ARF symptoms and diagnosis

Diagnosing acute rheumatic fever (ARF) can be challenging, as there is no single diagnostic laboratory test available, with diagnosis based on clinical decisions plus supporting laboratory evidence. Diagnosis relies on identification of major and minor manifestations of the illness, as outlined by Australian Guidelines (RHD Australia 2012).

Manifestations

Manifestations are important to assist in the diagnosis of ARF. Data on specific manifestations that can occur with ARF are reported to the National Collection by registers. This report presents information on those manifestations for which reliable data could be provided by all jurisdictions: carditis, chorea, and prolonged P-R interval. 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.

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, RHD Australia 2020, Karacan 2010). 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 Indigenous ARF patients with chorea go on to develop RHD (RHD Australia 2020).

Refer to Box 2 for more information on manifestations.

In 2014–2018, of the 1,963 ARF diagnoses among Aboriginal and Torres Strait Islander people:

  • carditis was present in 19%
  • prolonged P-R interval was present in 23%
  • Sydenham’s chorea was present in 8%
  • 1 in 3 (36%) had either carditis, prolonged P-R interval, or both.

ARF symptoms at diagnosis among Indigenous Australians. A vertical bar chart showing the proportion of cases with selected ARF symptoms at diagnosis among Indigenous Australians by state and territory, grouped by manifestation – carditis, prolonged P-R interval and Sydenham’s chorea – in 2014-2018. Carditis and prolonged P-R interval were more commonly present compared to Sydenham’s chorea.

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Box 2: Examples of ARF manifestations

Arthritis: a swollen and hot joint with pain on movement. Can involve one joint (monoarthritis) or several joints (polyarthritis), which may be affected at the same time or one after the other. The large joints such as the knees and ankles are most commonly affected. Arthritis is the most common presenting symptom of ARF, and the pain is generally greater than would be expected based on the clinical signs.

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 diagnosis of ARF.

Source: RHD Australia 2020.

Diagnostic categories

In 2014–2018, of all 1,963 ARF diagnoses among Indigenous Australians:

  • 1,670 diagnoses were definite or probable diagnoses
  • 251 were possible diagnoses.

Refer to Box 3 for more information on ARF diagnostic categories.

Between 2014 and 2018, the rate of definite or probable ARF diagnoses increased from 65 to 80 per 100,000 population (273 to 366 diagnoses). This was in line with overall increases in ARF, regardless of diagnostic category. However, the proportion of definite or probable ARF diagnoses decreased, from 91% to 80% from 2014 to 2018—with a corresponding increase in the proportion of possible diagnoses.

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 (RHD Australia 2020).

Source: RHD Australia 2012.

References

Caldas Á, Terreri M, Moises V, Silva C, Len C, Carvalho A, Hilario M. 2008. What is the True Frequency of Carditis in Acute Rheumatic Fever? A Prospective Clinical and Doppler Blind Study of 56 Children with up to 60 Months of Follow-Up Evaluation. Paediatric Cardiology (29):1048–1053.

Karacan M, Isıkay S, Olgun H, Ceviz N. 2010. Asymptomatic rhythm and conduction abnormalities in children with acute rheumatic fever: 24-hour electrocardiography study. Cardiology in the Young 20(6):620-30.

Matsui T, Yamaguchi K, Ikebe T, Aiga S and Kusakawa I. 2019. Prolonged PR Interval and Erythema Marginatum in a Child with Acute Rheumatic Fever. The Journal of Pediatrics.

RHD Australia, (ARF/RHD writing group) 2020. The 2020 Australian guideline for the prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease (3rd edn). Northern Territory: RHD Australia, Menzies School of Health Research.

RHD Australia, (ARF/RHD writing group), National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand, 2012. The Australian guideline for the prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease (2nd edn). Northern Territory: RHD Australia, Menzies School of Health Research.

WHO (World Health Organization). 2014. Rheumatic Fever and Rheumatic Heart Disease. WHO technical report series (923). Geneva: WHO.