URGENT CARE Special Section Radiographs showing a long spiral fracture of the tibia in a 2½-year-old boy. Amy H. Kaji, MD, PhD Evaluation of the Assistant Clinical Professor of Medicine David Geffen School of Medicine at UCLA Urgent Care Section Urgent Care Los Angeles, California Medical Director Limping Child Department of Emergency Medicine South Bay Disaster Resource Center Harbor-UCLA Medical Center A common problem in children, limp has numerous Torrance, California etiologies, such as infection, inflammation, trauma, and Genevive Santillanes, MD developmental issues. A thorough examination helps Clinical Instructor the urgent care physician determine the treatment David Geffen School of Medicine at UCLA Los Angeles, California course and whether child abuse is a possible factor. Pediatric Emergency Medicine Fellow Department of Emergency Medicine Harbor-UCLA Medical Center imp is a relatively common presenting symptom in children.1 Torrance, California Defined as “any deviation from a normal gait pattern for the 2 Marianne Gausche-Hill, MD, FACEP, child’s age” or an “uneven, jerky, or laborious gait, usually FAAP caused by pain, weakness, or deformity,”3 pediatric limp has Professor of Clinical Medicine Lmultiple etiologies (Table 1).1-17 David Geffen School of Medicine at UCLA Los Angeles, California Certain factors are particularly helpful in distinguishing the cause of a Director, Emergency Medical Services and limp: patient age, whether the limp is acute or chronic, whether the limp Pediatric Emergency Medicine Fellowships is painful or painless, and whether there are any associated systemic Department of Emergency Medicine Harbor-UCLA Medical Center symptoms or a preceding trauma. Although some conditions may appear Torrance, California at any age (eg, fracture, osteomyelitis, septic arthritis), many conditions © 2009 Scott Camazine/Phototake 30 EMERGENCY MEDICINE | DECEMBER 2009 www.emedmag.com THE LIMPING CHILD typically present in a particular age range (Table thritis can result in osteonecrosis of the femur, 2).17 For instance, slipped capital femoral epiphy- femoral osteomyelitis, and sepsis.20 sis (SCFE) typically presents in preadolescence Children with septic arthritis typically are febrile or adolescence. An acute onset of limp suggests and appear ill. Weight bearing and movement of trauma or infection, whereas gradual progres- the hip are usually resisted in all age-groups. Only sion suggests a neuromuscular disorder, Legg- 8% of septic arthritis is multifocal or polyarticular; Calvé-Perthes disease (LCPD), SCFE, rheumato- classically, it is monoarticular.21 Importantly, prior logic disease, or malignancy. Nocturnal pain and antibiotic use (eg, in partially treated septic ar- associated systemic complaints should raise sus- thritis) may alter the presentation. Septic arthritis picion for malignancy. It is often difficult to elicit may also be a presentation of Lyme disease; thus, a history of trauma or even pain, and it should in endemic regions, children should be evaluated be noted that referred pain is not uncommon in with antibody titers and serology.22 children. Thus, hip pathology may present as Since septic arthritis can be a challenging di- knee pain, and pain from the lower back may be agnosis, decision algorithms have been devel- referred to the lateral thigh. oped to identify predictors of disease. One large retrospective study demonstrated a less than CASE PRESENTATIONS 1% risk of septic arthritis in the absence of all Case 1 the following: fever greater than 38.5°C within 1 A 2-year-old boy presents with a 2-day history of week of presentation, refusal to bear weight, ESR fever, refusal to walk, and decreased activity. On greater than 40 mm/h, and WBC count greater Section Urgent Care examination, the child is irritable, has a fever of than 12,000 cells/mm3.23 These findings were later 39°C, and cries when the physician’s examining validated.24 Additionally, a CRP level greater than hand reaches toward his right hip. Plain films 2 mg/dL (>20 mg/L) was prospectively found to be demonstrate no abnormalities. The patient’s an independent predictor of septic arthritis.25 white blood cell (WBC) count is 15,000 cells/mm3, The diagnosis of septic arthritis is confirmed erythrocyte sedimentation rate (ESR) is 60 mm/h, by ultrasound-guided aspiration of inflammatory and C-reactive protein (CRP) level is 4 mg/dL (40 hip fluid with positive identification of a causative mg/L); hip ultrasound is pending. organism in a culture of synovial fluid or blood. A joint aspirate showing a WBC count of greater Septic Arthritis than 50,000 cells/mm3 along with neutrophil pre- After the knee, the hip joint is the second most dominance or the demonstration of bacteria by commonly infected joint in children