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Theme 2 > Anaemia > Flashcards

Anaemia Flashcards

1
Q

Definition anaemia

A

Haemoglobin (Hb) concentration falls below defined level (outside normal range) - Units of Hb are g/L

Causes:
Decrease red blood cells (RBCs)
Decrease Hb content (diagnostic criterion)
Altered Hb does not carry sufficient O2

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2
Q

Symptoms

A
  • Lethargy
  • Shortness of breath
  • Palpitations
  • Headache
    Often non-specific: worse if acute onset

Signs:
Pallor, pale conjunctivae
Tachypnoea
Tachycardia

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3
Q

Koilonychia

A

Spoon shaped nails

Iron deficiency

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4
Q

5 Broad Causes

A

Bleeding

Deficiency in necessary components: Iron, B12, folic acid

Haemolytic: Increased red cell destruction & shortened RBC lifespan

Bone Marrow Dysfunction / Infiltration
E.g. Aplastic anaemia

Poor O2 Utilisation / Carriage

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5
Q

Classification

A

Size of red cell

Acute or chronic

Underlying aetiology

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6
Q

Iron Deficiency

A

A range of causes
Bleeding (esp. occult)
Nutrition
Increased Requirements

Confirm with iron studies:
Ferritin
Fe, Transferrin, Saturation

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7
Q

Diagnostic Tests for Iron

A

Serum Ferritin
Storage form of iron
Low = iron deficient (high = iron overload or reactive)

Serum Iron
Labile so reflects recent intake of iron

Serum Transferrin
Carrier molecule for iron
Homeostatically goes up if iron deficient
Similar to total iron binding capacity (TIBC)

Percent Transferrin Saturation
Sensitive measure of iron status
Low = iron deficient

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8
Q

Causes of Iron Deficiency in UK

A

Bleeding

 - Menstrual
 - Occult GI Malignancy
 - GI peptic ulceration

Unlikely to be iron deficient from diet alone

- Vegan/vegetarian
 - Malabsorption, e.g. coeliac disease and Crohn’s

Increased Requirements - pregnancy

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9
Q

Categorise by size

A

Mean Corpuscular Volume
Normally about 80-100fL

Microcytic (Small)
Iron deficiency
Inherited disorders of haemoglobin (thalassaemia)

Macrocytic (Large)
B12 and folate deficiency
Myelodysplasia

Normocytic (Normal)

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10
Q

Blood Film benefits

A

Easy
Quick
Useful

Red cells last 100 days in the circulation

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11
Q

Reticulocyte Count

A

Represents RBC production rate by marrow

Low if bone marrow infiltrated
Low during precursor deficiencies (e.g. iron)
High in haemolysis
High in chronic bleeding
If in normal range when anaemic, bone marrow is not responding appropriately

Can be used to monitor progress of treatment

Measured by flow cytometry that counts cells with nucleic acids (i.e. RNA) or using a specific stain and microscopy

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12
Q

Blood Film Features

– Iron Deficiency

A

Hypochromia

Microcytosis

Pencil Cells

Target Cells

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13
Q

History when anaemia suspected

A

GI Symptoms:

   - Dyspepsia
    - Change in Bowel Habit (?melaena) 
     - Weight Loss

Menstrual History

Dietary history
Travel History
Ethnic Origin
Family History

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14
Q

Megaloblastic Anaemia

A

Macrocytic (MCV > 100)
Due to deficiency of: Vitamin B12 & Folate

Required for DNA
 Large RBCs
 Sufficient iron for Hb
 Sufficient precursors for cell growth
 Insufficient precursors for cell division
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15
Q

B12 Deficiency

A

Dietary - strict vegans

Pernicious Anaemia
Autoimmune – parietal cell loss
Deficiency of intrinsic factor

Malabsorption:
Post gastric / ileal surgery
Crohn’s disease

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16
Q

Folate Deficiency

A

Dietary – common

Malabsorption: Coeliac & Crohn’s disease

Excess Utilisation: Chronic haemolysis & Pregnancy

Alcohol

Drugs
Phenytoin
Methotrexate

17
Q

Anaemia of Chronic Disease

A

Most common form of anaemia in hospitalised patients

Common causes:

