Diagnostic ultrasound ( PDFDrive )

CHAPTER 41 Fetal Hydrops 1419
A
B
FIG. 41.10 Skin Thickening in Fetus With Hydrops. (A) Transverse view of skull shows marked edematous appearance of the skin (arrows).
(B) In the same fetus, transverse M-mode image of fetal thorax shows normal cardiac rhythm, bilateral pleural effusions, and marked skin
thickening.
A
B
FIG. 41.11 Scalp and Body Wall Edema Are Measured Differently. (A) Fetal scalp edema. Head measurements (cursors) are obtained
around the bone, not the skin. (B) Abdominal wall thickening. Abdominal wall measurements are obtained around the abdomen, including the
skin thickening. Note that gestational age is 27 weeks by head circumference (HC) but 34 weeks if only abdominal circumference (AC) is used.
BPD, Biparietal diameter.
metabolic efects, and thus the pattern of hydrops may evolve
over time.
IMMUNE HYDROPS
Immune hydrops, or erythroblastosis fetalis, occurs when a
sensitized mother develops antibodies to fetal RBCs that lead to
hemolysis. Circulating maternal immunoglobulin G (IgG) antibodies
cross the placenta and attack antigen-positive fetal RBCs. he
majority of cases still occur in the presence of Rh(D) antibodies.
Other antibodies such as Kell, Rh(C), and Rh(E) develop in 1%
to 2% of individuals ater blood transfusion and cause 2% of
hemolytic disease of the fetus. he result is anemia, extramedullary
erythropoiesis, hepatosplenomegaly, hypoalbuminemia,
and congestive heart failure. Hydrops develops when the fetal
hemoglobin (HbF) deicit exceeds 7 g/dL, 16 probably because
of reduced oncotic pressure secondary to hypoalbuminemia,
combined with high-output cardiac failure. Eventually, the fetus
develops both metabolic and lactic acidosis, 17,18 and once this
decompensation occurs, progression of hydrops is rapid, leading
to fetal demise within 48 hours.
Causes of maternal sensitivity include fetal maternal hemorrhage
and transplacental hemorrhage. In women with incompatible
blood types with respect to the fetus (Rh alloimmunization
or other RBC antigen), antibodies can be made. his typically
occurs ater delivery of the irst pregnancy and therefore will
afect the second pregnancy. Other times of blood sharing include
miscarriage, therapeutic abortion, amniocentesis, placental