Acute and Non-acute Lower Extremity Pain in the Pediatric Population

Part III

Allison D. Duey-Holtz, MSN, RN, CPNP; Sara L. Collins, MSN, RN, CPNP; Leah B. Hunt, PA-C, MMSc; Polly F. Cromwell, MSN, RN, CPNP


J Pediatr Health Care. 2012;26(5):380-392. 

In This Article

Infectious Conditions


Definition. Discitis is an inflammatory or infectious condition of the thoracic versus lumbar spinal disc spaces.

History of Present Illness.

  • Infant/toddler: May display signs of fever, irritability, limping or refusal to walk, and/or nausea/vomiting

  • Older child/adolescent: May complain of back, abdominal, and possibly even radiating leg pain; may have a history of a recent respiratory infection and fever

  • Average age of onset is 2.5 years for discitis and 7.5 years for discitis with osteomyelitis

Physical Examination.

  • Pain with palpation over the affected area

  • Pain with back flexion/extension

  • ± Positive straight leg raise

  • Normal lower extremity examination with a limp

Diagnostic Tests.

  • Imaging: AP/lateral radiograph of the affected area to rule out another etiology; often the disc space narrowing and end plated changes are not visualized until a few weeks into the disease process

  • MRI for definitive diagnosis; perform a bone scan if unsure of the location

  • Laboratory tests: CBC with manual differential, ESR, CRP, and blood culture; the CRP often is markedly elevated, and the ESR often is mildly elevated


  • Typical treatment with intravenous antibiotics followed by a course of oral antibiotics

    • Refer to the most up to date Red Book for current treatment guidelines (AAP, 2012)

    • Assume it is bacterial; the most common organism is Staphylococcus aureus, but the frequency of methicillin-resistant S. aureus continues to increase depending on the geographic location

  • Recommend use of a the lumbosacral back brace for comfort

  • Refer the patient to orthopedics or an infectious disease specialist based on the guidelines of the institution (AAP, 2012; Herring, 2008; Morrissy & Weinstein, 2006; Shereck & Schwend, 2004; Staheli, 2006)

Gonococcal/Chlamydial Arthritis


  • The causal organism is either gonorrhea (monoarticular septic arthritis as part of disseminated gonococcal infection [DGI]) or chlamydia (reactive arthritis [RA])

  • A localized mucosal infection becomes bacteremic and spreads to joints and other systems

  • Gonococcal arthritis/DGI is more common in female patients and RA is more common in male patients

  • Gonococcal/chlamydial arthritis always should be considered in adolescents who have acute arthritis, even if sexual activity is denied

  • An asymptomatic urogenital/pharyngeal sexually transmitted infection is most common in patients with gonococcal arthritis/DGI; urethritis is common with classic RA but may be asymptomatic and thus overlooked

Gonococcal Arthritis

  • Gonococcal arthritis may be part of the presentation of DGI (see the following section) or may present solely as a septic joint

  • If monoarticular arthritis is the presenting complaint, the knee joint often is affected, but the wrist, elbow, or ankle also may be affected; occasionally sternoclavicular, temporomandibular, or the small joints of the hands

  • Gonococcal arthritis is indistinguishable from other causes of septic joints

  • A septic joint is always a medical emergency, and infectious disease experts should be consulted promptly in evaluation and treatment

  • An increase in third-generation cephalosporin-resistant gonorrhea (the only treatment option that exists) makes consultation especially important (Bolan, Sparling, & Wasserheit, 2012)

Disseminated Gonococcal Infection

History of Present Illness.

  • The classic presentation includes the acute onset of a triad of findings: migratory polyarthritis, dermatitis, and tenosynovitis

    • Symptoms often appear within 7 days of menses and also may occur during pregnancy

    • May have recently had or currently have systemic symptoms (e.g., fever, headache, chills, anorexia, or weight loss)

    • Most likely a continuum of presentations (versus a clearly delineated progression to a septic joint)

Physical Examination.

  • Migratory polyarthritis: asymmetrical, most often seen in the wrist and the metacarpophalangeal, ankle, and knee joints

  • Arthralgias may be more common as a symptom of DGI

  • If a septic joint is present, it usually is monoarticular as previously described

  • Dermatitis: often a tender, necrotic pustule on an erythematous base

    • May see macules, papules, pustules, petechiae, bullae, or ecchymosis

    • Found on distal portions of extremities; usually < 30 in number

    • May have resolved by time of presentation (or never been present)

  • Tenosynovitis: often affecting multiple joints at once, usually the wrists, fingers, ankles, and toes

    • Pain with passive range of motion at tendon insertion sites (Holmes et al., 2008)

Reactive Arthritis

History of Present Illness.

