Haematology Flashcards

1
Q

What are the 4 mechanisms behind iron deficiency anaemia?

A
  1. Increased loss of iron
  2. Malabsorption
  3. Reduced intake
  4. Increased utilisation of iron
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2
Q

What Hb levels indicate iron deficiency anaemia in men and non-pregnant women?

A

Men - <130g/L

Non-pregnant women - <120g/L

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3
Q

What is the most common form of anaemia?

A

Iron deficiency - globally affects 500 million people

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4
Q

How much iron on average is absorbed daily from the diet?

A

Only 1mg on average of iron is absorbed daily from the diet so even modest blood loss over time can lead to iron deficiency

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5
Q

Give some conditions that can cause iron deficiency anaemia via an increased loss of iron?

A
  • Menorrhagia
  • GI bleeding e.g. ulcers
  • Hookworm
  • IBD
  • Malignancy
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6
Q

What is the biggest risk factor for iron deficiency anaemia due to reduced intake of iron>

A

Poor diet – Main sources of dietary iron; meat, leafy green vegetables, fortified foods including bread and cereals

Vegans, vegetarians, poor or restricted diets at risk

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7
Q

Where does most iron absorption occur?

A

Small intestine

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8
Q

Which conditions can result in iron deficiency anaemia due to malabsorption?

A
  • Coeliac disease & IBD – result in reduction in the mucosal surface area available for iron absorption
  • Gastrectomy & cystic fibrosis – malabsorption of iron occurs at pre-mucosal level when digestive enzyme activity is disrupted
  • Intestinal resection & jejuno-illeal bypass: inadequate absorption in the small intestine
  • Lymphoma: causes lymphatic obstruction leads to post-mucosal absorption
  • Drugs: Reduce absorption of iron e.g. tetracyclines/quinolones (chelate iron), PPIs (decrease gastric acid necessary for iron absorption)
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9
Q

Why can IBD and coeliac disease predispose to iron deficiency anaemia?

A

Conditions result in reduction in the mucosal surface area available for iron absorption

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10
Q

Why can CF predispose to iron deficiency anaemia?

A

malabsorption of iron occurs at pre-mucosal level when digestive enzyme activity is disrupted

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11
Q

Why can PPIs predispose to iron deficiency anaemia?

A

decrease gastric acid necessary for iron absorption

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12
Q

What 2 patient populations are at risk of iron deficiency anaemia due to increased utilisation of iron?

A
  1. Pregnancy
  2. Growth spurts in children
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13
Q

Describe the MCV in iron deficiency anaemia

A

Low (microcytic)

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14
Q

Describe the appearance of RBCs in iron deficiency anaemia

A

Higher % of hypochromic cells (pale cells)

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15
Q

What type of heart failure can iron deficiency anaemia cause?

A

High-output heart failure

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16
Q

What are 2 other causes of microcytic hypochromic anaemia? (i.e. differentials for iron deficiency anaemia)

A
  • Thalassaemia
  • Sideroblastic anaemia
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17
Q

What is thalassaemia?

A

A genetic defect of Hb production common in certain parts of the world e.g. Mediterranean coast

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18
Q

What is sideroblastic anaemia?

A

A congenital or acquired inability to integrate iron into haemoglobin

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19
Q

Give some causes of anaemia of chronic disease?

A
  • Inflammatory arthritis
  • Cancer
  • Kidney disease
  • Infections (e.g. TB, HIV)
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20
Q

What symptoms are common in iron deficiency anaemia?

A

N.B. Iron deficiency anaemia is often asymptomatic or only causes mild symptoms, especially if the anaemia develops gradually in otherwise healthy individuals (able to compensate).

  • Lethargy
  • Tiredness
  • Weakness
  • Jaundice
  • Heavy periods
  • Change in bowel habits
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21
Q

What red flags may be seen in iron deficiency anaemia?

A
  • Dysphagia
  • Weight loss
  • Dyspepsia
  • Abdominal pain
  • Rectal bleeding
  • Change in bowel habit
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22
Q

Clinical signs potentially seen in iron deficiency anaemia?

A
  • Conjunctival pallor
  • Pale mucosal membranes (mouth)
  • Angular cheilitis (ulcers/cracking at corners of mouth)
  • Atrophic glossitis (painful tongue with loss of papillae)
  • Koilonychia (spoon-shaped nails)
  • Dry skin and hair
  • In severe anaemia:
    • Tachycardia
    • Murmurs
    • Signs of cardiomegaly
    • Sins of heart failure e.g. peripheral oedema
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23
Q

results of FBC in iron deficiency anaemia?

A
  • Low Hb - anaemia
  • Low MCV (<95fl) - microcytic
  • Reduced MCH - hypochromic
  • Reduced MCHC
  • Increased red cell distribution width (RDW)
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24
Q

What is the MCH?

