Physician Specialist Glossary

Osteoporosis is a disease that causes a decrease in bone mass, putting you at risk for broken bone. Most cases of osteoporosis show up in adult postmenopausal women. However, it is possible for children and teens to develop juvenile osteoporosis. This most often occurs in children between the ages of 8 and 14. It sometimes develops in younger children during growth spurts.

Juvenile osteoporosis in children is hard to define. Bone density scans are the most accurate way to detect reduction in bone mass early on. But this type of scanning can't be used the way it is with adults to make a clear diagnosis in children. Instead, doctors usually diagnose juvenile osteoporosis when there is evidence of a fragile skeleton. This might show up when a bone breaks without trauma, such as from a serious fall, and a bone mineral density score is below -2.0.

Types of Juvenile Osteoporosis

There are two kinds of juvenile osteoporosis: secondary and idiopathic.

Secondary osteoporosis refers to osteoporosis that develops as a result of another medical condition. This is by far the most common kind of juvenile osteoporosis. Some of the diseases that can lead to osteoporosis in children include:

• Juvenile arthritis
• Diabetes
• Cystic fibrosis
• Leukemia
• Osteogenesis imperfecta ("brittle bone disease")
• Homocystinuria (a genetic metabolic disorder)
• Hyperthyroidism
• Hyperparathyroidism
• Cushing's syndrome
• Malabsorption syndromes
• Anorexia nervosa
• Kidney disease

Sometimes juvenile osteoporosis is a direct result of disease itself. With rheumatoid arthritis, for example, children may have lower than expected bone mass, especially near arthritic joints. Certain drugs can also lead to juvenile osteoporosis. These can include chemotherapy for cancer, anticonvulsants for seizures, or steroids for arthritis. If your child has one of these conditions, talk to his or her doctor about carefully monitoring bone density.

Idiopathic osteoporosis means that there is no known cause of the disease. This type of juvenile osteoporosis is much less common. As of 1997, only about 150 cases had been reported in the medical literature. Boys have the condition more often than girls. It develops most often just before the onset of puberty. Then the children's bone density increases during puberty. Although most of the bone density may return during puberty, children with juvenile osteoporosis usually have lower peak bone mass as adults.

No matter what the cause, juvenile osteoporosis is a very serious condition. You build about 90% of your bone mass by the time you're 18 to 20. Losing bone mass during prime bone-building years can put a child at serious risk for long-term complications such as fractures.

Juvenile rheumatoid arthritis (JRA), also called juvenile idiopathic arthritis (JIA) and juvenile chronic arthritis (JCA), is the most common childhood arthritis. This disease may affect up to 294,000 children in North America alone.

What Is Juvenile Rheumatoid Arthritis?

Juvenile rheumatoid arthritis consists of joint inflammation and stiffness for more than six weeks in a child aged 16 or younger. Inflammation causes redness, swelling, warmth, and soreness in the joints. Still, many children with JRA do not complain of joint pain.

Any joint can be affected with JRA. The ongoing inflammation may limit the mobility of affected joints.