QuestionSBA
QuestionChoice
Transfusion-associated circulatory overload presents with features of fluid overload, e.g. peripheral oedema, coarse inspiratory crackles on auscultation. This patient is well and not presenting with any examination or auscultation findings, so it is unlikely to be transfusion-related circulatory overload
33697
e
Transfusion-associated circulatory overload
QuestionChoice
Anaphylaxis typically presents with angiooedema, urticaria, stridor, wheeze and hypotension. This patient is very well, so this is unlikely to be anaphylaxis
33695
c
Anaphylaxis
QuestionChoice
Transfusion-related acute lung injury typically presents with signs of pulmonary oedema, e.g. coarse inspiratory crackles on auscultation. This patient is well and not presenting with auscultation findings, so it is unlikely to be transfusion-related acute lung injury
33696
d
Transfusion-related acute lung injury
QuestionChoice
Febrile non-haemolytic transfusion reaction typically presents with fever (with or without chills and rigors) only, with otherwise normal observations. This is the case with this patient. Typical management would be to stop transfusion, give paracetamol and reintroduce the transfusion at a slower rate
33693
a
Febrile non-haemolytic transfusion reaction
QuestionChoice
Acute haemolytic transfusion reaction typically presents with other symptoms, e.g. hypotension, back pain, disseminated intravascular coagulation. This typically occurs as a result of ABO incompatibility. This patient is very well, so this is unlikely to be an acute haemolytic transfusion reaction
33694
b
Acute haemolytic transfusion reaction
Concept
Chapter
# Summary

Blood comprises two core components: cellular elements and plasma. Cellular components consist of white blood cells (neutrophils, eosinophils, basophils, monocytes, lymphocytes), red blood cells (RBCs or erythrocytes), and platelets (thrombocytes). Plasma encompasses clotting factors, albumin, and immunoglobulins. Blood groups, notably ABO and Rh, influence transfusion compatibility, with group O individuals universal donors. Acute and late transfusion reactions require vigilant monitoring and management. Iron overload can result from frequent transfusions, necessitating interventions to lower iron levels.

# Blood Components

Blood is made of two main components: cells and plasma

- The cellular components of blood include: 
  - white blood cells (neutrophils, eosinophils, basophils, monocytes, lymphocytes)
  - RBCs (erythrocytes) 
  - platelets (thrombocytes)

- Plasma consists of: 
  - clotting factors
  - albumin 
  - immunoglobulins

## Lifespan of components

The normal lifespan of the following cellular components of blood is:

- RBCs, 90–120 days
- platelets, 10 days
- neutrophils, 4 days

## Products for transfusion

Four products are readily transfusable:

- **Red blood cells**
  - Generally **stored at 4 °C** for up to 35 days 
  - In vivo, RBCs typically have a lifespan of about 120 days; however, it is important to note that transfused red cells last around 50–60 days


- **Fresh frozen plasma** (FFP)
  - **Stored at –30 °C**, with a shelf life of a year
  - Used in patients with coagulopathy (impaired blood coagulation) to replace clotting factors
  - The type of FFP used depends on the patient's blood group


- **Platelets**

  - **Stored at room temperature** for up to 7 days
  - Have a lifespan of 10 days before they are phagocytosed in the spleen and liver
  - 1 pool of platelets comes from 4 donors
  
  
    - Platelets are given if levels are <10 x 10<sup>9</sup>/l in patients with thrombocytopenia due to marrow failure from chemotherapy and radiotherapy – This threshold can be increased if there is sepsis or bleeding, or for a planned surgical procedure 
  
  
    - Platelet transfusions should not be used in conditions where there is immune destruction of platelets (eg. immune thrombocytopenia unless there is a haemorrhagic emergency)
  
  
    - Platelet transfusion is also contraindicated in TTP or HUS as it can contribute to the microvascular occlusion in the brain and kidneys that is associated with these conditions
  


- **Cryoprecipitate**

  - Cryoprecipitate is made by thawing FFP overnight at 4–8 °C
  - It has a shelf life of 1 year **stored at –30 °C**
  - It contains fibrinogen, factor VIII and von Willebrand factor
  - It is generally used in patients with massive bleeding and low fibrinogen

# Blood Groups

* Blood groups, defined as antigens on the surface of red blood cells, are critical in determining blood compatibility for transfusions. 
* There are over 400 blood groups but the ABO and Rh blood groups are the most important, each with distinct inheritance patterns. 
* The ABO antigens develop on red cells 16 weeks after birth, meaning neonates do not require blood cross-matching for transfusions. 
* Adults with group O red cells can universally donate due to the absence of A or B antigens, and group AB plasma can be universally donated due to the lack of anti-A or anti-B antibodies.
* The A and B genes show co-dominant inheritance, whereas the O gene is recessive.

