Today, I link to and excerpt from the 2018 ACR Appropriateness Criteria Acutely Limping Child Up To Age 5 [PubMed Abstract] [Full-text PDF]. J Am Coll Radiol. 2018 Nov;15(11S):S252-S262. doi: 10.1016/j.jacr.2018.09.030.
See the charts in the criteria and review the written summary.
ACR Appropriateness Criteria Acutely Limping Child Up To Age 5. Variants 1 to 5 and Tables 1 and 2
Variant 1. Child up to age 5. Acute limp. Nonlocalized symptoms. No concern for infection. Initial imaging.
Radiography tibia/fibula Usually Appropriate ☢
Radiography femur May Be Appropriate ☢☢
Radiography foot May Be Appropriate (Disagreement) ☢
Radiography lumbar spine Usually Not Appropriate ☢☢
Radiography pelvis Usually Not Appropriate ☢☢
US hips Usually Not Appropriate B
US lower extremity Usually Not Appropriate B
CT lower extremity with IV contrast Usually Not Appropriate ☢☢☢☢
CT lower extremity without and with IV contrast Usually Not Appropriate ☢☢☢☢☢
CT lower extremity without IV contrast Usually Not Appropriate ☢☢☢☢
MRI lower extremity without and with IV contrast Usually Not Appropriate B
MRI lower extremity without IV contrast Usually Not Appropriate B
MRI whole-body without and with IV contrast Usually Not Appropriate B
MRI whole-body without IV contrast Usually Not Appropriate B
Tc-99m 3-phase bone scan whole-body Usually Not Appropriate ☢☢☢☢Variant 2. Child up to age 5. Acute limp. Pain. Localized symptoms. No concern for infection. Initial imaging.
Radiography lower extremity area of interest Usually Appropriate ☢☢
MRI lower extremity area of interest without IV contrast Usually Not Appropriate B
US hips Usually Not Appropriate B
US lower extremity area of interest (not pelvis or hip) Usually Not Appropriate B
CT lower extremity area of interest with IV contrast Usually Not Appropriate ☢☢☢☢
CT lower extremity area of interest without and with IV contrast Usually Not Appropriate ☢☢☢☢☢
CT lower extremity area of interest without IV contrast Usually Not Appropriate ☢☢☢☢
MRI lower extremity area of interest without and with IV contrast Usually Not Appropriate B
Tc-99m 3-phase bone scan whole-body Usually Not Appropriate ☢☢☢☢Variant 3. Child up to age 5. Acute limp. Nonlocalized symptoms. Concern for infection. Initial imaging.
MRI lower extremity without and with IV contrast Usually Appropriate B
MRI lower extremity without IV contrast Usually Appropriate B
US hips May Be Appropriate B
MRI whole-body without and with IV contrast May Be Appropriate B
MRI whole-body without IV contrast May Be Appropriate B
Tc-99m 3-phase bone scan whole-body May Be Appropriate ☢☢☢☢
(continued)Variant 3. Continued
US lower extremity Usually Not Appropriate B
Radiography femur Usually Not Appropriate ☢☢
Radiography foot Usually Not Appropriate ☢
Radiography lumbar spine Usually Not Appropriate ☢☢
Radiography pelvis Usually Not Appropriate ☢☢
Radiography tibia/fibula Usually Not Appropriate ☢
CT lower extremity with IV contrast Usually Not Appropriate ☢☢☢☢
CT lower extremity without and with IV contrast Usually Not Appropriate ☢☢☢☢☢
CT lower extremity without IV contrast Usually Not Appropriate ☢☢☢☢Variant 4. Child up to age 5. Acute limp. Symptoms localized to the hip. Concern for infection. Initial imaging.
US hips Usually Appropriate B
MRI pelvis without and with IV contrast Usually Appropriate B
MRI pelvis without IV contrast Usually Appropriate B
Tc-99m 3-phase bone scan whole-body May Be Appropriate ☢☢☢☢
Radiography pelvis May Be Appropriate ☢☢
Radiography lumbar spine Usually Not Appropriate ☢☢
CT pelvis with IV contrast Usually Not Appropriate ☢☢☢☢
CT pelvis without and with IV contrast Usually Not Appropriate ☢☢☢☢
CT pelvis without IV contrast Usually Not Appropriate ☢☢☢☢Variant 5. Child up to age 5. Acute limp. Symptoms localized to lower extremity (not pelvis or hips). Concern for infection. Initial imaging.
