Haemolytic Anaemia Flashcards
What is it?
Anaemia due to lysis of RBCs
2 types - what are they?
Intravasvular - in circulation
Extravascular - mainly the spleen
4 questions used:
(1) Is there increased red cell breakdown?
- What will the MCV be?
- What type of bilirubin will be raised and what will this lead to?
- What type of bilirubin byproduct is found in the urine, and therefore increased in the urine?
- Why does serum LDH become raised?
Normal or raised
Unconjugated bilirubin - pre-hepatic jaundice
Urobilinogen
It is released from RBCs
4 questions used:
(2) Is there increased red cell production?
- What immature RBCs will be raised if there is increased production?
Reticulocytes - causes raised MCV as well
4 questions used:
(3) Is it mainly intravascular or extravascular?
- What may you find on abdo examination which would indicate extravascular breakdown?
- Free plasma haemoglobin can be found from broken down RBC’s. Methaemalbuminaemia is also found. What is it?
- Plasma haptoglobin is lowered in this. What it’s role which explains why is it lowered?
- What colour does the urine turn?
Splenomegaly
Free Hb is broken down in the circulation to produce haem and globin, haem combines with albumin to make methaemalbuminaemia.
Mops up free plasma Hb then removed by the liver - so lowered
Red-brown colour due to haemoglobinuria
(4) What is causing this? - Acquired haemolytic anaemia:
Immune-mediated - The following at DAT + ve:
What is DAT?
What antibiotics could induce the formation of RBC autoantibodies?
You can get autoimmune HA which is either warm or cold.
What does warm or cold mean?
Warm:
- What type of antibodies are produced?
- What can cause it?
- How is it Rx?
Cold (less common):
- What type of antibodies are produced?
- What triggers it? - think about the name
- What can cause it?
Direct antiglobulin test - is +ve
Beta-lactams - penicillin, cephalosporins
Warm - antibodies IgG-mediated bind at a temp of 37*C:
- SLE
- RA
- Lymphoma
Steroids/immunosuppresents +/- splenectomy
Cold - antibodies IgM-mediated bind between temp (28-31*C):
- Cold weather
- Cold drink
- Unwarmed IV fluids
Primary (idiopathic)
Secondary to lymphoproliferation (lymphoma)
Infection (HIV)
(4) What is causing this? - Acquired haemolytic anaemia:
The following at DAT + ve.
Why can it happen post-transfusion?
Haemolysis of the newborn - why does it happen?
If the blood is not compatible
All people have a blood type (A, B, AB, or O). Everyone also has an Rh factor (positive or negative). There can be a problem if a mother and baby have a different blood type and Rh factor.
HDN happens most often when an Rh-negative mother has a baby with an Rh-positive father. If the baby’s Rh factor is positive, like his or her father’s, this can be an issue if the baby’s red blood cells cross to the Rh-negative mother.
This often happens at birth when the placenta breaks away. But it may also happen any time the mother’s and baby’s blood cells mix. This can occur during a miscarriage or fall. It may also happen during a prenatal test. These can include amniocentesis or chorionic villus sampling. These tests use a needle to take a sample of tissue. They may cause bleeding.
The Rh-negative mother’s immune system sees the baby’s Rh-positive red blood cells as foreign. Your immune system responds by making antibodies to fight and destroy these foreign cells. Your immune system stores these antibodies in case these foreign cells come back again. This can happen in a future pregnancy. You are now Rh sensitized.
Rh sensitization normally isn’t a problem with a first pregnancy. Most problems occur in future pregnancies 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 cells, the baby gets sick. This is called erythroblastosis fetalis during pregnancy. Once the baby is born, it’s called HDN.
(4) What is causing this? - Acquired haemolytic anaemia:
Non-immune mediated - The following are DAT - ve:
Microangiopathic haemolytic anaemia (MAHA):
- What type of breakdown does it cause?
- Why does this breakdown happen? - think angio
Why is it important to remember infections in any haemolysis case?
What infection is particularly important to be mindful of?
Extravascular
Due to endothelial damage/injury
All infections exacerbate haemolysis
Malaria
(4) What is causing this? - Hereditary haemolytic anaemia:
There are a range of genetic haemolytic disorders
There are a range of genetic haemolytic disorders
History:
What is important to ask about in social history?
What symptoms would they experience - remember still anaemia?
What sign would you see?
What may be found in abdo examination?
Why may they get gallstones? What type of gallstones would they get?
Why could they get leg ulcers?
Recent travel - malaria
Drugs
Fatigue
SOB
Pallor
Pre-hepatic jaundice
Splenomegaly
Due to increased bilirubin
Pigmented gallstones
Due to poor blood flow
Investigations:
Bloods:
FBC - what would expect?
Why are reticulocytes in the bloods raised?
Why type of enzyme is released due to RBC breakdown?
What can be tested for to look at levels of free Hb?
Why are U&E and LFTs done?
What further test can be done for blood?
What extra investigation should be done for those who have suspected malaria?
Urinalysis:
- What will you find in the urine?
Low Hb
In anaemia, the reticulocyte count will be abnormal because the levels of red blood cells and haemoglobin are low. Also, reticulocytes make up a higher percentage of the blood count in anaemia, which makes the reticulocyte count falsely high.
LDH - Lactate dehydrogenase (LDH) is an enzyme required during the process of turning sugar into energy for your cells.
Haptoglobin - low levels means high free Hb
Liver or kidney disease
Blood films
Thick and thin blood films
Raised urobilinogen
Further Investigations - if diagnosis not clear:
Direct Antiglobulin (Coombs Test):
- What does it detect?
- What type of cause does this therefore identify?
Hb electrophoresis - what blood clotting disorders is this used for?
Antibodies or complement-coated RBCs so can detect immune-mediated causes
Thalassaemia
Sickel cell anaemia
Management:
General:
- Main Rx is to treat precipitant!!!
- When should they be transfused?
- What drug can be given if they reticulocytosis?
Very low Hb
Folic acid, as it needed for RBC production
