Sudden Thigh Swelling in a 6-Week Old Infant
Radiology Cases in Pediatric Emergency Medicine
Volume 2, Case 17
Rodney B. Boychuk, MD
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
This 6-week old male was well until two days prior to
presenting to the ED when his left thigh suddenly
became swollen. His mother, who cares for him both
day and night, states that there is no history of trauma.
She denies any rough play, shaking, or any chance of
trauma, such as rolling off the bed or the couch.
Further questioning reveals that sometimes the infant's
father, paternal grandmother, paternal grandfather, and
paternal aunt, all living in the same household, also
care for the infant. There is also a one-year old female
sibling a 2-year old female cousin, and great
grandparents all living in the same house, who
sometimes play with the infant. Both mother and father
are 18 years of age. This infant was born full-term with
a birth weight of 3.4 kg. Immunizations are up to date
(hepatitis B vaccine X2). No allergies are noted. He is
on no medications and has had no illnesses,
hospitalizations or surgery since birth. His mother
states that the thigh swelling is somewhat less that the
day prior, but the child still will not move his leg, which
is her greatest concern.
Exam VS T37.4 (rectal), HR 160, R30, weight 4.2
kg. Quiet, well developed, well nourished, active and
alert. His anterior fontanelle is flat and soft. Pupils are
equal and reactive to light. The red reflex is present,
and the fundi (exam with difficulty) appear clear. There
are no bruises noted anywhere on the head or
elsewhere on the body. Tympanic membranes appear
normal. Chest reveals no bony deformity, with good
aeration bilaterally. Heart regular with a grade 2/6
vibratory systolic murmur present at the left sternal
border. The abdomen is soft. Active bowel sounds are
noted. No masses are evident, and no bruising is
noted. Normal male external genitalia are noted.
Except for an abnormal left lower extremity, other
extremities appear normal. The left thigh is very
swollen, with the foot being somewhat externally
rotated. Pedal pulses are good, and capillary refill time
is less than 2 seconds. The thigh is very firm and
warm, but not discolored. No spontaneous movement
is present in the left leg, and the leg is tender to touch
(baby cries when the leg is touched).
Radiographs of the left lower extremity are done.
This radiograph shows an obvious oblique fracture
of the proximal shaft of the left femur, with superior and
anterior displacement of the distal fracture fragment.
There is also a hairline fracture component involving the
middle and distal shaft of the left femur. On the lateral
view (left image), this can be seen as a faint oblique
linear lucency over the distal 1/3 of the femur. On the
AP view (right image), this can be seen as a faint linear
lucency extending from the obvious fracture above,
downward and through the mid femur and continuing
obliquely into the distal 1/3 of the femur. The left knee,
tibia and fibula are unremarkable.
Because of the strong suspicion of intentional
trauma (child abuse), the infant is hospitalized and a
skeletal survey is done. The following positive
radiographs are shown:
View Right UE and LE.
The upper extremity radiograph (left image) reveals
an old fracture of the right proximal radius. There is
some periosteal elevation surrounding the fracture
indicating that the fracture did not occur recently. The
lower extremity radiograph (right image) reveals a
healing fracture of the right tibia with periosteal reaction
along the entire shaft of the right tibia. The fracture line
itself is not easily identified.
View Torso radiographs.
The vertebral body of T12 appears much flatter than
the other thoracic vertebra. T10 and L2 may also be
slightly flattened. Because of the difficulty in diagnosing
these as vertebral body compression fractures, a bone
scan is done for correlation.
View Bone Scan.
This bone scan confirms the long bone fractures.
There is an obvious hot spot in the right radius. The
entire left femur and right tibia are hot. There is also a
hot spot over the occiput suggesting a fracture or a
subperiosteal contusion. There are no obvious
vertebral hot spots suggesting that the flattened
vertebral bodies may not represent fractures. This
study is a "planar" bone scan. More conventional bone
scanners utilizing the SPECT (single photon emission
computed tomography) method are more accurate in
identifying such fractures.
The remainder of the skeletal survey was negative.
The skull radiographs were not able to identify any
fractures. A CT scan of the head was negative for
fracture or brain injury. An ophthalmology examination
found no retinal hemorrhages. The infant remained
medically stable. He was feeding well and gaining
weight. After being fitted with an orthopedic Pavlik
harness, child protective services placed the infant in a
foster home. The young children living in the household
were also removed and placed in foster homes.
Physical abuse is any non-accidental injury to a child
caused by a parent or caretaker. This might be
shaking, beating, burning, scalding, poisoning, or other
trauma. Physicians must maintain a high index of
suspicion, particularly when the history of an injury is
inconsistent with physical findings. Excessive delay in
seeking medical treatment, trauma inconsistent with
age-related injury, unexplained or multiple trauma, or
sibling-inflicted injuries must raise suspicion of abuse.
Physical abuse most often is a pattern of repeated
behavior, with bruises and welts being the most
frequent evidence of such. Typical sites for inflicted
bruises include the neck (choke marks), upper lip and
frenulum (forceful feeding), ear lobe (pinch or slap
marks), cheeks (slap marks), buttocks and lower back
(paddling), the genital area and inner thighs. Human
bite marks leave concentric bruises that contain
individual teeth marks. If the point-to-point distance
between the canines (eye teeth) is greater than 3.0 cm,
the injury was inflicted by someone with permanent
teeth. Dating bruises is also important, and multiple
colors suggest multiple times of injury. An initial bruise
would be swollen, tender, and bright red-to-blue.
