How to test for rheumatic fever

We all know that rheumatism is a human disease. People with rheumatism will feel pain in all the joints of their body every day, especially when the weather outside is bad, the pain will be more severe. Many people believe that rheumatism and rheumatic fever are the same disease, just with different names. This view is very wrong. Rheumatic fever and rheumatism are not the same disease. So, how do you check for rheumatic fever?

Rheumatic fever is a common, recurrent acute or chronic systemic connective tissue inflammatory disease that primarily affects the heart, joints, central nervous system, skin, and subcutaneous tissue. The main clinical manifestations are carditis and arthritis, which may be accompanied by fever, toxemia, rash, subcutaneous nodules, chorea, etc. It usually occurs 2 to 4 weeks after a streptococcal infection. It is an allergic disease to pharyngeal group A hemolytic streptococcal infection. Arthritis is usually more obvious during acute attacks, but rheumatic carditis can cause death in patients at this stage. After an acute attack, heart damage of varying severity is often left behind.

【Imaging examination】

1. Electrocardiogram

Typical changes in patients with rheumatic carditis are atrioventricular conduction block (PR interval prolongation is more common), atrial and ventricular premature contractions, ST-T changes, atrial fibrillation and pericarditis may also occur occasionally. In the past, it was believed that PR interval prolongation was common, even as high as 70% to 80%, but in recent years it has only been seen in about 1/3 of cases.

2. Echocardiography

Since the 1990s, the application of two-dimensional echocardiography and Doppler echocardiography to the examination of rheumatic fever and rheumatic carditis has made great progress. Not only is there a high positive rate for ultrasound changes in heart valves in patients with obvious clinical symptoms of carditis, but Vasan RS et al. also found that in 2 cases of acute rheumatic fever, although there were no clinical symptoms of carditis (polyarthritis and chorea), there were also changes in mitral valve ultrasound. Small nodules appeared in the anterior leaflet of the mitral valve. After treatment and follow-up examination, the nodular changes disappeared. Therefore, the authors believe that such changes should be a manifestation of ultrasound carditis in acute rheumatic fever. At present, the most diagnostic ultrasound changes are considered to be:

(1) Valvular thickening: It may present as diffuse leaflet thickening or focal nodular thickening. The former may occur in up to 40% of cases, and the latter in up to 22% to 27%. Both are more common in the mitral valve, followed by the aortic valve. The focal nodules are approximately 3 to 5 mm in size and are located in the body and/or cusp of the valve leaflets. This type of nodular thickening is the most characteristic morphological change and is generally believed to be related to the formation of rheumatic vegetations. Its morphology and mobility are different from those of vegetations in infective endocarditis.

(2) Mitral valve prolapse: The incidence rate varies greatly among different reports, ranging from 51% to 100% to as low as 5% to 16%. This difference is believed to be related to the technical proficiency and vigilance of the examiner. Mitral valve prolapse is most common in the anterior leaflet (accounting for 51% to 82%), while isolated posterior leaflet prolapse of the mitral valve (accounting for 7%) and aortic valve (15%) are less common.

(3) Valvular regurgitation: It is the most common valvular change. Mitral regurgitation is much more common than aortic and tricuspid regurgitation. Skilled operators can accurately distinguish between physiological and pathological regurgitation. The accuracy is higher when combined with color Doppler ultrasound. According to statistics, the incidence of mitral regurgitation is as high as 84% ​​to 94%, among which severe regurgitation can reach 25% in recurrent rheumatic fever.

(4) Pericardial effusion: Most cases are small effusions, occurring in 7% of cases of initial rheumatic fever and 29% of cases of recurrent rheumatic fever. It is worth noting that although rheumatic fever may present with the above-mentioned echocardiographic manifestations, in the absence of clinical evidence of carditis, a diagnosis of rheumatic fever or rheumatic carditis should not be made based solely on certain positive changes in echocardiography, so as to avoid confusion with other causes such as primary mitral valve prolapse, various non-rheumatic valvular heart diseases, cardiomyopathy, and pericarditis caused by ultrasound changes.

3. Chest X-ray examination

Clinically, only severe carditis with obvious heart enlargement can be detected during physical examination. Most cases of rheumatic carditis with mild heart enlargement are difficult to detect without a chest X-ray. Sometimes the reduction of the heart shadow after treatment is necessary to confirm the existence of the original carditis heart enlargement.

It can show PR interval prolongation or sinus tachycardia. ST-T changes indicate possible myocarditis. The elevation of ST in the horseback-down direction in conventional leads (except AVR) indicates possible pericarditis.

To prevent rheumatic fever, you need to prevent respiratory infections, and the living environment must be clean and dry. You should participate in more physical activities to improve your physical fitness. Pharyngitis and tonsillitis must be treated promptly because these diseases may cause rheumatic fever. People who have had rheumatic fever before should take precautions against streptococcal infection.