Immunopathogenesis of reactive arthritis: Role of the cytokines

Diagnostic considerations in the clinical management of sudden swelling of the knee: a case report and review of the literature

BACKGROUND

Reactive arthritis and septic arthritis rarely present concomitantly in the same joint and patient. Reactive arthritis presenting after coronavirus disease 2019 is also exceedingly rare, with less than 30 cases reported thus far. Less common pathogens such as Clostridium difficile have been reported to cause reactive arthritis, especially in patients with a positive human leukocyte antigen B27, and therefore should be considered in diagnostic algorithms. The aim of this case report is to highlight the difficulties and precautions in discerning and diagnosing patients presenting with sudden swelling of the knee.

CASE PRESENTATION

We report the case of a 70-year-old Caucasian male with a recent history of coronavirus disease 2019 upper respiratory infection and diarrhea and negating trauma, who presented with a swollen and painful knee. Pain and swelling worsened and inflammatory parameters increased after an intraarticular corticosteroid injection. The patient was therefore treated with arthroscopic lavage and intravenous antibiotics for suspected septic arthritis. Synovial fluid and synovium samples were taken and sent for microbiological analysis. Synovial fluid cytology showed increased leukocytes at 10,980 × 106/L, while polymerase chain reaction and cultures came back sterile. Clostridium difficile toxin was later detected from a stool sample and the patient was treated with oral vancomycin. The patient was tested for the presence of human leukocyte antigen B27, which was positive. We present a review of the literature about the challenges of distinguishing septic from reactive arthritis, and about the mechanisms that predispose certain patients to this rheumatological disease.

CONCLUSIONS

It is still a challenge to differentiate between septic and reactive arthritis of the knee, and it is even more challenging to identify the exact cause of reactive arthritis. This case report of a human leukocyte antigen-B27-positive patient highlights the necessity of contemplating different, less common causes of a swollen knee joint as a differential diagnosis of an apparent septic infection, especially in the coronavirus disease 2019 era. Treating the patient for septic arthritis prevented any possible complications of such a condition, while treating the C. difficile infection contributed to the substantial relief of symptoms.

[History of reactive arthritis. Historical milestones and future]

The introduction of the term reactive arthritis (ReA) for the joint inflammation observed after infection with Yersinia enterocolitica, in which "a causative pathogen cannot be isolated from the synovial fluid", and the association with the HLA-B27 were the historical milestones for a new classification and assignment to the spondylarthritides (SpA). The division into postinfectious and reactive arthritis proposed in 1976 was put into perspective in the 1990s because of investigations with the newly available molecular biological method of the polymerase chain reaction. Microbial products could be identified from joint samples of patients with ReA. Therefore, it was proposed to abandon the distinction between the two groups of diseases and to prefer the term ReA for both. This created a terminological and nosological issue. On the one hand, there are generally accepted classification and diagnostic criteria for the classical HLA-B27-associated ReA that are assigned to SpA. On the other hand, an increasing number of bacterial pathogens, viruses, amoebas, helminths as well as antiviral and antibacterial vaccinations are described as triggers of arthritis, which have been published under the term ReA. Since the beginning of the SARS-CoV‑2 pandemic, cases of acute post-COVID-19 arthritis have been described, which were also classified as ReA because of comparable clinical features.

Reactive Arthritis After Intravesical Bacillus Calmette-Guérin Therapy

ABSTRACT

Reactive arthritis (ReA) is a sterile arthritis that occurs in genetically predisposed individuals secondary to an extra-articular infection, usually of the gastrointestinal or genitourinary tract. Sterile arthritis associated with instillation of intravesical bacillus Calmette-Guérin (iBCG) therapy used for bladder cancer can also be included under ReA based on the pathogenic mechanism. Similar to spondyloarthritis, HLA-B27 positivity is a known contributor to the genetic susceptibility underlying iBCG-associated ReA. Other genetic factors, such as HLA-B39 and HLA-B51, especially in Japanese patients, can also be involved in the pathophysiology of iBCG-associated ReA. The frequencies of ReA- and ReA-related symptoms are slightly different between Japanese and Western studies. Proper understanding of possible complications, their epidemiology and pathogenesis, and their management is important for the rheumatologist when noting symptomatic patients using iBCG. Herein, we will review the most current information on ReA after iBCG therapy.

Reactive arthritis: a clinical review

Reactive arthritis (ReA) is a form of inflammatory arthritis triggered by a remote antecedent infection, usually in the genitourinary or gastrointestinal tract. It is part of the spondyloarthropathy (SpA) spectrum, an umbrella term for a group of distinct conditions with shared clinical features. Typically, it presents with an asymmetric oligoarthritis of the lower limb joints, and patients may also have sacroiliitis, enthesitis and dactylitis. Other features often seen include anterior uveitis, urethritis and skin manifestations such as pustular lesions on the plantar areas. Although ReA was characterised initially as a sterile arthritis, the detection of metabolically active Chlamydia species in the joint fluid of some affected patients has generated further questions on the pathophysiology of this condition. There are no formal diagnostic criteria, and the diagnosis is mainly clinical. HLA-B27 can support the diagnosis in the correct clinical context, and serves as a prognostic indicator. The majority of patients have a self-limiting course, but some develop chronic SpA and require immunomodulatory therapy.

Chlamydia-induced reactive arthritis diagnosed during gout flares: A case report and cumulative effect of inflammatory cytokines on chronic arthritis

RATIONALE

The pathology of gouty arthritis and reactive arthritis (ReA) partially overlaps, and both diseases are characterized by the production of inflammatory cytokines associated with the activation of monocytes and macrophages. However, the precise cytokine profile of cases with a coexistence of both diseases is unknown, and there are few reports on the course of treatment in patients with both gouty arthritis and ReA.

PATIENT CONCERNS

A 39-year-old man with a recurrent episode of gouty arthritis presented prednisolone-resistant polyarthritis with high level of C-reactive protein (CRP). He had the features of gouty arthritis such as active synovitis of the first manifestation of metatarsophalangeal (MTP) joints and the presence of monosodium urate (MSU) crystals from synovial fluid. But he also had the features of ReA such as the presence of tenosynovitis in the upper limb, the positivity of human leukocyte antigen (HLA)-B27, a history of sexual contact and positive findings of anti-Chlamydia trachomatis-specific IgA and IgG serum antibodies.

DIAGNOSES

He was diagnosed with HLA-B27 associated Chlamydia-induced ReA accompanied by gout flares.

INTERVENTIONS

He was treated with 180 mg/day of loxoprofen, 1 mg/day of colchicine, and 10 mg/day of prednisolone for gout flares. However, his polyarthritis worsened with an increased level of CRP (23.16 mg/dL). Accordingly, we added 500 mg/day of salazosulfapyridine followed by adalimumab (ADA) 40 mg once every 2 weeks.

OUTCOMES

After starting ADA, the patient's symptoms and laboratory findings showed rapid improvement and he achieved clinical remission 1 month after initiation of ADA treatment. As of this writing, the patient's clinical remission has been maintained for >1 year.

LESSONS

This case suggests that with exacerbation of arthritis during gouty arthritis, coexistence with other pathologies such as peripheral spondyloarthritis should be considered, and early intensive treatment including tumor necrosis factor inhibitors may be necessary.