Vitamin B12 deficiency Flashcards
What are the main categories of blood product transfusion complications?
Blood product transfusion complications may be classified into immunological, infective, transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), and other complications such as hyperkalaemia, iron overload, and clotting.
What are the features and management of a non-haemolytic febrile reaction?
Features include fever and chills. Management involves slowing or stopping the transfusion, administering paracetamol, and monitoring the patient.
What causes a minor allergic reaction during a blood transfusion?
Minor allergic reactions are thought to be caused by foreign plasma proteins, leading to symptoms like pruritus and urticaria. Management includes temporarily stopping the transfusion, administering antihistamines, and monitoring.
What symptoms indicate anaphylaxis during a blood transfusion?
Symptoms include hypotension, dyspnoea, wheezing, and angioedema. Management requires stopping the transfusion, administering intramuscular adrenaline, and providing ABC support, oxygen, and fluids.
What is an acute haemolytic reaction and its management?
Acute haemolytic reaction results from ABO-incompatible blood, causing fever, abdominal pain, and hypotension. Management includes stopping the transfusion, confirming diagnosis, checking patient identity, sending blood for direct Coombs test, and supportive care.
What characterizes transfusion-associated circulatory overload (TACO)?
TACO is characterized by pulmonary oedema and hypertension due to excessive transfusion rates, especially in patients with pre-existing heart failure. Management involves slowing or stopping the transfusion and considering intravenous loop diuretics and oxygen.
What are the features of transfusion-related acute lung injury (TRALI)?
TRALI features include hypoxia, pulmonary infiltrates on chest x-ray, fever, and hypotension. Management requires stopping the transfusion and providing oxygen and supportive care.
What are the risks associated with red blood cell (RBC) transfusions?
RBCs are primarily at risk for transmitting viral agents such as HIV, HBV, and HCV. Bacterial contamination is less common but possible, particularly from skin flora during collection.
What pathogens are associated with platelet transfusions?
Platelets are at risk for bacterial contamination due to storage at room temperature, with common contaminants including Staphylococcus epidermidis and Bacillus cereus.
What measures have been taken to minimize the risk of vCJD transmission via blood transfusion?
Measures include leucodepletion of all donations since late 1999, sourcing plasma derivatives from imported plasma, and excluding recipients of blood components from donating blood.
What is pernicious anaemia?
Pernicious anaemia is an autoimmune disorder affecting the gastric mucosa that results in vitamin B12 deficiency.
‘Pernicious’ means ‘causing harm, especially in a gradual or subtle way’.
What are other causes of vitamin B12 deficiency besides pernicious anaemia?
Other causes include atrophic gastritis (e.g. secondary to H. pylori infection), gastrectomy, and malnutrition (e.g. alcoholism).
What is the pathophysiology of pernicious anaemia?
Antibodies to intrinsic factor and/or gastric parietal cells lead to reduced intrinsic factor production, resulting in decreased vitamin B12 absorption.
What are the risk factors for pernicious anaemia?
More common in females (F:M = 1.6:1), typically develops in middle to old age, and is associated with other autoimmune disorders.
What are the features of pernicious anaemia?
Features include anaemia, lethargy, pallor, dyspnoea, peripheral neuropathy, and neuropsychiatric symptoms.
What neurological features are associated with pernicious anaemia?
Peripheral neuropathy, subacute combined degeneration of the spinal cord, and neuropsychiatric features like memory loss and confusion.
What investigations are done for pernicious anaemia?
Full blood count, vitamin B12 and folate levels, and antibodies testing for anti-intrinsic factor and anti-gastric parietal cell antibodies.
What is the management for pernicious anaemia?
Vitamin B12 replacement is usually given intramuscularly, with specific dosing based on the presence of neurological features.
What are the complications of pernicious anaemia?
Increased risk of gastric cancer.
What is the main use of Vitamin B12 in the body?
Vitamin B12 is mainly used for red blood cell development and maintenance of the nervous system.
How is Vitamin B12 absorbed in the body?
Vitamin B12 is absorbed after binding to intrinsic factor and is actively absorbed in the terminal ileum.
What are the common causes of Vitamin B12 deficiency?
Common causes include pernicious anaemia, post gastrectomy, vegan diet or poor diet, disorders/surgery of the terminal ileum, Crohn’s disease, and rare cases due to metformin.
What are the features of Vitamin B12 deficiency?
Features include macrocytic anaemia, sore tongue and mouth, neurological symptoms, and neuropsychiatric symptoms.
Which neurological symptoms are associated with Vitamin B12 deficiency?
The dorsal column is usually affected first (joint position, vibration) prior to distal paraesthesia, along with mood disturbances.
