Four different patients with the same condition have undergone conventional radiographic evaluation. What is the most likely diagnosis?
Four different patients with the same condition have undergone
conventional radiographic evaluation. What is the most likely
Vitamin D therapy for rickets in childhood.
Rachitic and osteomalacic syndromes display remarkably similar
histologic and radiological features regardless of etiology, making
a specific diagnosis difficult from radiographs alone. A few of the
rachitic and osteomalacic syndromes may have characteristic
radiological findings that permit a more precise diagnosis.
General radiological features (figures 1 to 4)-Changes of
rickets occur at open growth plates and are best seen in those
areas showing most active growth. The growth plate shows axial and
latitudinal widening. The trabecular bone subjacent to the growth
plate is de-mineralized and disorganized.1,2 Changes of
osteomalacia may be identified in the already mature areas of the
skeleton. The deformities caused by rickets exhibit different
patterns, depending on the age of the child when the disease
develops; such deformities are related to posture and
activity.3,4,15 The diagnosis of the specific disease entity
requires correlation of the radiographs with clinical history and
laboratory data. Infection in the newborn, such as rubella, can
present irregularities of the physis region. Trauma sometimes may
produce widening of growth plate areas, but the changes are not
The diagnosis of osteomalacia is difficult. In addition to
generalized osteopenia, areas of spongy bone may show a decrease in
the total number of trabeculations owing to a loss of secondary
trabeculae. The remaining trabeculae appear prominent and project a
"coarsened" pattern; their margins may reveal an unsharpness
reflecting the inadequately mineralized surface matrix (osteoid
borders or seams). Lucent areas in the cortex indicate irregular
haversian canals, which appear widened due to surface accumulations
Osteoid may be deposited in excessive amounts at various sites,
particularly in the spine and pelvis. Although this osteoid remains
relatively mineral deficient per unit area, the excessive quantity
of osteoid can result in increased radiodensity. This is
particularly true in renal osteodystrophy.
Pseudofractures, or Looser's zones, may precede other
radiographic changes of osteomalacia.21 These linear radiolucencies
are oriented at right angles to the cortex and incompletely span
the diameter of the bone. Pseudofractures commonly are symmetric
and occur in characteristic sites, such as the superior and
inferior pubic rami, ribs, axillary margins of the scapula, inner
margins of the proximal femurs, and posterior margins of the
proximal ulna. Sclerosis often demarcates the margins. New bone on
the periosteal aspects suggests callus formation, and true
fractures can occur through these weakened areas. Pseudofractures
occur at sites of stress having a high bone turnover.
Histologically, pseudofractures consist of unmineralized osteoid
deposited during the repair process.
The general radiological features described previously are
shared (at least in part) by all of the various rachitic and
osteomalacic syndromes. When confronted with these nonspecific
radiological changes, the diagnostic considerations may be
etiologically organized. The following points also may be helpful.
In rachitic patients less than 6 months of age, consider neonatal
rickets, biliary atresia, vitamin D-dependent rickets, and
hypophosphatasia. If there is "resistance" to usual therapeutic
doses of vitamin D (in the absence of chronic glomerular renal
disease), consider a renal tubular disorder, tumor,
hypophosphatasia, or metaphyseal chondrodysplasia,
Schmid-type.Syndromes that may have characteristic radiological
findings in addition to the general features of rickets or
1. Renal osteodystrophy (uremic osteopathy)-Radiological changes
of secondary hyperparathyroidism usually are present and frequently
are prominent. Osteosclerotic foci in trabecular rich bone,
particularly adjacent to the end plates of the vertebral bodies
("rugger-jersey spine"), are characteristic. Vascular calcification
of the Mönckeberg type and, less commonly, large deposits
("tumoral") of amorphus calcification may be identified,
particularly around joints.
2. X-linked hypophosphatemia-In children, rachitic changes at
the growth plates often are only moderate or mild in degree.
Osteopenia may not be prominent; in fact, the bones often are
"strong" in appearance. Bowing of long bones, particularly of the
lower extremities, may occur, but deformity frequently is minimal,
and the condition may be overlooked in childhood. With increasing
age, the trabecular pattern becomes coarsened. By adulthood, a
generalized increase in bone density, especially in the axial
skeleton, is characteristic.16,20
In addition to increased vertebral body density, calcification
in the paravertebral ligaments, annulus fibrosus, and capsules of
apophyseal joints may develop. The changes superficially resemble
those of idiopathic ankylosing spondylitis.16 In the pelvis, sites
of calcification may involve the acetabulum, iliolumbar ligaments,
and sacroiliac joints. The appendicular skeleton shows multiple
sites of new bone formation at various muscle and ligamentous
attachments. Separate small ossicles may develop around various
joints, particularly the carpus.2,16
3. Atypical axial osteomalacia-Radiological abnormalities of
osteomalacia are confined to the lumbar spine, pelvis, and ribs.
The cervical spine may show a dense, coarse trabecular pattern. The
skull is normal. Looser's zones have not been identified.3,6
4. Hypophosphatasia-Radiological changes vary
in severity. Newborns may show advanced demineralization.
Rachitic growth plates show characteristic multiple radiolucent
extensions into the metaphysis. Wormian bones and craniosynostosis
may be present.
5. Metaphyseal chondrodysplasia, Schmid-type-Multiple small bony
projections extend from the metaphysis into the widened growth
plates. Long bones maintain normal density. Spontaneous improvement
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