Type 2 Tissue-Specific Hypersensitivity (Second Mechanism): Hemolytic Disease of the Fetus and Newborn by Steve Donkor https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0 A padlet on Type 2 Tissue-Specific Hypersensitivity (Second Mechanism): Hemolytic Disease of the Fetus and Newborn en-us 2022-10-14 17:07:02 UTC 2022-10-17 03:51:21 UTC hello@padlet.com Overview of Condition stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340791208 Type II hypersensitivity reaction refers to an antibody-mediated immune reaction in which antibodies (IgG or IgM) are directed against cellular or extracellular matrix antigens, resulting in cellular destruction, functional loss, or damage to tissues. Damage can occur through multiple mechanisms such as: antibody binding to cell surface receptors and altering its activity, activation of the complement pathway or antibody dependent cellular cytotoxicity. A second mechanism for Type II reactions is characterized by ADCC induced by natural killer (NK) cells recognizing IgG attached to target cells bearing these antigens. 
Hemolytic disease of the fetus and newborn (HDFN) is a disease which – if untreated – can cause perinatal mortality and morbidity with a substantial risk for long-term sequelae. HDFN is caused by maternal red cell alloantibodies of the IgG class that are actively transported across the placenta and destroy fetal erythroid cells carrying the involved antigen. It is a blood problem in newborn babies. It occurs when your baby's red blood cells break down at a fast rate. It’s also called erythroblastosis fetalis. 
Hemolytic disease of the fetus and newborn conforms to the traditional definition of type II hypersensitivity since

]]> 2022-10-14 17:30:08 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340791208 Risk Factors of Condition stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340799701 HDN most frequently occurs when an Rh negative mother has a baby with an Rh positive father. When the baby's Rh factor is positive, like the father's, problems can develop if the baby's red blood cells cross to the Rh negative mother. 
This usually happens at delivery when the placenta detaches. However, it may also happen anytime blood cells of the two circulations mix, such as during a miscarriage or abortion, with a fall, or during an invasive prenatal testing procedure (such as an amniocentesis or chorionic villus sampling).
The mother's immune system sees the baby's Rh positive red blood cells as "foreign." Just as when bacteria invade the body, the immune system responds by developing antibodies to fight and destroy these foreign cells. The mother's immune system then keeps the antibodies in case the foreign cells appear again, even in a future pregnancy. The mother is now "Rh sensitized."

In a first pregnancy, Rh sensitization is not likely. Usually, it only becomes a problem in a future pregnancy with another Rh positive baby. During that pregnancy, the mother's antibodies cross the placenta to fight the Rh positive cells in the baby's body. As the antibodies destroy the red blood cells, the baby can become sick. This is called erythroblastosis fetalis during pregnancy. In the newborn, the condition is called hemolytic disease of the newborn.

]]> 2022-10-14 17:37:37 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340799701 Cellular Pathophysiology of Condition stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340802916 There are two mechanisms causing hemolytic disease of the fetus and newborn.
First, the fetomaternal pair can have inherent ABO incompatibility, which occurs in 15 to 25% of pregnancies. Only about 1% of those pairs, those with high IgG titers, will develop HDFN due to ABO incompatibility. In ABO incompatibility, naturally occurring antigens against A or B blood types are present in mothers with O blood type. If the mother's fetus has an A or B (or AB) blood type, these maternal anti-A and/or anti-B antibodies, respectively, will attack the foreign blood type of the fetus. The anti-A and anti-B antibodies are IgG, which can cross the placenta and affect the developing fetus. Compared with FMH, ABO incompatibility generally causes a less severe form of HDFN. Postulated theories for this include fetal RBCs express less ABO blood group antigens than adult levels and that ABO blood group antigens are expressed by many tissues, which reduces the chance that antibodies specifically target the antigens on fetal RBCs.
The second mechanism most commonly causing HDFN is through fetomaternal hemorrhage (FMH), where maternal antibodies develop after exposure to fetal blood. When fetal RBCs enter the maternal blood circulation, maternal antibodies can develop to an antigen presented on the fetal RBC surface. The most common antigen involved in this mechanism is the Rhesus D antigen. It is estimated that 1.5 to 2.5% of obstetric patients will develop antibodies to other "minor" antigens. While most of these cases of alloimmunization do not cause significant hemolytic disease of the newborn, some can cause severe anemia at low titer thresholds. ]]> 2022-10-14 17:40:29 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340802916 Clinical Manifestations stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340812041 During pregnancy the most common symptoms of hemolytic disease of newborn include:
a. With amniocentesis, the amniotic fluid may have a yellow coloring and contain bilirubin.
b. Ultrasound of the fetus shows enlarged liver, spleen, or heart and fluid buildup in the fetus's abdomen, around the lungs, or in the scalp.
Although each baby may experience different symptoms the common symptoms after birth include: 
a. A pale coloring been evident due to anemia. 
b. Jaundice, or yellow coloring of amniotic fluid, umbilical cord, skin, and eyes may be present. The baby may not look yellow immediately after birth, jaundice can develop quickly, usually within 24 to 36 hours. 
c. The newborn may have an enlarged liver and spleen.
d. Babies with hydrops fetalis have severe edema (swelling) of the entire body and are extremely pale. They often have difficulty breathing.]]> 2022-10-14 17:48:38 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340812041 Therapeutic Management stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340824014 Infants with HDN may be treated with: feeding often and receiving extra fluids. Light therapy (phototherapy) using special blue lights to convert bilirubin into a form which is easier for the baby's body to get rid of. 
If anemia is diagnosed in the fetus, the fetus may be given blood transfusions before birth. Transfusions may be done until the fetus has matured and can be delivered safely. Before delivery, the mother may be given corticosteroids to help the fetus's lungs mature to prepare for the possible delivery of the fetus earlier than usual if necessary. After delivery, the newborn may need more transfusions.

