Anemia/Polycythemia Flashcards
twin to twin transfusion syndrome
- hemorrhage*
- occurs in monozygotic, monochorionic twin pregnancies
- Hgb difference between twins > 5 g/dL
- often size discrepancy as well: >20% difference with chronic hemorrhage
- smaller twin has elevated retic count d/t chronic blood loss
placental/cord problems
- hemorrhage*
- umbilical cord rupture
- cord or placental hematoma
- anomalous cord insertion
- rupture of anomalous vessels of cord or placenta
- accidental incision of cord or placenta
- placenta previa or placental abruption
fetal/maternal hemorrhage
- spontaneous
- from traumatic amniocentesis
- external cephalic version?
gold standard to detect fetal/maternal hemorrhage?
Kleihauer-Betke test
Internal causes of hemorrhage
- intracranial (subdural, subarachnoid, intraventricular), smbgaleal
- organ rupture (liver, spleen, adrenal, kidney)
- pulmonary
external causes of hemorrhage
- phlebotomy
- iatrogenic
Rh Blood group incompatibilities
hemolysis
also called erythroblastosis fetalis
What causes Rh incompatibilities
hemolysis
Rh+ fetal cells enter the bloodstream of an Rh- mother resulting in maternal antibody production to the Rh+ fetal cells
-subsequent pregnancies will have destruction of fetal RBCs if the fetus is Rh+
What to look for in Rh incompatibility?
- hemolysis*
- anemia: ongoing hemolysis
- tissue hypoxia, acidosis: decreased oxygen carrying capacity
- congestive heart failure & hydrops fetalis: generalized edema d/t increased blood volume and cardiac output
- ascites, pleural effusion: collection of fluid
- hepatosplenomegaly: increased extramedullary hematopoiesis
- petechiae: thrombocytopenia
- hypoglycemia: hyperinsulinemia d/t RBC destruction
- positive direct coombs test result
- increased retic count: ongoing hemolysis
ABO blood group incompatibilities
- hemolysis*
- most commonly seen with O blood type mother carrying fetus with A or B blood type
How does ABO incompatibility occur?
-can occur with 1st pregnancy d/t to maternal exposure to A & B antigens (food, bacteria, pollen) that results in production of anti-A and anti-B antibodies
What to look for in ABO incompatibility?
- mild hemolysis
- anemia
- reticulocytosis
- hyperbili
How to treat ABO and Rh incompatibilities?
- RhoGAM
- phototherapy
- good hydration
- IVIG 1 gm/kg over 4 hrs
- consider blood or exchange transfusion
What does RhoGAM do?
RhoGAM: for Rh- mothers; prophylactic anti-D immune globulin
-blocks maternal antibody production by destroying fetal red blood cells in maternal circulation
When should RhoGam be given?
-given at 28 weeks, then again within 72 hours following delivery and any time there may be fetal-maternal blood mixing in Rh- pregnant women
G6PD (glucose-6-phosphate dehydrogenase deficiency)
- hemolysis*
- most common inherited red cell disorder
- sex linked, mainly male offspring, occasional female carriers
- most common in American black infants, also mediterranean, african, asian descent
Pathogenesis of G6PD
- hemolysis*
- hemolysis and shortened erythrocyte life due to deficiency of red cell enzyme and exposure to antioxidant stress (drugs, infection)
Infection
- hemolysis*
- intrauterine: TORCH (rubella and parvo cause decreased RBC production in addition to hemolysis, thus increased risk for hydrops)
- postnatal: bacterial infections
- both may cause hemolysis, anemia, thrombocytopenia, DIC
About anemia of prematurity
-considered physiologic
How does anemia of prematurity happen?
- erythropoietin falls to minimal level d/t improved relative oxygenation after birth
- Hgb falls by 1 g/dL/week in preterm infants starting at 2 weeks of age to an average nadir of 7-9 g/dL at 6 to 8 weeks of life
- smaller/more immature infants will reach lower nadir at earlier age d/t shortened RBC life span
- premature infants have persistent hepatic pathway
- ensuing anemia triggers a hypoxic stimulus, thus increasing the presence of erythropoietin and ultimately RBC production
What to look for with anemia of prematurity?
- symptoms of hypoxia: poor feeding, poor weight gain, dyspnea, tachypnea, tachycardia, diminished activity, pallor, increased A/B events
- retic count
How to treat anemia of prematurity?
- minimize blood losses
- iron supplementation
- transfusion
- EPO
Iatrogenic anemia
caused by the need for frequent blood sampling of critically ill infants
-removal of >20% of blood volume over 24-48 hours can produce anemia
Findings with acute blood loss
- pallor followed by cyanosis and desaturation
- shallow, rapid, irregular respirations
- tachycardia
- weak or absent peripheral pulses
- low or absent blood pressure
- acidosis
