Haematology Flashcards
What is anaemia defined as in men and women?
Men - Hb <130g/L
Women - Hb <120g/L
What is the underlying cause of a microcytic anaemia?
Cytoplasmic problem resulting in a low MCV
`What are causes of a microcytic anaemia?
Iron deficiency
Thalassaemia
Sideroblastic
What are causes of a normocytic anaemia?
Blood loss
Chronic disease
Renal failure
Pregnancy
What are the two categories of macrocytic anaemia?
Megaloblastic and non-megaloblastic
What is the underlying cause of a megaloblastic anaemia?
A nuclear (DNA) problem
What are some causes of a megaloblastic anaemia?
Vitamin B12 deficiency
Folate deficiency
Drugs
Pernicious anaemia
What are some causes of non-megaloblastic anaemia?
Alcohol/liver disease
Hypothyroidism
Marrow failure - myelodysplasia, aplastic anaemia
What are some signs of iron deficient anaemia?
Pallor, tiredness, koilonychia, glossitis, angular chelitis
What test should you do to check the bodies iron levels?
Serum ferritin
How is iron deficient anaemia treated?
Treat the cause first
Ferrous sulphate orally
What is sideroblastic anaemia?
X-linked condition of ineffective erythropoeisis. Results in a microcytic anaemia that does not respond to iron
What is the dietary source of vitamin B12?
Animal products
What is the dietary source of folate?
Green leafy vegetables
How long do body stores of B12 last?
2-4 years
How long do body stores of folate last?
4 months
Where is vitamin B12 absorbed in the gut?
Terminal ileum
Where is folate absorbed in the gut?
Jejunum
What are some causes of B12 deficiency?
Veganism, decreased stomach acid, pancreatitis, small bowel issues
What are some causes of folate deficiency?
Inadequate intake, coeliac, crohns. pregnancy, anti-convulsants
What are some general symptoms of megaloblastic anaemia?
Anaemia, weight loss, diarrhoea, beefy tongue
What are some symptoms specific to B12 deficiency?
Neurological problems - neuropathy, dementia, subacute combined degeneration of the cord
How is vitamin B12 deficiency treated?
initially, 3 IM injections of hydroxycobalamine per week for 2 weeks
If diet related -> biyearly injections
If not diet related -> injection every 3 months for life
How is folate deficiency treated?
Folic acid tablets 5mg/day
If a patient has both B12 and folate deficiency which one should be treated first and why?
B12 as folate can precipitate subactube combined degeneration of the cord
What is pernicious anaemia?
Autoimmune destruction of gastric parietal cells leading to macrocytosis and pancytopenia
What antibodies will be positive in pernicious anaemia?
Anti-GPC, Anti-IF
How is pernicious anaemia treated?
B12 injections and folate tablets for life
What is a normal haemoglobin molecule made of?
Haem & Globin - 2 alpha chains and 2 beta chains
On what chromosome is the gene for alpha globin chains?
Chromosome 16
On what chromosome is the gene for beta globin chains?
Chromosome 11
How does alpha trait present?
Clinically asymptomatic. Microcytic haemochromatic cells. Normal ferritin. No treatment needed.
What is HbH disease?
3 faulty alpha chains (–l-a)
What is seen in bloods of HbH disease?
Anaemia, very low MCV and MCH
How does HbH present?
Variable - spelnomegaly, jaundice, growth retardation, gallstones, iron
What is the inheritance of HbH disease?
Autosomal recessive
What is Hb Barts Hydrops Fetalis?
Most severe form of alpha thalassamia - –l–
What haemoglobin types are commonly seen in Hb Barts hydrops fetalis?
Hb Barts and HbH
Why is Hb Barts so bad?
It has a high affinity for oxygen and so does not give it up readily to tissues
How does Hb Barts present?
Pallor, oedema, cardiac failure. Most babies die in utero or shortly after birth
What is seen on alpha thalassaemia blood films?
Anisopoikilocytosis
Target Cells
What is the inheritance of B-thalassaemia?
Autosomal recessive
How will beta-thalassaemia trait present?
Asymptomatic. Low MCV/MCH.
Raised HbA2 is diagnostic.
What is beta thalassaemia intermedia?