Between days 1-5, a combination of colors can be
seen, being red, blue, or purple. The bruise will change
to a green color between days 5-7, a yellow color
between days 7-10, and a brown color after 10 days.
Child abuse is a common cause of burns. Scald or
immersion burns are the most common, bearing the
characteristic glove or stocking pattern that is observed
on physical examination. With a water temperature of
145 degrees or greater, an almost instantaneous
full-thickness burn will occur. With a water temperature
of 130 degrees, it takes approximately 30-45 seconds.
Contact burns from a hot metal object or cigarette are
another type of burn seen with child abuse.
Head injuries are the most common cause of death
from child abuse. In 1946, Dr. John Caffey reported six
children who had chronic subdural hematomas in
association with multiple fractures of the peripheral
skeleton. In 1974, Caffey described a syndrome of
severe central nervous system injury caused by "the
shaken infant syndrome." Shaking produces a whiplash
injury to the brain tissue, causing injury to the axons
and bridging vessels that leads to subdural hematoma
and/or subarachnoid hemorrhage. Retinal
hemorrhages and changes in sensorium are
characteristic findings resulting in a clinical picture of
coma, apnea, seizures, sepsis or other non-specific
neurological signs (see Case 1 in Volume 1).
Abdominal injury is the second most common cause
of death among battered children. Ruptures of the
spleen, liver or bowel caused by a punch or kick can
result in the above with no visible bruises or marks on
the abdomen in over half the cases. Rupture of the
bladder may also occur.
A child who presents with multiple fractures at
multiple sites and in various stages of healing should be
considered abused until proven otherwise.
Epiphyseal-metaphyseal injury is virtually diagnostic of
physical abuse in an infant, since an infant cannot
generate enough force to fracture a bone at the
epiphysis. Fractures secondary to abuse are more
commonly seen in children less than 3 years of age.
Conversely, less than 10% of children over 5 years of
age who are abused sustain fractures. In general, a
complete skeletal survey should be done on all children
less than 2 years of age who are possible abuse
A spiral or oblique fracture of long bones is
produced by a twisting mechanism. Whether accidental
or non-accidental, a large amount of force is required to
produce a fracture of the femur. A direct blow causing
a transverse fracture can also be seen with major
violence. Young children who are not ambulatory
cannot produce enough force to fracture their femur. A
history of getting his/her leg "caught in the crib" should
be viewed with suspicion.
Rib fractures are highly suggestive of abuse in
infants and young children. Squeezing usually
produces fractures of the posterolateral aspects of the
ribs. Shaking or choking a child has been shown to
produce fractures anteriorly in the first or second ribs.
Rib fractures secondary to trauma that is NOT child
abuse tend to occur in the middle or anterior part of the
Spinal fractures are infrequently seen in child abuse
cases. The mechanism is usually one of compression,
as a child is forcibly seated into a chair or onto a
A skeletal survey is often diagnostic of the child
abuse syndrome. The survey should include, at a
minimum, two views of the skull, lateral view of the
thoracolumbar spine, and anterior-posterior views of
both upper extremities, hands, pelvis, and both lower
extremities, including the feet. There are several
radiologic signs suggestive of abuse. These include
healing fractures, multiple fractures, fractures of
unusual locations, and metaphyseal fractures. The
typical radiographic appearances have been described
as: a) "corner fractures", b) "bucket handle" fractures,
and c) subperiosteal hematoma with new bone
formation. Other radiographic findings suggestive of
abuse include posterior rib fractures, spinous process
fractures, sternal fractures, complex skull fractures, and
diaphyseal spiral and oblique fractures. Fractures
showing different stages of healing are almost
pathognomonic of abuse. Any fracture which already
shows signs of healing suggests that the fracture is at
least ten days old.
Technetium 99 bone scanning has been shown to
be highly sensitive when used to assess skeletal injury,
particularly in occult areas not easily accessible to
clinical exam. This scan is frequently "hot" for many
weeks during healing.
American law requires the reporting of any
suspected abuse. A report of suspected abuse is a
responsible attempt to protect a child. A significant
number of children may be further abused if not
protected and may even die from further injury.
Physicians must consider abuse as a potential
diagnosis and maintain a high index of suspicion in
order to prevent further morbidity and mortality in
children unable to speak for themselves.
1. Gibson G, Block R. Child Abuse. In: Surpure
JS (ed). Synopsis of Pediatric Emergency Care, 1993,
Boston, Andover Medical Publishers, pp. 367-372.
2. Black GB. Child Abuse Fractures. In: Letts RM.
Management of Pediatric Fractures, 1994, New York,
Churchill Livingstone, pp. 931-944.
3. Caffey J. Multiple Fractures in Long Bones of
Infants Suffering from Chronic Subdural Hematoma.
American Journal of Radiology 1946:56;163.
4. Caffey J. On the Theory and Practice of Shaking
Infants. American Journal of Disease in Children
5. O'Conner JF, Cohn J. Diagnostic Imaging of
Child Abuse. In: Kleinman PK (ed). Diagnostic
Imaging of Child Abuse, 1987, Baltimore, Williams &
Wilkins, 1987, p.112.
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