Anaemia Flashcards

1
Q

Anaemia - definition

A

A reduction in one or more of the major RBC components obtained in a full blood count’:

  • RBC count
  • Haemoglobin
  • Haematocrit (ratio of RBCs to whole blood)
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2
Q

Microcytic anaemia - causes (4)

A
  • Iron deficiency
  • thalassaemic syndromes
  • sideroblastic anaemia
  • anaemia of chronic disease/chronic inflammation

(SIT = sideroblastic, iron def, thalassaemia)

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3
Q

Normocytic anaemia - causes (5)

A
  • Anaemia of chronic disease
  • haemolytic anaemias
  • mixed deficiency
  • acute blood loss
  • hypersplenism
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4
Q

Macrocytic anaemia - causes (7)

A
  • vitamin B12 deficiency
  • folate deficiency
  • chronic haemolysis (premature RBC destruction)
  • alcoholism/liver disease
  • drugs (methotrexate, anti-epileptic drugs, trimethoprim, metformin)
  • haematological disorders (myelodysplasia)
  • hypothyroidism
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5
Q

Explain the FBC (RBC related)

A
  • Hb = haemoglobin
  • RBC count
  • Hct ratio = haematocrit - volume % of RBC in blood
  • MCV = mean corpuscular volume
  • MCH = mean corpuscular Hb - mean quantity of Hb in blood cells, affects the colour of the RBCs
  • MCHC = mean corpuscular Hb concentration in blood cells
  • RBC distribution width = variation of blood cell volumes to assess if there is a mixed pattern
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6
Q

Microcytic vs Macrocytic anaemia - FBC

A
  • Hb = ↓
  • RBC count = ↓
  • Hct ratio = ↓
  • MCV = ↓ in micro, ↑ in macro
  • MCH = ↓ in micro, ↑ in macro
  • MCHC = ↓ in micro, N or ↑ in macro
  • RBC distribution width = N or ↑
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7
Q

Normocytic anaemia - further subtypes

A
  1. Hyperproliferative (reticulocyte count >2%): increases as part of a compensatory response to increased destruction or loss of RBCs. The cause is usually acute blood loss or haemolysis.
  2. Hypoproliferative (reticulocyte count <2%): primarily disorders of decreased RBC production, and the proportion of circulating reticulocytes remains unchanged.

(reticulocyte = immature RBC)

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8
Q

Macrocytic anaemia - further subtypes

A
  1. Megaloblastic: deficiency of DNA production or maturation resulting in the appearance of large immature RBCs (megaloblasts) and hypersegmented neutrophils in the circulation. (a/w B12 or folate def)
  2. Non-megaloblastic: encompasses all other causes of macrocytic anaemia in which DNA synthesis is normal.
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9
Q

MCV ranges for 3 types

A
  • microcytic = < 80 fL
  • normocytic = 80-100 fL
  • macrocytic = > 100 fL
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10
Q

Anaemia - symptoms and signs

A

Symptoms

  • Fatigue
  • Weakness
  • SOB
  • Dizziness or lightheadedness
  • Chest pain
  • Headache

Signs

  • pallor (skin, conjunctival)
  • Cold extremities
  • angular stomatitis
  • glossitis
  • koilonychia
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11
Q

Vit B12 deficiency - risk factors

A
 age >65 years
gastric surgery (bypass or resection)
chronic gastrointestinal (GI) disease - IBD
vegan diet
metformin use
H2 receptor antagonist or PPI use
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12
Q

Vit B12 deficiency - clinical features

A

Can cause glove and stocking peripheral neuropathy

  • paraesthesias
  • ataxia
  • decreased vibration sense
  • positive Romberg’s test
  • petechiae
  • glossitis, angular cheilitis
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13
Q

Vit B12 deficiency - complications

A
  • progressive neurological damage
  • haematological: progressive anaemia, leukopenia, and thrombocytopenia.
  • gastric cancer (complication of untreated pernicious anaemia - with antibodies to intrinsic factor)
  • low birth weight and preterm delivery (pregnancy)
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14
Q

Vit B12 deficiency vs Pernicious anaemia

A
  • Pernicious Anaemia (Autoimmune Metaplastic Atrophic Gastritis) is the most common cause of Vitamin B12 Deficiency
  • however vit B12 deficiency can have other causes
  • Pernicious anemia refers to anemia that results from lack of intrinsic factor - can be autoimmune, or post-gastrectomy or genetic or a/w hypothyroidism (both autoimmune)
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15
Q

Vit B12 deficiency - treatment

A

Initially: hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks. Then:

  • if diet-related: administer every 2–3 months for life
  • if not diet-related: twice-yearly injections

Dietary advice - foods with Vit B12 include:

  • Eggs
  • fortified foods for example some soy products, and some breakfast cereals and breads
  • Meat
  • Milk and other dairy products.
  • Salmon and cod.
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16
Q

Folate deficiency - treatment

A
  • Check vitamin B12 levels in all people before starting folic acid!!!
  • Prescribe oral folic acid 5 mg daily — in most people, treatment will be required for 4 months
  • Foods rich in folate = green veg - Asparagus, broccoli, peas - brown rice, brussels sprouts, chickpeas
  • no alcohol
17
Q

Why must Vit B12 be checked before replacing folate?

A

B12 helps folate be taken up by cells, so it “uses” the available B12 - if you are B12 deficient it will worsen it

Folic acid treatment can sometimes improve your symptoms so much that it masks an underlying vitamin B12 deficiency - if you do not have enough B12 and you replace the folate you can get neuro complications like subacute combined degeneration of the cord – bilateral spastic paresis, loss of sensation - vibration/fine touch/proprioception (dorsal column affected)

18
Q

Iron deficiency - treatment

A
  • Address the underlying causes as necessary (for example treat menorrhagia or stop NSAIDs)
  • prescribe oral ferrous sulfate 200 mg tablets two or three times a day — for 3 months
  • Recheck haemoglobin levels after 2–4 weeks
  • advise to eat iron-rich foods (dark green vegetables, iron-fortified bread, meat, apricots, prunes, and raisins)
19
Q

Intrinsic factor:

  • site of production
  • function
  • related condition
  • test
A
  • produced by the stomach parietal cells
  • helps to absorb B12 in the ileum
  • lack of IF commonly a/w pernicious anaemia
  • test: anti-IF antibodies and anti-parietal antibodies
20
Q

B12 deficiency - causes

A
  • pernicious anemia
  • post-gastrectomy
  • post- H pylori/chronic gastritis
  • PPIs
  • Crohn’s (ileum affected)
21
Q

Absorption of

  • iron
  • folate
  • B12
A
  • iron = duodenum
  • folate = jejunum
  • B12 = ileum