for massive pericarditis causing compromise of cardiac output, or if significant
symptoms persist despite therapy with NSAIDs. In the presence of tamponade or
progressive deterioration, pericardiocentesis provides temporary relief, whereas antiinflammatory medications are used to prevent re-accumulation of fluid.
Pulmonary Emergencies. Pleural effusions are a recognized manifestation of sJIA (
Fig. 101.9 ). Occasionally, pleural fluid collections may be massive, resulting in
respiratory distress. Other pleuropulmonary complications include pneumonitis, diffuse
interstitial disease, lymphoid bronchiolitis, and pulmonary arteritis. In the absence of
the need for thoracentesis for diagnostic or therapeutic purposes, treatment is aimed at
the underlying disease process, primarily involving control of inflammation with
NSAIDs, corticosteroids, or anakinra. Children with pleural effusions often require
admission in order to address the overall severity of systemic features of the disease.

FIGURE 101.9 Pericardial and pleural effusions in a child with systemic onset juvenile idiopathic
arthritis.


Iridocyclitis. Iridocyclitis (inflammation of the iris and ciliary body) occurs in
approximately 10% to 20% of all children with JIA. This can be of acute or chronic
onset. The chronic type of iridocyclitis occurs primarily in young children with
oligoarticular JIA, especially girls with oligoarthritis and a positive ANA. In contrast,
acute iridocyclitis occurs most often in older boys with oligoarticular disease.
Acute iridocyclitis is characterized by sudden onset of redness, tearing, pain, and
photophobia, and urgent management may be required to preserve vision. Immediate
consultation with an ophthalmologist is essential. The usual emergent treatment
includes topical corticosteroids and mydriatics.
Flare of a Single Joint in a Patient with JIA. In a patient known to have JIA and
receiving anti-inflammatory medication, acute swelling with pain and limitation of
range of movement of a single joint raises a common management problem. Potential
causes of such an acute monoarthritis include a flare of JIA versus septic arthritis or
Lyme arthritis, and careful attention to physical examination and historical features are
essential to avoid misdiagnosis.

Physical findings characteristic of infection of a joint are fever, extreme pain,
tenderness, erythema, and warmth over the joint. The affected joints of JIA, while often
swollen, warm, and stiff, are rarely red. With infection, there is usually pronounced
splinting of an infected joint due to pain; the slightest movement may cause muscle
spasm. In contrast, some range of motion is usually possible even with severely
inflamed joints of JIA. If the patient is taking an immunosuppressive medication,
physical findings of inflammation and/or infection may be masked.
If infection cannot be excluded with confidence, joint fluid must be aspirated, and
the fluid sent for cell count, Gram stain, and culture. Synovial fluid is bacteriostatic and
some fastidious organisms, such as Kingella , may be particularly difficult to culture, so
joint fluid samples should be inoculated into blood culture bottles to optimize
sensitivity. If there is any doubt about the diagnosis, it is best to also obtain a blood
culture (which increases diagnostic yield, as the organisms causing septic arthritis are
generally spread hematogenously) and then to initiate treatment for septic arthritis.
For the acute swelling and pain in a single joint caused by a JIA flare, resting the
involved extremity for 2 to 3 days may be adequate. After infection has been excluded,
injection of the joint with a topical steroid preparation such as triamcinolone
hexacetonide (1 mg/kg, maximum 40 to 60 mg) may provide rapid and sustained relief.
If multiple joints are involved during a flare, treatment with systemic agents from
NSAIDs to corticosteroids may be necessary, as may escalation of the baseline antiarthritis regimen for severe or persistently active arthritis.
Ruptured Popliteal Cyst. There are six bursae around the knee joint. Of these, the
gastrocnemius semimembranosus bursa is the one that most often communicates with
the synovial space. Consequently, in the presence of effusion in the knee joint, fluid


may enter the bursa and produce a popliteal cyst (Baker cyst). Patients with popliteal
cysts have a palpable and visible enlargement in the popliteal area, best seen while the
patient is standing with knees extended.
Rupture of a popliteal cyst with drainage of fluid into the calf muscles may present
as an emergency. Affected patients complain of sudden pain in the calf associated with

swelling in the leg. On physical examination they have induration, erythema, warmth,
and tenderness of the calf, as well as ankle edema. An effusion in the knee joint and
evidence of synovial thickening are often present. Homan sign may be positive, but
other signs of venous thrombosis, including palpable venous cords, dilation of
collateral veins, or arterial spasm, are usually absent.
Differentiation of a ruptured popliteal cyst from thrombophlebitis may be difficult,
though the latter are very rare in otherwise healthy children, and the former relatively
common in children with arthritis. Elevated D -dimers and other evidence of a
consumptive coagulopathy characterize venous thrombosis, while most children with
JIA do not have such abnormalities (with the exception of patients with sJIA
experiencing MAS). Ultimately, ultrasound or MRI may be needed to establish the
diagnosis. Intra-articular administration of steroids (triamcinolone hexacetonide, 1
mg/kg) is the recommended initial treatment for a ruptured Baker cyst. If there is an
inadequate response or if the syndrome is chronic, surgical excision of the cyst may be
necessary.
Cervical Spine Involvement. This complication usually is seen in children with
established severe polyarticular JIA. Although cervical spine involvement is known to
occur in 30% to 50% of patients with JIA, subluxation of the atlantoaxial (AA) joint or
the lower cervical spine is less common in children than adults. Clinical evidence of
pressure on the spinal cord is seen in 23% to 65% of adults with radiologic evidence of
AA subluxation. Similar data are not available for children.
Neck stiffness that is worst in the morning is the most common symptom of cervical
spine involvement in JIA. Occasionally, torticollis may be the presenting manifestation
of cervical arthritis. Severe pain in the neck and referred pain over the occipital and
retro-orbital areas also may occur. The pain has a dull, aching quality and is often
aggravated by neck movement. On physical examination, torticollis and/or loss of
lordosis of the cervical spine, as well as limitation of range or movement of the neck,
are the typical findings.
Paresthesia of the fingers is the most common symptom of spinal cord compression.
Weakness of the arms and legs and inability to control the bladder or bowels are other

complaints that should suggest spinal cord compression. During the initial stages,
exaggerated deep tendon reflexes and an extensor plantar reflex are noted. Chronic
myelopathy results in muscle atrophy and loss of deep tendon reflexes. Lateral
radiographs of the neck in flexion and in extension are required for complete evaluation
of the cervical spine. The patient should be asked to actively and slowly flex and


extend the neck to tolerance without discomfort; care should be taken not to force these
movements. On some occasions, CT or MRI may be indicated.
The distance between the anterior surface of the odontoid and the posterior surface
of the anterior arch of atlas when measured in a lateral film with neck in flexion is
usually 4 mm or less. In the presence of AA subluxation, this may be as wide as 10 to
12 mm ( Fig. 101.10 ). Other radiologic abnormalities characteristic of cervical spine
involvement in JIA include loss of curvature, osteoporosis, erosions and sclerosis of
joints, disc-space narrowing, and altered height-to-width ratio of the vertebral bodies.
Although most children with AA subluxation do not have evidence of spinal cord
compression, the physician must be wary of its occurrence with excessive movement,
as occurs during endotracheal intubation. Regular use of a light plastic cervical collar is
often all that is required to relieve pain and prevent excessive anterior flexion,
particularly during automobile rides. In the presence of spinal cord compression,
surgical stabilization may be required.