Numerous blood-related disorders, including various
anemias
leukemias
lymphomas and
clotting-deficient diseases (hemophilia) can cause
skeletal alterations
The most notable osseous changes are seen in the
congenital hemolytic anemias (thalassemia , sickle cell
anemia.
Chronic iron deficiency anemia produces minor skeletal
changes, usually isolated to the skull.
Thalassemia is characterized by abnormal hemoglobin
synthesis that produces variable degree of anemia.
Classified according to the severity of the disease:
Thalassemia major,
Thalassemia minor, and
Thalassemia intermedia.
The effects on the skeleton can be severe and manifest
radiographically as signs of increased marrow
hematopoiesis.
Most frequently arthralgia (30%) and low back
pain (25%)
Cardiac failure due to repeated blood
transfusions.
Physical findings include pallor, lethargy,
retarded growth, hepatosplenomegaly ,
mongoloid facies, maxillary overgrowth (rodent
facies), and inhibited sexual development.
Rarely, epidural extramedullary hematopoietic
tissue in the spinal cord can produce spinal
cord compression.
Pathologic Features:
The essential defect is an imbalance in globin chain
production (α- and β-chains), which leads to
ineffective hemopoiesis, hemolysis, and anemia.
In infants and children the entire skeleton is
involved
because of the presence of red marrow.
With increasing age there may be regression of
peripheral skeletal changes because the red
marrow is normally replaced by fatty marrow.
In contrast, the pelvis, spine, and skull may show
progression of changes with age.
General features:
Coarsened trabecular
pattern(honeycomb)
Cortical thinning
Expanded bone
calibre
Osteoporosis
Vascular channel
enlargement
Widened medullary
cavity
Special features:
Erlenmeyerflask
deformity
Hair on end
appearance of skull
Paraspinal
extramedullary
haematopoiesis
Growth Disturbances:
There is a lack of remodeling within long bones,
resulting in undertubulation, especially at the
metadiaphyseal junction.
This produces an Erlenmeyer flask-type deformity.
Premature fusion of a portion of a growth plate may
result in Shortening and deformity, particularly in
the proximal humerus and distal femur.
Skull.
In the calvaria, there is a distinct lack of changes below
the inferior occipital protuberance owing to the lack of
marrow in this area.
The frontal bones reveal the earliest and most severe
changes.
Three patterns of involvement may be visible:
granular osteoporosis,
widened diploe, and
vertical radiating spicules of new bone (hair-on-end
appearance) with loss of definition of the outer table.
Circumscribed lytic lesions of the calvaria up to 5 cm
are occasionally seen.
The vascular impressions from the middle meningeal
In the facial bones, the effects of erythroid
hyperplasia may be severe, a feature rarely
seen in sickle cell anemia.
The major abnormalities are lack of
pneumatization of the frontal, maxillary,
sphenoid, and mastoid air cells but not the
ethmoids, which remain aerated.
The orbits may be displaced laterally, and the
upper incisors may be displaced forward,
producing malocclusion (rodent facies).
Spine:
osteopenia, coarse vertical trabeculae, thin cortical
outlines, and involvement of both the body and
neural arch of each segment. also seen in the
sacrum and pelvis.
Extramedullary hematopoiesis affecting the spinal
cord or nerve roots may exit but is rare.
MRI and CT examination are essential to assess
these lesions.
On MRI, the mass appears heterogenous on both
T1- and T2-weighted images with enhancement on
administration of paramagnetic agents.
Chest.
Cardiomegaly is a consistent finding.
Posterior mediastinal extramedullary hemopoietic
masses will be evident as bilateral opaque
paraspinal lobulated masses below the
diaphragm.
liver and abdominal lymph nodes may be
radiopaque owing to hemosiderin deposits.
The ribs are widened and osteopenic with a
coarsened trabecular pattern.
Characteristically, there is a symmetric, bulbous
enlargement of the posterior ribs.
Sickle cell disease is a chronic, congenital, and
hereditary hemolytic anemia.
It was first described in 1910 by Herrick.
It is characterized pathologically by an abnormal
molecular structure of hemoglobin that, under low
oxygen tension, will distort the red blood cell into
an
elongated, curved, sickle configuration.
The end result is increased hemolysis, vascular
occlusion, and tissue anoxia.
The osseous changes are primarily related to
infarction, avascular necrosis, marrow hyperplasia,
and retarded growth.
Clinical Features
All individuals who possess the sickle cell hemoglobin
(Hb) do not necessarily have symptoms or
radiographic changes.
Usually, only those that are homozygous (Hb SS) have
symptoms.
The onset of clinical signs and symptoms in
homozygous patients is usually after 6 months of age,
owing to the progressive decrease in levels of fetal
hemoglobin (Hb F).
Weakness and pallor are usual but non-specific.
Episodic abdominal crises, jaundice, acute bone pain,
and dactylitis.
A common symptom in infancy is the so-called
hand-foot syndrome.
