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Haematology > Anaemia > Flashcards

Anaemia Flashcards

1
Q

Definition of anaemia:

A

Low Hb concentration, due to either low red cell mass or increased plasma volume (e.g. pregnancy)

A low Hb is <135g/L for men and <115g/L for women

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2
Q

Symptoms of anaemia

A

fatigue, dyspnoea, faintness, palpitations, headache, tinnitus, anorexia - and angina if there is pre-existing coronary artery disease

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3
Q

Signs of anaemia?

A

may be absent even in severe anaemia:

  • may be pallor (eg conjunctival pallor)
  • severe anaemia (<80g/L): signs of hyperdynamic circulation, eg tachy, flow murmus, cardiac enlargement, retinal haemorrhages.
  • later: heart failure may occur: here, rapid blood transfusion can be fatal
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4
Q

Normal mean cell volume (MCV)?

A

76-96 femtolitres

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5
Q

What is the first step in diagnosis of anaemia?

A

to look at the mean cell volume (MCV)

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6
Q

Types of Low MCV anaemia (microcytic anaemia)?

A
  1. Iron-deficiency anaemia (IDA), most common cause
  2. Thalassaemia (suspect if MCV is ‘too low’ for the Hb level and red count is raised)
  3. Sideroblastic anaemia (v rare)
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7
Q

Types of normal MCV anaemia (normocytic anaemia)?

A
  1. Acute blood loss
  2. Anaemia of chronic disease (or low MCV)
  3. Bone marrow failure
  4. Renal failure
  5. Hypothyroidism (or high MCV)
  6. Haemolysis (or high MCV)
  7. Pregnancy
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8
Q

Normocytic anaemia with low WCC and low platelets, what would you suspect?

A

Marrow failure

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9
Q

Types of high MCV anaemia (macrocytic anaemia)?

A
  1. B12 or folate deficiency
  2. Alcohol excess - or liver disease
  3. Reticulocytosis
  4. Cytotoxics, e.g. hydroxycarbamide
  5. Myelodysplastic syndromes
  6. Marrow infiltration
  7. Hypothyroidism
  8. Antifolate drugs (e.g. phenytoin)
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10
Q

When would you suspect haemolytic anaemias?

A

These do not fit into the normal classification as the anaemia may be normocytic, or if there are many young (hence larger) RBCs and reticulocytes, macrocytic.

Suspect if there is a reticulocytosis (>2% of RBCs; or reticulocyte count >100x10^9/L), mild macrocytosis, low haptoglobin, increased bilirubin, high LDH, or high urobilinogen.

Patients will often be mildly jaundiced (but note that haemolysis causes pre-hepatic jaundice so there will be no bilirubin in their urine.

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11
Q

Does the patient need a blood transfusion?

A

Probably not if Hb >70g/L

In acute anaemia (eg haemorrhage with active peptic ulcer), transfusion for those with Hb <70g/L may be indicated

other factors to consider: other comorbidities (particularly IHD) and whether patient is symptomatic

severe anaemia with heart failure: transfusion is vital to restore Hb to a safe level, e.g. 60-80g/L, must be done with great care.

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12
Q

Transfusion in severe anaemia with heart failure:

A

Transfusion is vital to restore Hb to a safe level, eg 60-80 g/L

give it slowly with 10-40 mg Furosemide IV/PO with alternate units (dose depends on previous exposure to diuretics)

check for signs of worsening overload: rising JVP and basal crackles: in this eventuality, stop and treat.

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13
Q

Causes of iron deficiency anaemia?

A

This is common : seen in up to 14% of menstruating women

causes:
- blood loss, e.g. menorrhagia or GI bleeding

  • poor diet or poverty may cause IDA in babies or children (rarely in adults)
  • malabsorption (e.g. coeliac disease) is a cause of refractory IDA
  • In the tropics, hookworm (GI blood loss) is the most common cause
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14
Q

Signs of IDA

A

chronic (signs now rare):

kiolonychia, atrophic glossitis, angular cheilosis, and rearely, post-cricoid webs (plummer-vinson syndrome)

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15
Q

Tests for IDA?

A

Blood film:
- microcytic, hypochromic anaemia with anisocytosis and poikilo-cytosis

low MCV, low MCH and low MCHC

confirmed by low ferritin (also low serum iron with high TIBC, but less reliable)

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16
Q

Treatment of IDA?

A

treat the cause

oral iron, e.g. ferrous sulfate (200mg/8h PO)

Hb should rise by 10g/L/week

IV iron is only indicated if the oral route is impossible or ineffective, e.g. functional iron deficiency in chronic renal failure, where there is inadequate mobilisation of iron stores in response to erythropoietin therapy.

