On Call: Your Child Could Have Arthritis

Arthritis is an illness that is often associated with older adults; however, children may also be affected. Although a diagnosis of childhood arthritis (also referred to as juvenile arthritis) can be frightening for the child and the family, most children with arthritis live a full and active life. About one child in every 1,000 develops some type of arthritis, and it can manifest in multiple forms in children. Early diagnosis and treatment by experienced professionals are essential for any child with arthritis in order to help prevent joint damage and disability.

What is arthritis?
According to The Arthritis Foundation, arthritis is a term used for a group of more than 100 medical conditions that collectively affect nearly 46 million adults and 300,000 children in America alone. All of these conditions affect the musculoskeletal system and specifically the joints — where two or more bones meet. Arthritis causes pain, stiffness and inflammation of the joints, and can result in damage to joint cartilage and surrounding structures. This damage can lead to joint weakness, instability and visible deformities. Arthritis can also cause damage to virtually any bodily organ or system, including the heart, lungs, kidneys, blood vessels and skin; however, arthritis-related conditions most commonly affect the muscles and the bones.

Is there more than one type of childhood arthritis?
Several different types of arthritis can affect children. The most common is juvenile rheumatoid arthritis (JRA), also known as juvenile idiopathic arthritis (JIA). JRA may be further described as systemic onset, polyarticular or pauciarticular. All three subtypes begin before the age of 16 and give rise to joint inflammation, but are otherwise quite different.

Systemic onset JRA is the least common type of JRA. Systemic means that all the body systems can be affected. It presents with a recurrent fever that can be 103° F or higher and can last for weeks to months. The fever is often accompanied by a pink rash that comes and goes. Swelling of the joints may not initially be present and may not appear until months or even years after the onset of fevers. Anemia (a low red blood cell count) and elevated white blood cell counts are often present as well. The arthritis may persist after the fevers and rash have resolved. In about half of children with systemic JRA, the illness will resolve within one year.

Polyarticular JRA means that multiple joints are affected, specifically five or more. Usually affected are the small joints of the fingers and hands, but polyarticular JRA can also affect weight-bearing joints (including the knees, hips and ankles) as well as the neck and jaw. Often affected are the same joints on both sides of the body (symmetrical arthritis). Other possible symptoms might include a low grade fever. Children with polyarticular JRA may actually have the adult form of rheumatoid arthritis which has just developed earlier than expected.

Pauciarticular JRA means “few joints” and involves four or fewer joints. Usually, large joints (knees, ankles or elbows) are most often involved. Other joints such as wrists, spine and even small finger or toe joints can also be affected but less commonly. Often a particular joint on one side of the body, such as only one knee, rather than both sides at the same time, are affected.

Pauciarticular JRA can also cause inflammation in the eyes. Children who develop this form of JRA when they are younger than 7 years old have the best chance of having their joint disease subside with time; however, older children with pauciarticular JRA may continue to have arthritis into adulthood.

How is childhood arthritis diagnosed?
Arthritis can be difficult to diagnose in children, because some children may not complain of pain at first, and joint swelling may not be immediately obvious. There is no one blood test that is diagnostic for childhood arthritis, although there are tests that can be helpful. Diagnosis therefore depends on physical findings, medical history and the ruling out of other disorders. Typical symptoms include:
• limping
• joint stiffness following rest
• reluctance to use an arm or leg
• decreased activity level
• persistent fever
• joint swelling

A number of other conditions can present similarly to childhood arthritis, such as infections, cancer or bone disorders. These disorders must be ruled out before a diagnosis of childhood arthritis can be confirmed.

What causes childhood arthritis?
Childhood arthritis targets the lining of the joint, known as the synovial membrane, causing inflammation. When this inflammation persists, damage to the joint may occur. The exact cause of childhood arthritis is unknown, and these conditions are not regarded as hereditary as they rarely affect more than one family member. Dietary, lifestyle and emotional factors do not play a role in the development of JRA.

How is childhood arthritis treated?
Children and teens with the symptoms of childhood arthritis should be evaluated by their primary health-care provider. Often a rheumatologist, a specialist in the care of arthritis, is consulted to establish the diagnosis and to initiate treatment when needed. The overall goal of treatment of childhood arthritis is to control symptoms, prevent joint damage and maintain function. With appropriate treatment, most children with arthritis can expect to lead normal lives.

Kristin M. Rager, M.D., M.PH.