17: 4-year-old female refusing to walk

Question 1

Accidental vs. Non-accidental Bruising

Answer 1

> > Bruises over bony prominences (e.g., shins and forearms) are common in toddlers and young active children.
Bruises seen over well-cushioned areas (e.g., buttocks, back, and genitalia) are less common and potentially raise the suspicion of NON-accidental trauma.

Question 2

Differential Diagnosis of Limp or Refusal to Walk: Leukemia (1/9)

Answer 2

• Replacement of bone marrow by leukemic cells can cause bone pain that presents as limp, refusal to walk, or localized discomfort of the jaw, long bones, vertebral column, hip, scapula or ribs.
• Bone pain may precede systemic signs such as fever and weight loss.
• Leukemia must always be considered in a child refusing to walk.

Question 3

Differential Diagnosis of Limp or Refusal to Walk: Osteomyelitis (2/9)

Answer 3

• Osteomyelitis is an infection of the bone, usually bacterial in origin, most often caused by Staphylococcus aureus and, before the era of routine immunization, Haemophilus influenzae (Hib).
• In toddlers, it usually presents with pain and refusal to bear weight (when affecting a leg bone).
• A h/o fever is present in about half of cases.
• B/c of its usually indolent presentation, diagnosis can be delayed 5-10d
• Osteomyelitis in the ilium may present with hip pain.

Question 4

Differential Diagnosis of Limp or Refusal to Walk: Reactive arthritis (3/9)

Answer 4

• -Occurs primarily in adolescents or young adults.
• -This is a relatively uncommon inflammatory process that usually presents two to four weeks after an infection outside of the joint, most often in the gastrointestinal or genitourinary tract.
• -The classic association with urethritis and conjunctivitis is uncommon in children.
• -Children are frequently afebrile at presentation.

Question 5

Differential Diagnosis of Limp or Refusal to Walk: Septic arthritis (4/9)

Answer 5

• Peak age is 0 to 6 years of age.
• Most commonly involves bacterial infection of a single joint, usually in a lower extremity.
• High fever is common, as are constitutional symptoms (decreased appetite, irritability, malaise).
• Requires prompt treatment to prevent joint damage.

Question 6

Differential Diagnosis of Limp or Refusal to Walk: Transient synovitis (5/9)

Answer 6

• Peak age is 3 to 8 years.
• Presents as acute onset of joint pain without significant constitutional symptoms other than possible low-grade fever. Transient synovitis often occurs during or following a viral URI.

Question 7

Differential Diagnosis of Limp or Refusal to Walk: Trauma (6/9)

Answer 7

• Minor accidental trauma such as a sprain or an occult fracture is possible after a fall.
• The possibility of non-accidental trauma must always be considered.

Question 8

Differential Diagnosis of Limp or Refusal to Walk: Juvenile idiopathic arthritis (JIA) (7/9)

Answer 8

Formerly called juvenile rheumatoid arthritis (JRA), JIA refers to a group of disorders characterized by chronic inflammation of the joints. To meet diagnostic criteria, children must be less than 16 years of age and have arthritis in at least one joint for more than six weeks. There are several subtypes, including:

• -Systemic (includes constitutional symptoms such as fever and rash)
• -Oligoarthritis (previously called pauciarticular, this type of oligoarthritis typically affects the knee; onset of the arthritis is acute, and it is associated with an asymptomatic iridocyclitis)
• -Polyarthritis (rheumatoid factor positive and rheumatoid factor negative)
• -Psoriatic arthritis
• -Enthesitis-related arthritis
• -“Other arthritis” (has overlapping features with multiple categories or does not meet full criteria for one category)

Question 9

Differential Diagnosis of Limp or Refusal to Walk: Slipped capital femoral epiphysis (8/9)

Answer 9

• -Most common hip disorder in adolescents
• -Characterized by posterior displacement of the capital femoral epiphysis from the femoral neck through the cartilage growth plate
• -Causes limp and impaired internal rotation
• -Most commonly presents with months of vague hip or knee symptoms and limp with or without an acute exacerbation
• -Etiology is not clearly defined. Occurs more commonly in obese adolescents, suggesting that mechanical strain on the growth plate could be at least partially responsible for the slip. Endocrine factors also may be important.
• -Diagnosis: Usually with plain film showing posterior displacement of the femoral head, like an ice-cream scoop slipping off a cone.
• -Prognosis: Depends on degree of slip and accompanying complications, particularly avascular necrosis of the femoral head and destruction of the articular cartilage
• -Therapy usually involves pinning to stabilize the epiphysis but no manipulation.

Question 10

Differential Diagnosis of Limp or Refusal to Walk: Legg-Calve- Perthes disease (9/9)

Answer 10

• -Most commonly affects boys between the ages of 4 and 10.
• -Involves avascular necrosis of the capital femoral epiphysis.
• -Typically presents with indolent or chronic pain rather than acute.
• -Various etiologies have been postulated, including infectious, trauma, developmental, and prothrombotic conditions.
• –Typically self-resolving, but may lead to complications including femoral head deformity and degenerative arthritis.
• -Treatment usually involves referral to an orthopedic surgeon, with the goal of preventing damage to the hip by containing the femoral head within the acetabulum, ideally through conservative methods.