This consists of painful swellings of the hands and feet
and is the result of either infarction or Salmonella
infection.
predisposition to develop Salmonella osteomyelitis,
which at times will be bilateral and symmetric The
incidence of femoral and humeral head necrosis is
equal, but the incidence of postprosthesis failure is
as much as 50%.)
Occasionally, widespread generalized bone
marrow necrosis is evident in patients with sickle
cell disease.
Initial splenic enlargement, usually up to
approximately
10 years of age, later, with progressive infarction and
fibrosis, the spleen may completely atrophy, resulting
in
autosplenectomy.
Cardiomegaly is a common complication.
Gallstones may be found in up to 65% of patients,
owing to hyperbilirubinemia from increased
hemolysis.
Mesenteric vascular thromboses result in acute, severe
abdominal pain, the so-called sickle cell crisis.
Renal failure from papillary necrosis also occurs.
SPINE:
In the developing spine, vascular compromise and regional
ischemia result in a unique vertebral body endplate configuration
(fish vertebrae, step-down sign, H vertebra, Reynolds’
phenomenon).
The central portion of the endplate receives a direct blood supply
from branches of the nutrient artery.
At the periphery of the endplates there is a diffuse network of
anastomotic perforating vessels.
This pattern of vascular distribution and circulatory dynamics
results in ischemia of the central endplate zone when the nutrient
artery becomes obstructed, such as in a sickling crisis.
The peripheral vessels, allow collateral circulation to develop more
easily if they become obstructed.
SICKLE CELL ANEMIA: SPINAL CHANGES. A. Normal. Normal circulatory
dynamics in a developing vertebral body. B. After Thrombosis. Following
thrombosis of the central nutrient vessels, central growth is inhibited, producing
the characteristic H vertebra. C. Early Changes. Note that initially, the depression
of the endplates is smooth, concave, and shallow. D. Later Changes. Observe that
later the configuration becomes sharp
and more characteristic
Skeletal manifestations
generalized osteopenia,
coarsened trabecular pattern,
large vascular channels,
widened medullary cavity,
cortical thinning, and a loss of the diaphyseal
constriction in the small tubular bones.
Skull: the osseous changes are limited to the
area above the internal occipital protuberance
because of the absence of marrow below this
point.
Skull changes consist of a widened diploic
space, granular texture and, in severe cases, a
hair-on-end trabecular pattern.
In the adult a generalized sclerotic pattern may
appear in the entire skeleton, except in the
spine, due to chronic endosteal appositional
new bone formation.
Splenic infarcts, appearing as punctate or
amorphous calcific configurations, are seen in
up to 30% of patients with sickle cell anemia.
Infarction:
The earliest radiographic sign, especially in the tubular
bones of the hands and feet, is initial soft tissue
swelling, followed in about 2 weeks by diaphyseal and
linear periostitis.
Gadolinium-enhanced MRI is unreliable in
distinguishing between osteomyelitis and bone
infarction.
The best method for differentiation is the combined use
of technetium and gallium scintigraphy, by which
both show focal uptake in the presence of infection in
contrast to infarctions, which show uptake of
technetium but normal to low uptake of gallium.
MRI shows acute infarction as reduced signal on T1-
and increased signal on T2-weighted studies.
Serpiginous, medullary infarcts are sometimes
seen.
Infarction of an epiphysis, especially of the
femoral and humeral heads, is identical to the
idiopathic or post-traumatic forms of ischemic
necrosis in these locations.
Alterations in bone growth result in cupped
metaphyses and shortened bone length.
Protrusio acetabuli may be evident in up to 5%
of males and 12% of females.
SICKLE CELL ANEMIA: MARROW CONVERSION. A. T1-Weighted MRI,
Coronal Knee. B.
T2-Weighted MRI, Coronal Knee. Note that the low signal intensity seen in the
distal femur abutting the metaphysis is abnormal reconversion of red marrow from
yellow marrow. COMMENT: This 27-year-old sickle cell patient was not a smoker. This
marrow conversion was associated with the hemolytic abnormality of sickle cell
anemia.
Manifestations of marrow hyperplasia:
Cortical thinning
Large vascular channels
Diffuse decrease in bone density
Loss of diaphyseal constriction
Sparse and coarsened trabecular pattern
Widened medullary cavity
Osteomyelitis:
Causative organism is Salmonella paratyphi
Bilateral
Symmetrical
Diaphyseal
Prominent, moth-eaten pattern of destruction and
periosteal response.
Prominent involucrum
Femur, and tibia.
Long Bones:
coarsening of the trabecular pattern
patchy medullary sclerosis
bone within a bone appearance of the cortex
laminated or solid periosteal new bone
growth abnormalities
epiphyseal ischemic necrosis
It is the blood coagulation disorders
characterized by a deficiency of specific
clotting factors.
1)Classic hemophilia (hemophilia A)
2)Christmas disease (hemophilia B)
Both are sex linked, recessive, and inherited.
Female is the carrier
Manifests clinically only in the male.
Clinical features:
Mild – bleeding tendencies
Severe- spontaneous bleeding or bleeding from
minor injuries
Initial - bleeding episodes may resolve
completely with no sequelae.
