Hemolytic disease of the newborn - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 03-22-2013
USMLE Forums Scout
 
Steps History: ---
Posts: 75
Threads: 12
Thanked 63 Times in 33 Posts
Reputation: 73
Pediatrics Hemolytic disease of the newborn

A 1-day-old neonate has hemolytic disease of the newborn. The parents are both Rh-positive, but IgG isohemagglutinins are found in the mother's blood. Which of the following parental blood types is most likely to cause this condition?

A. Mother: A & Father: O
B. Mother: AB & Father: O
C. Mother: B & Father: A
D. Mother: B & Father: O
E. Mother: O & Father: AB

Please explain.
Reply With Quote Quick reply to this message



  #2  
Old 03-22-2013
MedicalExaminer's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 824
Threads: 66
Thanked 465 Times in 298 Posts
Reputation: 475
Default

E. Mother: O & Father: AB

mild hemolytic disease occurs when mom is group O and baby is either A or B

Rh incompatibility cant be the cause cause in that case mom should be Rh - and baby Rh +
__________________
Everything is possible for him who believes (MARK 9:23)
245/247/passed on 1st attempt/223/2mos Obsie /3 US LORS/visa not needed/2008 grad
Reply With Quote Quick reply to this message
  #3  
Old 03-22-2013
USMLE Forums Addict
 
Steps History: Not yet
Posts: 125
Threads: 17
Thanked 67 Times in 38 Posts
Reputation: 77
Default

ABO HDN
MOTHERS-BLOOD GROUP O
FETUS-BLOOD GROUP A OR B
BLOOD GROUP O INDIVIDUALS HAVE ANTI-A AND B -IgG ANTIBODIES
IgG CROSS PLACENTA AND ATTACH TO FETAL A OR B RBCs
FETAL SPLENIC MACROPHAGES PHAGOCYTOSE RBCs-MILD ANEMIA
UNCONJUGATED BILIRUBIN FROM EXTRAVASCULAR HEMOLYSIS IS DISPOSED OF IN THE MOTHER'S LIVER
JAUNDICE DEVELOPS WITHIN THE FIRST 24 HOURS AFTER BIRTH
NEWBORN LIVER CANNOT HANDLE THE EXCESS BILIRUBIN LOAD
RISK FOR KERNICTERUS IS VERY SMALL
ANEMIA-MILD NORMOCYTIC OR NO ANEMIA AT ALL
POSITIVE DIRECT COOMBS' TEST ON FETAL CORD BLOOD RBCs
DUE TO ANTI-A OR B IgG ANTIBODIES COATING FETAL A OR B RBCs
SPHEROCYTES ARE PRESENT ,DUE TO MACROPHAGE REMOVAL OF A PORTION OF THE RBC MEMBRANE
TRANSFUSIONS ARE RARELY INDICATED
RH HDN
MOTHER-RH NEGATIVE
FETUS-RH POSITIVE
MOTHER DEVELOPS ANTI-D-IgG ANTIBODIES WHEN EXPOSED TO FETAL RH POSITIVE CELLS
FIRST RH INCOMPATIBLE PREGNANCY DOES NOT AFFECT THE FIRSTBORN
ANTI-D-IgG ANTIBODIES CROSS THE PLACENTA AND ATTACH TO FETAL RH POSITIVE RBCs,FETAL SPLENIC MACROPHAGES PHAGOCYTOSE RBCs-SEVERE ANEMIA,MAY DEVELOP HIGH-OUTPUT CARDIAC FAILURE LEADING TO HYDROPS FETALIS WHICH IS A COMBINED LEFT-AND -RIGHT HEART FAILURE WITH ASCITES AND EDEMA
JAUNDICE DEVELOPS SHORTLY AFTER BIRTH
MOST OF THE UNCONJUGATED BILIRUBIN IS NOT BOUND BY ALBUMIN AND CIRCULATES FREE IN THE BLOOD
INCREASED RISK FOR KERNICTERUS(IN THE BASAL GANGLIA)
POSITIVE DIRECT AN INDIRECT COOMBS' TEST
NO SPHEROCYTES -MACROPHAGES PHAGOCYTOSE THE ENTIRE RBC
TRANSFUSIONS ARE REQUIRED -CORRECTS ANEMIA,REMOVES ANTIBODIES AND UNCONJUGATED BILIRUBIN
Reply With Quote Quick reply to this message
 
  #4  
Old 03-22-2013
USMLE Forums Veteran
 
Steps History: CS Only
Posts: 219
Threads: 44
Thanked 44 Times in 33 Posts
Reputation: 54
Default

But first aid 2011 p 345 says:
Note: anti-AB antibodies _IgM (do not cross placenta), anti-Rh _ IgG (cross placenta).

