Page 20 - Delaware Medical Journal - June 2016
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The classic blue sclerae of a person with osteogenesis
imperfecta.
Photo courtesy of Wikimedia Commons
– Herbert L. Fred, MD and Hendrik A. van Dijk
authors advocate for serial DEXA scans at least four to six months apart.23,24 Disease severity and bone fragility depends
on the bone mass, size and shape of bone, microarchitecture
of cortical and trabecular bone, trabecular bone volume and thickness, and interplay between the inorganic and organic phases of bone. These properties are not discernable in the clinical context and thus indirect data from DEXA is used to help qualify bone quality. In order to assess material and hierarchical bone structure, a bone biopsy is necessary.25
CLINICAL MANIFESTATIONS
As type I collagen is present in a plethora of locations about
the body, OI can affect multiple systems including the skeleton, eyes, teeth, ears, skin, blood vessels, and heart. The hallmark clinical manifestation of OI is multiple bone fractures and limb deformity. Bone fragility results in fracture. Immobilization of the bone results in osteoporosis, which further diminishes bone strength thus resulting in further susceptibility to fracture and an ongoing cycle. Bones may also be deformed in the absence of the long bones.26
OCULAR
Blue sclera are evident in OI types I and initially in III. This
sclera and reduced tissue thickness.27 It should also be noted that thickened choroid layer and relatively thin scleral tissue.28
DENTAL
Dentinogenesis imperfecta (DI) occurs in both the primary and secondary dentine structures with teeth appearing translucent, bluish, or amber in color. Affected teeth are soft, easily cracked, and cavity prone.29
AUDITORY
the middle ear bones and soft tissues of the ear. Its etiology is
not fully understood but thought to be either from atrophy or fractures of the middle ear bones, abnormalities in cochlear hair progress to sensorineural with time and is typically progressive in nature. Kuurila et al. conducted a nationwide survey of adults with OI demonstrating hearing loss in approximately 60 percent of patients with OI type I and in 42 percent of those with OI
type IV.30 Surveillance should begin in adolescence and proceed at steady intervals into adulthood. A stapedectomy can be successful with progressive hearing loss; however fragility of the affected bones can affect long-term results. Cochlear implantation 31
SPINE
Scoliosis is present in up to 80 percent of patients with OI.32 Decreases in vital capacity have been documented when curves patient population due to fragile ribs. Deformity correction and its effect on vital capacity is unknown.33 Kyphosis, craniocervical junction problems, and spondylolisthesis in the lumbosacral spine are other common problems. Use of bisphosphonates has been found to decrease scoliosis progression rates in OI. A lateral cervical X-ray is recommended by school age in these children for surveillance of craniocervical junction abnormalities such as basilar impression.34
OTHER MANIFESTATIONS
Other manifestations of the disease include thin skin that is prone to subcutaneous hemorrhage, mitral valve prolapse and aortic regurgitation due to valvular disease, wormian bones in the skull, and metabolic abnormalities. Patients can also be affected by ligamentous laxity and joint instability.27
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Del Med J | June 2016 | Vol. 88 | No. 6
