Anaemia Flashcards
What is haemoglobin (Hb)?
A protein found in RBC
what is the function of Hb?
Haemoglobin is responsible for picking up oxygen in the lungs and transporting it to the body’s cells
What is the role of iron in Hb?
Iron is essential in creating haemoglobin and forms part of it’s structure.
What does mean cell volume (MCV) mean?
The mean cell volume (MCV) refers to the size of the red blood cells
Normal Hb ranges for men & women?
Women: 120 – 165 grams/litre
Men: 130 -180 grams/litre
Anaemia is divided into three categories based on the mean cell volume.
What are they?
1) microcytic anaemia (low MCV)
2) Normocytic anaemia (normal MCV)
3) Macrocytic anaemia (large MCV)
What should new onset microcytic anaemia in older patients always be urgently investigated for?
underlying malignancy.
Give some causes of microcytic anaemia
Mneumonic: TAILS
T - thalassaemia
A - anaemia of chronic disease
I - iron deficiency
L - lead poisoning
S - sideroblastic anaemia
Macrocytic anaemia can be megaloblastic or normoblastic.
Name some causes of both
Megaloblastic bone marrow:
- B12 deficiency
- folate deficiency
- e.g. secondary to methotrexate
Normoblastic bone marrow:
- alcohol
- reticulocytosis (usually from haemolytic anaemia or blood loss)
- hypothyroidism
- liver disease
- drugs e.g. aziothioprine
- pregnancy
What is the difference between macrocytic and megaloblastic anaemia?
Megaloblastic anaemia is a type of macrocytic anaemia.
Macrocytes are enlarged RBCs (raised MCV).
Megaloblasts are large RBC precursors due to impaired DNA synthesis, preventing the cells from dividing normally. Rather than dividing, they grow into large, abnormal cells.
What causes the production of megaloblasts?
Impaired synthesis of RBC DNA e.g. folate deficiency
Define reticulocytosis
An increased concentration of reticulocytes (immature red blood cells.
This happens when there is a rapid turnover of red blood cells, such as with haemolytic anaemia or blood loss.
Anaemia of chronic disease often occurs with CKD.
How?
Reduced production of EPO by kidneys (hormone responsible for production of RBCs).
Treatment of anaemia caused by CKD?
erythropoietin
What are the causes of normocytic anaemia?
(3 As and 2 Hs)
A - acute blood loss
A - anaemia of chronic (more likely than microcytic) e.g. CKD
A - aplastic anaemia
H - haemolytic anaemia
H - hypothyroidism
What type of anaemia does CKD cause?
Typically normocytic
What is sideroblastic anaemia?
Sideroblastic anaemia is a disorder where the body produces enough iron but is unable to put it into the haemoglobin (iron levels will be normal/high)
What is the main cause of sideroblastic anaemia?
Alcohol excess
Generic symptoms of anaemia?
- Tiredness
- Shortness of breath
- Headaches
- Dizziness
- Palpitations
- Worsening of other conditions, such as angina, heart failure or peripheral arterial disease
What 2 symptoms are specific to iron deficiency anaemia?
1) Pica (dietary cravings for abnormal things, such as dirt or soil)
2) Hair loss
Generic signs of anaemia?
- pale skin
- conjunctival pallor
- tachycardia
- raised RR
What is koilonychia?
spoon-shaped nails
What can koilonychia indicate?
iron deficiency anaemia
What is angular cheilitis?
a common inflammatory condition affecting the corners of the mouth.
What anaemia can cause angular cheilitis?
Iron deficiency
What is atrophic glossitis?
a smooth tongue due to atrophy of the papillae
What anaemia can atrophic glossitis indicate?
Iron deficiency
What type of anaemia can cause brittle hair and nails?
iron deficiency
What type of anaemia can cause jaundice?
Haemolytic
What type of anaemia cause cause bone deformities?
Thalassaemia
Possible blood tests in anaemia?
