9%20ECOGRAFIA%20ABDOMINAL%20COMO%20CUANDO%20DONDE

108
ABDOMINAL ULTRASOUND
RHV
MHV
HV
A
B
Figure 4.26 (A) Budd–Chiari syndrome (BCS). The MHV
is tortuous and strictured, and difficult to identify on
ultrasound. (B) Large collaterals are seen (arrows) near
the surface of the liver in BCS. (C) Tumour thrombus
from a renal carcinoma occludes the inferior vena cava
(IVC), causing BCS.
C
Dilated serpiginous collateral veins may form to
direct blood away from the liver and in some cases
the portal venous flow reverses to achieve this. The
spleen also progressively enlarges and, if the disease
is long-standing, the liver becomes cirrhotic,
acquiring a coarse texture.
Ascites may also be present, particularly if there
is complete obstruction involving the IVC. The
cause of IVC obstruction may be a web, which can
occasionally be identified on ultrasound. If the
cause of BCS is a coagulation disorder, the portal
venous system may also be affected by thrombosis,
causing portal hypertension.
Doppler is particularly helpful in diagnosing
BCS. 21 The hepatic veins and IVC may be totally
or partially occluded; if partial, the waveforms may
become flattened, losing their characteristic triphasic
pattern. In some cases flow may be reversed in
the IVC, hepatic and/or portal veins. Ultrasound
may miss partial hepatic vein occlusion, but the use
of contrast agents in suspected cases of BCS may
improve diagnostic accuracy.
Management of Budd–Chiari syndrome
This depends upon the cause. Both medical and
surgical treatments have mixed success. Severe
coagulative disorders may have to be transplanted,
although there is a significant risk of recurrence. If
the cause is an IVC web, this may be surgically