Reactive arthritis: a review

Hand conditions as sequelae of infection with COVID-19: a literature review

Patients have attended our clinics with various hand pathologies after contracting COVID-19 or receiving vaccination. We postulate the virus stimulates a systemic inflammatory response that triggers these pathologies and conducted a search of the literature for associated conditions. Twenty publications were included for this review. Three studies identified skeletal muscle inflammation, and several identified reactive arthritis post-infection. Rheumatoid arthritis post-infection was also recognized, along with crystalline arthropathy. Carpal tunnel syndrome was seen in two cases. There is a current paucity in published scientific material regarding COVID-19 sequalae in the hand. This review aims to stimulate discussion in how a virus can induce pathological processes causing common hand pathologies.

Evaluating the Diagnostic Performance of Systemic Immune-Inflammation Index in Childhood Inflammatory Arthritis: A Focus on Differentiating Juvenile Idiopathic Arthritis from Reactive Arthritis

In pediatric care, the range of potential diagnoses for arthritis can be relatively extensive, primarily involving infectious and inflammatory causes and, to a lesser extent, oncological conditions. Specifically, when addressing inflammatory causes, differentiating between Juvenile Idiopathic Arthritis (JIA) and Reactive Arthritis (ReA) can prove to be challenging during the first weeks, owing to the lack of specific antibodies in several JIA subtypes. This single-center retrospective study of 108 children with arthritis aimed to evaluate in greater detail the complete blood count (CBC) profiles of children with JIA and ReA in greater detail. The most significant differences were noted in terms of the Systemic Immune-Inflammation Index (SII), with higher values in the JIA group. Moreover, within the JIA group, SII displayed a significant positive correlation with conventional inflammatory biomarkers, specifically C-reactive protein (ρ = 0.579) and Erythrocyte Sedimentation Rate (ρ = 0.430). It was the only independent factor associated with the presence of JIA after adjusting for age (p = 0.030). Also, even with the moderate diagnostic value, the discriminating capacity of SII was superior to those of each of its component CBC parameters according to receiver operating characteristic (ROC) analysis. In summary, this study identified elevated SII values in the JIA group compared to the ReA group, indicating the potential utility of SII as an adjuvant discriminatory marker between these two arthritis forms.

A Case Report of Intratesticular Hematoma in a Patient with Reiter's Syndrome

We present a case of a 28-year-old male patient with a spontaneous intratesticular hematoma. He had no history of trauma but experienced sudden onset of painful swelling in his right testis. Initially, testicular malignancy was suspected. The tumor marker of testis, including alfa-fetoprotein, lactic dehydrogenase, and β-human chorionic gonadotropin, was within normal range. The patient had been diagnosed with Reiter's syndrome at the age of 20 and had been treated with sulfasalazine, non-steroidal anti-inflammatory drugs, and acetaminophen for eight years. Various imaging techniques before operation planning, including ultrasonography and computed tomography, revealed a hematoma that accounted for 32% of the testicular volume. During the waiting period before the operation, the patient was diagnosed with a hematoma and avoided a possible diagnosis of malignancy. Follow-up imaging with computed tomography and magnetic resonance imaging confirmed the presence of an intratesticular hematoma that had decreased in size. Since no other related factor contributed to this hematoma, and considering the possible hematological side effects of sulfasalazine, we suggest that this may be a rare side effect of sulfasalazine. Although the patient's testis was preserved, further fertility should be observed because animal studies have reported that testicular hematoma may cause fertility changes if the initial volume occupied is over 30% of the testis.

Reactive arthritis following COVID-19 current evidence, diagnosis, and management strategies

BACKGROUND

Immune-mediated conditions associated to Corona Virus Disease-19 (COVID-19) have been reported, including vasculitis, antiphospholipid antibody syndrome, myositis, and lupus. Emerging studies have reported the potential occurrence of reactive arthritis in patients previously infected with COVID-19. This systematic review summarised the current evidence on the occurrence of reactive arthritis in patients previously infected by COVID-19.

