Acute Myocarditis in Children: Clinical Features, Possibilities of Using New Diagnostic and Treatment Methods

The dissertation is dedicated to the study of acute myocarditis in children, its clinical features, and the development and testing of new diagnostic and treatment methods. The research was conducted at the Perm State Medical Academy and the Children's City Clinical Hospital No. 3 of Perm. The study identified the role of acute respiratory viral infections in the formation of myocardial damage in children, proposed an informative diagnostic complex based on the determination of cardiac-specific enzymes and troponin T in whole blood, and developed a new treatment scheme for residual manifestations of transferred myocarditis using enterosorbents, a vitamin-antioxidant complex, and immunostimulants.

The problem of acute myocarditis is currently attributable to its widespread prevalence, particularly in childhood. The reason for this is the steady increase in viral infections and the sensitization of the pediatric population [76].

One of the main causes of acute myocarditis today are acute respiratory viral infections (ARVI), which remain the most prevalent and globally significant diseases in children. Despite relative epidemiological well-being over the past 8–10 years, they still account for 70–90% of infectious pathology and cause enormous socio-economic damage [11]. Every influenza epidemic is accompanied by an increase in the number of cases of acute myocarditis, which determines the relevance of studying this problem. The most significant significance in clinical practice is acquired by complicated forms of ARVI, which determine a severe disease course and an unfavorable prognosis (B.P. Bogomolov, A.V. Devyatkin, 2000).

The growing interest of pediatricians and cardiologists in Russia and abroad in the problem of acute myocarditis is also associated with contradictory opinions on questions of terminology, pathogenesis, diagnosis, and treatment of this disease. The terms "unspecific" and "non-rheumatic" myocarditis are still being debated, which appear to be inappropriate due to their lack of specificity, vagueness, and limited usefulness for the practicing physician [61]. Clear unified diagnostic criteria have not been established. This is partly related to the features of disease development, in which, alongside acute onset and a typical clinical picture, a paucisymptomatic onset with sudden heart failure occurring months or years later is often encountered. Vegetovascular dystonia manifested as asthenia, rhythm disturbances, and often following ARVI or bacterial infection may also be mistaken for myocarditis. All of this explains the hypo- and hyperdiagnosis of myocarditis [6,7,105].

The aim of the study is to investigate the current features of clinical-laboratory indicators and to determine the most specific and informative methods for early diagnosis of acute myocarditis in children in the context of ARVI, along with the development of a new treatment scheme for its residual manifestations.

Research objectives

1. To investigate the current clinical-laboratory features of acute myocarditis in children in the context of ARVI.

2. To study the features of the state of humoral immunity in acute myocarditis in the context of ARVI.

3. To determine the level of cardiac-specific enzymes in serum blood and the possibility of using qualitative determination of troponin T in whole blood for early diagnosis of acute myocarditis in children in the context of ARVI.

4. To develop a new diagnostic method using special coefficients of the ratio of cardiac-specific enzymes.

5. To study, in a comparative aspect, the diagnostic and prognostic value of various laboratory indicators.

6. To evaluate the efficacy of specialized treatment in children with residual manifestations after transferred acute myocarditis.

Scientific novelty

The features of the course of acute myocarditis in children have been studied and diagnostic criteria have been proposed.

An informative diagnostic complex for the early detection of acute myocarditis in the context of ARVI in the absence of typical clinical manifestations of the disease has been identified and determined, consisting of the determination of creatine kinase-MB (cardiac fraction), total creatine kinase, total lactate dehydrogenase, α-hydroxybutyrate dehydrogenase in serum blood, and qualitative determination of troponin T in whole blood.

For the first time, the calculation of coefficients of the ratio of cardiac-specific enzymes has been proposed for the diagnosis of acute myocarditis, which allows for a more accurate and timely diagnosis in 80% of children.

For the first time, an effective treatment using an enterosorbent, a vitamin-antioxidant complex with microelements, and an immunostimulator has been proposed, which contributes to the resolution of residual manifestations of transferred acute myocarditis and the normalization of humoral immunity in 70% of patients.

Practical significance of the work

The investigation of creatine kinase-MB (cardiac fraction), total creatine kinase, total lactate dehydrogenase, α-hydroxybutyrate dehydrogenase in serum blood, and qualitative determination of troponin T in whole blood as laboratory diagnostics has been proposed, which allows for the early diagnosis of acute myocarditis in the context of ARVI in a greater percentage of children. Coefficients of the ratio of cardiac-specific enzymes have been proposed for the diagnosis and prognosis of the course of acute myocarditis. An effective therapy has been recommended for children who have transferred acute myocarditis.

Implementation of the work

The results of the dissertation research have been introduced into the practical work of the Children's City Clinical Hospital (DGPU) No. 3 of Perm, and are used in the educational process of the Department of Pediatrics of the Advanced Training Course for Physicians with a course of pediatric infectious diseases and the Department of Pediatric Diseases of the therapeutic and dental faculties of the State Educational Institution of Higher Professional Education "Perm State Medical Academy of Roszdrav". The results of the research may be used in pediatric hospitals, polyclinics, and rehabilitation centers.

Defense of the dissertation material

The materials of the research were presented at the international scientific-practical conference "Health and Education. Medical, Social, and Economic Problems" (Paris, 2004), at the IX Congress of Russian Pediatricians "Actual Problems of Pediatrics" (Moscow, 2004), at the international scientific-practical conference "Perinatal Neurology" (Kazan, 2004), at the IX All-Russian Scientific-Practical Conference of Young Scientists "Young Scientists in Medicine" (Kazan, 2004), at the scientific session of the interregional inter-university conference (Perm — Izhevsk, 2004), at the All-Russian Scientific-Practical Conference with international participation "Efferent, Immunocorrecting, and Intensive Therapy in Clinical Practice" (Izhevsk, 2004), as well as published in the "Perm Medical Journal" (No. 4, 2004).

Based on the results of the research, 7 printed works have been published (4 articles, one of which is in the central press, and 3 abstracts).

Methodological recommendations titled "Diagnosis of Acute Myocarditis in Children" (Perm, 2004) have been published.

A Russian Federation invention patent No. 2245554 dated 27.01.2005 (Moscow) titled "Method for Diagnosing Acute Myocarditis" has been obtained.

3 certificates for intellectual products have been obtained at the Federal State Unitary Enterprise "All-Russian Scientific-Technical Information Center" (Moscow): certificate No. 73200300241 dated 02.12.2003 "Diagnosis of Acute Myocarditis in Children Using the Calculated Coefficient of Cardiac-Specific Enzymes: Total Creatine Kinase and Creatine Kinase-MB (Cardiac Fraction)"; certificate No. 73200300242 dated 02.12.2003 "Diagnosis of Acute Myocarditis in Children Using the Calculated Coefficient of Cardiac-Specific Enzymes: Total Lactate Dehydrogenase and Creatine Kinase-MB (Cardiac Fraction)"; certificate No. 73200300243 dated 02.12.2003 "Diagnosis of Acute Myocarditis in Children Using the Calculated Coefficient of Cardiac-Specific Enzymes: Total Lactate Dehydrogenase and α-Hydroxybutyrate Dehydrogenase.

Structure of the dissertation