L.5 Haemolytic Disease of Newborn Flashcards by neasa ni ogain

Who were the first to demonstrate foetal/maternal blood group incompatibility as a mechanism for HDN?

Levine and Stetson (1939)

HDN stands for Hemolytic Disease of the Newborn.

How well did you know this?

Not at all

Perfectly

What is a normal physiological event involving the transfer of antibodies from mother to foetus?

Maternal transfer of IgG antibodies

IgG antibodies are crucial for providing passive immunity to the foetus.

How well did you know this?

Not at all

Perfectly

What leads to a total cure for the newborn after birth in cases of HDN?

No further transfer of antibody if treatment is prompt and complete

Prompt treatment can offset complications from gross red cell haemolysis.

How well did you know this?

Not at all

Perfectly

What is the most common cause of HDN?

Anti-D

Anti-D refers to antibodies against the RhD antigen.

How well did you know this?

Not at all

Perfectly

Do other IgG blood group antibodies cause HDN to the same extent as Anti-D?

Many other IgG blood group antibodies have caused HDN, but not as significantly as Anti-D.

How well did you know this?

Not at all

Perfectly

Does the first pregnancy normally immunize the mother?

Some foetal RBCs can enter the maternal circulation during the first pregnancy, but this does not typically lead to immunization.

How well did you know this?

Not at all

Perfectly

What is the danger period for RhD negative mothers after the birth of a RhD positive baby?

The first 72 hours after birth

This period is critical due to potential sensitization to Rh antigens.

How well did you know this?

Not at all

Perfectly

How can foetal RBCs enter the mother’s circulation?

Through breaks in the placenta during delivery, trauma, or miscarriage

This entry can trigger an immune response in Rh-negative mothers.

How well did you know this?

Not at all

Perfectly

What happens if a Rh-negative mother has a Rh-positive foetus?

The maternal immune system produces IgG antibodies against Rh antigens = Anti-Rh antibodies

This process is known as alloimmunization or sensitization.

How well did you know this?

Not at all

Perfectly

What occurs during subsequent pregnancies with a Rh+ foetus in a sensitized mother?

Maternal IgG anti-Rh antibodies can cross the placenta and bind to Rh antigens on foetal RBCs

This leads to the destruction of foetal RBCs via phagocytosis.

How well did you know this?

Not at all

Perfectly

What condition results from continuous RBC destruction in the foetus?

Severe anaemia

This can lead to significant health issues for the developing foetus.

How well did you know this?

Not at all

Perfectly

What compensatory response occurs in the foetus due to severe anaemia?

Increased erythropoiesis and release of nucleated RBCs into circulation

The foetus attempts to overcome the anaemia by producing more red blood cells.

How well did you know this?

Not at all

Perfectly

What is the term for the condition characterized by the presence of immature red blood cells in the foetus?

Erythroblastosis foetalis

This condition is a direct result of the maternal immune response against foetal RBCs.

How well did you know this?

Not at all

Perfectly

What serious consequence does severe anaemia in the foetus lead to?

Tissue hypoxia and cardiac failure

This can result in fluid leakage into foetal tissues, causing oedema.

How well did you know this?

Not at all

Perfectly

What is the life-threatening condition resulting from fluid leakage into foetal tissues?

Hydrops foetalis

This condition is characterized by excessive fluid accumulation in the foetal compartments.

How well did you know this?

Not at all

Perfectly

What leads to excess breakdown of haemoglobin in HDN?

Haemolysis

Haemolysis in HDN results in increased unconjugated bilirubin levels.

How well did you know this?

Not at all

Perfectly

What role does the maternal liver play in bilirubin elimination during pregnancy?

Helps eliminate bilirubin

The maternal liver assists in bilirubin elimination in utero.

How well did you know this?

Not at all

Perfectly

Why is the neonatal liver unable to efficiently conjugate bilirubin after birth?

Immature neonatal liver

After birth, the support from the maternal liver is lost, impacting bilirubin processing.

How well did you know this?

Not at all

Perfectly

What is the effect of limited neonatal albumin on bilirubin?

Binds bilirubin is limited

Limited neonatal albumin contributes to increased levels of unconjugated bilirubin.

How well did you know this?

Not at all

Perfectly

What condition can unconjugated bilirubin cause due to its lipophilic nature?

Kernicterus

Unconjugated bilirubin can cross the blood-brain barrier and cause kernicterus.

How well did you know this?

Not at all

Perfectly

What percentage of affected fetuses are born with pallor?

25-30%

Pallor is one of the clinical presentations observed in affected fetuses.

How well did you know this?

Not at all

Perfectly

How soon after birth does progressive jaundice develop in affected infants?

Within hours to days

Jaundice is a critical sign to monitor post-birth in these infants.

How well did you know this?

Not at all

Perfectly

When do neurological signs typically appear in infants with HDN?

Within 3-4 days

Early recognition of neurological signs can be vital for management.

How well did you know this?

Not at all

Perfectly

What percentage of infants with HDN die without intervention?

90%

Most deaths occur due to respiratory arrest from kernicterus.

How well did you know this?

Not at all

Perfectly

What are some potential outcomes for the 10% of infants who survive HDN?

Severe brain damage such as: * Hearing loss * Cerebral palsy * Intellectual disability ## Footnote Survivors may face significant long-term disabilities.

What tests are performed during the first prenatal visit for HDN?

ABO and Rh grouping, antibody screening ## Footnote Initial tests help assess the risk of HDN.

What follows if the antibody screen is positive?

Perform antibody identification ## Footnote Identifying specific antibodies is crucial for risk assessment.

What is quantitated at 28 weeks if Anti-D is present?

Quantitation of Anti-D ## Footnote Monitoring Anti-D levels helps manage Rh incompatibility.