METHODS

This study was conducted according to the 2020 PRISMA guidelines. All the clinical investigations describing the occurrence of reactive arthritis following COVID-19 were accessed. In September 2022, the following databases were accessed: PubMed, Web of Science, Google Scholar, Embase. The generalities of the study were extracted: author, year and journal of publication, country of the main author, study design, sample size, mean age, number of women, main results of the study. The following data on COVID-19 severity and management were retrieved: type of treatment, hospitalization regimes (inpatient or outpatient), admission to the intensive care unit, need of mechanical ventilation, pharmacological management. The following data on reactive arthritis were collected: time elapsed between COVID-19 infection to the onset of reactive arthritis symptoms (days), pharmacological management, type of arthritis (mono- or bilateral, mono- or polyarticular), extra-articular manifestations, presence of tenosynovitis or enthesitis, synovial examination at microscopic polarised light, imaging (radiography, magnetic resonance, sonography), clinical examination, laboratory findings.

RESULTS

Data from 27 case reports (54 patients) were retrieved, with a mean age of 49.8 ± 14.5 years. 54% (29 of 54 patients) were women. The mean time span between COVID-19 infection and the occurrence of reactive arthritis symptoms was 22.3 ± 10.7 days. Between studies diagnosis and management of reactive arthritis were heterogeneous. Symptoms resolved within few days in all studies considered. At last follow-up, all patients were minimally symptomatic or asymptomatic, and no additional therapy or attentions were required by any patient.

CONCLUSION

Poor evidence suggests that COVID-19 could target the musculoskeletal system causing reactive arthritis at its post infectious stage. COVID-19 can act as a causative agent or as a trigger for development of reactive arthritis even without presence of antibodies of rheumatological disorders. Treating physicians should have a high index of suspicion while treating post infectious COVID-19 patient with arthralgia.

LEVEL OF EVIDENCE

Level IV, systematic review.

Reactive arthritis following COVID-19: cause for concern

Low-quality evidence suggests that COVID-19 may trigger reactive arthritis one to four weeks after the infection. Post COVID-19 reactive arthritis resolves within a few days, and no additional treatment is required. Established diagnostic or classification criteria for reactive arthritis are missing, and a deeper understanding of the immune mechanism related to COVID-19 prompt us to further investigate the immunopathogenic mechanisms capable of promoting or contrasting the development of specific rheumatic diseases. Caution should be exerted when managing post-infectious COVID-19 patient with arthralgia.

Can SARS‐CoV‐2 infection trigger rheumatoid arthritis? A case report

Inflammatory arthritis has been reported after SARS‐COV‐2 infection. We present a case of a 38‐year‐old female patient who developed polyarthralgia 1 month after SARS‐COV‐2 infection. Musculoskeletal examination was significant for synovitis of hands and wrists. Antinuclear antibody (ANA), rheumatoid factor (RF), and anti‐cyclic citrullinated peptide (CCP) antibodies were positive. Magnetic resonance imaging of the hands showed synovitis of the metacarpophalangeal joints and proximal interphalangeal joints of the hands, wrist joints, and tendinitis with tenosynovitis. The patient was diagnosed with seropositive nonerosive rheumatoid arthritis (RA) and initiated on therapy using nonsteroidal anti‐inflammatory agents and disease‐modifying anti‐rheumatic drug methotrexate leading to an improvement in symptoms.

Cases of autoimmune and auto‐inflammatory diseases triggered after COVID‐19 have been reported. We report the case of a 38‐year‐old female patient who developed seropositive, nonerosive rheumatoid arthritis (RA) one month after SARS‐CoV‐2 infection.

Clinical profiles of post-infectious arthritis and transient synovitis of the hip in children

BACKGROUND

Acute inflammatory arthritides can present as a result of immune reaction following infections. Post-infectious arthritis and transient synovitis of the hip in children are included in this disease entity. The aim of this study was to describe the clinical profiles of post-infectious arthritis and transient synovitis of the hip in Thai children.

METHODS

A retrospective review was performed at a tertiary care hospital in Bangkok, Thailand from January 2005 to July 2017.

