Osteoporosis can cause compression fractures in the spine.
Cerebral palsy is movement disorder caused by brain damage that occurs in the womb, during birth or in early infancy. The muscle impairment associated with cerebral palsy has adverse effects on bone growth and strength, beginning in childhood and persisting throughout life. People living with cerebral palsy have a high risk for osteoporosis, a condition marked by bone fragility and an increased risk for fractures.
Bone mass is acquired through childhood and into early adulthood, bur children with cerebral palsy have significantly lower bone density than their peers. This lack of bone strength can lead to painful fractures that can occur with minimal trauma. Most children with cerebral palsy have decreased bone density in the tibia, the large lower leg bone. Children more severely affected by cerebral palsy also often have decreased bone density in the spine and thigh bone.
Bone density is typically lower in children and adults living with cerebral palsy, particularly if they are unable to walk. Those who are able to walk still have an increased risk for osteoporosis due to general muscle weakness and decreased overall movement. Bone growth depends on forces placed on the bone by the muscles and mechanical loading of the bone -- placing weight through the bone in a standing position. These factors are reduced people living with cerebral palsy and at least partially account for the bone weakness that commonly occurs with this condition.
The bones of people with cerebral palsy are often shorter and less bulky than those of their healthy peers, increasing the risk for fractures. Females with cerebral palsy are particularly at risk for osteoporosis and fractures as they age due to decreasing levels of estrogen, a hormone that helps bones stay strong.
Osteoporosis may first be suspected in people with cerebral palsy after a bone fracture, particularly from a low-impact trauma. Bone mineral density is usually tested using specialized x-rays -- dual-energy x-ray absorptiometry -- that measure how many grams of minerals are present in a particular segment of bone.
Prevention and Treatment
Few treatments are available to help prevent osteoporosis among people living with cerebral palsy. Standing more often -- which accomplishes mechanical loading of the bones -- may increase bone strength. Adaptive equipment, called standers or standing frames, can be used to help a person stand up. Standing on a moving or vibrating platform activates muscles in the legs and may help stimulate bone growth.
Medications called bisphosphonates may be prescribed for adults with cerebral palsy to prevent or treat osteoporosis. Examples include alendronate (Fosamax), risedronate (Actonel) and zoledronic acid (Reclast). These drugs slow bone breakdown to help maintain bone strength.