A

The mean corpuscular haemoglobin is he average mass of haemoglobin per red blood cell in a sample of blood → diminished in hypochromic anaemias.

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25
Q

What is MCHC?

A

The mean corpuscular hemoglobin concentration (MCHC) is the average concentration of hemoglobin in your red blood cells.

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26
Q

What does an increased red cell distribution width (RDW) indicate?

A

indicates variation in size of RBCs

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27
Q

Describe the ferritin levels in iron deficiency anaemia

A

Low - as iron stores in the body are mobilised to counteract the iron deficiency

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28
Q

Ferritin is an acute phase reactant. What does this mean?

A

It rises in inflammatory states

Patients who are iron deficient may appear to have normal (or even raised) serum ferritin levels in the context of acute inflammation (infection, autoimmune disease)

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29
Q

Describe the transferrin saturation levels in iron deficiency anaemia

A

Low - as less iron to saturate the transferrin

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30
Q

Describe the total iron binding capacity (TIBC) in iron deficiency anaemia

A

Raised total iron-binding capacity (TIBC) → there is increased capacity to bind iron due to reduced levels of iron

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31
Q

In what form is iron best absorbed?

A

In its ferrous state (Fe2+)

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32
Q

Once absorbed into the bloodstream, what is iron bound by?

A

Transferrin

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33
Q

What stores iron?

A

Ferritin

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34
Q

Describe a blood film in iron deficiency anaemia

A

Hypochromic cells (pale) which differ in size (anisocytosis) and shape (poikilocytosis)

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35
Q

Define anisocytosis

A

having red blood cells (RBCs) that are unequal in size

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36
Q

Define poikilocytosis

A

an increase in abnormal red blood cells of any shape

37
Q

When should B12 and folate levels be checked in anaemia?

A
  • Presenting with normocytic/macrocytic anaemia and low or normal ferritin
  • Who have not demonstrated an adequate response to iron treatment
38
Q

Which antibody is screened for in suspected coeliac disease?

A

tissue transglutaminase antibody

39
Q

If a patient has recently travelled to high-risk areas, what test can be done if they present with anaemia?

A

Stool examination → detect parasites

40
Q

What are some red flags for GI malignancy in those presenting with iron deficiency anaemia?

A
  • > 60 y/o
  • Premenopausal women with bowel symptoms
  • Family history of GI cancer
  • Persistent anaemia despite treatment
41
Q

What is the treatment for iron deficiency anaemia?

A
  • Ferrous sulphate (oral or IV)
  • Treat underlying cause
42
Q

Risk of IV ferrous sulphate?

A

Anaphylaxis

43
Q

Side effects of oral iron?

A
  • Unreliable, not good compliance
  • Side effects: nausea, GI irritation, constipation/diarrhoea
44
Q

Give 3 major causes of microcytic anaemia

A
  • Iron deficiency anaemia (most common)
  • Sideroblastic anaemia
  • Alpha and Beta Thalassaemia
45
Q

Define microcytic anaemia

A

Microcytic anaemia is defined as the presence of small, often hypochromic, RBCs in a peripheral blood smear and is usually characterised by a low MCV (less than 83 microns)

46
Q

What are the major causes of macrocytic anaemia?

A
  • B12/folate deficiency
  • Haemolysis
  • Marrow damage
  • Metabolic e.g. thyroid/liver disease
47
Q

Give 3 major causes of normocytic anaemia

A
  • Anaemia of chronic disease
  • Inflammatory
  • Acute blood loss
48
Q

Do we have an excretory mechanism for iron?

A

No excretion, only 7% is consumed. Therefore, mostly recycled.

49
Q

How can B12 deficiency lead to anaemia?

A

B12 is essential for synthesis of RBCs

50
Q

Where is B12 absorbed?

A

Terminal ileum

51
Q

What is required for the absorption of B12 in the terminal ileum?

A

Intrinsic factor

52
Q

Which cells produce intrinsic factor?

A

Gastric parietal cells

53
Q

Why is a daily intake of folate required?

A

Not stored well

54
Q

Where is folate absorbed?

A

Upper small bowel

55
Q

Define macrocytosis

A

Refers to RBCs that are larger than normal

56
Q

Define macrocytic anaemia

A

Fall in Hb + large RBCs

57
Q

Macrocytic anaemia can be divided into what 2 groups?

A
  1. Megaloblastic
  2. Non-megaloblastic
58
Q

What are megaloblastic types of macrocytic anaemia caused by?

A

due to B12/folate deficiency → characterised by the failure to synthesise adequate amounts of DNA

59
Q

What is the most common cause of B12 deficiency in the UK?

