Book of Medical Disorders in Pregnancy - Tintash

Blood brain barrier and bilirubin
encephalopathy: This barrier prevents
free union gusted bilirubin from crossing
from blood to brain. The barrier is less
effective in premature infants and in
unwell infants, in bilirubin encephalopathy
there will be Hypotonia, High piyched
cry and Seizures, Long term
sequelae of encephalopathy will result in
Athetoid CP or Endoneural deafness.
Prolonged jaundice:
Common in breast fed infants; around
20% it is very co-mmon in premature
breast fed infants where it is >30%
Investigations of persistent Jaundice
for more than 2 week:
Blood for split bilirubin check urine for
WBC ‘S, urobilinogen screen for TSH.
Phototherapy:
The efficacy of phototherapy depends on
the spectrum of light deviled, the blue –
green region of visible light being the
most effective; irradiance (mW/cm2nm);
and surface area of the infant exposed.
Nonpolar bilirubin is converted into 2
type of water soluble photo isomers as a
result of phototherapy. The initial and
most rapidly formed configurational
isomer 4z, 15e bilirubin accounts for
20% of total serum bilirubin level in
newborn undergoing phototherapy and is
produced maximally at conventional
levels of irradiance (6-9 mW/cm2/nm).
The structural isomer lum rubin is formed
slowly and its formation is irreversible
and is directly proportional to
the irradiance of phototherapy on skin.
Lum rubin is the predominant isomer
formed during high intensity
phototherapy. Decrease in bilirubin is
131
mainly the result of excretion of these
photo products in bills and removal via
stool. In the absence of conjugation,
these ph-oto isomers can be reabsorbed
by way of the enterohepatic circulation
and dimin-ish the effectiveness of
phototherapy.
Indications of phototherapy: It should
be used only when significant
unconjugated (indirect) hyperbilirubinemia
is present. Its use with
elevated conjugated (direct) bilirubin
levels is contraindica-ted. Skin jaundice
is not a reliable indi-cator of serum
bilirubin level, therefore determination
of serum bilirubin level of infants
receiving photo therapy is necessary.
The eyes of the babies receiving photo
therapy should be protected from intense
light. Conjunctivitis and corneal abrasion
may occur if eyes are not protected.
Water intake should be increased during
photo therapy.
Exchange transfusion - Neonatal
mortality can be reduced to less than 5
per cent and kernicterus, almost eliminated
by this method. Anemia as well as
excess fluid containing anti-bodies and
bilirubin can be removed along with the
bulk of the infant's vulnerable red cells
and substituted with red cells that are
compatible with the maternal antibodies.
Nearly a third of the total bilirubin in the
body can be removed with the infant's
blood. In case of congestive heart failure
more blood is removed than given. The
aim should be to reduce the venous
pressure to normal. Venous pressure can
be measured by the same plastic tubing
inserted into the umbilical vein for
exchange transfusion. Normal venous
pressure is usually less than 7 em of
water. About 10 ml. of blood is