The heart in juvenile rheumatoid arthritis

# Overview
Juvenile Idiopathic Arthritis (formerly known as Juvenile Rheumatoid Arthritis) (JIA), as defined by the American Rheumatism Association (ARA), is the presence of arthritis (chronic, seronegative, and peripheral) before age 16 years, of at least 3 months duration, when other causes have been excluded. Chest pain, chest discomfort and dyspnea may found in polyarticular and systemic onset forms.  
Cardiac involvements are usually subclinical with early diastolic dysfunction followed by latent onset of symptoms with increasing systolic dysfunction and heart failure which is a late finding. Abnormal diastolic function of the left ventricle has also been reported in juvenile idiopathic arthritis    
When occurs, cardiac involvement is the second major cause of mortality in Juvenile Idiopathic Arthritis.
Cardiac involvement occurs in about 4.7% of all cases  and includes pericarditis, aortitis, coronary vasculitis, valvulitis (endocarditis), conduction system involvement, pulmonary hypertension and myocarditis.
Cardiac involvements may be seen due to disease progression and applied medical treatment. It has been shown that the cause of abnormal diastolic parameters may be multiple and may be a cumulative effect of several factors such as pericarditis with or without pericardial effusion, hypertension, left ventricular hypertrophy, therapy with cardiotoxic agents such as cyclosporine, gold salts d-penicillamine  chloroquine   and hydroxychloroquine, hypertension due to steroid therapy, secondary amyloidosis and vascular stiffness from vasculitis.

# Classification of Juvenile Idiopathic Arthritis

## 1- Oligoarticular (pauciarticular) onset of Juvenile Idiopathic Arthritis (JIA)
40-60% of all cases
A. More frequently occurs in girls (girls/boys = 5/1)
B. Peak age of onset is at age 2 years.
C. Four or fewer joints are involved during the first 6 months of the disease (often asymmetric involvement).
Oligoarticular onset commonly involves the knees and, less frequently, the ankles and wrists.
The arthritis may be evanescent, rarely destructive, and radiologically insignificant.
D. Approximately 75% of these patients test positive for antinuclear antibody.
E. This mode of onset rarely is associated with systemic signs. A high risk for uveitis exists. 

## 2. Polyarticular onset of juvenile idiopathic arthritis
20-40% of all cases
A. More frequently occurs in girls (girls/boys=3/1).
B. Peak age of onset is at age 3 years.
C. It involves 5 or more joints during the first 6 months of the disease.
Polyarticular onset juvenile idiopathic arthritis commonly involves the small joints of the hand and, less frequently, the larger joints of the knee, ankle, or wrist.
Asymmetric arthritis may be acute or chronic and may be destructive in 15% of patients.
D. Immunoglobulin M form of rheumatoid factor is present in 10% of children with this juvenile idiopathic arthritis subgroup. It is associated with subcutaneous nodules, erosions, and a poor prognosis.
Approximately 40% of these patients test positive for antinuclear antibody.
E. Systemic symptoms, including anorexia, anemia, and growth retardation are moderate. An intermediate risk for uveitis exists. 

## 3. Systemic onset of juvenile idiopathic arthritis
10-20% of all cases.
A. Equal frequency in boys and girls and can appear at any age.
B. Symmetric polyarthritis is present and may be destructive in 25% of patients.
C. Hands, wrists, feet, ankles, elbows, knees, hips, shoulders, cervical spine, and jaw may be involved.
D. Antinuclear antibody is positive in only 10% of the patients.
E. Systemic onset is associated with fever (high in evening and normal in morning), macular rash, leukocytosis, lymphadenopathy, and hepatomegaly. Serositis and cardiac involvement may also occur with pericardial (pericarditis)  and myocardial involvement (myocarditis) 
Pleural pleuritic and  splenic involvement splenomegaly, and abdominal pain less commonly are observed. A low risk for uveitis exists.
Although it is not common; aortic (cusp thickening) and mitral valve involvement (mild mitral insufficiency) may be found in polyarticular formation of juvenile idiopathic arthritis.  Following the valve involvement, an atrial flutter can be a manifestation.

# Diagnosis of Cardiac Involvement

## Electrocardiography
Non specific T wave changes (bi-phasic or negative T vawes) may be observed.  Pericarditis can develop secondary to JIA. When occurs, all characteristics ECG changes of pericarditis can be seen.

## Echocardiography
Pericardial effusion can be recognized quite accurately by echocardiographic examination even in latent stages. In some cases, left ventricular diastolic diameter may be reduced.  

# Treatment
The medical therapy, is designed to reduce pain and the single most useful agent is that of the non-steroidal anti-inflammatory drug. Commonly used varieties include - Aspirin 75 - 90mg/kg/day.
Higher doses are tolerated in the younger. The dose should be given 4 times a day, with meals.
Occasionally, elevation of liver enzymes may develop in some children. Overt manifestation of liver disease are extremely uncommon. A potential association between Aspirin and Reye's syndrome with encephalopathy has been identified often with viral illnesses. These children should be immunized for influenza and possibly also to chicken pox.

# Prognosis
Cardiac functions should be evaluated by annually performed echocardiographic examinations in all patients during follow-up period. The prognosis in pericarditis seems to be good if patients do not develop cardiac tamponade or constrictive pericarditis.