RESULTS

Eighty-six patients (56 boys and 30 girls) were included in this study. Mean age was 8.4 ± 4.8 years. Reactive arthritis was diagnosed in two patients (2.3%) following Salmonella spp. and Chlamydia trachomatis infections. Post-streptococcal reactive arthritis was present in 10 patients (11.6%). Transient synovitis of the hip was found in 30 patients (34.9%). Forty-four patients (51.2%) were clinically diagnosed with post-infectious arthritis. Mono/oligoarthritis was the most common clinical profile (84.9%). The distribution of lower-extremity involvement was as follows: hip, 47.6%; knee, 46.5%; and ankle joints, 30.2%. The documented preceding illness consisted mostly of upper respiratory tract symptoms (30.2%). Non-steroidal anti-inflammatory drugs were prescribed for 70 patients (81.4%).

CONCLUSION

Mono/oligoarthritis of the lower extremity was the main clinical profile. Preceding viral illness was documented in one-third of children. Reactive arthritis was rarely seen.

Reactive arthritis after COVID-19: a case-based review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 19 (COVID-19) pandemic, which is deeply affecting the whole world. In this new case for the scientific world, scientists are investigating the etiopathogenesis of viral infection-induced damage and have started to focus on the short and long-term immune system effects and alterations after SARS-CoV-2 infection. The case is here reported of a 53-year-old female patient with acute monoarthritis after SARS-CoV-2 infection, who responded adequately to 150 mg/day diclofenac treatment, and the available case reports are comprehensively reviewed. With the focus on arthritis after SARS-CoV2 infection, which emerges as a new pathological condition associated with COVID-19, it was aimed to examine the possible immunological mechanisms of post-COVID-19 arthritis based on the current data on SARS-CoV-2 and the known pathogenetic background of viral arthritis.

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.

Inflammasomes in the Pathophysiology of Aortic Disease

Aortic diseases comprise aneurysms, dissections, and several other pathologies. In general, aging is associated with a slow but progressive dilation of the aorta, along with increased stiffness and pulse pressure. The progression of aortic disease is characterized by subclinical development or acute presentation. Recent evidence suggests that inflammation participates causally in different clinical manifestations of aortic diseases. As of yet, diagnostic imaging and surveillance is mainly based on ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Little medical therapy is available so far to prevent or treat the majority of aortic diseases. Endovascular therapy by the introduction of covered stentgrafts provides the main treatment option, although open surgery and implantation of synthetic grafts remain necessary in many situations. Because of the risks associated with surgery, there is a need for identification of pharmaceutical targets interfering with the pathophysiology of aortic remodeling. The participation of innate immunity and inflammasome activation in different cell types is common in aortic diseases. This review will thus focus on inflammasome activities in vascular cells of different chronic and acute aortic diseases and discuss their role in development and progression. We will also identify research gaps and suggest promising therapeutic targets, which may be used for future medical interventions.

Axial and peripheral spondyloarthritis triggered by sars-cov-2 infection: a report of two cases

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can show musculoskeletal symptoms such as peripheral arthritis. In rare cases, peripheral arthritis can develop after the resolution of SARS-CoV-2. We present two cases of spondyloarthritis induced by SARS-CoV-2; one case with axial and peripheral spondyloarthritis and the other with peripheral spondyloarthritis. Both cases refer to Lebanese patients who were HLA-B27 positive. These two cases highlight the possible predisposition of HLA-B27 positive patients to the development of spondyloarthritis symptoms triggered by SARS-CoV-2.

Case Report of a Rare Cause of Reactive Arthritis: Leptospirosis

Introduction

Leptospirosis is a zoonosis caused by infection with pathogenic Leptospira species. Leptospirosis has protean manifestations and rare, unusual presentations should be kept in mind in relevant epidemiological scenario. Reactive arthritis refers to acute non-purulent arthritis complicating an infection elsewhere in the body. It is attributed to an immune activation following certain infections; it is, therefore considered as aseptic arthritis. Very few case reports are available attributing leptospirosis as an established cause of reactive arthritis. We present a case of reactive arthritis of the hip joint due to leptospirosis.

