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MEH My own decs > Session 7 ILO's > Flashcards

Session 7 ILO's Flashcards

1
Q

Define the term anaemia

A

Haemoglobin concentration lower than the normal range

(normal range varies with gender, age and ethnicity so the point at which a patient becomes anaemic depends on those parameters)

It is NOT a diagnosis
It is a clinical manifestation of an underlying disease state
It is important to ESTABLISH CAUSE

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2
Q

What are the 3 categories of reasons for the development of anaemia?

A
  • Bone Marrow Reasons
  • RBC reasons
  • Removal/Loss reasons
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3
Q

Reasons anaemia can develop (bone marrow)

A
  • Reduced or dysfunctional erythropoesis
  • Abnormal Haem synthesis
  • Abnormal globin chain synthesis
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4
Q

Reasons anaemia can develop (RBC)

A

Abnormal structure

Mechanical damage

Abnormal metabolism

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5
Q

Reasons anaemia can develop (removal/loss)

A

Excessive bleeding

Increased removal by reticuloendothelial system

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6
Q

Reasons for reduced/dysfunctional erythropoesis (5)

A

Lack of erythropoietin (chronic kidney disease as kidney produces it)

Bone marrow cannot respond to erythropoietin (eg after chemo)

If marrow is infiltrated by cancer cells or fibrous tissue (myelofibrosis), the number of normal haemopoeitic cells is reduced

Anaemia of chronic disease = no iron available to marrow for bc production

Myelodysplastic syndromes (rare forms of blood cancer) = abnormal clones of stem cells so no capacity to make RBC or WBC

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7
Q

Reasons haemoglobin synthesis can be affected

A
  • Sideroblastic anaemia
  • Iron deficiency anaemia
  • Anaemia of chronic disease - results in a lack of functional iron
  • Mutations in genes encoding gloin chain proteins ( we see that in patients with a and b thalassaemia and sickle cell disease)
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8
Q

What is defect in haem pathway called?

A

Sideroblastic anaemia

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9
Q

Inherited reasons for haemolytic anaemia

A
  • Mutations in genes coding for proteins in membrane and cytoskeleton of RBC
  • Cause cells to be less deformable and more fragile
  • They break up in circulation and removed by RES

= haemolytic anaemia (eg Hereditary spherocytosis)

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10
Q

Acquired reasons for haemolytic anaemia

A

Microangiopathic haemolytic anaemia (MAHA) from mechanical damage

Heat damage from severe burns

Osmotic damage (drowning in fresh water)

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11
Q

Reasons for mechanical damage in patients with MAHA (Microangiopathic haemolytic anaemia) occurs

A

Shear stress as cells pass through defective heart valve

Cells snag on fibrin strands in small vessels where clots have been formed and they break down (eg in Disseminated Intravascular Coagulation)

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12
Q

What would a blood film of blood cells with mechanical damage look like?

A

Schistocytes - fragments of RBC resulting from mechanical damage

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13
Q

Causes of defect in RBC metabolism

A

G6PDH deficiency

Pyruvate kinase deficiency

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14
Q

Why does G6PDH deficiency cause anaemia?

A
  • Mature RBC’s don’t have mitochondria to give energy, they rely on certain glycolytic pathways
  • Decreased G6PDH = Lack of NADPH
  • Lack of NADPH = lower GSH (glutathione)
  • lower GSH = less protection of RBC from oxidative stress
  • Oxidative stress
  • Oxidative stress (eg from infection, drugs like anti malaria, and broad beans)
  • Oxidative stress leads to
    Lipid peroxidation (leads to cell membrane damage) and protein damage to RBC
    =
    Heinz bodies (aggregates of cross linked haemoglobin)
    Red cells recognised by RES as defective and removed
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15
Q

Why does pyruvate kinase deficiency cause anaemia?

A
  • RBC have no mitochondria so depend on glycolysis for energy production
  • Pyruvate kinase is final enzyme of glycolysis
  • Some patients may have rare genetic defects in this enzyme
  • A defective glycolytic pathway causes RBC’s become deficient in ATP and undergo haemolysis
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16
Q

What are the 3 excessive bleeding causes of anaemia?

