Causes of Hemolytic Disease of the Newborn
Hemolytic disease of the newborn (HDN), also known as erythroblastosis foetalis (Hatfield, 2007), is a condition which results due to the bloods of the foetus and that of the mother being incompatible. This happens if the fetus expresses rhesus D (RhD) in the red blood cells whereas the mother’s RBCs do not express the antigens. The immune system of the mother mounts immunity against the baby’s Rh(D) antigens. The Rh antibodies attack the RBCs of the foetus causing hemolysis, better known as the hemolytic disease of the newborn.
The rhesus antibody (Rh antibody) is primarily the etiology of the hemolytic disease of the newborn. Severe cases of HDN occur in cases where the Rh (D) is activated. It has also been identified that some alloimmune antibodies have a role is the development of the hemolytic disease of the newborn. Wagle and Deshpande (2010) indicate that “alloimmune antibodies belonging to the K (K and k), Duffy (Fya), Kidd (Jka and Jkb), and MNSs (M, N, S and s) systems (para. 4)” can also contribute to the development of the disease. Significant HDN occurs if the concentration of the RhD, anti-K or anti-C concentrations are high enough. It is important to note that the disease is hereditary in that the rhesus antigen positive foetus acquires the antigens from the father. These antigens cross the placenta in case of hemorrhage involving disruption of the placenta such as during delivery (Davis, Davies & Lip, 2007). In most cases, the first baby does not experience the disease since the mother’s blood has not been sensitized. However, subsequent births become more prone to the condition since the mother’s immune system has been sensitized and rhesus D antibodies concentration has increased (Dean & NCBI, 2005).
Antibodies associated with ABO system are also linked with the development of the hemolytic disease of the newborn. Although it is not common to have the blue baby disease being caused by the Kell system antibodies, these cells cannot be ruled out as possible etiology. It is also notable that Duffy and MNSs system antibodies are possible causes of the disease, despite being in rare cases only. In HDN where incompatibility involves the ABO system, three conditions are most likely to be the cause. These include: a blood type O mother who carries a blood type A or B foetus (which is the most common type of incompatibility), a blood type A mother who bears a blood type B foetus and a blood type B mother bearing a type B baby. Whereas severe form of erythroblastosis foetalis occurs due to activation of RhD, incompatibility of the ABO system causes a less severe form of the disease (Lucile Packard Children’s Hospital, 2010).
Possible Exam Questions
- What is hemolytic disease of the newborn?
- Describe the pathogenesis of the hemolytic disease of the newborn.
- Explain the various causes of HDN.
- Describe the hereditary possibilities that lead to the hemolytic disease of the newborn.
- How can the HDN be prevented and treated?
References
Davis, R. C., Davies, M. K. and Lip, G. Y. H. (2007). ABC of heart failure. Fourth edition. Oxford, UK: Blackwell Publishing Ltd.
Dean, L. and NCBI. (2005). Blood groups and red cell antigens. Bethesda MD: NCBI.
Hatfield, N. T. (2007). Broadribb’s introductory pediatric nursing. 7th edition. Philadelphia, PA: Lippincott Williams & Wilkins.
Lucile Packard Children’s Hospital. (2010). Hemolytic disease of the newborn. Web.
Wagle, S. and Deshpande, P. G. (2010). Hemolytic disease of the newborn. emedicine. Web.