1) FBC: Hb & MCV
2) Reticulocyte count (indicates red blood cell production)
3) Blood film for abnormal cells and inclusions
4) Renal profile: for CKD
5) LFTs for liver disease and bilirubin (raised in haemolysis)
6) Ferritin (iron)
7) B12 & folate
8) Intrinsic factor antibodies for pernicious anaemia
9) TFTs for hypothyroidism
10) Coeliac disease serology (e.g., anti-tissue transglutaminase antibodies)
11) Myeloma screening (e.g., serum protein electrophoresis)
12) Haemoglobin electrophoresis for thalassaemia and sickle cell disease
13) Direct Coombs test for autoimmune haemolytic anaemia
What investigations are indicated for unexplained iron deficiency anaemia?
A colonoscopy and oesophagogastroduodenoscopy (OGD).
How can iron deficiency lead to anaemia?
Iron is needed to make the Hb in RBCs, therefore a deficiency of iron leads to a reduction in RBCs/Hb.
Who does iron deficiency have the highest incidence among?
Pre school-age children
What are the 4 most common causes of iron deficiency anaemia?
1) excessive blood loss
- women: menorrhagia
- men & postmenopausal women: GI bleeding (suspect colon cancer)
2) inadequate dietary intake
3) poor intestinal absorption e.g. coeliac
4) increased iron requirements
- growth periods in children
- pregnancy
What can cause anaemia in pregnancy?
1) increased demands during pregnancy as the baby will receive their iron supply from the mother
2) an increase in plasma volume during pregnancy causes iron deficiency anaemia through dilution i.e. the proportion of fluid in comparison to red blood cells increases.
Iron deficiency causes microcytic hypochromic anaemia.
What does microcytic mean?
What does hypochromic mean?
Microcytic: small RBCs with a low MCV
Hypochromic: pale cells due to reduced Hb conc
what are causes of blood loss causing iron deficiency anaemia?
1) menorrhagia
2) GI tract bleeding:
- Cancer (e.g., stomach or bowel cancer)
- Oesophagitis and gastritis
- Peptic ulcers
- Inflammatory bowel disease
- Angiodysplasia (abnormal vessels in the wall)
What is the most common cause of iron deficiency anaemia in children?
Dietary insufficiency - during growth, iron requirements often exceed the dietary intake
What is a common exam presentation for iron deficiency anaemia in children?
Pica (e.g. eating soil or dirt)
Where is iron mainly absorbed?
Duodenum & jejunum
Mechanism of absorption of iron:
1) Iron is mainly absorbed in the duodenum and jejunum.
2) It requires the acid from the stomach to keep the iron in the soluble ferrous (Fe2+) form
3) When the stomach contents are less acidic, it changes to the insoluble ferric (Fe3+) form.
How can PPIs result in iron deficiency?
PPIs reduce stomach acid –> changes iron to the insoluble ferric (Fe3+) form.
How can coeliac disease or Crohn’s disease cause iron deficiency?
Inflammation of the duodenum or jejunum can also reduce iron absorption.
Features of iron deficiency anaemia?
- Fatigue
- Shortness of breath on exertion
- Palpitations
- Pallor
- Nail changes: this includes koilonychia (spoon-shaped nails)
- Hair loss
- Atrophic glossitis
- Post-cricoid webs
- Angular stomatitis
- Pica
Important history aspects in iron deficiency anaemia?
1) changes in diet
2) medication history
3) menstrual history
4) weight loss
5) change in bowel habit & blood
What is transferrin?
Carrier protein for iron (transports iron around the blood)
What is total iron binding capacity (TIBC)?
The space for iron to attach to on all the transferrin molecules combined.
TIBC is directly related to the amount of transferrin in the blood.
What does transferrin saturation refer to?
The proportion of the transferrin molecules bound to iron, expressed as a percentage.
The formula for transferrin saturation is:
Transferrin saturation = serum iron / total iron-binding capacity
How is TIBC and transferrin affected by iron levels?
Iron excess –> TIBC & transferrin decrease
Iron deficiency –> TIBC & transferrin increase
Why is serum iron often not a useful measure on its own?
Serum iron varies significantly throughout the day, with higher levels in the morning and after eating iron-containing meals.
What does transferrin saturation indicate?
Transferrin saturation indicates the total iron in the body.
How do iron levels affect transferin saturation?
Less iron –> transferrin less saturated
More iron –> transferrin more saturated