MRI lower extremity area of interest (not pelvis or hip) without and with IV contrast Usually Appropriate B
MRI lower extremity area of interest (not pelvis or hip) without IV contrast Usually Appropriate B
US lower extremity area of interest (not pelvis or hip) May Be Appropriate B
Radiography lower extremity area of interest (not pelvis or hip) May Be Appropriate ☢☢
CT lower extremity area of interest (not pelvis or hip) with IV contrast Usually Not Appropriate Varies
MRI whole-body without and with IV contrast Usually Not Appropriate B
MRI whole-body without IV contrast Usually Not Appropriate B
Tc-99m 3-phase bone scan whole-body Usually Not Appropriate ☢☢☢☢
CT lower extremity area of interest (not pelvis or hip) without IV contrast Usually Not Appropriate Varies
CT lower extremity area of interest (not pelvis or hip) without and with IV contrast Usually Not Appropriate Varies
Note to myself: Be sure and reread the SUMMARY OF LITERATURE REVIEW on pp 4 – 11 of the PDF.
Introduction/Background
Acute onset of limp or refusal to walk is a common complaint in children, accounting for approximately 4% of visits in one pediatric emergency department [1]. The acutely limping child can be a diagnostic dilemma for clinicians. Most commonly, the acute limp is caused by minor trauma or self-limiting benign conditions butcan also be caused by limb-threatening or life-threatening etiologies [2-6]. The cause of limp can usually be
determined by a careful history and physical examination. The differential diagnosis of limping isbroad and depends on the presence of signs of infection, localization of pain, and history of trauma [6]. The differential diagnosis in a limping child also
depends on age. This discussion relates to the initial imaging of the ambulatory child under the age of 5 years who presents with an acute onset of a limp.The presence of fever, elevated white blood cell count, elevated erythrocyte sedimentation rate, or elevated C-reactive protein suggests infection. Localization of pathology is based on site of pain, tenderness, presence of erythema, swelling, and positive physical maneuvers and signs, such as the Trendelenburg test, Galeazzi sign, Patrick/FABER test, pelvic compression test, and psoas sign [7]. A detailed analysis of gait can suggest the diagnosis [6].
The decision-making process about initial imaging must take into account the level of suspicion for infection and whether symptoms can be localized specifically. Localizing symptoms enables a focused examination. When symptoms cannot be localized, imaging approaches that can cover wider anatomic areas may have more diagnostic value.
In this document, when symptoms cannot be localized, “lower extremity” imaging includes the hips through the feet.
Be sure and review the discussion of the procedures by variant starting on p. 4 of the PDF The discussion of each variant has important information. I have included only excerpts.
Variant 1: Child Up to Age 5. Acute Limp. Nonlocalized Symptoms. No Concern for Infection. Initial Imaging pp 4 + 5
The most common noninfectious etiology of acute
limping in children is a minor traumatic injury [8].
Unfortunately, particularly in younger children, it is
common that the pain cannot be accurately localized to
one focal area. When there is no concern for infection
and pain cannot be localized through history or physical examination, an imaging strategy designed to
first localize the source of the pain and subsequently
better characterize the cause is typically pursued.Radiography Lower Extremities. In children <4 years
of age, it is common for clinicians to order radiographs
from the pelvis through the feet because of the patients’
typical lack of verbalization and inability to localize
symptoms [9]. Radiographs of the lower extremities are
often normal [10,11], with reports of fracture incidence
ranging from 4% to 20% [12]. Spiral tibial fractures
are by far the most common fractures found in children
<4 years of age presenting with nonlocalized limp or
refusal to bear weight. Other fractures in the ankle and
foot are also described [12]. Therefore, in the walking
child, initial evaluation with limited tibial/fibula
radiographs was suggested rather than total extremity
(pelvis, femur, tibia/fibula, and/or ankle/foot)
radiographs [13].
