C h a p t e r 4 4
Disorders of the Skeletal System: Metabolic and Rheumatic Disorders
1127
elevated ESR. The person also may have a mild normo-
cytic normochromic anemia. HLA typing is not diag-
nostic of the disease and should not be used as a routine
screening procedure. Radiologic evaluations help dif-
ferentiate ankylosing spondylitis from sacroiliitis due to
other diseases. However, x-ray images may be normal
in early disease. One important advance in diagnosis of
ankylosing spondylitis is the use of magnetic resonance
imaging (MRI) to assess sacroiliac changes.
51
Whereas
plain radiographic images can detect structural changes
such as joint erosion and subchrondral bone sclerosis
seen in the late stage of the disease, MRI allows for the
visualization of synovial fluid, synovitis within the sac-
roiliac joint, and subchondral bone edema seen in ear-
lier stages of the disease.
51
Treatment of ankylosing spondylitis is directed at
controlling pain and maintaining mobility by suppress-
ing inflammation.
54
Proper posture and positioning are
important. This includes sleeping in a supine position
on a firm mattress and using one small pillow or no
pillow. A bed board may be used to supply additional
firmness. Therapeutic exercises are important to assist
in maintaining motion in peripheral joints and in the
spine. Muscle-strengthening exercises for extensor mus-
cle groups also are prescribed. Swimming is an excellent
general conditioning exercise that avoids joint stress and
enhances muscle tone. Immobilizing joints is not recom-
mended. Maintaining ideal weight reduces the stress
on weight-bearing joints. Deep breathing exercises and
avoidance or discontinuation of smoking should be
emphasized.
Pharmacologic treatment includes the use of NSAIDs
to reduce inflammation, relieve pain, and reduce mus-
cle spasm. Disease-modifying antirheumatic drugs are
potential second-line therapies, but their efficacy in anky-
losing spondylitis is unproven. Sulfasalazine and metho-
trexate have not shown benefit for spondylitis-associated
back pain, but have shown efficacy for peripheral joint
involvement. Anti–TNF-
α
therapies, including etaner-
cept, infliximab, adalimumab, and golimumab, have
demonstrated rapid effectiveness in reducing both the
axial and peripheral symptoms of ankylosing spondyli-
tis, as well as improving quality of life.
54
The disease process in ankylosing spondylitis var-
ies considerably among individuals. Exacerbations and
remissions are common; almost all persons have persis-
tent symptoms over decades. Fortunately, most of those
affected are able to lead productive lives. Progression
during the first decade of the disease tends to predict the
prognosis.
Reactive Arthritis
Reactive arthritis is an inflammatory joint disorder that
arises after certain inciting gastrointestinal or genitouri-
nary tract infections and manifests as a sterile oligoar-
thritis, typically of the lower extremities.
55
Most cases
of reactive arthritis develop after either a gastrointes
tinal infection (
Salmonella, Shigella, Campylobacter,
or
Yersinia
) or sexually transmitted infection (
Chlamydia
trachomatis
). The infecting agents cannot be cultured
and are not viable after reaching the joints. A clinically
indistinguishable syndrome can occur without anteced-
ent infection, suggesting that subclinical infection or
some other unrecognized agent can precipitate reactive
arthritis.
Reiter syndrome
is a form of reactive arthritis
defined by a triad of arthritis, nongonococcal urethritis
or cervicitis, and conjunctivitis.
3
Enteropathic arthritis
is a reactive arthritis that is associated with inflamma-
tory bowel disease (i.e., Crohn disease and ulcerative
colitis) or triggered by enterogenic bacteria.
Clinical Manifestations.
Reactive arthritis is most
commonly asymmetric and frequently involves the
lower extremities. Symptoms typically start within 1 to
4 weeks of the initial infection. Hip disease is uncom-
mon and involvement of the upper extremities is rare.
The joints are typically warm, swollen, and tender.
Systemic manifestations including fever and weight loss
are common at the onset. Enthesitis is a common fea-
ture of reactive arthritis. The Achilles tendon and plan-
tar fascia are the most common sites of involvement,
but pain in the iliac crests, ischial tuberosities, and back
may occur. This aspect of the disease can be disabling,
with marked restriction in weight bearing and ambu-
lation. Extra-articular lesions are common and include
circinate balanitis (shallow ulcers on the glans or shaft
of the penis), stomatitis (e.g., painless oral ulcers on the
hard palate or tongue), and keratoderma blennorrhagi-
cum (a papulosquamous rash most commonly affecting
the palms of the hands and soles of the feet [Fig. 44-9]).
While most of the signs and symptoms disappear within
days or weeks, the arthritis may persist for several
months, and in a small number of cases, it may follow a
continuous and unremitting course.
Treatment.
The treatment is largely symptomatic.
NSAIDs are used in treating the arthritic symptoms.
55
Vigorous treatment of possible triggering infections is
thought to prevent relapses of reactive arthritis, but in
many cases the triggering infection passes unnoticed or
FIGURE 44-9.
Keratoderma blennorrhagica of soles due to
reactive arthritis (Reiter syndrome). (From the Centers for
Disease Control and Prevention Public Health Images Library.
No. 6950. Courtesy of M. F. Rein.)
