Anaemia - Classification, investigation and general approach Flashcards Preview

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Flashcards in Anaemia - Classification, investigation and general approach Deck (30):
1

Where does erythropoiesis occur?

Bone marrow

2

Where does is also occur in pre-natal life?

Liver and spleen (this can also occur in adult life, but is abnormal)

3

What is different about childhood erythropoiesis?

All sites of the skeleton are involved

4

Where is involved in adults?

The axial skeleton and proximal ends of the femora and humerii.

5

What is the total maturation time of red blood cells in the marrow?

7 days – 4 days in division, 3 days in maturation and Hb synthesis

6

What are young red cells called?

Reticulocytes – nucleus has been extruded

7

How long do red cells survive?

120 days –around 1% of circulating red cells are destroyed and replaced each day

8

What are the principle nutrients required for erythropoiesis?

Iron, vit B12 and folate

9

What are the key hormones involved?

EPO, thyroxine, GH, adrogens, corticosteroids

10

Where are red cells destroyed?

Principally by macrophages in the spleen

11

Which parts of red cells are recycled?

The iron and globin chains

12

What else is formed when haemoglobin is broken down? Where is it transported and metabolised?

Bilirubin is formed by destruction of the porphyrin ring. It is transported by serum haptoglobins to the liver where it is metabolised, conjugated and excreted in the bile.

13

What is the definition of anaemia?

A reduction in the red cell mass or haemoglobin to a level which is insufficient to meet the body’s physiological needs

14

What are the normal ranges?

They vary from high in neonates (dropping within the first week of life), to low in childhood, to a male range of 130-180g/L, female of 115-160g/L

15

Why are women’s levels lower?

Why are women’s levels lower? Differing androgen levels, menstruation.

16

What are the 3 mechanism of anaemia?

Defective production:
- defective proliferation of erythroid precursors
- defective maturation of erythroid precursors
- both
Increased destruction (haemolysis) or loss (bleeding)

17

How is anaemia classified? (3 ways)

1. By specific cause – eg. iron deficiency anaemia, folate deficiency anaemia.
2. By the morphological abnormalities on the blood film or bone marrow
a. Normocytic (normal sized red cells)
b. Microcytic (small red cell cells)
c. Macrocytic (large red cells)
d. Hypochromic (pale red cells)
e. Megaloblastic (erythroid precursor cells in the marrow with a distinctive morphological appearance)
f. Leucoerythroblastic (denotes the presence of both precursor white and red cell blood cells on a stained blood film)
3. By the underlying pathophysiological process – eg. haemolytic anaemia, aplastic anaemia

18

How might the body adapt to anaemia?

How might the body adapt to anaemia?
1. Increased cardiac output
2. Redistribution of blood flow between organs – increased flow to high need organs e.g. brain, myocardium
3. Increased O2 dissociation from Hb – brought about by and increase in the amount of 2, 3-diphosphoglycerate (2, 3DPG)

19

What in general is the cause of the symptoms of anaemia? Widespread and multi-organ inadequate tissue oxygenation

Widespread and multi-organ inadequate tissue oxygenation

20

What influences the clinical features of anaemia?

1. The severity of the anaemia
2. The speed of onset
3. The presence of co-morbidities
(This is a good way of thinking about the clinical features of all diseases)

21

In acute blood loss, which should be the guiding factor of management?

Estimated blood loss and cardiovascular function, NOT Hb as this may be near normal, and it is the hypovolaemia that is the problem, which would ideally be treated with red cell transfusion.

22

What are the common symptoms of anaemia?

• Fatigue
• Breathlessness on exertion
• Light headedness
• Headaches
• Poor concentration
• An increased awareness of the heart beat due to the increased cardiac output
• Other symptoms such as angina, menstrual abnormalities, loss of libido etc. may be reported by the patient

23

What are the general signs of anaemia?

1. Pallor – check mucous membranes rather than skin
2. Hyperdynamic circulation – rapid, bounding pulse and flow murmurs etc.
3. Heart failure, only seen in severe cases like patients with poor cardiovascular reserve (elderly + cardiovascular disease)

24

Write out how to take a detailed anaemia history.

