Haemotology Flashcards
What are the three main categories of anaemia?
Microcytic anaemia <80
Normocytic anaemia 80-100
Macrocytic anaemia >100
What are the causes of microcytic anaemia?
TAILS
Thalassaemia Anaemia of chronic disease Iron deficiency anaemia Lead poisoning Sideroblastic anaemia
What are the causes of normocytic anaemia?
3As and 2Hs
Acute blood loss Anaemia of chronic disease Aplastic anaemia Haemolytic anaemia Hypothyriodism
What are the causes of macrocytic anaemia?
Can be megaloblastic or normoblastic.
Megaloblastic anaemia:
B12 deficiency
Folate deficiency
Normoblastic macrocytic anaemia: Alcohol Reticulocytosis Hypothyroidism Liver disease Drugs such as azathioprine
What are the symptoms of anaemia?
Tiredness SOB Headaches Dizziness Palpitations
What are the symptoms of iron deficiency anaemia in particular?
Pica: abnormal dietary cravings such as dirt
Hair loss
What are the generic signs of anaemia?
Pale skin
Conjunctival pallor
Tachycardia
Raised respiratory rate
What are the signs of specific causes of anaemia?
Iron deficiency:
- Koilonychia
- Angular chelitis
- Atrophic glossitis
- Brittle hair
Haemolytic anaemia:
- Jaundice
Thalassaemia:
- Bone deformities
CKD:
- Oedema, HTN and excoriations of the skin
What are the initial investigations for anaemia?
Hb MCV B12 Folate Ferritin Blood film
What are the causes of iron deficiency anaemia?
Blood loss is the most common cause in adults.
Dietary insufficiency is the most common cause in growing children
Poor iron absorption
Increased requirements during pregnancy.
How is iron mainly absorbed and what interferes with this process?
In the duodenum and jejunum.
Medications that reduce stomach acid such as PPIs stop the acid keeping iron in the soluble form.
Conditions that result in inflammation of the duodenum or jejunum such as coeliac disease or crohn’s disease
What is transferrin saturation?
If you measure iron in the blood and then measure the total iron binding capacity of that blood, you can calculate the proportion of the transferrin molecules that are bound to iron, the transferin saturation.
What is the significance of ferritin in blood tests?
Low ferritin means the pt most likely is anaemic.
High ferritin may be due to inflammation as extra is released in response to infection or cancer.
Normal ferritin can still mean that the patient in iron deficient.
What can cause the results of iron test results to be high?
- Supplementation with iron
- Acute liver damage
What is the management for iron deficiency anaemia?
Oral iron e.g. ferrous sulfate 200mg three times daily. This slowly correct the iron deficiency but can cause constipation and black coloured stool.
Iron infusion. There is a small risk of anaphylaxis but it quickly corrects iron deficiency
Blood transfusion. Immediately correct the anaemia but not the underlying iron deficiency
Define pernicious anaemia
is a cause of B12 deficiency.
Give the pathophysiology of pernicious anaemia
Parietal cells of the stomach produce intrinsic factor which is essential for the absorption of vitamin B12 in the ileum.
Pernicious anaemia is an autoimmune condition where antibodies form against the parietal cells or intrinsic factor.
What are the symptoms of B12 deficiency?
- Peripheral neuropathy or paraesthesia
- Loss of vibration sense or proprioception
- Visual changes
- Mood or cognitive changes.
What is the diagnostic test for pernicious anaemia?
- Intrinsic factor antibody is the first line investigation
- Gastric parietal cell antibody can also be tested but is less helpful
What is the management of B12 deficiency?
Dietary deficiency can be treated with oral replacement with cyanocobalamin.
Pernicious anaemia: 1mg IM hydroxycobalamin 3 times weekly for 2 weeks then every 3 months.
Why must you treat a patients B12 deficiency before treating their folate deficiency?
Treating patients with folic acid when they have a B12 deficiency can lead to subacute combined degeneration of the cord.
Which are the inherited haemolytic anaemias?
Hereditary spherocytosis Hereditary elliptocytosis Thalassaemia Sickle cell anaemia G6D deficiency
Which are the acquired haemolytic anaemias?
- Autoimmune haemolytic anaemia
- Alloimmune haemolytic anaemia
- Paroxysmal nocturnal haemoglobinuria
- Microangiopathic haemolytic anaemia
- Prosthetic valve related haemolysis
What are the investigations for haemolytic anaemia and what will they show
FBC shows normocytic anaemia
Blood film shows schistocytes
Direct coombs test is positive in autoimmune haemolytic anaemia