Diagnosing ARF can be challenging as there is no single diagnostic laboratory test available, with diagnosis based on clinical decisions plus supporting laboratory evidence. The Jones criteria for the diagnosis of ARF were introduced in 1944 and have been periodically modified and rearticulated in the Australian Guidelines for prevention, diagnosis and management of Acute Rheumatic Fever and Rheumatic Heart Disease (2012). The Jones criteria specify the manifestations, counting rules and criteria which determine a diagnosis of ARF. Specific manifestations occurring in ARF that are reliably collected by jurisdictions and are related to an increased risk of RHD are presented in this report. These manifestations are: carditis, Sydenham chorea, and prolonged P-R interval (Box 2). People with carditis and/or a prolonged P-R interval are more likely to sustain heart damage (and hence to develop RHD) than those without.
Box 2: ARF manifestations associated with an increased risk of RHD
Carditis: inflammation of the heart muscle and heart tissue, including the membrane which lines the chambers of the heart and forms the surface of the heart valves (endocardium). It causes a rapid heart rate, fatigue, shortness of breath and exercise intolerance, and in ARF is associated primarily with the mitral valve. Carditis occurs in about 40%–50% of people with ARF.
Prolonged P-R interval: detected through electrocardiography (ECG). Refers to when the time between specific electrical features of a heartbeat is longer than expected. Often the person has no symptoms.
Sydenham Chorea: involuntary movements of the hands, feet, tongue and face, which stop during sleep. This is more common in females; globally it affects up to 36% of cases, and is associated with carditis.
A complete list of major and minor manifestations of ARF is provided in Australian guidelines for notification of ARF.
Source: RHD Australia 2020.
Global data suggest that between 30%–82% of people with their first episode of ARF experience carditis and around 20% of children with ARF have a prolonged P-R interval (Caldas et al. 2008; Karacan 2010; RHD Australia 2020). Chorea reportedly occurs in 5%–36% of people with ARF worldwide, primarily in children and females (WHO 2014). Australian data suggest that between a quarter and one-half of Aboriginal and Torres Strait Islander ARF patients with chorea go on to develop RHD due to an increased associated risk of concurrent carditis (RHD Australia 2020).
In 2015–2019, of the 2,128 ARF notifications among Indigenous Australians, 34% had at least one manifestation of carditis, prolonged P-R interval, or Sydenham chorea. The inclusion of Sydenham chorea in this value may cause an overestimation of the number of cases at a higher risk of progressing to RHD, as it is most often associated with the development of carditis rather than directly to RHD.
Diagnostic categories
Box 3: ARF diagnostic categories
There is no one specific diagnostic test for ARF. Instead, it is diagnosed based on medical history and a pattern of clinical features (‘manifestations’) as follows:
Definite ARF, first episode: 2 major or 1 major and 2 minor manifestations plus evidence of preceding Strep A infection. Long–term preventive penicillin should commence.
Definite ARF, recurrent episode: 2 major or 1 major and 1 minor manifestations or 3 minor manifestations plus evidence of preceding Strep A infection. Long–term preventive penicillin should commence.
Probable ARF: clinical presentation falls short by either one major or one minor manifestation, or the absence of streptococcal serology results, but where ARF is the most likely diagnosis. Long-term preventive penicillin should commence.
Possible ARF: Strong clinical suspicion of ARF, but insufficient signs and symptoms for diagnosis of definite or probable ARF. Preventive penicillin should commence, with a clinical review scheduled for 12 months later, to determine if it should continue long-term.
Note that these definitions applied when the data in this report were collected, and have been updated in the most recent clinical guidelines.
Source: RHD Australia 2012.
In 2015–2019, of all 2,128 ARF notifications among Indigenous Australians:
- 1,772 notifications were definite or probable diagnoses (Box 3)
- 318 were possible diagnoses
- 38 did not have this information recorded.
Note that probable and possible diagnoses are only notifiable in some jurisdictions (Table 1), and so may not necessarily be recorded on registers.
Between 2015 and 2019, the rate of definite or probable ARF notifications increased from 67 to 81 per 100,000 population (285 to 367 notifications). The rate of possible ARF episodes also increased during the same period. The proportion of definite or probable ARF notifications decreased, from 87% in 2015 to 79% in 2019—with a corresponding increase in the proportion of possible diagnoses. This may relate to ‘possible’ ARF diagnoses becoming notifiable in South Australia and Western Australia during this period.