  • Classic presentation is a two-phase process

    • The first phase includes urethritis or cervicitis and may be unrecognized

    • The second phase, which usually occurs within 2 to 4 weeks of the first phase, includes arthritis, conjunctivitis, and dermatitis

  • Resolution of symptoms or lack of a classic presentation results in underevaluation and underdiagnosis

  • May have had or currently have systemic symptoms (e.g., fever, headache, chills, anorexia, or weight loss)

  • Aseptic, immune-mediated synovitis is a hallmark of reactive arthritis

Physical Examination.

  • Arthritis: asymmetrical, monoarticular or oligoarticular, and often affects distal weight-bearing joints

    • Knees, ankles, feet

    • Spine and sacroiliac joint

  • Sacroiliitis: a combination of synovitis and enthesitis is common

  • Enthesitis: inflammation at the transitional zone where collagenous structures, such as tendons and ligaments, insert into bone

    • Occurs most commonly at plantar fascia or Achilles tendon

  • Dermatitis

    • Circinate balanitis

    • Keratoderma blennorrhagicum

      • Becomes almost indistinguishable from psoriatic lesions, thus confusing the diagnosis (Holmes, 2008)

Gonococcal Infection and Reactive Arthritis

Diagnostic Tests.

  • Gonococcal (GC)/chlamydia (Chl) nucleic acid amplification tests (NAAT) of urine, vagina, and/or cervix

  • NAAT, rectal, and throat cultures for GC/Chl

  • Synovial joint aspirate for evaluation

    • For monoarticular joint involvement in which joint sepsis is under consideration, joint aspiration is indicated to include gram stain, NAAT tests for GC/Chl, nucleated cell count, and aerobic, gonococcal, anaerobic, fungal, and mycobacterium cultures

    • A nucleated cell count from joint aspirate is helpful because results are received quickly (within hours), whereas cultures will take days

      • > 50,000 white blood cell count (WBC) with > 80% polymorphonuclear leukocytes is consistent with a bacterial infection

      • 25,000–50,000 WBC can be reactive or infectious

      • < 25,000 WBC is likely reactive synovitis

  • NAAT results are positive in up to 50% of cases

  • CBC, ESR, and CRP levels usually are elevated and consistent with inflammation but not specific for diagnosis


  • Often made clinically because culture/gram stain/NAAT tests of synovial fluid are positive no more than 50% of the time

  • If septic arthritis is possible, treatment should be started and the response used to assess the accuracy of the diagnosis


  • Suspected gonococcal septic arthritis

    • Treatment should cover all possible bacterial pathogens unless gonococcal arthritis has been proven

    • Treatment of possible/probable gonococcal infection in adolescents

      • Ceftriaxone 1 g intramuscularly every 24 hours until clinical improvement is seen, usually within 48 to 72 hours; then switch to Cefixime, 400 mg twice a day, until 7 total days of treatment

      • Treat for chlamydia as well with azithromycin, 1 g (Centers for Disease Control and Prevention [CDC], 2010)

  • Reactive Arthritis

    • Azithromycin, 1 g by mouth if + NAAT or other signs/symptoms consistent with chlamydial RA in adolescents (CDC, 2010)

    • Chlamydial antigens often persist, even after treatment of a localized mucosal infection

    • The mainstay of treatment, beyond azithromycin, is NSAIDs to treat the joint pain and swelling; corticosteroids and other antirheumatic drugs also may be used (Carter and Hudson, 2009;Holmes, 2008)

    • Consult with infectious disease and rheumatology

    • Chronic or recurrent RA is beyond the scope of this practice guideline

Lyme Arthritis or Other Tickborne Diseases

Definition. Lyme arthritis or other tickborne diseases consist of infection with Borrelia burgdorferi (Lyme arthritis) or other pathogens that can present arthritis symptoms.

History of Present Illness. The patient has a history of possible exposure to black-legged ticks and signs and symptoms as discussed in the following sections.

Physical Examination.