Chronic inflammation & chronic infection e.g. TB

Auto-immune conditions e.g. rheumatoid arthritis

Cancer

18
Q

Anaemia of Chronic Disease mechanism

A

Poor Utilisation of Iron in Body
Iron is stuck in macrophages of the reticuloendothelial system and cannot be mobilised into the early erythroblasts

Dysregulation of Iron Homeostasis
Decreased transferrin
Increased hepcidin

Impaired proliferation of erythroid progenitors
Blunted response to Epo (erythropoietin)
Iron is unavailable

19
Q

Sickle Cell Anaemia

A

Point mutation in beta globin gene causing HbS (sickle Hb)

RBCs turnover = approx 20 days due to haemolysis

Sickle cell crisis
Triggered by low blood O2 level
Vaso-occlusive
Ischaemia, pain, necrosis and often organ damage

Management – Analgesics, hydration, transfusion

Genetic, autosomal recessive
Sub-Saharan Africa, shortened life expectancy

20
Q

Sickle cell anaemia mechanism

A

Sickle cell disease = Mutated Sickle Haemoglobin (HbS)
forms long filamentous strands
insoluble at low O2 tension
RBCs become inflexible + spiky -> crisis

Sickle cell trait = heterozygous for HbS and HbA,
much lower risk of sickling and crisis
resistant to malaria infection

21
Q

Thalassaemia

A

Insufficient Hb production
Due to altered Hb gene expression
Inherited autosomal recessive

Clinical features:
enlarged spleen, liver, and heart
bones may be misshapen

Alpha versus Beta thalassaemia
Intermedia versus major
Life-long transfusions

22
Q

Thalassaemia - history & diagnosis

A

Family history
Trait vs disease
Distribution as per malaria

FBC – characteristic indices
Microcytic
Hypochromic

Hb electrophoresis
Blood Film

23
Q

Bone Marrow Infiltration

A

Leukaemia
Non-specific symptoms
Bone marrow failure

Lymphoma
Lymphadenopathy
Weight loss

Myeloma
Anaemia
Hypercalcaemia
Renal Failure

Bone Marrow obtained from iliac crest:
aspirate film for morphology of cells
trephine biopsy for histological sections

24
Q

Acute anaemia management

A

When to transfuse:
Acute > chronic
Be guided by symptoms rather than Hb level
Can the patient replenish the blood cells?
If not, then transfuse for symptoms (usually <90g/L)

Acute on chronic haemorrhage
Haematemesis (vomiting blood)
Melaena (darkened stools)

25
Q

Chronic anaemia management

A

Treat the underlying cause:
Iron supplementation (oral ferrous sulphate 3 months)
Folic acid (oral folate for 3 months)
B12 (injections every 3 months)

Erythropoietin (EPO) in patients with kidney failure particularly if on haemodialysis

Long-term transfusion causes:
Iron overload
Allo-antibodies

26
Q

High Reticulocyte Count

A

High in haemolysis or chronic bleeding

Measured by flow cytometry that counts cells with nucleic acids (i.e. RNA) or using a specific stain and microscopy

27
Q

Low Reticulocyte Count

A

Low if bone marrow infiltrated
Low during precursor deficiencies (e.g. iron)

Measured by flow cytometry that counts cells with nucleic acids (i.e. RNA) or using a specific stain and microscopy

28
Q

Vomiting blood

A

Haematemesis (vomiting blood)

29
Q

Darkened stools

A

Melaena (darkened stools)

30
Q

Leukaemia

A

Non-specific symptoms

Bone marrow failure

31
Q

Lymphoma

A

Lymphadenopathy

Weight loss

32
Q

Myeloma

A

Anaemia
Hypercalcaemia
Renal Failure

33
Q

Morphology of cells

A

Aspirate film

34
Q

Histological sections

A

Trephine biopsy

Theme 2 (8 decks)

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