with sep- Gram stain is the diagnostic threshold for septic tic arthritis.4 Bacteria may infect the hip either arthritis.23 Immediate aspiration of the hip joint is hematogenously or by direct extension from recommended in the patient with an irritable hip osteomyelitis of the femoral head. The physis to expedite diagnosis and treatment.26 of the hip is intracapsular; thus, infection of the Therapy consists of proximal femoral metaphysis can easily spread IV antibiotics and urgent to invade the joint space. Due to the potential for drainage of the hip fluid >>FAST TRACK<< rapid joint destruction and long-term morbidity, to avoid buildup of intra- Delayed treatment of it is critical to rapidly recognize and diagnose articular pressure that septic arthritis can septic arthritis.18 The most common organisms may impede the arterial result in osteonecrosis involved are streptococci and Staphylococcus supply. Empiric antibiotic of the femur, femoral aureus. The bacterial enzymes and products of regimens should cover osteomyelitis, and sepsis. the inflammatory cells can destroy the joint or gram-positive and gram- the growth plate. Increased pressure from an negative organisms, such as S aureus (often effusion within the capsule may impede blood methicillin-resistant) and Kingella kingae; cef- flow, resulting in avascular necrosis and conse- triaxone or cefazolin with vancomycin may be quent limb length discrepancy and decreased the best choice prior to availability of culture joint mobility.19 Delayed treatment of septic ar- results.27 www.emedmag.com DECEMBER 2009 | EMERGENCY MEDICINE 31 THE LIMPING CHILD TABLE 1. Etiologies of Limp in Children Infection Developmental Septic arthritis Slipped capital femoral epiphysis Osteomyelitis Developmental dysplasia of the hip Discitis Tarsal coalition Psoas abscess Aseptic necrosis Inflammation Legg-Calvé-Perthes disease Transient synovitis Psoriatic arthritis Osteochondrosis Systemic lupus erythematosus Kohler disease—osteochondritis of the tarsal navicular Juvenile idiopathic arthritis Freiberg disease—osteochondritis of the second, Spondyloarthropathy third, and fourth metatarsal Trauma Tumors Toddler’s fracture Benign—osteoid osteoma, unicameral bone Foot fractures (eg, calcaneus, cuboid) cysts, aneurysmal bone cysts, fibrous dysplasia, eosinophilic granuloma Child abuse Malignant—osteogenic sarcoma, Ewing sarcoma, Overuse injuries leukemia, lymphoma, neuroblastoma Chondromalacia patellae Neuromuscular causes Stress fractures Peripheral neuropathy Sever disease—calcaneal apophysitis at the Achilles tendon insertion Muscular dystrophy Sinding-Larsen-Johansson syndrome or Cerebral palsy “jumper’s knee”—apophysitis of inferior pole Urgent Care Section Urgent Care of the patella at the patellar tendon insertion Other systemic causes Osgood-Schlatter disease—osteochondrosis Gastrointestinal causes—appendicitis of the tibial tuberosity Genitourinary causes—testicular torsion, epididymitis, ovarian cysts, pelvic inflammatory disease Data extracted from Singer1; Leung and Lemay2; Brady3; Krogstad and Smith4; Taylor and Clarke5; Alexander et al6; Halsey et al7; Wenger et al8; Weinstein9; Lehmann et al10; Ledwith and Fleisher11; Aronsson et al12; Loder et al13; Gunner and Scott14; Flynn and Widmann15; Barkin et al16; Leet and Skaggs.17 Case 2 Transient Synovitis A 4-year-old boy is brought to urgent care by his Characterized by pain and limited motion of the mother because of a 1-day history of left hip pain. hip, transient synovitis, once called toxic syno- He recently had a viral upper respiratory tract infec- vitis, is relatively common, with an annual inci- tion, although he has no fever upon presentation. dence of 0.2% and a cumulative lifetime incidence On examination, he appears well and holds his of 3%.28 It is the most common cause of hip pain hip in external rotation and abduction. He walks in children ages 3 to 10 years, with a 2:1 male upon request, but he has an antalgic gait. His radio- predominance.28,29 The etiology of transient sy- graphs are normal, WBC count is 8,000 cells/mm3, novitis is unknown, although it frequently occurs ESR is 3 mm/h, and CRP level is 0.3 mg/dL. after a bacterial or viral infection, and symptoms 32 EMERGENCY MEDICINE | DECEMBER 2009 www.emedmag.com THE LIMPING CHILD generally resolve within 1 week. Typically, chil- dren with transient synovitis are afebrile, appear TABLE 2. Etiologies of Limp by Age in well, and present with unilateral hip pain. The Toddlers and Children child usually prefers to keep the hip in external rotation and abduction and may refuse to walk or Ages 1 to 3 years may walk with an antalgic gait. However, some Septic arthritis children present with a high fever, and up to 5% Osteomyelitis may have bilateral symptoms.