Repeated hemarthroses - precipitate synovial
proliferation (pannus) and synovial hemosiderin
deposition
Articular adhesions and progressive
Fibrosis of the sub synovium, capsule, and
periarticular tissues
Marginal erosions and degenerative changes .
Subarticular bone osteoporosis, cysts,
and epiphyseal overgrowth may be evident.
Intraosseous and subperiosteal hemorrhages
result in localized bone resorption,
expansion, and periosteal new bone
formation.
Soft Tissue Swelling.
increased soft tissue density owing to hemosiderin
may be evident.
MRI is useful in depicting synovial hypertrophy,
inflammation, fluid accumulation, and loss of
articular cartilage.
Osteoporosis.
Subchondral Cysts.
Beneath the articular cortex, well-demarcated,
localized regions of radiolucency represent either
escaped synovial fluid or localized hemorrhages.
Expansile Bone Lesions (Pseudo-Tumors):
Hemorrhage within bone may result in expansile, geographic
lesions simulating a neoplasm (hemophilic pseudotumor).
The occurrence of pseudo-tumors is rare, being estimated in only
1-2% of patients.
Variable, ranging from a small, benign-appearing lesion to a large,
aggressive
destruction.
The bones most commonly involved are, in order of frequency, the
femur, pelvis, tibia, and hand.
Pseudo-tumors can also occur in soft tissues, producing a cyst-like
lesion, which on T1-weighted and T2-weighted MRI studies is of
low to heterogeneous signal intensity.
Epiphyseal Abnormalities.
In the growing skeleton, chronic hyperemia of
the epiphyseal cartilage can produce
accelerated growth and maturation of
epiphyses.
The epiphyses appear ballooned
and enlarged in relation to the adjacent
diaphysis, similar to the appearance of juvenile
rheumatoid arthritis.
HEMOPHILIA: PSEUDO-TUMORS. A. Ilium. B. Femur. C. Calcaneus. Observe
the tumor-like expansions of the ilium, femur, and calcaneus that are the result of
repeated intraosseous hemorrhage. COMMENT: Hemophiliac pseudo-tumors are
most common in the ilium but can be found anywhere in the skeleton. The
radiographic appearance of an expansile, trabeculated lesion often makes the
exclusion of other tumors, such as plasmacytoma, renal, or thyroid metastases and
even giant cell tumors, difficult. When located adjacent to a joint,arthritic changes
may provide the key differential clue to the diagnosis.
Joint disorganization: Chronic changes, such as
complete loss of joint space, considerable
articular fragmentation, sclerosis, osteophytes,
and bony misalignment, may become apparent
in long-standing hemophilia patients.
The similarity to neurotrophic joint disease is
striking.
the knee is the most common site of hemophilic
arthropathy.
In general, intra-articular hemorrhage distal to
the elbow and ankle is rare.
Distal femur:The femoral condyles are often
grossly enlarged, severely osteoporotic, and exhibit
an irregular, flattened contour of their articular
weight-bearing surfaces.
Widening of the intercondylar notch is thought to
be related to repeated hemorrhage at the
cruciate ligament attachments.
Proximal tibia: The tibial plateau may be flattened,
usually with an irregular articular contour.
The epiphysis is enlarged and osteoporotic, with a
thin cortex and accentuated vertical trabeculae.
The proximal fibula exhibits similar abnormalities.
Patella: The inferior pole is sharply attenuated and
squared, in contrast to the normal tapered apex.
Repeated hemarthrosis during growth periods inhibits
the secondary growth center, resulting in this squared
configuration.
The same appearance of the patella is visible in juvenile
rheumatoid arthritis.
HEMOPHILIA. A. AP
Knee. Note that the
overgrowth of the
medial condyle has
altered the joint
orientation. Note the
irregular flattened
articular contour and
widened intercondylar
notch. B. Lateral
Knee.
Observe the increase
in the periarticular
densitycharacterizing
hemosiderin deposits
from repeated
hemarthrosis.
HEMOPHILIA.
A. AP Knee.
Observe the
altered joint
orientation that is
caused by
overgrowth of the
medial condyle,
irregular articular
surfaces, widened
intercondylar
notch, and
osteoporosis. B.
Lateral Knee.
Note
that the inferior
pole of the patella
is squared and
attenuated
(arrow).
HEMOPHILIA:
POLYARTICULAR
INVOLVEMENT. A and B.
Knee. C. Ankle. D.
Shoulder. E.
Elbow. F. Wrist. Note that
the characteristic features
of hemophilic arthropathy
are visible in multiple
joints in
severe, long-standing cases.
Observe the destruction of
the articular surfaces,
regional osteopenia, and
secondary
degenerative changes
(subchondral sclerosis and
cyst formation often are
congruent with the patient’s
age).
HEMOPHILIA. AP
Ankle. Note the
prominent
osteoporosis and
alteration of the ankle
mortise joint
plane (tibio-talar slant
deformity).