Fever is defined by specialists as a protective and adaptive reaction. Thus, the body responds to the effects of pathogenic (harmful, pathogenic) factors. These include bacteria, viruses, immune complexes and others). The most important manifestation of fever is the restructuring of thermoregulation. As a result, a higher norm of the level of heat content and a higher body temperature is maintained.
Acute rheumatic fever is a systemic disease. This pathology is inflammatory in nature and affects the connective tissue. Acute rheumatic fever, as a rule, develops in people with a genetic predisposition to this after two or four weeks after they have had streptococcal infection (usually angina). The causative agent in this case is the beta-hemolytic microorganism of group A.
Acute rheumatic fever and chronic rheumatic heart disease are combined under the common term rheumatism.
The influence of the genetic predisposition is clearly demonstrated by the high prevalence of pathology in individual families.
Acute rheumatic fever develops under the influence of several mechanisms. Damage to the elements of the myocardium of a toxic nature may have a certain value. In this case, cardiotropic enzymes of streptococcus (beta-hemolytic) A-group have a pathogenic effect. However, a special role is given to the development of a humoral and cellular immune response.
Rheumatism includes four stages of the pathological process involving connective tissue:
1. Mucoid swelling.
2. Fibrinoid changes are a stage of disorganization in the connective tissue of an irreversible nature.
3. Proliferative reactions. As a result of proliferation (neoplasm) of cells and tissue necrosis , Ashoff-Talalayev granulomas are formed. They consist of large basophilic elementary units of irregular shape. Granulomas also include plasma and lymphoid cells, as well as giant multinucleated cells with eosinophilic cytoplasm of myocytic origin. They are located, as a rule, in the endocardium, myocardium, perivascular cardiac connective tissue.
4. Sclerosis.
The nature of the course of the pathology has a close relationship with the age of the patients. In more than half of cases, acute rheumatic fever in children develops after two to three weeks after a sore throat. At the same time, there is a sudden increase in body temperature, the development of migrating (asymmetric) pains in large joints (usually knee joints), as well as signs of carditis (shortness of breath, pericardial pain in the chest area, palpitations, etc.). Other patients have a monosymptomatic course. In this case, signs of carditis or arthritis prevail.
For adolescents and patients at a young age, a gradual onset is characteristic (after relief of the clinical manifestations of angina) - with arthralgia of large joints, low-grade fever, or moderate symptoms of carditis. Relapse (re-development) of rheumatic fever in almost all cases is associated with a previous infection (streptococcal) and is manifested mainly by the development of carditis.
As a rule, the cause of the fever becomes clear amid the onset of symptoms of a particular infection. In many cases, the condition stabilizes on its own. However, acute fever of unclear etiology suggests increased attention of the doctor, including repeated examination of the patient (especially the child). A regular examination will allow you to timely diagnose the symptoms of a serious illness or the development of a threatening condition.