Case Report

Here, we present a case of a 12-years- old female child who was admitted to our hospital with complaints of fever, headache, and pain in the right hip joint since past 5 days from admission. Subsequent elaboration revealed a past history of fever, headache, and myalgia for around 5-7 days around a week before the present complaints. There was rat infestation near her house and her father was working as sewage cleaner. Routine investigations, Ultrasonography (USG), Magnetic Resonance Imaging (MRI) of both hips and subsequently, diagnostic hip aspiration was performed. USG revealed synovitis, MRI revealed hip joint arthritis of infective or inflammatory origin. Diagnostic hip aspiration was negative for any microorganism. On 10th day of admission, patient started developing icterus with yellowish discolouration of urine. Patient was evaluated for the cause of jaundice. Screening for Leptospira was positive. Synovial biopsy of hip was performed, which showed inflammation with no specific pathology and no growth of any microorganism. In addition, Leptospira IgM MAC ELISA was done which was positive. Patient was thus confirmed to be having leptospirosis and reactive arthritis as a consequence of it.

Conclusion

The presentation of reactive arthritis secondary to leptospirosis is rare. Leptospirosis can be an etiological factor for reactive arthritis, especially if reactive arthritis is complicated with jaundice.

Reactive Arthritis After COVID-19 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is a novel virus that results in a variety of clinical manifestations. In this report, I describe an uncommon presentation of reactive arthritis (ReA) following COVID-19. I report the case of a 39-year-old woman who presented with arthritis in the small joints of the hands after recovery from COVID-19 infection. To my knowledge, only four cases involving such a presentation have been reported in the literature so far.

Spezielle Schmerztherapie bei rheumatischen Erkrankungen

Schmerz als Hauptsymptom vieler chronisch-entzündlicher Erkrankungen stellt für den Patienten, aber auch für den behandelnden Arzt besonders in seiner chronifizierten Form eine große Herausforderung dar. Es gibt leider keine „Wunderpille“ mit der man Schmerzen für jeden gleich zuverlässig beseitigen kann. Es gibt aber viele Ansätze pharmakologischer als auch nicht-pharmakologischer Art und deren Kombination, um für den einzelnen Patienten wirksame Behandlungsstrategien zu finden. Um diese Strategien für jeden Patienten individuell optimal festzulegen, bedarf es zum einen eines fundamentierten Wissens über das Spektrum zur Verfügung stehender Mittel, zum anderen aber auch Erkenntnis darüber, wie diese sinnvoll nach Art der vorliegenden Schmerzformen einzusetzen sind. In dieser Übersicht wird beides behandelt, mit einem Fokus auf die medikamentöse Therapie von Schmerzen bei entzündlich-rheumatischen Erkrankungen. Dabei wird herausgearbeitet, dass es für die in diesem Zusammenhang relevantesten Formen des Schmerzes, akut-entzündlich nozizeptiv, neuropathisch und durch periphere und zentrale Sensibilisierung chronifizierte Schmerzen, jeweils andere wirksame Konzepte gibt.

Elucidating potential molecular signatures through host-microbe interactions for reactive arthritis and inflammatory bowel disease using combinatorial approach

Reactive Arthritis (ReA), a rare seronegative inflammatory arthritis, lacks exquisite classification under rheumatic autoimmunity. ReA is solely established using differential clinical diagnosis of the patient cohorts, where pathogenic triggers linked to enteric and urogenital microorganisms e.g. Salmonella, Shigella, Yersinia, Campylobacter, Chlamydia have been reported. Inflammatory Bowel Disease (IBD), an idiopathic enteric disorder co-evolved and attuned to present gut microbiome dysbiosis, can be correlated to the genesis of enteropathic arthropathies like ReA. Gut microbes symbolically modulate immune system homeostasis and are elementary for varied disease patterns in autoimmune disorders. The gut-microbiota axis structured on the core host-microbe interactions execute an imperative role in discerning the etiopathogenesis of ReA and IBD. This study predicts the molecular signatures for ReA with co-evolved IBD through the enveloped host-microbe interactions and microbe-microbe 'interspecies communication', using synonymous gene expression data for selective microbes. We have utilized a combinatorial approach that have concomitant in-silico work-pipeline and experimental validation to corroborate the findings. In-silico analysis involving text mining, metabolic network reconstruction, simulation, filtering, host-microbe interaction, docking and molecular mimicry studies results in robust drug target/s and biomarker/s for co-evolved IBD and ReA. Cross validation of the target/s or biomarker/s was done by targeted gene expression analysis following a non-probabilistic convenience sampling. Studies were performed to substantiate the host-microbe disease network consisting of protein-marker-symptom/disease-pathway-drug associations resulting in possible identification of vital drug targets, biomarkers, pathways and inhibitors for IBD and ReA.Our study identified Na(+)/H(+) anti-porter (NHAA) and Kynureninase (KYNU) to be robust early and essential host-microbe interacting targets for IBD co-evolved ReA. Other vital host-microbe interacting genes, proteins, pathways and drugs include Adenosine Deaminase (ADA), Superoxide Dismutase 2 (SOD2), Catalase (CAT), Angiotensin I Converting Enzyme (ACE), carbon metabolism (folate biosynthesis) and methotrexate. These can serve as potential prognostic/theranostic biomarkers and signatures that can be extrapolated to stratify ReA and related autoimmunity patient cohorts for further pilot studies.

