Chapter 211

Among the causes of gait abnormality in childhood, those that should be kept in mind in acute settings include infection, trauma, and malignancy. Children who develop a limp acutely should be evaluated carefully with a detailed history and physical examination, appropriate radiographs and laboratory studies, and timely referral for subspecialty evaluation in order to exclude these potentially worrisome causes. When necessary, the lower extremity should be carefully immobilized and protected from weight bearing until a definitive diagnosis can be achieved. When infection is suspected, the workup should be conducted in either an observation or inpatient status until the diagnosis is confirmed or excluded. This ensures that appropriate diagnostic and therapeutic resources can be brought to bear in a timely manner before the infection worsens without a correct diagnosis. Regardless of the underlying cause of the limp, vigilance is necessary in order to make an accurate diagnosis in a timely manner to ensure the best outcome.

Infections of bone and joint are discussed in Chapter 234.

From an epidemiological perspective, the most common cause of an unexplained limp in childhood is infection. Whereas injury generally occurs as a discretely observed event and results in a sudden onset of limited mobility, infection often has a more insidious onset. Following trauma, radiographs usually reveal the alteration in skeletal anatomy which makes the diagnosis clear. Although exceptions may exist, such as Salter Harris type 1 physeal injuries or occult elbow fractures with positive fat pad signs, the ability to distinguish fractures with plain radiographs is usually straightforward. However, with infection, plain radiographic findings may be subtle, with deep soft tissue swelling being the first identifiable sign in many cases.

Trauma may be reported as an antecedent event in approximately 35% of children with infection.1 In these circumstances, the physician should be mindful of subtle details in the history and physical examination. One should ask about the timing of the injury with respect to the onset of symptoms, the mechanism of injury, and the presence of fever. One should also inspect the area of concern for signs of erythema, warmth, and swelling that may not be consistent with injury, based on the reported timing or mechanism of the injury.

Whenever infection is suspected, laboratory studies should be obtained to assess for a systemic response to the infection. These should include a complete blood count (CBC) with differential, C-reactive protein (CRP), and the erythrocyte sedimentation rate (ESR). Among these studies, the most sensitive test for identifying the inflammation associated with acute musculoskeletal infection is the CRP.2 Abnormalities of the infectious indices should raise the level of concern and motivate the physician to perform more dedicated imaging to help define the nature and extent of the problem.

If a precise location can be determined from physical examination, then magnetic resonance imaging (MRI) with and without intravenous contrast is the most sensitive and specific study to evaluate ...

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

## Subscription Options

### AccessPediatrics Full Site: One-Year Subscription

Connect to the full suite of AccessPediatrics content and resources including 20+ textbooks such as Rudolph’s Pediatrics and The Pediatric Practice series, high-quality procedural videos, images, and animations, interactive board review, an integrated pediatric drug database, and more.