A

Pernicious anaemia

60
Q

Give some other causes of B12/folate deficiency

A
  • Dietary insufficiency
  • Malabsorption:
    • Crohn’s disease
    • Gastrectomy
    • Atrophic gastritis
  • Malnutrition (e.g. alcoholism)
61
Q

Give some causes of non-megaloblastic macrocytic anaemia

A
  • Alcoholism
  • Liver disease
  • Bone marrow failure
  • Myelodysplastic syndromes (MDS)
62
Q

How does haemolysis lead to macrocytic anaemia?

A

Causes reticulocytosis - RBCs are large and immature due to compensation

63
Q

What conditions cause haemolysis?

A

Malaria

Autoimmune conditions e.g. lupus

64
Q

Risk factors for B12 deficiency?

A
  • Pernicious anaemia
  • Dietary (think vegan/veggie)
  • Medications; PPIs
  • Gastrectomy
  • Elderly age
  • Atrophic gastritis
  • Small bowel problems; Crohn’s disease, terminal ileum resection
65
Q

Risk factors for folic acid deficiency?

A
  • Dietary
  • Small bowel disease/malabsorption
  • Increased usage (pregnancy, haemolysis, inflammatory disorders)
  • Drugs: PPI’s & certain anticonvulsants (e.g. Phenytoin) can prevent uptake of folic acid
  • Alcohol
  • Pregnancy
66
Q

Complications of macrocytic anaemia?

A
  • Heart failure
  • Enlarged heart
  • Circulatory problems

Why → when the blood does not have enough Hb, it does not have enough oxygen so the body will try to fix this by increasing heart rate and/or blood pressure

67
Q

Symptoms of B12 deficiency?

A
  • Jaundice
  • Glossitis
  • Aphthous ulcers
  • Angular cheilitis
  • Paraesthesia
  • Visual disturbances
  • Irritability
  • Depression
  • Pseudo-dementia (always check B12 in new onset dementia)
68
Q

Why should you always check B12 in new onset dementia?

A

Can be a cause

69
Q

MCV in macrocytic anaemia?

A

High

70
Q

Treatment for B12/folate deficiency anaemia?

A
  • IM B12 injections
  • Folic acid supplements
  • Often need potassium & iron too (B12 can cause potassium to drop)
71
Q

What foods are rich in B12?

A

fish, meat and dairy

72
Q

What is pernicious anaemia?

A

An autoimmune disorder affecting the gastric mucosa, resulting in vitamin B12 deficiency (pernicious means – causing harm, especially in a gradual or subtle way).

73
Q

Pathophysiology behind pernicious anaemia?

A
  • Antibodies to intrinsic factor +/- gastric parietal cells
    • IF antibodies → bind to IF, blocking the B12 binding side
    • Gastric parietal cell antibodies → reduced acid production and atrophic gastritis
  • Reduced IF production → reduced B12 absorption
74
Q

Why can small bowel bacterial overgrowth lead to b12 deficiency?

A

as bacteria utilise vitamin B12

75
Q

2 major complications of pernicious anaemia?

A
  • Megaloblastic anaemia → B12 is important in the production of blood cells
  • Neuropathy → B12 is important in the myelination of nerves
76
Q

Why can B12 deficiency lead to neuropathy?

A

B12 is important in the myelination of nerves

77
Q

What blood group is at risk of pernicious anaemia?

A

A

78
Q

Neurological features of B12 deficiency?

A
  • Peripheral neuropathy – pins and needles, numbness (typically symmetrical and affects the legs more than the arms)
  • Neuropsychiatric features – memory loss, poor concentration, confusion, depression, irritability
  • Progressive weakness
  • Ataxia
  • Paraesthesia
79
Q

MCH in pernicious anaemia?

A

High (macrocytic)

80
Q

What is the MCH?

A

the average amount of Hb in each RBC

81
Q

Blood film results in pernicious anaemia?

A

megaloblasts (large) and oval-shaped RBCs

82
Q

What Abs can be tested in suspected pernicious anaemia?

A

Anti-intrinsic factor Abs

83
Q

Management of pernicious anaemia?

A

Life-long replacement treatment with cobalamin (B12)

84
Q

What is cobalamin?

A

vitamin B12

85
Q

What characterises Hodgkin’s lymphoma?

A

Reed-Sternberg cells in lymph node biopsy

86
Q

Risk factors for Hodgkin’s lymphoma?

A
  • Epstein Barr virus
  • HIV
  • Smoking
  • Immunosuppression
87
Q

Presentation of Hodgkin’s lymphoma?

A
  • Young adults
  • Cervical or supraclavicular tender lymphadenopathy
  • Alcohol induced pain
  • Compression of surrounding structures e.g. SOB, abdominal pain
  • B symptoms – fever, night sweats, weight loss)
88
Q

Which 2 infections can predispose to anaemia of chronic disease?

A
  1. HIV
  2. TB