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UPSC MainsMEDICAL-SCIENCE-PAPER-II201518 Marks
Q14.

Rh Incompatibility & Neonatal Jaundice: Diagnosis

A term neonate born to Rh negative mother is brought at 22 hours of life with jaundice, fever and one episode of convulsion. (i) What is the most likely diagnosis and its basis? (ii) Enumerate the key investigations and principles of management. (iii) List four important long-term complications of this disease. (iv) Mention the preventive measures.

How to Approach

This question requires a systematic approach focusing on a likely diagnosis given the clinical presentation, followed by investigations, management, long-term complications, and preventive measures. The answer should demonstrate understanding of Rh incompatibility, hemolytic disease of the newborn (HDN), and neonatal care protocols. Structure the answer into four distinct sections corresponding to the question's parts (i, ii, iii, iv). Prioritize clarity and conciseness, using medical terminology accurately.

Model Answer

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Introduction

Hemolytic Disease of the Newborn (HDN), historically known as erythroblastosis fetalis, is a condition caused by incompatibility between the blood types of the mother and fetus. The most common cause is Rh incompatibility, where an Rh-negative mother carries an Rh-positive fetus. This leads to maternal antibody production against fetal red blood cells, causing their destruction and resulting in anemia, jaundice, and potentially severe complications like hydrops fetalis. The presentation of a term neonate with jaundice, fever, and convulsions at 22 hours of life strongly suggests a severe form of HDN requiring immediate attention.

(i) Most Likely Diagnosis and its Basis

The most likely diagnosis is Severe Hemolytic Disease of the Newborn (HDN) due to Rh incompatibility. The basis for this diagnosis lies in the following:

  • Rh-negative mother with a potentially Rh-positive neonate: This sets the stage for alloimmunization.
  • Jaundice: Caused by the breakdown of red blood cells and subsequent bilirubin release.
  • Fever: Can be a sign of sepsis secondary to hemolysis or a manifestation of the hemolytic process itself.
  • Convulsions: Indicate severe hyperbilirubinemia leading to kernicterus (bilirubin-induced neurological damage).
  • Timing: Jaundice appearing within the first 24 hours of life is highly suggestive of HDN, as physiological jaundice typically appears later.

(ii) Key Investigations and Principles of Management

Key Investigations:

  • Blood Group and Rh Typing: Of both mother and neonate.
  • Direct Coombs Test (Direct Antiglobulin Test - DAT): Detects antibodies coating the fetal red blood cells. A positive DAT confirms the diagnosis.
  • Indirect Coombs Test (Indirect Antiglobulin Test): Detects maternal antibodies against Rh-positive red blood cells.
  • Complete Blood Count (CBC): To assess the degree of anemia.
  • Reticulocyte Count: Elevated in HDN, indicating increased red blood cell production.
  • Serum Bilirubin (Total and Direct): To quantify the severity of jaundice.
  • Peripheral Blood Smear: May show erythroblasts, confirming hemolysis.

Principles of Management:

  • Phototherapy: First-line treatment to convert bilirubin to a water-soluble form for excretion.
  • Exchange Transfusion: Indicated for severe hyperbilirubinemia unresponsive to phototherapy. It removes bilirubin and maternal antibodies, replacing them with Rh-negative blood.
  • Intravenous Immunoglobulin (IVIG): Can reduce the need for exchange transfusion by blocking the destruction of red blood cells.
  • Supportive Care: Maintaining hydration, glucose control, and monitoring for complications.
  • Monitoring: Continuous monitoring of bilirubin levels and clinical status.

(iii) Long-Term Complications

Four important long-term complications of HDN include:

  • Kernicterus: Permanent neurological damage due to bilirubin encephalopathy, leading to cerebral palsy, hearing loss, and intellectual disability.
  • Neurological Sequelae: Even without overt kernicterus, subtle neurological deficits can occur.
  • Growth Retardation: Chronic anemia can impair growth and development.
  • Splenomegaly: Chronic hemolysis can lead to splenic enlargement.

(iv) Preventive Measures

Preventive measures are crucial to avoid HDN:

  • Antenatal Rh Immunoglobulin (RhoGAM) Prophylaxis: Administered to Rh-negative mothers at 28 weeks of gestation and within 72 hours of delivery of an Rh-positive baby.
  • Postpartum Rh Immunoglobulin: Administered after any potentially sensitizing event (miscarriage, ectopic pregnancy, amniocentesis).
  • Prenatal Screening: Identifying Rh-negative mothers early in pregnancy.
  • Fetal Blood Grouping: Determining the fetal blood group via amniocentesis or chorionic villus sampling to assess the risk of incompatibility.

Conclusion

Severe HDN due to Rh incompatibility remains a significant cause of neonatal morbidity and mortality, despite advancements in prevention and treatment. Early diagnosis, prompt initiation of appropriate management, and diligent preventive strategies are essential to minimize the risk of long-term complications. Continued research into novel therapies and improved antenatal care protocols is crucial for further reducing the incidence and severity of this condition.

Answer Length

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Additional Resources

Key Definitions

Kernicterus
Brain damage caused by high levels of bilirubin in the blood of a newborn. It can lead to permanent neurological problems.
Alloimmunization
The process by which an individual develops antibodies against antigens present in another individual, such as in the case of Rh incompatibility where the mother develops antibodies against fetal Rh antigens.

Key Statistics

Approximately 1 in 10 babies born to Rh-negative mothers and Rh-positive fathers are at risk of developing HDN. (Based on knowledge cutoff 2023)

Source: American Pregnancy Association

The incidence of RhD alloimmunization has decreased significantly with the widespread use of RhD immunoglobulin prophylaxis, from approximately 16% to less than 1% in many developed countries. (Based on knowledge cutoff 2023)

Source: World Health Organization

Examples

Case of Severe HDN

A full-term neonate born to an Rh-negative mother presented with severe jaundice and lethargy. DAT was positive, and bilirubin levels were rapidly rising despite intensive phototherapy. Exchange transfusion was performed, and the infant required prolonged NICU care but ultimately recovered without significant neurological sequelae due to timely intervention.

Frequently Asked Questions

▶What is the role of amniocentesis in managing Rh incompatibility?

Amniocentesis can determine the fetal blood group and assess the severity of fetal anemia by measuring bilirubin levels in the amniotic fluid. This helps guide the timing of delivery and intrauterine transfusions if necessary.

Topics Covered

PediatricsNeonatologyJaundiceRh FactorNeonatal Care
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