Reactive Arthritis in a 37-Year-Old Female With SARS-CoV2 Infection

We report the case of a 37-year-old female who presented for evaluation of acute 10/10 right hand pain, 12 days after testing positive for SARS-CoV2. The patient was admitted to the hospital due to the severity of her pain. As an inpatient, extensive workup by the medicine team and rheumatology revealed no structural, vascular, or neurogenic cause of her pain. The patient's blood work was unremarkable for elevations in lyme serology, antinuclear antibody (ANA), rheumatoid factor, and uric acid. It was determined that the cause of her pain was most likely reactive arthritis (ReA) secondary to her SARS-CoV2 infection. She was treated with voltaren gel, neurontin, and oral dilaudid as needed and discharged. Upon follow-up, her pain improved and she was prescribed a wrist splint, ultram, and occupational therapy for perceived wrist tendinitis. To our knowledge, this is the first description of a case of ReA caused by the SARS-CoV2 virus.

Microbes, helminths, and rheumatic diseases

There has been a progressive interest on modifications of the human defense system following insults occurring in the interface between our body and the external environment, as they may provoke or worsen disease states. Studies suggest that billions of germs, which compose the gut microbiota influence one's innate and adaptive immune responses at the intestinal level, but these microorganisms may also impact rheumatic diseases. The microbiota of the skin, respiratory, and urinary tracts may also be relevant in rheumatology. Evidence indicates that changes in the gut microbiome alter the pathogenesis of immune-mediated diseases such as rheumatoid arthritis and ankylosing spondylitis but also of other disorders like atherosclerosis and osteoarthritis. Therapeutic strategies to modify the microbiota, including probiotics and fecal microbiota transplantation, have been received with skepticism, which, in turn, has drawn attention back to previously developed interventions such as antibiotics. Helminths adapted to humans over the evolution process, but their role in disease modulation, particularly immune-mediated diseases, remains to be understood. The present review focuses on data concerning modifications of the immune system induced by interactions with microbes and pluricellular organisms, namely helminths, and their impact on rheumatic diseases. Practical aspects, including specific microbiota-targeted therapies, are also discussed.

An overview of reactive arthritis

Reactive arthritis, also known as Reiter syndrome, is a spondyloarthropathy that typically follows a urogenital or gastrointestinal infection, and is characterized by conjunctivitis, urethritis, and arthritis. The frequency of reactive arthritis in the United States is estimated at 3.5 to 5 patients per 100,000. Physician assistants (PAs) can manage the condition; therefore, they should be familiar with the disease's signs and symptoms, diagnostic criteria, and treatment regimens. Without proper management, reactive arthritis can progress to a chronic destructive arthritis. Prompt recognition of the condition is key to early intervention and a better patient outcome with fewer complications.

Evolving patterns of reactive arthritis

OBJECTIVE

To characterize rheumatologists' perspectives on evolving trends of reactive arthritis (ReA).

METHODS

After ethics approval, 548 members of the Canadian Rheumatology Association were surveyed with 37 questions covering their demographic information, subspecialty, level of experience, practice setting and opinions on prevalence, treatment, and causes of ReA. Results were analyzed with descriptive statistics.

