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pancreatitis or gastric ulcer, both of which may occur from the disease or secondary to
medical therapy. Malabsorption syndrome may be a manifestation of SLE. When
accompanied by melena, it suggests poorly controlled disease complicated by GI
vasculitis. This is associated with a 50% mortality rate without expeditious evaluation
and treatment. Of course, abdominal pain in SLE is not always related to the
underlying disease but may stem from other causes, including appendicitis, ruptured
ovarian cyst, or pelvic inflammatory disease. Further complicating evaluation is the
fact that manifestations of any of these conditions may be masked or altered by the
corticosteroids and immunosuppressive agents most patients receive.
Mild to moderate anemia is common in SLE. Hemolytic anemia associated with a
positive Coombs test is most characteristic. An acute decrease in the hemoglobin or
hematocrit should alert the physician to the possibility of internal hemorrhage or
massive hemolysis. Autoimmune thrombocytopenia, even in the absence of offending
drugs, is commonly seen in SLE; up to 20% of adults initially diagnosed with
idiopathic thrombocytopenic purpura (ITP) progress to full-blown lupus over the
ensuing years. Leukopenia and lymphopenia are additional hematologic abnormalities
characteristically seen in SLE; apart from viral infections and drug toxicity, few other
conditions cause children’s lymphocyte counts to fall to <1,000/mm3. Circulating
antibodies to specific clotting factors, deficiencies of one or more clotting factors, and
abnormal platelet function, often lead to abnormal hemostasis in SLE. A specific
circulating anticoagulant, the “lupus anticoagulant,” has been described in up to 10% of
patients. The antibody is so named because in vitro assays of coagulation are prolonged
in its presence. In vivo, this antibody predisposes to arterial or venous thrombosis.
Proteinuria, hematuria, and cellular casts are the usual urinary abnormalities. Acute
renal failure and nephrotic syndrome are possible complications of SLE (see Chapter
100 Renal and Electrolyte Emergencies ).
The most important single test in children suspected of having SLE is measurement
of antinuclear antibody (ANA) titers. Up to 2% of normal children have low to
intermediate titers of ANA; in most cases, these antibodies are transient by-products of
a viral infection. In SLE, the ANA titer is typically quite high—significant levels are
greater than 1:640 and often it is accompanied by antibodies to double-stranded DNA,

a more specific marker for lupus. The level for the anti–double-stranded DNA (anti-ds
DNA) should be above the laboratory reference range, and if tested by ELISA, should
be twice that of the upper limit of the laboratory reference range. Antiphospholipid
antibodies may be positive as determined by detecting any of the following: the lupus
anticoagulant, false-positive RPR, medium- or high-titer anticardiolipin (IgA, IgG, or
IgM), or presence of anti–beta-2 glycoprotein I antibodies (IgA, IgG, or IgM). Finally,
low complement levels: C3, C4, or total CH50, and a direct Coombs test in the absence
of hemolytic anemia, are the additional immunologic tests that may point the clinician
to a diagnosis of SLE. Nonetheless, it must be remembered that SLE may only be