Rheumatic fever and post-streptococcal arthritis

Revising the value of Antistreptolysin O titre in childhood and its interpretation in the diagnostic approach of rheumatic diseases

The burden of group A streptococcus (GAS) infection and its rheumatic sequelae remains dramatically high, especially in low-income countries. Recently, an increased number of Acute Rheumatic Fever (ARF) cases was documented in many regions of Italy. The diagnosis of rheumatic sequelae relies on clinical signs and on the evaluation of the Antistreptolysin O titre (ASO), whose variations are globally reported. To re-examine the standard reference value of ASO titre, by measuring either its upper limit of normal (ULN) in a population of healthy children (HC) or comparing these values with streptococcal antibodies registered in a cohort of patients affected by the rheumatic sequelae of GAS infection. We performed a multicenter retrospective study. We enrolled 125 HC, aged 2-17 years, and a total of 181 patients affected by ARF, acute streptococcal pharyngitis, post-streptococcal arthritis, Henoch-Schönlein purpura and erythema nodosum, divided into four groups. The levels of ASO and anti-deoxyribonuclease B (anti-DNase B) titres were analyzed and compared among the various groups. Moreover, the 80th percentile value was calculated and established as the ULN for ASO titre in HC group. The ULN for ASO titre in overall HC group was 515 IU/mL, resulting in higher than used in the routine investigation. The ASO titre was significantly higher in patients with rheumatic sequelae compared with HC group, with a peak in the age between 5 and 15 years.    Conclusion: Our study established a new ULN normal value of streptococcal serology in a childhood and adolescent population of Italy, suggesting the need to extend this revaluation to the critical areas, in order to avoid underestimating ARF diagnosis. The correct interpretation of ASO and anti-DNase B values in the context of rheumatic diseases has been discussed. What is Known: • The global burden of disease caused by group A streptococcus is not known and remains an important cause of morbidity and mortality. Acute rheumatic fever continues to be a serious worldwide public health problem and a recent recurrence of group A streptococcus infection cases is observed. • The streptococcal sequelae requires evidence of preceding streptococcal infection, commonly elevated streptococcal antibody titre, but the upper limit for these titres varies considerably based on age group, region, and origin. What is New: • This study provides population-specific values for streptococcal antibody titres in Italy. • Interpret the results of group A streptococcal antibody tests within the clinical context.

Characterization of rheumatic heart disease from electrocardiogram recordings

Objective. Rheumatic Heart Disease (RHD) is one of the highly prevalent heart diseases in developing countries that can affect the pericardium, myocardium, or endocardium. Rheumatic endocarditis is a common RHD variant that gradually deteriorates the normal function of the heart valves. RHD can be diagnosed using standard echocardiography or listened to as a heart murmur using a stethoscope. The electrocardiogram (ECG), on the other hand, is critical in the study and identification of heart rhythms and abnormalities. The effectiveness of ECG to identify distinguishing signs of rheumatic heart problems, however, has not been adequately examined. This study addressed the possible use of ECG recordings for the characterization of problems of the heart in RHD patients.Approach. To this end, an extensive ECG dataset was collected from patients suffering from RHD (PwRHD), and healthy control subjects (HC). Bandpass filtering was used at the preprocessing stage. Each data was then standardized by removing its mean and dividing by its standard deviation. Delineation of the onsets and offsets of waves was performed using KIT-IBT open ECG MATLAB toolbox. PR interval, QRS duration, RR intervals, QT intervals, and QTc intervals were computed for each heartbeat. The median values of the temporal parameters were used to eliminate possible outliers due to missed ECG waves. The data were clustered in different age groups and sex. Another categorization was done based on the time duration since the first RHD diagnosis.Main results. In 47.2% of the cases, a PR elongation was observed, and in 26.4% of the cases, the QRS duration was elongated. QTc was elongated in 44.3% of the cases. It was also observed that 62.2% of the cases had bradycardia.Significance. The end product of this research can lead to new medical devices and services that can screen RHD based on ECG which could somehow assist in the detection and diagnosis of the disease in low-resource settings and alleviate the burden of the disease.

