Rheumatic fever screening

Overview
Screening of rheumatic fever and carditis is important as many cases of RHD are subclinical. Echocardiography among inhabitants of high risk regions is recommended. If any abnormality is detected on echocardiography, further cardiac evaluation is done followed by prophylactic treatment.

Screening
Rheumatic fever is a delayed sequel to upper respiratory track infection by Group A streptococcus, which can lead to immunologic damage of heart and heart valves. Rheumatic heart disease usually results from the repeated damage by recurrent episodes of acute rheumatic fever. Cardiac auscultation becomes unremarkable in one-third of children after a first episode of carditis. But even these children may progress to significant valvular disease, as confirmed by echocardiography. Therefore early detection of subclinical disease process helps in early treatment and there by improves prognosis by preventing recurrence.

Screening of rheumatic heart disease involves:
 * 1) Eliciting history of rheumatic fever
 * 2) Cardiac auscultation for murmurs
 * 3) Echocardiography

Evidence of valve abnormalities with a history of rheumatic fever is suggestive of rheumatic heart disease (RHD). Previously, individuals from high risk communities with abnormal auscultatory findings were subjected for further evaluation with echocardiography. But studies relying on echocardiography in the diagnosis of RHD have demonstrated that rates of subclinical carditis is up to 10 times higher than that diagnosed by clinical examination. Therefore current screening approach involves screening of all individuals in high risk communities with portable echocardiography.

WHO recommends that antibiotic prophylaxis should be administered to patients with echocardiographically detected significant subclinical RHD i.e. "very mild regurgitant jet, more than 1.0 cm, localized immediately above or below the valve, throughout systole at the mitral valve or diastole at the aortic valve". This criteria was found to be inadequate as it did not include valves with morphological features of RHD without pathological regurgitation. A study compared the use of WHO criteria with the use of combined criteria which included morphological abnormalities. Up to three quaters of cases with subclinical RHD were missed with WHO criteria.