And i remember kaplan lectures said tha ABO system doesnt cause hemolysis..

Im confsed =s

May i ask where this question is from?
Reply With Quote Quick reply to this message
  #5  
Old 03-22-2013
MedicalExaminer's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 824
Threads: 66
Thanked 465 Times in 298 Posts
Reputation: 475
Default

Quote:
Originally Posted by ` Faith ` View Post
But first aid 2011 p 345 says:
Note: anti-AB antibodies _IgM (do not cross placenta), anti-Rh _ IgG (cross placenta).

And i remember kaplan lectures said tha ABO system doesnt cause hemolysis..

Im confsed =s

May i ask where this question is from?

somtimes O-mom develops anti-A or anti-B IgGs which may produce mild hemolysis in newborn
__________________
Everything is possible for him who believes (MARK 9:23)
245/247/passed on 1st attempt/223/2mos Obsie /3 US LORS/visa not needed/2008 grad
Reply With Quote Quick reply to this message
The above post was thanked by:
Faith-USMLE (03-22-2013)
  #6  
Old 03-22-2013
USMLE Forums Veteran
 
Steps History: Step 1 Only
Posts: 283
Threads: 35
Thanked 206 Times in 115 Posts
Reputation: 216
Default

Quote:
Originally Posted by luschka View Post
A 1-day-old neonate has hemolytic disease of the newborn. The parents are both Rh-positive, but IgG isohemagglutinins are found in the mother's blood. Which of the following parental blood types is most likely to cause this condition?

A. Mother: A & Father: O
B. Mother: AB & Father: O
C. Mother: B & Father: A
D. Mother: B & Father: O
E. Mother: O & Father: AB

Please explain.

The answer is E. This is Type 2 hypersensitivity - Erythroblastosis fetalis. Only mother antibodies will circulate to and from placental; and that would be IgG antibodies, hence, type 2 hypersensitivity.

Next we look at and understand the blood group. Blood group A, B, and AB DO NOT HAVE IgG on them. Instead, these blood groups have IgM on them. IgM does not cross placental. Therefore, these blood groups won't do a thing because they don't cross placental because they contain IgM and IgM does not cross placental.

Blood group O have IgG on them and therefore, will cross the placental.

To sum up:

1. Mother antibodies play role
2. Only Blood group O have IgG on them and therefore this blood group will cross the placental.
3. Example:

Mother Blood group O and Father Blood group O is correct answer
Mother Blood group O and Father Blood group A, AB, B is correct answer.
Mother Blood group A, AB, B and Father Blood group A, AB, B is incorrect answer.
Mother Blood group A, AB, B and Father Blood group O is incorrect answer.
Reply With Quote Quick reply to this message
  #7  
Old 03-22-2013
USMLE Forums Addict
 
Steps History: Not yet
Posts: 135
Threads: 3
Thanked 73 Times in 48 Posts
Reputation: 83
Default

Quote:
But first aid 2011 p 345 says:
Note: anti-AB antibodies _IgM (do not cross placenta), anti-Rh _ IgG (cross placenta).

And i remember kaplan lectures said tha ABO system doesnt cause hemolysis..

Im confsed =s
You're right in most cases anti-A and anti-B antibodies are IgM. But in some cases, for example if there is tranfusion of fetal blood into maternal circulation. The mother can produce anti-A-IgG or anti-B-IgB, depending on the incompatibility of the fetus. This can also happen spontaneously in some monthers due to bugs in the GI that have similar antigens.

Also note, this is not like the anti-Rh-IgG system where the mother has to be sensitized first with a previous pregnancy. In this case it can happen during the very first pregnancy itself. But the hemolysis is milder as someone already pointed out.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
You can't confuse the confused!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message
The above post was thanked by:
Faith-USMLE (03-22-2013)



Reply

Tags
Genetics-, Immunology-, Pathology-, Pediatrics-, Step-1-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Confusing Hemolytic Anemia tyagee USMLE Step 2 CK Forum 17 2 Weeks Ago 03:41 PM
Wilson disease and Hemolytic anemia Lilianacu USMLE Step 1 Forum 2 10-24-2012 10:39 AM
Beta Hemolytic Microorganisms lee-usmle USMLE Step 1 Buzzwords 1 09-18-2011 11:18 AM
Newborn Congenital Heart Disease Dx from Chest X ray! aksyonez USMLE Step 2 CK Forum 8 07-07-2011 06:35 AM
Hemolytic anemia & sulfas bebix USMLE Step 1 Forum 12 05-21-2011 01:59 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)