  • Early localized stage: A red, expanding rash called erythema migrans (EM) occurs in 7% to 80% and presents 3 to 30 days after the bite (average, 7 days); as the rash enlarges, the center may clear, resulting in a "bull's-eye" appearance; the rash can be associated with fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes

  • Early disseminated stage (days to weeks after a tick bite): Additional EM lesions in other areas of the body with development of facial or Bell palsy (loss of muscle tone on one or both sides of the face); additional manifestations include meningitis, pain and swelling of large joints, heart palpitations with vertigo, and night waking pain to extremities; many of these symptoms will resolve over a period of weeks to months, even without treatment; lack of treatment can result in additional complications, described in the following sections

  • Late disseminated stage (months to years after a tick bite): Intermittent bouts of large joint pain and swelling, especially of the knees; chronic neurological complaints months to years after a tick bite, including shooting pains, numbness or tingling in the hands or feet, and problems with short-term memory (CDC, 2011)

Diagnostic Tests.

  • Lyme serology with Western Blot confirmation

    • First Tier Testing: Enzyme immunoassay or immunofluorescence assay; when results are positive or equivocal, proceed to the second tier

    • Second Tier Testing

      • For signs and symptoms < 30 days: obtain IgM and IgG Western blot

      • For signs and symptoms > 30 days: obtain IgG Western blot only (CDC, 2011)


  • See Red Book for most updated treatment guidelines (AAP, 2012)

  • Early localized stage including Bell palsy and erythema migrans without neurologic manifestations

    • < 8 years: amoxicillin, 50 mg/kg/day three times a day × 14 days

    • > 8 years: doxycycline, 4 mg/kg twice a day × 14 days (maximum 100 mg/dose)

  • Disseminated disease with acute neurologic manifestations including meningitis and/or radiculopathy

    • Ceftriaxone, 50–75 mg/kg/day every 6 to 8 hours × 14 days, administered intravenously (Wormser et al., 2006)

      • Alternatives include cefotaxime, 150–200 mg/kg/day administered intravenously every 8 hours or penicillin G, 200,000–400,000 units/kg/day administered intravenously every 4 hours with normal renal function (Wormser et al., 2006)

  • Antibiotic treatment does not decrease the length of resolution of cranial nerve VII palsy but does prevent further disease sequelae

  • Refer to infectious disease for complex disease. May need to also consult rheumatology for arthralgias ((AAP, 2012; CDC, 2011; Steere, Coburn, & Glickstein, 2004; Wormser et al., 2006)


Definition. Osteomyelitis is infection of bone.

History of Present Illness.

  • Possible history of trauma

  • Preceding recent upper respiratory infection

Physical Examination.

  • Fever

  • Acute change in weight-bearing status

  • Localized pain, erythema, and associated joint effusion

  • Ill-appearing

Diagnostic Tests.

  • CBC, ESR, amd CRP

    • WBC, ESR, and CRP will be elevated

  • Normal radiographs unless infection is more than about 2 weeks old

  • A bone scan should be performed in young children to localize the infection; an MRI should be performed in older children who can localize their pain

  • Perform a bone aspiration with a nucleated cell count and culture if possible


  • Identify the pathogen if possible; initial antibiotic treatment is based on current Red Book guidelines (AAP, 2012)

  • Pathogens

    • < 1 year of age: Streptococcus pneumoniae and/or Kingella kingae

    • School age: methicillin-sensitive S. aureus, methicillin-resistant S. aureus, and/or Group A beta streptococcus (AAP, 2012; Herring, 2008; Liu et al., 2011)

Septic Arthritis

Definition. Septic arthritis is bacterial infection in a joint.

History of Present Illness.

  • Septic arthritis generally affects a single joint and normally causes extreme joint pain

  • Septic arthritis is a surgical emergency to prevent joint damage

Physical Examination.

  • Redness, swelling and/or warmth of the joint

  • Pain with joint motion

  • Restricted joint motion

  • Refusal to bear weight

  • Fever

Diagnosis. Diagnosis is made via elevated CBC, CRP, and ESR values and possibly via positive blood cultures.


  • Treatment is based on the local treatment pattern

    • Perform an ultrasound of the hip joint or proceed with joint aspiration of small joints

      • Joint fluid must be sent for cell counts and culture prior to antibiotic treatment

    • Refer to orthopedics, emergency department, or admission to hospital for joint aspiration and therapy based on laboratory data; antibiotic treatment is based on current Red Book guidelines (AAP, 2012; Herring, 2008; Kocher et al., 2003; Mathews et al., 2007; Morrissy & Weinstein, 2006)