RESULTS

Ninety-seven responded to the survey (18% response rate); 66 fully completed it. Nearly half of respondents believed that the incidence of ReA is declining and causes of ReA may be changing. Physicians reported that most of the ReA cases in their practices were caused by an unknown organism, sexually transmitted, or gastrointestinal infection. Full triad ReA increased the chance of recurrence according to their impressions. Common investigations in ReA included inflammatory markers, HLA-B27, chlamydia and gonorrhea testing, stool cultures, synovial fluid analyses, SI joint imaging. ReA treatment included NSAIDs, intra-articular corticosteroid injections, and DMARDs. Two-thirds said they used TNF alpha inhibitors in chronic ReA occasionally or more frequently.

CONCLUSION

ReA may be decreasing in frequency and severity in Canada. Changes could be due to less food borne illness, cleaner water, or more rapid treatment of sexually transmitted infections. The cause is often unknown in clinical practice.Key Points• Reactive arthritis (ReA) is likely decreasing in prevalence and severity.• Patients with classic trial of arthritis, urethritis, and conjunctivitis are more likely to have recurrent and/or chronic ReA.• The causal organisms are often not detected and seem to be changing over time.

Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department

Septic arthritis is a dangerous medical condition associated with significant morbidity and mortality. However, the differential diagnosis can be broad with conditions that mimic this disease and require different evaluation and treatment. This narrative review presents the emergency medicine evaluation and management, as well as important medical conditions that may mimic this disease. Septic arthritis commonly presents with monoarticular joint pain with erythema, warmth, swelling, and pain on palpation and movement. Fever is present in many patients, though most are low grade. Blood testing and imaging may assist with the diagnosis, but the gold standard is joint aspiration. Management includes intravenous antibiotics and orthopedic surgery consult for operative management vs. serial aspirations. Clinicians should consider mimics, such as abscess, avascular necrosis, cellulitis, crystal-induced arthropathies, Lyme disease, malignancy, osteomyelitis, reactive arthritis, rheumatoid arthritis, and transient synovitis. While monoarticular arthritis can be due to septic arthritis, other medical and surgical conditions present similarly and require different management. It is essential for the emergency clinician to be aware how to diagnose and treat these mimics.

Cross-Sectional Imaging for Inflammatory Arthropathy of the Pelvis

Inflammatory arthropathy predominantly affecting the axial skeleton can cause pain, stiffness, disability, and ankylosis. This article discusses the use of cross-sectional imaging in the domain of inflammatory pelvic and axial arthropathy highlighting the key distinguishing features of common known diseases and their differential diagnoses.

Benefit of adjunct universal rectal screening for Chlamydia genital infections in women attending Canadian sexually transmitted infection clinics

Adding universal rectal screening to urogenital screening should positively impact rectal Chlamydia trachomatis (CT) incidence in affected populations. A dynamic Markov model was used to evaluate costs and outcomes of three rectal CT screening strategies among women attending sexually transmitted infection clinics in Alberta, Canada: universal urogenital-only screening (UG-only), additional selected (exposure-based) rectal screening (UG+SR), and additional universal rectal screening (UG+UR). The model included two mutually exclusive health states: infected and susceptible. Additionally, the model included two rounds of transmission: male sex partners of women infected with rectal-only CT and female sex partners of those men. CT complications impacting patients' quality of life (QALY) were considered. Alberta and Canadian data were used to estimate model inputs. We used a health care perspective, a time period of 10 years, and a discount rate of 3% for analyses. Compared to UG-only screening, the incremental cost effectiveness ratios (ICERs) were CA$34,000 and CA$49,000 per QALY gained for UG+SR and UG+UR screening strategies, respectively. Compared to UG+SR, the ICER was CA$62,000 per QALY gained for the UG+UR strategy. Both adjunct selected and universal rectal screening strategies are cost effective compared to UG-only screening, and UG+UR screening is cost effective when compared to UG+SR screening.

Cross-sectional imaging of adult crystal and inflammatory arthropathies

This article highlights the key aspects and current perspectives of the role of cross-sectional imaging in adult crystal and inflammatory arthropathies in adults, briefly discussing CT, and particularly focusing on MRI and US imaging as it supplements the conventional radiography. The role of conventional and advanced MR imaging techniques and imaging findings in this domain is discussed and illustrated with case examples. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article contains images and data, which were collected from patients as a part of a retrospective IRB from the institutional teaching files and informed consent was waived.