# Antigens and Compatibility

* **Rhesus antigen** - The Rh group includes 5 main antigens with Rhesus D being the most important. The Rhesus D antigen has an autosomal dominant mode of inheritance.
- **ABO antigens** - not expressed on red cells until 16 weeks after birth. Therefore, in neonates, there is no need to cross-match for blood transfusions as antibodies are not yet made.

Please see the summary table below on blood group compatibility and donation:


| Blood Type | Can Receive From | Can Donate To |
|------------|-----------------|--------------|
| A+         | A+, A-, O+, O-   | A+, AB+      |
| A-         | A-, O-           | A+, A-, AB+, AB- |
| B+         | B+, B-, O+, O-   | B+, AB+      |
| B-         | B-, O-           | B+, B-, AB+, AB- |
| AB+        | All Blood Types  | AB+          |
| AB-        | AB-, A-, B-, O-  | AB+, AB-     |
| O+         | O+, O-           | A+, B+, AB+, O+  |
| O-         | O-               | All Blood Types  |

# Acute Transfusion Reactions

## Allergy 

- Presentation ranges from urticaria to angioedema and anaphylaxis
- Management – stop the transfusion if concerns over anaphylaxis (if mild urticaria, can slow the transfusion and give antihistamine), give saline, adrenaline (in case of anaphylaxis), chlorphenamine, and hydrocortisone

## Acute haemolytic transfusion reaction 

- Caused by giving an incompatible blood bag to a patient
- Early signs include fever, abdominal pain, hypotension and anxiety
- Late complications include generalised bleeding secondary to DIC
- Management – stop the transfusion, give saline, treat DIC

## Febrile non-haemolytic transfusion reaction 

British Society for Haematology guidelines recommend that: 

- In patients with a **mild** reaction:

 - A temperature rise of 1 - 2°C leading to pyrexia ≥38°C, but <39°C
 - And/or pruritus or a rash
 - WITHOUT other features

The transfusion can be continued with appropriate treatment (oral paracetamol 500 - 1000mg) and direct observation. If a rash/pruritis is also present, slow the transfusion)
 
- In patients who develop **moderate** reactions:
 - Temperature ≥39°C OR a rise of ≥2°C from baseline
 - AND/OR systemic symptoms such as chills, rigors, myalgia, nausea or vomiting)

Symptomatic treatment should be considered. If symptoms settle, the transfusion can be resumed. If symptoms are sustained, bacterial contamination or a haemolytic reaction should be considered.

## Transfusion-related acute lung injury (TRALI)

- Presents with pulmonary oedema and can cause acute respiratory distress syndrome (ARDS)

- Management – stop the transfusion, give saline, treat ARDS and give supplementary oxygen as needed

## Transfusion-associated circulatory overload (TACO)

- Presents with fluid overload

- Management – Slow the transfusion, give furosemide and supplementary oxygen as needed

# Late Transfusion Reactions

## Delayed haemolytic transfusion reaction 

- Caused by an exaggerated response to a foreign red cell antigen that the patient has been exposed to before
- Patients present with jaundice, anaemia, and fever, usually on day 5 post-transfusion

## Transfusion-associated graft-versus-host disease 

- Caused by donor blood lymphocytes attacking the recipient's body 
- Rare but carries a high risk of mortality

## Iron Overload

- Iron overload may be related to the pathophysiology of the condition (eg. haemochromatosis) or iatrogenic (eg. related to a blood transfusion or excess oral iron) 
  - There is no secretion pathway for iron and approximately 1 mg of iron is lost via gut mucosal cells
  - Absorption of luminal iron is mediated by enterocytes, which respond to iron stores in the body
  - The enterocyte is modulated via its transferrin receptor, which regulates transferrin uptake from the plasma
  - In turn, the HFE protein modulates transferrin receptor activity
- Iron overload usually becomes an issue after 20 units have been given or if serum ferritin rises above 1000 µg/l 
- Subcutaneous desferrioxamine is required regularly to lower iron levels

# References

[Click here to see more information on Patient UK about transfusion reactions](https://patient.info/doctor/blood-transfusion-reactions)

[Click here to see more information on the British Society for Haematology guidelines on acute transfusion reactions](https://onlinelibrary.wiley.com/doi/full/10.1111/bjh.18789)
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Blood Products, Groups and Transfusions
Topic
8
Haematology
6739
A 23-year-old female is receiving a blood transfusion in the respiratory ward. After 10 minutes, she reports that she feels cold. Her observations are as follows: heart rate 70/min, blood pressure 123/81 mmHg, respiratory rate 13/min, oxygen saturations 97% and temperature 38.6ºC.

What is the most likely diagnosis?
a