44. Rh-isoimmunization in pregnancy.Pathophysiology , diagnosis , amniocentesis and treatment.

Question 1

pathophysiology if rh isoimunisation?

Answer 1

mother is rhesus negative

bu tahe baby is rhesus positive (because father is rhesus positive)

when the fetal blood gets into the mothers blood

anti rhesus antibodies will be formed - and the fetal red blood cells are destroyed

usually no harm IN THE CURRENT PREGNANCY

however IN FUTURE PREGNANCY - the antibodies will be able to cross the placental barrier
and attack the blood cells - hemolytic anemia or hemolytic disease of a new born
or erythroblastosis fetalis

Question 2

what are the sensitising events where the baby’s blood can get into the mothers blood stream?

Answer 2

miscarriage 
abdominal trauma 
placental abruption
during normal vaginal delivery
ECV 
amniocentesis

Question 3

how can we prevent hemolytic diseases associated with rhesus antigen ?

Answer 3

check the rhesus status - if positive no worries
if negative we assume the baby is rhesus positive

anti d antibodies - IM injection at any point the mother might be sensitised

destroys the fetal blood cells - before the the mother has an immune response

Question 4

what re the erythroblastosis fetalis complication ?

Answer 4

hydros fetals

most serious form of Rh hemolytic disease (HDFN).

Excessive destruction of the fetal red cells leads to severe anemia, tissue anoxemia and metabolic acidosis damage to the liver leading to hypoproteinemia which is responsible for generalized edema (hydrops fetalis) ascites and hydrothorax. Fetal death occurs sooner or later due to cardiac failure

The baby is either stillborn or macerated and even if born alive, dies soon after

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icterus gravis

Question 5

diagnosis for hydros fetalis ?

Answer 5

mother is Rh-negative;

(2) serological examination reveals
presence of Rh-antibody;

(3) may be polyhydramnios;

sonography—(real time combined with
pulse Doppler) to detect edema in the
skin, scalp and pleural or pericardial
effusion and echogenic bowel;

(6)
straight X-ray abdomen showing—
“Buddha” position of the fetus with a
halo around the head due to edematous
scalp;