Severe anemia caused by hemolytic disease of the newborn is treated in the same way as any other anemia. Doctors also observe the newborn for jaundice. Jaundice is likely to occur because the rapid breakdown of red blood cells produces a lot of bilirubin. Bilirubin is a yellow pigment, and it gives the newborn’s skin and whites of the eyes a yellow appearance. If the bilirubin level gets too high, it can injure the baby. High bilirubin levels can be treated by exposing the newborn to special bright lights or, occasionally, by having the newborn undergo an exchange transfusion. Very high levels of bilirubin in the blood can lead to brain damage (kernicterus) unless it is prevented by these measures.

]]> 2022-10-14 17:59:40 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2340824014 Type II Hypersensitivity Reaction stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342153434 Does hemolytic disease of the newborn fit into the category of a type II hypersensitivity reaction? Yes. As summarized in this article, type II hypersensitivity reactions occur when antibodies attack cellular or extracellular matrix antigens. As also summarized in this article, this disease occurs when the mothers antibodies believe the blood of the fetus is foreign, and begins to attack these blood cells. Because of this, the fetus's blood cells do not last 120 days as they normally would. This correctly falls under the type II hypersensitivity reaction because it is antibody-mediated, and is attacking foreign extracellular matrix antigens. ]]> 2022-10-16 21:07:29 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342153434 Educational Video stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342155856 For those who learn about topics best by visual aid, attached is a video explaining the process of HDN. This video is from Alila Medical Media]]> 2022-10-16 21:13:00 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342155856 Hemolytic disease of the newborn https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342167352 Hemolytic Disease of the Fetus and Newborn happens when the blood type of the mother and the baby is incompatible. Usually the mother is Rh negative and has a baby with a Rh positive father. ]]> 2022-10-16 21:39:47 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342167352 Hemolytic disease of the newborn https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342178854 Hemolytic disease tends to happen during a mothers second or subsequent pregnancy.
HDN can be life threatening for some infants. HDN occurs when the immune system of the mothers sees the baby's red blood cells as foreign. Antibodies then develop and attack the baby's red blood cells and causes them to break down too early.]]> 2022-10-16 22:06:45 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342178854 Hemolytic Disease of the Fetus and Newborn https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342180527 Some of the signs for HDN include anemia, jaundice, swelling of the body, and enlarged liver or spleen. ]]> 2022-10-16 22:11:04 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342180527 Signs and Symptoms of Hemolytic Disease of the Fetus and Newborn https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342182281 Hydrops is another symptom which is fluid throughout the body tissues which can lead to heart failure or respiratory failure due to too much fluid.]]> 2022-10-16 22:15:09 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342182281 Hemolytic disease of the fetus and newborn: diagnosed alanizmaria https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342191725 HDN can be done by using a blood test to look for Rh positive in the body, Ultrasound to look for enlarged organs or fluid buildup, Amniocentesis to check the amount of bilirubin in the amniotic fluid, and a percutaneous umbilical cord blood sampling this is done to check the blood for antibodies, bilirubin, and anemia. ]]> 2022-10-16 22:36:51 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342191725 Reference: stevedonkor87 https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342483572 https://europepmc.org/article/MED/32491355.
https://www.ncbi.nlm.nih.gov/books/NBK557423/
https://medlineplus.gov/ency/article/001298.htm]]> 2022-10-17 03:46:54 UTC https://padlet.com/stevedonkor87/4bw1i64i8bghbgi0/wish/2342483572