Juvenile rheumatoid arthritis (JRA) is basically an autoimmune disease. This means that the body’s immune system fails to recognize the body’s own tissues and thinking them foreign or infections or tumors, attacks them.
The cause of JRA is not known. There may be certain genes that may predispose a person to develop JRA in their childhood.
There are three different types of JRA that include:-
- In this type of JRA four or fewer joints are involved and this type accounts for nearly half of all the cases of JRA.
- The patients are usually very young girls aged between 1 and 4 years or are older boys. Both young boys and older girls however may also be affected.
- Usually the knees, ankles or elbows are affected. It often affects a particular joint on just one side of the body
- These children with the condition may develop associated eye disorders including chronic uveitis that affects the anterior chamber of the eyes. This may cause permanent damage to the eye. Uveitis eventually affects up to 20% of children with this condition.
- There may be minimal symptoms with pauciarticular JRA.
Polyarticular onset JRA
- In this type of JRA five or more joints are involved.
- This occurs in nearly 40% of all children with JRA. This condition affects girls more often than boys.
- There is a later onset and chances of a positive result with Rheumatoid factor.
- In this type of JRA typically small joints such as those in the hands and feet as well as weight-bearing joints such as the knees, ankles and feet are affected. Polyarticular JRA often affects the same joint on both sides of a child’s body.
- Apart from joint involvement there are symptoms like irritability, fatigue, anemia, loss of appetite, growth retardation etc.
Systemic onset JRA
- This is a less frequently seen type of JRA seen in around 10% of the JRA population. It is also known as Still’s disease.
- This condition affects both boys and girls similarly and the peak age of detection is usually between one and six years.
- Initially there are symptoms like once daily or twice-daily fever spikes along with a characteristic pale pink rash commonly seen over the trunk and upper arms and thighs. The fever is usually low in the morning and must be present for a minimum of two weeks for diagnosis.
- The children with the condition may have other systemic symptoms affecting other vital organs including:-
- hepatosplenomegaly (enlargement of the liver and spleen)
- lymphadenopathy (enlargement of the lymph nodes)
- pericarditis (accumulation of fluid within the coverings around the heart)
Another group of inflammatory arthritis that may affect children include spondyloarthropathies. These types of arthritis cause similar clinical symptoms. They are classified according to their symptoms. Types of spondyloarthropathies include:-
This leads to inflammation in larger joints of the lower limbs such as hip joints. The pain is located at the point where tendons and ligaments attach to bones. If the condition spreads to the back, the disease is called juvenile ankylosing spondylitis
These have an infective origin and are seen after an infection of the gastrointestinal tract by Shigella, salmonella or Yersinia-associated diarrhea or a respiratory infection. There may be associated fever, rash and inflammation of the eyes
This condition is associated with the skin disorder psoriasis. There may be a scaly rash behind the ears or on the eyelids, elbows, knees or navel in addition to arthritis. This type of arthritis can affect large or small joints.