Sequelae of foodborne illness caused by 5 pathogens, Australia, circa 2010

Foodborne gastroenteritis results in a substantial amount of severe and disabling sequelae.

In Australia circa 2010, 4.1 million (90% credible interval [CrI] 2.3–6.4 million) episodes of foodborne gastroenteritis occurred, many of which might have resulted in sequelae. We estimated the number of illnesses, hospitalizations, and deaths from Guillain-Barré syndrome, hemolytic uremic syndrome, irritable bowel syndrome, and reactive arthritis that were associated with contaminated food in Australia. Data from published studies, hospital records, and mortality reports were combined with multipliers to adjust for different transmission routes. We used Monte Carlo simulation to estimate median estimates and 90% CrIs. In Australia, circa 2010, we estimated that 35,840 (90% CrI 25,000–54,000) illnesses, 1,080 (90% CrI 700–1,600) hospitalizations, and 10 (90% CrI 5–14) deaths occurred from foodborne gastroenteritis–associated sequelae. Campylobacter spp. infection was responsible for 80% of incident cases. Reducing the incidence of campylobacteriosis and other foodborne diseases would minimize the health effects of sequelae.

Reactive arthritis

Reactive arthritis (ReA) is an immune-mediated seronegative arthritis that belongs to the group of spondyloarthropathies and develops after a gastrointestinal or genitourinary system infection. The condition is considered to be characterized by a triad of symptoms (conjunctivitis, arthritis and urethritis) although a constellation of other manifestations may also be present. ReA is characterized by psoriasiform dermatological manifestations that may resemble those of pustular psoriasis and, similar to guttate psoriasis, is a post-infectious entity. Also, the articular manifestations of the disorder are similar to those of psoriatic arthritis and both conditions show a correlation with HLA-B27. These facts have led several authors to suggest that there is a connection between ReA and psoriasis, listing ReA among the disorders related to psoriasis. However, the pathogenetic mechanism behind the condition is complex and poorly understood. Bacterial antigenicity, the type of host response (i.e. Th1/Th2 imbalance) and various genetic factors (i.e. HLA-B27 etc.) play an important role in the development of the disorder. It is unknown whether all the aforementioned factors are part of a mechanism that could be similar to, or share basic aspects with known psoriasis pathogenesis mechanisms.

Cross-reactivity of T cells and its role in the immune system

T-cell receptors recognize peptides presented by the major histocompatibility complex (MHC) on the surface of antigen-presenting cells (APC). The ability of the T-cell receptor (TCR) to recognize more than one peptide-MHC structure defines cross-reactivity. Cross-reactivity is a documented phenomenon of the immune system whose importance is still under investigation. There are a number of rational arguments for cross-reactivity. These include the discrepancy between the theoretical high number of pathogen-derived peptides and the lower diversity of the T-cell repertoire, the need for recognition of escape variants, and the intrinsic low affinity of this receptor-ligand pair. However, quantifying the phenomenon has been difficult, and its immunological importance remains unknown. In this review, we examined the cases for and against an important role for cross reactivity. We argue that it may be an essential feature of the immune system from the point of view of biological robustness.

Reactive Arthritis due to Shigella Infection after a Visit to Egypt: A Late Complication of an Intestinal Infection

We describe a case of reactive arthritis following Shigella infection after a trip to Egypt. The diagnostic challenge and treatment of this acute medical condition are discussed.

Reactive Arthritis Secondary to Cauda Equina Injury following Spine Fracture: A Case Report

A 38-year-old man presented with a one-month history of muscle weakness and dysesthesia in the lower extremities, urinary retention, and urinary tract infection after lumbar burst fracture resulted from high fall. During the rehabilitation in our hospital, he had arthritis in both the ankle and knee. However, the patient was treated as gouty arthropathy initially. The arthritis was completely remitted in a few days after the patient was diagnosed as reactive arthritis and started with sulfasalazine therapy and there was no recurrence during 4 months of follow-up. Based on this case, early recognition of reactive arthritis is of major importance to avoid delayed initiation of appropriate treatment in the patients with polyarthritis secondary to neurogenic bladder following cauda equina injury after spine fracture.