17
Q

Commonest anaemia in hospital patients and 2nd most common woldwide?

A

anaemia of chronic disease

18
Q

Anaemia of chronic disease arises from 3 problems:

A
  1. poor use of iron in erythropoiesis
  2. cytokine-induced shortening of RBC survival
  3. lowered production of and response to erythropoietin
19
Q

Causes of anaemia of chronic disease?

A

Many, e.g. chronic infection, vasculitis, RA, malignancy, renal failure

20
Q

investigations/results for chronic anaemia?

A

Ferritin normal or high in mild normocytic or microcytic anaemia

check blood film, B12, folate, TSHm and tests for haemolysis

21
Q

Treatment for chronic anaemia?

A

Treat underlying disease (eg in 60% of patients with RA) may help

erythropoetin may help (SE: flu like symptoms, hypertension, mild rise in the platelet count and thromboembolism)

IV iron can safely overcome the functional iron deficiency

22
Q

Sideroblastic anaemia

A

Microcytic anaemia doesn’t always mean iron deficiency! 20% of older people with an MCV of <75fL are not iron deficient! - think of sideroblastic anaemia whenever microcytic anaemia not responding to iron

This condition is characterised by ineffective erythropoiesis, leading to increased iron absorption, iron loading in marrow +/- haemosiderosis (endocrine, liver, and heart damage due to iron absorption)

23
Q

Causes of sideroblastic anaemia?

A
  • congenital (rare, x-linked) or acquired, e.g. idopathic as one of the myelodysplastic/myeloproliferative diseases
  • following chemotherapy
  • anti-TB drugs,
  • irradiation
  • alcohol or lead excess
24
Q

Treatment of sideroblastic anaemia?

A

Remove the cause

pyridoxine (vitB-6) +/- repeated transfusions for severe anaemia

25
Q

Go through what you would see in plasma iron studies for IDA, chronic disease, chronic haemolysis, haemochromatosis, pregnancy and sideroblastic anaemia

A

IDA: low iron, high TIBC, low ferritin

CD: low iron, low TIBC, high ferritin

Chronic haemolysis: high iron, low TIBC, high ferritin,

Haemochromatosis: high iron, low TIBC, high ferritin

Pregnancy: high iron, high TIBC, varying ferritin

Sideroblastic anaemia: high iron, TIBC varies, high ferritin

26
Q

Macrocytosis means?

A

MCV > 96fL

may not always be accompanied by anaemia (e.g. in alcohol excess)

27
Q

Causes of microcytosis? (MCV > 96fL)

A
  • megaloblastic: a megaloblast is a cell in which nuclear maturation is delayed compared with the cytoplasm. This occurs with B12 and folate deficiency: both required for DNA synthesis. another cause is cytotoxic drugs
  • Non-megaloblastic: alcohol excess, reticulocytosis (e.g. in haemolysis), liver disease, hypothyroidism, pregnancy
  • other haematological disease: myelodysplasia, myeloma, myeloproliferative disorders, aplastic anaemia
28
Q

blood film: macrocytic anaemia?

A

B12 and folate deficiency will show hypersegmented neutrophils

Target cells if liver disease

29
Q

Tests for macrocytic anaemia?

A

LFT, TFT, serum B12, serum folate (or red cell folate which is more reliable)

If cause isnt found: bone marrow biopsy

30
Q

patient undergone initial tests for causes of macrocytic anaemia which were inconclusive, what may bone marrow biopsy show?

A
  1. Megaloblastic marrow
  2. Normoblastic marrow (eg liver disease, hypothyroidism)
  3. Abnormal erythropoiesis (sideroblastic anaemia, leukaemia, aplasia)
  4. Increased erythropoiesis (eg haemolysis)
31
Q

About folate

A

Found in green veg, nuts, yeast and liver

synthesised by gut bacteria, absorbed by duodenum/proximal jejunum

body stores can last 4 month

maternal folate defiency causes fetal neural tube dects

32
Q

Causes of folate defiency:

A
  • poor diet, poverty, alcoholics, elderly
  • increased demand (pregnancy, inflammatory disease, malignancy)
  • malabsorption, eg coeliac disease, tropical sprue
  • drugs: anti-epileptics (phenytoin, valporate), methotrexate, trimethoprim
33
Q

Treatment of macrocytic anaemia

A

assess for an underlying cause,

poor diet, malabsorption: treat with folic acid 5mg/day PO for 4 months (never without B12 unless patient is known to have normal B12 level)

pregnancy: prophylactic doses of folate (400mcg/day) are given from conception until at least 12 wks; helps prevent spina bifida and neural tube defects, as well as anaemia

Haematology (15 decks)

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