Pediatric emergency medicine trisk 1156 1156

CHAPTER 60 ■ PAIN: JOINTS
RICHARD J. SCARFONE, AARON E. CHEN

INTRODUCTION
Arthritis and arthralgia are common reasons for children to seek care in the
emergency department (ED). Arthritis is joint inflammation marked by swelling,
warmth, and limitation of motion; arthralgia is joint pain without inflammation.
Establishing a diagnosis for the child with joint pain is challenging because the
differential diagnosis is lengthy ( Table 60.1 ), clinical and laboratory findings are
rarely specific for a particular disease, and disease patterns for many of the
etiologies are often highly variable among different patients. Among the most
common causes of joint pain in children are infections, trauma, and postinfectious
conditions ( Table 60.2 ), whereas those most likely to be life-threatening are due
to systemic disease and malignancy ( Table 60.3 ). This chapter serves as a guide
to the approach to the child with arthritis or arthralgia, with an emphasis on
historical points and physical examination findings that can serve to narrow the
diagnostic possibilities.

DIFFERENTIAL DIAGNOSIS
The initial differential diagnosis usually focuses on the most common or
potentially serious etiologies ( Tables 60.2 and 60.3 ). Children from 6 to 24
months of age have the highest incidence of nongonococcal bacterial (septic)
arthritis, which results primarily from the hematogenous dissemination of an
organism. The diagnosis of septic arthritis of the hip should not be delayed
because pressure in the joint space will compromise the vascular supply to the
femoral head, leading to necrosis (see Chapter 94 Infectious Disease Emergencies
).
Osteomyelitis involving the distal end of long bones may manifest as arthralgia
with or without objective signs of joint inflammation. Children with sickle cell
anemia and Type 1 diabetes mellitus are at higher risk. Onset of symptoms is
typically more indolent compared to septic arthritis.

In the first 10 days of illness, children with Kawasaki disease may have
arthritis or arthralgia, often involving smaller joints in the hand. Beyond that
time, involvement of larger joints of the lower extremities is more common. If an
arthrocentesis is performed, the synovial fluid analysis resembles that seen with