Overview of diagnosis of acute rheumatic fever
Diagnosis of acute rheumatic fever is complex; detailed guidance is available from RHDAustralia1. An overview is included here.
In the absence of a specific diagnostic test, the diagnosis of acute rheumatic fever is based on a set of clinical manifestations considered in the context of whether or not an individual is at high risk of developing acute rheumatic fever (see Major and minor manifestations for the diagnosis of acute rheumatic fever). Risk of acute rheumatic fever is based on ethnic, geographic and socioeconomic considerations (see Determining risk of acute rheumatic fever to inform diagnosis).
A lower clinical threshold for diagnosis is applied for patients at high risk of acute rheumatic fever. The aim of this approach is to avoid missing the diagnosis of acute rheumatic fever in high-risk patients while minimising overdiagnosis in those at lower risk. Identifying high-risk patients with acute rheumatic fever is particularly important so secondary prophylaxis against Streptococcus pyogenes (group A streptococcus) infection can be started to prevent recurrent acute rheumatic fever, and the development or progression of rheumatic heart disease.
A diagnosis of acute rheumatic fever can be classified as definite, probable or possible, depending on the significance and number of clinical manifestations present (see Classifying the diagnosis of acute rheumatic fever) and whether there is evidence of preceding S. pyogenes infection; this classification has implications for long-term management and follow-up, including the duration of secondary prophylaxis against S. pyogenes infection.
In patients with suspected acute rheumatic fever, still consider alternative diagnoses, even if the diagnostic criteria for acute rheumatic fever are met. For example:
- Exclude septic arthritis in patients presenting with monoarthritis.
- Investigate patients with fever and murmur for infective endocarditis.
- Consider the possibility of disseminated gonococcal infection.