, specificity 92.3, and the difference was significant.

CONCLUSIONS

Thus we suggest that lymphocyte, PCT may be a useful tool to make a distinction between AOSD and sepsis, as supplementary biomarkers to ferritin.

Myocarditis in Adult-Onset Still's Disease: Case-Based Review

Cardiac involvement in adult-onset Still's disease (AOSD) usually manifests as a pericardial disease. Myocarditis is uncommon (prevalence of 7%). However, the cardiocirculatory failure is the second cause of life-threatening AOSD. Herein, we report the case of a 38-year-old man who was diagnosed with myocarditis caused by AOSD. He was treated medically with steroids and methotrexate, and his course was favorable. A literature search in PubMed/MEDLINE and Scopus databases from 1971 to 2019 identified 47 additional cases of myocarditis and AOSD. The main features found in these reports were reviewed and are the following: (i) myocarditis is a rare complication of AOSD manifested by fever, chest pain, dyspnea, and tachycardia; (ii) cardiac biomarkers, electrocardiogram (ECG), transthroracic echocardiography (ECHO), and cardiac magnetic resonance imaging (MRI) are useful noninvasive diagnostic tools; and (iii) myocarditis is a potentially life-threatening complication of AOSD but responds positively to steroids and other immunomodulatory drugs. This review suggests that this entity should be suspected in cases of acute febrile myocarditis after ruling out other causes since a prompt treatment results in a good prognosis.