Two defective copies of B gene or one absent B gene and one defective B gene
How is beta thalassaemia intermedia treated?
Occasional blood transfusion
What is beta thalassaemia major also known as?
Cooley’s anaemia
What is seen in FBC of beta thalassaemia major patients?
Moderate to severe anaemia
Very low MCV/MCH
What is seen on blood film in beta thalassaemia major?
Reticulocytosis
Anisopoikilocytosis
Target cells
What does liquid chromatography (HPLC) show in beta thalassaemia major?
Mainly HbF
Small HbA
Increased HbA2`
When does beta-thalassaemia major present?
Aged 6-24 months
How does beta-thalassaemia major present?
Failure to thrive, pallor, extramedullary haematopoesis, hepatosplenomegaly, skeletal changes, organ damage
How is beta-thalassaemia major managed?
Regular transfusions to maintain Hb 95-105g g/L
What are some complications of beta-thalassaemia major?
Viral infections, alloantibodies, iron overload, iron overload, transfusion reactions
What is sickle cell disease?
Point mutations change the structure of B globin chains to make HbS
How is sick cell disease inherited?
Autosomal recessive
What happens to HbS in periods of low oxygen?
Polymerises and damages RBC, leading to sickling where cells are fragile, haemolyse and block small vessels
What is sickle cell trait?
One abnormal copy of the gene, asymptomatic carrier state. HbS levels too low to polymerise
What are some precipitants of sickle cell crisis?
Hypoxia, dehydration, infection, cold, stress, fatigue
What is the management of sickle cell crisis?
Opiate analgesia
Hydration, rest, oxygen, antibiotics if infection
How could a severe sickle cell crisis be managed?
Blood transfusion
What causes an aplastic crisis in sickle cell disease?
Parvovirus B19
What is a sequestration crisis?
Pooling of blood in the spleen - requires an urgent transfusion
What temperature should red blood cells be stored at?
4 degrees C - in fridge
What temperature should platelets be stored at?
22 degrees C - room temperature
What temperature should FFP be stored at?
-30 degrees C - freezer
How long do you have to transfuse red cells and FFP?
Must be transfused within 4 hours
How long do you have to transfuse platelets?
Must be transfused within 1 hour
On what chromosome is ABO determined?
Chromosome 9
On what chromosome is Rhesus status determined?
Chromosome 1
What test should you use to screen patients plasma for irregular red cell antibodies?
Indirect antiglobulin test
What blood type is the universal donor?
O negative
What blood type is the universal acceptor?
AB positive
What antibody mediates an immediate transfusion reaction?
IgM - attack on RBCs
How does an immediate transfusion reaction present?
May occur after only 1ml has been transfused - fever, dizziness, sweating, tachycardia, hypotension, DIC, AKI, shock
How should you manage an immediate transfusion reaction?
STOP TRANSFUSION
Start IV fluids to maintain BP and urine output
Check bag of blood to see patient identity
Take bloods (FBC, U&Es, coag, cultures, LDH, blood film)
Contact haematology and return blood to the lab
What antibody mediates a delayed haemolytic transfusion reaction?
IgG - attack on antibodies in transferred blood
When does a delayed haemolytic transfusion reaction occur?
5 to 10 days following transfusion
How does a delayed haemolytic transfusion reaction present?
Jaundice, unexpected fall in Hb, AKI,
Lab results show anaemia, spherocytic red cells, raised bilirubin and raised LDH
How do you manage a delayed haemolytic transfusion reaction?
Supportive care for any AKI/clotting issues
Screen for irregular antibodies and give an antibody reference card for future transfusions
What is a febrile non-haemolytic reaction?
Reaction to white blood cells within the transfusion
When and how does a febrile non-haemolytic reaction present?
About 30 mins into transfusion - fever, rigors etc
How is a febrile non-haemolytic reaction managed?
Slow/stop transfusion. Paracetamol. Close monitoring. Next transfusion - give leucodepleted blood products
What mediates an urticarial transfusion reaction?
IgE - response to infused plasma proteins
How does an urticarial transfusion reaction present?
Rash/wheals within first few minutes
How is an urticarial transfusion reaction managed?
Slow/stop transfusion
Supportive care
Antihistamines
What is associated with an anaphylaxis transfusion reaction?
IgA deficiency