Investigations
1st investigations to order
skeletal survey
Test
A skeletal survey is recommended in most patients when establishing care and to assess the extent of fractures and bone deformities.
A skeletal survey includes radiographs of skull; bilateral upper limbs including wrists and hands; bilateral lower limbs including pelvis and feet; anterior-posterior and lateral views of chest; and anterior-posterior and lateral views of cervical, thoracis, and lumbar spine.
The radiographic features observed will vary according to the type and severity of OI.
Most people with severe forms of OI have evidence of multiple bone deformities and kyphoscoliosis.[57][58][59]
Result
may reveal fractures, bone deformities, or other features consistent with OI; OI type I and OI type IV: may have wormian bones on the skull, vertebral wedging, and thin cortices of long bones; children with OI type III: may have flared metaphyses with popcorn calcification; OI type III: may have evidence of kyphoscoliosis; OI type V: may have hyperplastic callus and calcification of interosseous membranes
genetic testing
Test
Genetic testing is recommended in all individuals in whom the diagnosis is to be established. Genetic testing can detect variants that are categorised by diagnostic laboratories into the following categories: benign, likely benign, variant of uncertain significance, likely pathogenic, and pathogenic. Genetic testing is important for molecular confirmation and for consideration of specific therapies depending on the underlying genetic variant.
Sanger sequencing for COL1A1 and COL1A2, massively parallel sequencing-based gene panel testing for OI or skeletal dysplasia, exome sequencing, and whole genome sequencing are available for diagnostic testing.
Pretest counselling and interpretation of genetic test results are best done by medical geneticists and/or genetic counsellors.
Result
may detect a disease-causing mutation, most commonly (90% of patients) in the COL1A1 or COL1A2 genes
dual-energy x-ray absorptiometry (DXA)
Test
Request this test in all patients as an initial test when establishing care to measure 2-dimensional (i.e., areal) bone mineral content and bone mineral density.[60] This test should also be considered in patients to measure changes in bone mineral density over time and to assess response to treatment.[60]
Note that DXA should not be performed in a child if safe and appropriate positioning cannot be assured.[60]
Result
may demonstrate low areal bone mineral density compared with age-matched peers in children and young adults, and compared with peak bone mass in older adults
Investigations to consider
audiology
Test
It is recommended, based on experience in practice, that:
Baseline audiology evaluation is performed in all patients at diagnosis; the frequency of further audiological evaluations should be based on the severity of hearing loss, with particular consideration given to the impact of hearing loss on quality of life for the patient.
Hearing evaluation is performed in children with OI before they start school and repeated every 3 years; annual evaluation should be carried out if abnormalities in hearing are detected.
Children with issues with speech, recurrent ear infections, or whose parents suspect a hearing loss should have a formal audiological assessment regardless of age.
Adults with reported hearing loss should have annual testing and follow-up appointments similar to the schedule for children.
If hearing loss is identified, regular ENT/audiology follow-up is recommended, with further review if hearing changes.
Adults experiencing tinnitus or symptoms of hearing loss should also have an audiological assessment to determine if hearing loss is conductive or sensorineural.
Result
may show conductive, sensorineural, or mixed hearing loss
spirometry
Test
Consider spirometry examination to evaluate lung function in OI in all patients when establishing care, especially in individuals with severe OI and in individuals who have scoliosis and chest deformities.[45]
In children, the first evaluation of lung function should be performed when the child is old enough to understand the test and again when transitioning to adult care.[45]
Perform periodic evaluations in adults and children with compromised lung functions.[45][63]
Result
may demonstrate reduced forced vital capacity and FEV₁; people with OI type III have reduced lung volumes
echocardiogram
Test
Order in people with symptoms suggestive of cardiovascular disease or physical findings suggestive of valvular disease.
Practices vary as to when and in which subset of individuals this test has to be ordered. Individuals with cardiovascular symptoms including easy fatigability, dyspnoea, palpitations, or abnormal examination findings such as cardiac murmurs should undergo echocardiographic examinations.
Result
may detect valvular regurgitation; rarely, dilatation of aorta has been reported
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