Acute Rheumatic Fever

Acute Rheumatic Fever - ARF is an auto-immune reaction which follows Group A streptococcus infection with multisystem involvement of heart, joints, brain and skin. 

Arthritis tends to occur early and is often migratory (sometimes called 'flitting' as it moves from joint to joint), tends to affect large joints (often legs first). 

Rheumatic heart disease is a serious complication with high morbidity and mortality. Treatment of ARF is with prolonged antibiotics and management of organ involvement such as heart failure from carditis or valvular disease. Neurological complications include chorea (erratic limb movements from extrapyramidal involvement). 

Features suggestive of Acute Rheumatic Fever include:

• Joint pain, swelling and warmth primarily affecting large joints, particularly knees, ankles, wrists and elbows.
• Usually initially one joint is affected and then migratory (moves to affect other joints) and additive (becomes many joints affected).
• Joint pain is prominent, occurs at rest and is increased by movement.
• Associated manifestations may include fever, arthralgia (if not arthritis), Carditis (signs ranging from tachycardia at rest, prolonged PR interval, new murmur suggesting mitral and/or aortic insufficiency to acute heart failure), Erythema marginatum (non-pruritic, macular, serpiginous rash with erythematous border especially on trunk and upper, inner aspects of limbs), Sydenham chorea (usually symmetric persistent, involuntary and purposeless movements of extremities) or Subcutaneous nodules (extensor surfaces, but rare).
• Evidence of streptococcal infection (streptococcal serology or throat swab positive for group A streptococcus)

Acute Rheumatic Fever (ARF) is the classic well recognized form of streptococcal post infectious arthritis.

ARF is important due to cardiac and neurologic complications and sequelae. Many paediatric rheumatology centres (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.

The diagnosis of ARF is established largely on clinical grounds. The "Jones criteria" have been revised. Major criteria include carditis, polyarthritis, chorea, erythema marginatum and subcutaneous nodules and minor criteria include arthralgia (i.e. when arthritis is not present), fever, elevated acute phase reactants and an electrocardiogram showing a prolonged PR interval. If supported by evidence of a preceding Group A Streptococcal infection (GAS), then the presence of two major manifestations or of one major and two minor manifestations is indicative of a high probability of ARF.

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. 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 aspirin. Rheumatic arthritis is treated with aspirin in doses of 90-120 mg/kg/day in four divided doses for 12 weeks. Corticosteroids may be needed according to clinical scenario and presence of active carditis. The child should receive a full course of penicillin followed by prophylaxis.

Clinical Features of Acute Rheumatic Fever:

Musculoskeletal

• Polyarthritis
• Arthralgia (often migratory) and legs first 
• Poor co-ordination 

Non-Musculoskeletal

• 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, headaches, Irritability
• Abdominal pain, vomiting
• Chest pain (valvulitis, carditis), heart failure
• 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.
• The history, serology or culture should document a positive streptococcal sore throat.
• 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 aspirin or corticosteroid.

Post-streptococcal reactive arthritis (PSRA). There are increasing reports of patients who develop arthritis following streptococcal infections and do not fulfil Jones criteria for ARF. They are seen to have distinct clinical, laboratory, immunologic and genetic features and these patients are labelled to have post-streptococcal reactive arthritis (PSRA). Peculiarly some of them do develop carditis leading to the belief that this entity is merely at one end of the spectrum of ARF. The important differences between ARF and PSRA are highlighted below.