The child with limp represents a common scenario in the pediatric ED. Evaluation of such patients may be difficult due to vague clinical histories and nonspecific physical examination findings. The differential diagnosis is broad and includes mild self-limited processes (eg, toxic synovitis), as well as potentially limb and life-threatening etiologies (eg, osteomyelitis, malignancy). Careful attention to historical clues and a focused physical examination are often suggestive of a diagnosis, but laboratory and radiographic studies are necessary in most cases.
While trauma is the most common source of limp in children, infectious, inflammatory, and anatomic causes are also frequently encountered. This review focuses on several of the most important etiologies of limp in children: toxic synovitis, septic arthritis, osteomyelitis, Perthes disease, slipped capital femoral epiphysis (SCFE), and Osgood-Schlatter disease.
Case Presentation
Kailey, a 28-month-old girl, was brought to the ED by her parents, who stated that their child “isn’t walking right.” They noted that their daughter’s right leg had been bothering her for about a week, but that the limp had become more noticeable. Aside from a cold a week before presentation, both parents stated that the child has been healthy; they also denied any trauma or systemic symptoms such as rash, weight loss, vomiting, or diarrhea. The mother believed Kailey may have had a low-grade fever earlier in the week. There were no sick contacts at home, but the child did attend daycare.
On examination, Kailey was well-appearing on her mother’s lap. Her vital signs were unremarkable and she was afebrile. She was able to bear weight on the right leg but walked with a slightly antalgic gait, which became more apparent when she was asked to run across the room to her mother. Her right leg was normal appearing on examination with normal reflexes; however, the child appeared to wince when passively ranging her right hip and right knee joint. The emergency physician (EP) was not able to determine any particular areas of point tenderness. The remainder of the examination, including neurological and musculoskeletal examinations, was normal.
Regarding further history, the child’s parents informed the EP that they had taken their daughter to an urgent care clinic earlier in the week. X-rays taken of the girl’s right knee and hip at this visit were both normal; however, the girl’s limp had been getting worse.
Overview
Limp is a common presenting complaint in the pediatric ED, and its evaluation is often challenging as the clinical course of limp in a child varies from benign and self-limited to serious and limb-threatening. However, with careful attention to the history and physical examination, appropriate laboratory evaluation, and focused imaging studies, a diagnosis can be made in most cases and treatment initiated. Of paramount importance for clinicians is to remember that limp in a child nearly always represents an organic disease.1,2
While trauma is the most common cause of limp in children, infectious, inflammatory, and anatomic processes are other potential etiologies. A clue to the diagnosis may also be inferred from the patient’s age, as certain conditions such as fracture, Perthes disease, and transient synovitis are seen in younger children, while SCFE and Osgood-Schlatter are more common in children older than 10 years of age. Other serious conditions such as septic hip or osteomyelitis may be encountered at any age.
Initial Management
A thorough history and physical examination provide the basis for subsequent laboratory and radiographic testing of children presenting with a limp. The duration and localization of symptoms should be elicited; traumatic or infectious causes are more common among those presenting with acute (<2 weeks) complaints. The presence of systemic symptoms (eg, fever, weight loss, chills, rashes, recurrent arthralgias) increases the likelihood of underlying oncologic or rheumatologic process. Examination of the child begins with a full physical examination to uncover other possible etiologic clues such as other involved joints (juvenile idiopathic arthritis), signs of old bruising (nonaccidental trauma), firm lymph nodes (malignancy), abdominal pain (eg, appendicitis, psoas abscess, constipation), or limb-length discrepancy (developmental dysplasia of the hip).
Focused assessment of the limp itself involves watching the child walk or run; different variations of limp may also offer a clue to the diagnosis. An antalgic gait simply refers to one in which the affected leg spends less time in the weight-bearing stage, and it is most commonly seen with infection and trauma. Trendelenburg gait, frequently seen with SCFE and Perthes disease, is characterized by a downward tilt of the pelvis away from the affected side while the affected leg is bearing weight.
In many cases, it may be difficult to accurately characterize a limp due to a patient’s pain or lack of compliance. Evaluation of any limp should also focus on the joint above and below the child’s apparent main source of pain. This is particularly true of knee complaints as referred pain from the hip may often present as isolated thigh or knee pain. Areas of point tenderness, erythema, joint effusion, and warmth strongly point to an infectious source but are frequently absent early in disease presentation. While swelling and severe pain with passive movement of a joint indicate septic arthritis, limitation of joint movement at the hip can be seen with SCFE and Perthes disease.