is minimal, the physical findings
may not be prominent
and the diagnosis may be more difficult to establish.
Today, establishing the underlying diagnosis and etiolo-
gy of SVCS has become more important because cer-
tain disorders that cause SVCS may be more amenable
to specific treatment regimens. For example, small cell
lung carcinoma and lymphoma respond dramatically to
chemotherapy/irradiation, whereas thrombosis from a
central line catheter does not respond to this treat-
ment.
4 –12
Laboratory Studies
Chest radiography.
The initial diagnostic test for sus-
pected SVCS is chest radiography. Although this test is
not specific for SVCS, chest radiography may be helpful
in identifying the cause of the disorder. Findings on chest
radiography that may be helpful include widening of the
superior mediastinum, pleural effusions, and a hilar or
mediastinal mass, usually on the right side (Table 3).
These radiologic findings usually suggest an underlying
malignancy, whereas calcified lymph nodes may be more
predictive of granulomatous disease. However, the results
of chest radiography may appear normal despite an
obstruction in the superior vena cava. In the absence of
previous catheterization or surgery, a normal result on
chest radiography in a patient with SVCS is almost
pathognomonic of chronic fibrous mediastinitis.
2–12
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