Update on Post-Streptococcal Reactive Arthritis: Narrative Review of a Forgotten Disease

PURPOSE OF THE REVIEW

This topical review attempts to build the concepts of PSRA as an independent entity and discuss prevalent diagnostic criteria. It utilizes a search strategy to collate all clinical features of PSRA reported from across the world and also discusses laboratory and treatment options in brief.

RECENT FINDINGS

There are several immune-mediated diseases described after acute streptococcal infections. Post-streptococcal reactive arthritis (PSRA) is a sterile, self-limiting arthritis that occur as an immune sequelae to streptococcal infection. Though PSRA resembles the arthritis of acute rheumatic fever superficially, it is a separate entity in its own right. It is different from classical reactive arthritis too. It was being recognized worldwide and more frequently in the recent past, possibly due to heightened awareness amongst clinicians. However, research on this enigmatic immune phenomenon is limited. Most acceptable hypotheses suggest molecular mimicry sensitizing the immune system towards synovial peptides such as keratin, vimentin and laminin, leading to arthritis in a genetically predisposed individual. There is still much to be learnt from this unique disease about the vagaries of the immune system.

[The significance of antistreptolysin O characteristics for the determination of indications for tonsillectomy in the children]

The objective of the present work was to evaluate the diagnostic significance of the measurement of the antistreptolysin O (ASLO) titers in the children presenting with chronic tonsillitis for determining the indications for tonsillectomy. The study included 54 patients at the age varying from 4 to 17 years who had undergone bilateral tonsillectomy for the treatment of chronic tonsillitis. The diagnosis was confirmed by the results of the histological study of the removed amygdalae. Prior to surgery, all the patients had been subjected to the bacteriological investigation of the smears taken from the surface of the palatal tonsils. The titers of antistreptolysin O in the serum were determined with the use of the kinetic nephelometric technique before, 6 and 12 months after the surgical intervention. The results of the measurements were treated using the Statzilla software package (version 3.2, R Foundation for Statistical Computing, Vienna, Austria). Streptococcus pyogenes (group A) was identified only in 7 (13%) patients. The initially enhanced content of ASLO ranging from 273 to 1880 IU/ml was documented in 42 (77.7%) of the 54 patients. Twelve patients had the ASLO titers within the normal limits (from 13 to 124 IU/ml). The removal of palatal tonsils resulted in a significant decrease of the ASLO titers in the patients who had presented with the initially enhanced content of antistreptolysin O (p < 0.05); nevertheless, their ASLO titers remained higher than the normal values in 69% and 82% of the patients examined within 6 and 12 months after the surgical intervention, respectively. The patients who had exhibited the high levels of antistreptolysin O during the preoperative period did not experience normalization of this parameter after surgery. It is concluded, taking into account the absence of correlation between the enhancement of serum antistreptolysin O titers and the presence of group A beta-chemolytic Streptococci (BCSA), that the result of the measurement of ASLO titers can not be considered as a valid indication for tonsillectomy in the children.

[How is Sydenham's chorea treated in Rio de Janeiro?]

BACKGROUND

Sydenham's chorea is the most common cause of acquired childhood chorea in Brazil. Thus it is relevant to know how physicians treat those patients.

OBJECTIVE

To describe the practice patterns of Sydenham's chorea among pediatricians.

METHOD

A descriptive study was undertaken using a questionnaire among specialists and emergency pediatricians who work in public hospitals of Rio de Janeiro district.

RESULTS

74% of the physicians informed not to use any severity scale; 81% informed to always prescribe benzathine penicillin; 64% informed to begin pharmacological treatment for all patients; and Haloperidol was the most remembered drug among all physicians.

CONCLUSION

Physicians do not routinely use severity scales in follow-up of choreic patients; there is a tendency of irregular prescription of benzathine penicillin by younger doctors; and 28.3% prescribe only haloperidol.

Pathology of inflammatory native valvular heart disease

Rheumatic disease is an important cause of inflammatory native heart valve disease. However, with increased understanding of the pathoetiology of valve disease and valve injury, it is evident that inflammation may play a role in many valve disorders. We are only beginning to understand these complex processes. With increasing knowledge that many of these processes are active, there may be opportunity for intervention or even prevention.