Acute Rheumatic Fever
Acute Rheumatic Fever (ARF) is the classic well recognized form of streptococcal post infectious arthritis. The manifestations of ARF are thought to be due to an auto-immune reaction which follows Group A streptococcus infection with multisystem involvement of heart, joints, brain and skin. ARF is important due to cardiac and neurolgic complications and sequelae. The prevalence of ARF around the world varies considerably. Some countries (such as in India) are observing declining numbers of presentations of ARF which is also reflected in reducing numbers of patients requiring valvular heart surgery in the major cardiac centres. In other countries, such as New Zealand, high rates are still seen in Maori and Pacific children and young adults.
The diagnosis of ARF is established largely on clinical grounds using the "Jones criteria" (Major and Minor criteria). These have been revised in 2015 to reflect variation in epidemiology and subclinical carditis detected by Echocardiography [ECHO] - see Further Reading.
- Major criteria include carditis (including subclinical carditis detected by ECHO), polyarthritis, chorea, erythema marginatum and subcutaneous nodules and minor criteria include arthralgia (i.e., when arthritis is not present), fever, elevated acute phase reactants (ESR>50mm/hr and CRP>30mg/L), and an electrocardiogram showing a prolonged PR interval (age adjusted and in the absence of ECHO or clinical carditis). There needs to be evidence of a preceding Group A Streptococcal infection (GAS), by streptococcal serology plus major and/or minor manifestations to indicate definite, probable, possible or recurrent ARF.
- The presence of two Major manifestations or of one Major and two Minor manifestations is indicative of a high probability of ARF. In high risk settings, the revised Jones criteria include a new murmur or subclinical echocardiographic evidence of rheumatic carditis and aseptic monoarthritis as Major criteria.
ARF typically begins after about 3-4 weeks following a streptococcal sore throat and arthritis is often an early manifestation of the disease. Arthritis in rheumatic fever is seen in about 30-50% children and more often in children with older age at presentation. Rheumatic arthritis is an asymmetric, migratory / fleeting polyarthritis with predominant involvement of large joints of lower limbs and migrates to the upper limb. ARF can present however with a monoarthritis. Classically, the joints are red, tender, swollen and the child cannot tolerate any movement about the joint. If untreated, then symptoms subside in about a week without residual damage followed by affection of other joint. The child responds dramatically to NSAIDS such as naproxen, ibuprofen or aspirin. Corticosteroids may be needed according to clinical scenario and presence of active carditis. The child should receive a full 10 day course of penicillin followed by prophylaxis, ongoing until they are aged 21 years or 10 years after the first episode, whichever is longer. In New Zealand, Maori and Pacific patients are at high risk of ARF and should be closely monitored for rheumatic fever in the absence of carditis and may require prophylaxis for a period of 5 years.
Clinical Features of Acute Rheumatic Fever:
- Musculoskeletal: Polyarthritis or monoarthritis. Arthralgia (often migratory) and legs first. Poor co-ordination.
- Systemic features - sore throat before onset of joint pains, fever, pallor, weight loss, anorexia, malaise and fatigue.
- Skin - erythema marginatum, nodules, nose bleeds.
- Neurological involvement - chorea (video demonstration), headaches, irritability.
- Gastrointestinal - abdominal pain, vomiting.
- Cardiac - chest pain (valvulitis, carditis), heart failure, subclinical carditis (ECG or ECHO).
- Renal - microscopic haematuria, pyuria.
ARF arthritis in contrast to JIA:
- In ARF, the arthritis is fleeting (i.e., seldom affects the same joint for more than a week) and leaves no residual deformity. In JIA the arthritis is additive and persistent.
- In ARF the large joints are involved while small joints are not. JIA can affect both large and small joints. A monoarthritis in ARF is also described.
- The history, serology or culture should document a positive streptococcal sore throat, as well as elevated streptococcal serology.
- Constitutional features namely fever are an important manifestation in ARF. In JIA constitutional features are usually absent - the exception being systemic onset JIA (SOJIA).
- In ARF there may be extra-articular features (e.g., carditis, chorea, erythema marginatum). With the exception of SOJIA, extra-articular features are absent in JIA
- ARF never involves the cervical spine or axial skeleton.
- ARF responds remarkably (even to single dose !) of NSAID, aspirin or corticosteroid.
Further Reading - New Zealand Guidelines for Acute Rheumatic Fever
Revision of the Jones Criteria for the Diagnosis of Acute Rheumatic Fever in the Era of Doppler Echocardiography A Scientific Statement From the American Heart Association Endorsed by the World Heart Federation. Gewitz MH et al