Question 11

Developmental Dysplasia of the Hip (DDH)

Answer 11

group of conditions in infants where the femoral head is not properly aligned with the acetabulum. The spectrum includes hips that are dysplastic, dislocatable, subluxated (partially dislocated), and dislocated

Question 12

There are many risk factors for DDH, including

Answer 12

Female sex
Breech delivery
Family history of DDH

Question 13

Important screening physical examination maneuvers in newborns to detect DDH

Answer 13

• -The Ortolani maneuver assesses for a dislocated hip by abduction of the flexed hip with gentle anterior force.
• -The Barlow maneuver assesses for a dislocatable hip by adduction of the flexed hip with gentle posterior force.

Question 14

Complications of Lyme Dz

Answer 14

• -Arthritis is the second most common manifestation of Lyme disease and typically begins four weeks after the skin lesion.
• -The large joints closest to the rash are most commonly affected.
• -The arthritis may relapse or occur only once.

Question 15

When septic arthritis is suspected

Answer 15

aspiration of the joint should be performed as soon as possible to confirm the diagnosis and facilitate initiation of treatment.

Question 16

Characteristics of Synovial Fluid in Septic Arthritis

Answer 16

• Turbid appearance
• Increased white cell count, predominantly polymorphs
• Gram stain positive for bacteria

Question 17

Most Common Causative Organisms of Septic Arthritis

Answer 17

• Staphylococcus aureus
• Streptococcus (neonate: group B; infant and older child: Group A and Streptococcus pneumoniae)
• Haemophilus influenzae type b (in unimmunized children)
• Neisseria gonorrhea (adolescents)
• Kingella kingae (in children less than 4 years)

Question 18

Treatment of Septic Arthritis

Answer 18

• -Empiric intravenous antibiotic coverage should begin immediately after joint fluid is obtained and sent for culture. Coverage should be narrowed once a specific organism and its antibiotic sensitivities are identified.
• -Surgical incision and drainage may be necessary to remove debris and reduce the pressure in the hip joint.
• -Septic arthritis of the hip requires a prolonged course of abx and may require repeated aspiration or incision and drainage to remove reaccumulated purulent effusion.

Question 19

Musculoskeletal Exam of the Child

Answer 19

1. Begin the exam by observing how the child is moving naturally.
2. Next, slowly approach the child, allowing her to remain on the parent’s lap or seated near the parent if this is
   where she feels most comfortable, and try to determine where the pain is originating.
3. It is helpful to start with what you believe to be the unaffected limb, both to postpone making the patient
   uncomfortable and to have an exam with which to compare the painful limb.
4. It is also important to closely examine the joints directly above and below the apparently affected site.
5. Examine each joint, distal to proximal, first palpating for evidence of tenderness, warmth or effusion.
6. Remember that a patient who is experiencing a primary hip problem may actually present with knee or thigh
   pain due to radiating pain.

Question 20

Ibuprofen Dosing and Concentration

Answer 20

• -Pediatric dose: 10 mg/kg every 6-8 hrs PO (maximum dose = 40mg/kg/24 hr PO)
• -Concentration of oral suspension: 100 mg/5 mL (20 mg/1 mL)

Question 21

Measures of Inflammation: The most useful laboratory tests are

Answer 21

• -White blood cell count (obtained by ordering a CBC)
• -CRP
• -ESR

Question 22

An 8-year-old obese male comes to the clinic with a chief complaint of right knee pain with the right foot medially rotated. On an exam the right knee is neither swollen nor erythematous but he is noted to have a limited ROM of the right hip. In addition, when he lifts his right leg, it externally rotates. The patient did not have a URI or any trauma preceding the onset of pain. The vital signs are normal at the time of the visit and he is well appearing and afebrile. What is/are the best next step(s) in management?

Answer 22

AP and lateral x-rays are needed to diagnose a slipped capital femoral epiphysis, which is considered an emergency. This patient’s age group, his obesity, and the description of the external rotation of the right leg when the hip is flexed all suggest this diagnosis.

Question 23

Leukemia

Answer 23

can present as bone pain due to replacement of bone marrow by leukemic cells. Patients may present with a limp or refusal to walk. Leukemia is associated with systemic symptoms such as low-grade fever, chronic/insidious joint pain, generalized LAD, weight loss, and/or hepatosplenomegaly.

Question 24

Transient synovitis of the hip

Answer 24

associated with a low-grade fever and frequently occurs during or after a URI. Between 32% and 50% of children who present with transient synovitis had a recent upper respiratory tract infection. It is also important to remember that transient synovitis is a diagnosis of exclusion, and it is important to rule out other causes of hip pain that may require urgent intervention, such as septic arthritis.

Question 25

Juvenile idopathic arthritis (JIA)

Answer 25

Pauciarticular juvenile arthritis is the most common type of JIA (60% of JIA) and causes pain in four or fewer joints for six or more weeks. This patient is generally well even after six weeks of pain, which would be unlikely if this patient had septic arthritis. Her pain improves with activity, and the ESR/CRP are only mildly elevated. On exam, she has a mild effusion but no obvious erythema. In cases of systemic JIA, patients may have a rash which lasts only a few hours (evanescent) that is also macular and salmon, and high-spiking and appears periodically (once or twice a day); however, this form of JIA is not consistent with this patient’s history.

Question 26

reactive arthritis

Answer 26

The patient likely had a recent case of mild to moderate gastroenteritis in Mexico, which may have been secondary to an bacterial enteritis such as shigella, or campylobacter. In reactive arthritis, joint inflammation occurs a few weeks later because antibodies made during the illness are attacking the joint. While several inflammatory cells would be seen in the aspirate, importantly, the cultures will turn out to be negative