Presenting symptoms
1. Symptoms of anaemia
- Patient may be asymptomatic if anaemia mild or if it’s developed over a long period
- Acute onset may suggest active bleeding or haemolysis

2. Symptoms of underlying cause
- Menorrhagia may suggest gynaeocological problem
- Change in bowel habit may suggest colorectal malignancy
- Bone pain may suggest myeloma
- Arthralgia may suggest an inflammatory arthritis etc
- Dietary history

Past medical history
1. Haematological disease
2. Non-haematological disease
3. Previous surgery (eg. gastrectomy) etc

Family history
1. Haematological disease (eg. pernicious anaemia)
2. Non-haematological disease
3. Previous surgery (eg. gastrectomy) etc

Gynaecological & obstetric history
1. Menstrual history
2. Current pregnancy or repeated pregnancies at short intervals etc

Social history
3. Occupational history
4. Alcohol and smoking
5. Socio-economic circumstances etc

Drug history
1. Current medicines including over-the counter products – many medicines adversely affect marrow function
2. Antiplatelet drugs (aspirin, clopidogrel etc)
3. Steroids etc.

25

What aspects should a physical examination for anaemia include?

General examination:
Pallor, jaundice, clubbing, cyanosis, lymphadenopathy, fever, oedema etc

Mouth:
Glossitis, angular stomatitis, ulcers, telangiectasia etc

Abdomen:
Hepatosplenomegaly, other masses, rectal examination if indicated etc

Cardiovascular:
Signs of hyperdynamic circulation, new murmurs etc

Respiratory:
Consolidation, pleural effusion, etc

Musculoskeletal:
Synovitis, arthritis, etc

Neurological:
Neuropathy, myelopathy etc.

26

What initial investigations should you carry out?

1. Full blood count
- Is the anaemia normocytic, microcytic or normocytic? Helps to narrow down list of possible causes
- Are there any other abnormalities of the blood count?

2. Blood
- Extremely important in the investigation of haematological abnormalities
- Morphology of red cell, white cells, platelets
- Any other abnormalities? (eg. blasts would suggest acute leukaemia)

3. Haematinics – serum B12, folate and iron studies

4. Biochemistry – U&Es, LFTs, inflammatory markers (if indicated)

27

Depending on the differential diagnosis what further investigations should you include?

1. Haemolysis screen if indicated
- Reticulocyte count, direct antiglobulin test etc

2. Bone marrow aspirate and trephine biopsy
- Key haematological investigation but not always indicated
- Many causes of anaemia can be diagnosed without recourse to a film examination bone marrow test

3. Other investigations will depend on suspected cause
- GI investigations – endoscopy, colonoscopy etc
- Imaging – eg. plain x-rays for myeloma, CT for lymphoma
- Other – complex cases may require sending away samples to a reference laboratory (eg. rare anaemias)

NB Sometimes a cause cannot be found despite extensive investigations

28

What the 3 considerations before beginning treatment for anaemia?

1. What is the severity of the anaemia – how low is the Hb?

2. What are the patient’s symptoms if any?

3. How ill is the patient / how urgent is treatment?

29

What is the process of correcting a patient’s anaemia?

1. Establish underlying cause of anaemia first before initiating if at all possible
2. Treat the patient not their haemoglobin
3. Patients with mild anaemia will usually not require correction of their anaemia
4. Some patients with congenital anaemia (eg. sickle cell anaemia) and acquired anaemia (eg. myelodysplastic syndrome) are tolerant of their low baseline haemoglobin. They will not need treatment unless their haemoglobin falls significantly from the baseline value.
5. Treating the underlying cause will raise the haemoglobin
6. Blood transfusion
- Not normally necessary unless the haemoglobin is very low, the patient is symptomatic or for acute blood loss.
- Purpose of transfusion is to raise the haemoglobin concentration to a to a safe level while the cause of the anaemia is being sought – it is not a cure. The decision to transfuse should be based on the patient’s symptoms and cardiovascular status.

30

How do you treat the underlying cause of anaemia?

This will depend upon the individual diagnosis. However, it may not always be possible to establish a cause for the anaemia, so symptom management is what is aimed for with these patients.