What does cffDNA testing determine?

RH group of fetus ## Footnote PCR on maternal blood can indicate the fetal RhD status.

What indicates that the fetus is RhD positive?

Presence of RhD positive DNA in PCR ## Footnote This finding is crucial for managing RhD incompatibility.

What procedure measures bilirubin levels in the fetus?

Amniocentesis ## Footnote Amniocentesis is used to evaluate fetal health in suspected HDN.

What does chorionic villus sampling measure?

Hb Anaemia ## Footnote Doppler ultrasound is now used to assess this condition.

What can Doppler ultrasonography detect in fetal health?

Fetal anaemia ## Footnote It evaluates cardiac output and blood viscosity.

How is the severity of fetal anaemia determined?

Evaluating peak systolic velocity in the middle cerebral artery ## Footnote This measurement helps assess the degree of anaemia.

What is the purpose of scanning amniotic fluid spectrophotometrically in aminocentesis?

To measure bilirubin by analyzing optical density (ΔOD) from 350 to 700 nm ## Footnote A change in optical density above baseline (450 nm) indicates bilirubin levels.

What does a ΔOD plotted on a Liley graph indicate?

The severity of hemolytic disease of the newborn (HDFN) ## Footnote Zones on the graph indicate: Zone 3 - severe HDFN, Zone 2 - moderate disease, Zone 1 - mild disease.

What is the upper zone on the Liley graph indicative of?

Severe hemolytic disease of the newborn (HDFN)

What does the middle zone on the Liley graph indicate?

Moderate disease

What is indicated by the lower zone on the Liley graph?

Mild disease

What is a key strategy for the prevention of HDN regarding ABO incompatibility?

Early recognition reduces the risk of Rh sensitization by clearing ABO-incompatible fetal RBCs ## Footnote This prevents the immune system from fully reacting to Rh antigens.

What was hypothesized about injecting Anti-D to prevent HDN?

It might mimic the protective effect of rapid clearance of D+ fetal RBCs from maternal circulation.

What was the purpose of injecting Rh D-negative volunteers with Rh D-positive red cells?

To identify 'good responders' for plasma donation to produce anti-D immunoglobulin.

When was RhIg developed and by whom?

In the mid-60s by Clarke et al in Liverpool and Levine et al in the USA.

What is RhIg?

A blood product, virus inactivated, from fractionation of plasma.

When is RhIg administered to Rh D negative mothers?

Within 72 hours of the birth of an Rh D positive baby.

What does RAADP stand for?

Routine antenatal anti-D prophylaxis

When did prenatal administration of RhIg start in Ireland?

In 2019 for Rh D negative females with Rh D positive fetuses.

What are some reasons for the failure of preventing HDN?

Anti-D not given, insufficient dosage, not given in time (<72hrs), silent FMH, large FMH, another antigen causing HDN ## Footnote Example of another antigen: Anti-Fy(a).

In which situations is RhIg not needed?

If the mother is sensitized, baby is Rh D-negative, mother has a weak D phenotype, or woman is not of childbearing potential.

True or False: RhIg is necessary if the mother is already producing anti-D antibodies.

False

Fill in the blank: RhIg is not required if the mother has a _______ phenotype.

weak D

What condition must be met for RhIg administration to be effective?

It must be given within 72 hours of birth.

What is the Kleihauer-Betke acid elution technique used for?

To calculate the appropriate dose of RhIG required after delivery/foetal-maternal trauma. ## Footnote It distinguishes fetal hemoglobin from adult hemoglobin based on their acid resistance.

What happens to fetal cells and adult cells during the Kleihauer-Betke technique?

Fetal cells remain pink while adult cells become ghost cells.

What is the purpose of the Rosetting technique?

Qualitative screening test to detect small numbers of Rh D-positive fetal cells in Rh D-negative maternal cells.

What volume of fetal-maternal bleeds can the Rosetting technique detect?

Approximately 10 mL or more.

What does flow cytometry use to quantify Rh D-positive fetal red cells?

Fluorescently labelled anti-D antibodies.

How does flow cytometry compare in terms of sensitivity and accuracy?

Highly sensitive and accurate method.

What does the Direct Coombes test detect?

Maternal antibodies bound to fetal RBCs.

What is the focus of treatment if hemolytic disease of the newborn (HDN) has already occurred?

Managing complications.

What is one prenatal intervention for HDN?

Intrauterine transfusions.

How are intrauterine transfusions administered?

Given directly to the fetus, usually via umbilical vein.

What was the historical use of plasma exchange in mothers?

To reduce maternal antibody levels.

What does an exchange transfusion do postnatally?

Removes antibody-coated fetal red cells and replaces them with Rh-negative donor cells.

What is the purpose of phototherapy in managing HDN?

To convert unconjugated bilirubin into water-soluble forms that can be excreted.

What condition does phototherapy help prevent?

Bilirubin buildup and neurologic damage (kernicterus).

What is a risky and uncommon treatment for HDN?

Intrauterine transfusion.

What type of blood is given during an exchange transfusion after delivery?

Blood ‘compatible’ with mother’s antibody, e.g., Group O Rh D Negative if the causative antibody is Anti-D.

What are the criteria for blood transfusion given to a fetus?

Leucocyte depleted, CMV negative donor, irradiated, small volume, HbS negative.

What is ABO HDN?

When Group O mothers with A or B give birth to babies.

Can the first pregnancy of a Group O mother be affected by ABO HDN?

Yes, it can be affected.

What is the usual disease state of ABO HDN?

Mild.

What is the causative antibody in ABO HDN?

Anti A + B (large IgG component).

When is action usually required in cases of ABO HDN?

After delivery if evidence of RBC destruction exists.

What type of blood is required if needed in ABO HDN?

Group O, D compatible blood.