If initial imaging is normal but symptoms persist,
follow-up radiographs or radiographs of areas besides the
tibia/fibula may be useful. In the Baron et al study [13],
approximately 10% of tibial fractures were only visible on
follow-up radiographs and not initial imaging. One patient, who was discharged, later returned with worsening
symptoms and signs of infection and was found to have
spinal discitis and epidural abscess. As these examples
illustrate, if the initial evaluation is negative and symptoms persist or worsen, a follow-up clinical reassessment
and further imaging evaluation may be necessary.Variant 2: Child Up to Age 5. Acute Limp. Pain. Localized Symptoms. No Concern for Infection. Initial Imaging pp 5 + 6
The body regions covered in this clinical scenario are: hip,
femur, knee, tibia/fibula, ankle, and foot.Localized pain may be due to trauma, in which case it
is important to exclude an underlying fracture. Clinical
examination and history may allow localization of the
pain or injury to a specific area, which allows a more
focused imaging evaluation [26].Radiography Lower Extremity. Targeted radiographs
of the areas of concern have a role in evaluating for
possible fracture [12,26-29]. Negative radiographs do not
completely exclude the possibility of a nondisplaced
fracture. Dunbar et al [30] first described the term
“toddler’s fracture” in 1963 as a nondisplaced oblique
distal tibial fracture that may often go unrecognized.
Halsey et al [27] reported that in 39 children with a
presumptive diagnosis of toddler’s fracture by clinical
criteria and a negative initial radiographic workup, 16
(41%) had radiographic evidence of toddler’s fracture
on follow-up radiographs. Other studies have found
that radiographs are not always sensitive to the presence
of toddler’s fracture [28,29].Other causes of limp or pain, such as osteochondritis,
apophysitis, osteonecrosis, or tumor, may be diagnosed
with radiographs, though MRI has better sensitivity for
such pathologies [31,32].Variant 3: Child Up to Age 5. Acute Limp.
Nonlocalized Symptoms. Concern for Infection.
Initial ImagingLimping in the presence of one or more of the following
clinical and laboratory signs should suggest the possibility
of infection: fever, elevated white blood cell count,
elevated erythrocyte sedimentation rate, or elevated
C-reactive protein. The differential diagnoses in this
scenario most commonly include septic arthritis, osteomyelitis, discitis pyomyositis, Langerhans cell histiocytosis, and tumor (eg, leukemia, osteosarcoma, Ewing sarcoma, and metastatic disease).When there are signs and symptoms suggestive of an
infectious process, imaging has a role in substantiating the
diagnosis, localizing the site of infection, evaluating for
complications that require surgical intervention, and
excluding other pathologies that mimic infection.Radiography Lower Extremities. Radiographs have low
yield in detecting infection when symptoms and signs are
not localized [39,40].US Hips or Lower Extremity. A small field of view
limits the role of US when symptoms and clinical evaluation cannot localize the site of pathology [14]. Because
pain that is due to hip pathology can be referred
elsewhere in the lower extremity, such as the thigh,
knee, or buttock [15], US of the hip could be
considered even when symptoms cannot be well localized.MRI Lower Extremity. MRI, given its sensitivity to
soft-tissue and bone marrow pathology, has high accuracy
in diagnosing infection, including septic arthritis, osteomyelitis, pyomyositis, and discitis [42,43], and could
be considered as the initial imaging study [44]. Large
field-of-view coronal T1-weighted and fluid-sensitive
sequences covering from the pelvis and hips to the
ankles may be performed to identify any abnormality.
Inclusion of the lower thoracic spine and lumbar spine should be considered if lower extremity or hip pathology
is not found and symptoms persist, as some patients
with discitis may not have localized symptoms to the back
[45-48]. Once localized, additional MRI sequences with
smaller fields of view can be performed for further
characterization [49]. Contrast administration in the
MRI evaluation of suspected soft-tissue or osseous
infection does not increase sensitivity or specificity but
may increase reader confidence and better delineate abscesses [50,51]. Contrast administration during MRI
should be considered in specific cases to improve
detection of an abscess when there is significant softtissue edema [50,51]. An exception to this may be
infants, in whom infection of the epiphyses can be
occult on unenhanced MRI sequences [52]. Given
these considerations, the use of IV contrast may vary
with institutional protocol.While no prospective study of MRI versus bone scan
has been performed, there are retrospective studies suggesting superiority of MRI over bone scan in detecting
the source of infection, with sensitivity of 99% to 100%
for MRI compared to 53% to 71% for bone scan [39,40].
Because of low bone scan sensitivity for soft-tissue pathology, MRI is often obtained after a positive bone scan
for further evaluation of soft-tissues, primarily to detect
abscess formation that requires drainage [41].Variant 4: Child Up to Age 5. Acute Limp.
Symptoms Localized to the Hip. Concern for
Infection. Initial ImagingStart here