A
  • Acute blood loss
  • Chronic NSAID’s (Nonsteroidal anti-inflammatory drugs)
  • Chronic bleeding (most common)
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17
Q

Acute blood loss causes of anaemia

A

Injury
Childbirth
Surgery
Ruptured vessel

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18
Q

Chronic excessive bleeding causes of anaemia

A
  • Heavy menstrual bleeding
  • Repeated nosebleeds
  • Haemorrhoids
  • GI bleeding (blood loss in stool)
  • Kidney/bladder tumours (blood loss in urine)
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19
Q

Causes of GI bleeding

A 
Ulcers (stomach or intestine)
Polyps in large intestine
Intestinal cancer 
NSAIDS
Diverticulotis
20
Q

How can NSAID usage lead to anaemia?

A

Nonsteroidal anti-inflammatory drugs treat conditions with pain and inflammation:

  • Asprin
  • Ibruprofen
  • Naproxen

They Induce GI bleeding by:

  • Inhibit cyclooxygenase activity
  • Direct cytotoxic effects to epithelium
21
Q

Describe the role of the Reticuloendothelial system in causing anaemia and

Describe what happens in autoimmune haemolytic anaemias

What can occur as a result of haemolytic anaemias?

A

Haemolytic anaemia = RBC destroyed more quickly due to abnormality or damage

Autoimmune haemolytic anaemia:
- Autoantibodies bind to RBC membrane proteins causing them to be recognised by macrophages in spleen and destroyed

(splenomegaly often occurs with haemolytic anaemias as the spleen is doing extra work)

22
Q

How can myelofibrosis lead to anaemia?

A
23
Q

How can thalassemia lead to anaemia?

A
24
Q

Understand the important causes of microcytic anaemia

A

T A I L S

  • Thalassaemia
  • Anaemia of chronic disease (sometimes)
  • Iron Deficiency
  • Lead Poisoning
  • Sideroblastic Anaemia
25
Q

Understand the important causes of macrocytic anaemia

A
  • Vitamin B12 deficiency
  • Folate deficiency
  • Myelodysplasia
  • Liver disease
  • Alcohol Toxicity
26
Q

Understand the important causes of normacytic anaemia

A

Normocytic:
Could be because they have got a combo of microcytic and microcytic cells
Primary bone marrow failure (e.g. aplastic anaemia)
Secondary bone marrow failure (HIV)

27
Q

What are the signs of anaemia?

A 
Pallor
Tachycardia
Systolic flow murmur 
Tachypnoea (fast breathing) 
Hypotension
28
Q

List the specific signs associated with the cause of anaemia

A

Koilonychia (spoon nails, iron deficiency)

Angular Stomatitis (inflammation around mouth, iron deficiency)

Glossitis (inflammation and smooth tongue, Vit B12 deficiency)

Abnormal facial bone development (Thalassaemia)

29
Q

What are the symptoms of anaemia?

A 
Shortness of breath
Headaches
Angina
Weakness/lethargy
Confusion 
Palpitations
Claudication
30
Q

What are the common clinical features of haematinic deficiency (iron, vitamin B12 or folate deficiency)? (does that mean symptoms?)

A

n/a

31
Q

What are the important underlying causes of haematinic deficiency (iron, vitamin B12 or folate deficiency)? FOLATE

A

Dietary deficiency (Poor diet)

Increased requirements - pregnancy, increased erythropoiesis (e.g haemolytic anaemia) , severe skin disease (psoriasis)

Disease of duodenum or jejunum (coeliac, crohns)

Drugs that inhibit dihydrofolate reductase (Methotrexate)

Alcoholism (poor diet and damage to intestinal cells)

Urinary loss of folate in Liver disease/Heart failure

32
Q

What are the important underlying causes of haematinic deficiency (iron, vitamin B12 or folate deficiency)? VITAMIN B12

A

Dietary deficiency (vegan diet lacking B12 supplementation)

Lack of intrinsic factor - Pernicious anaemia

Disease of ileum (Crohns)

Lack of transcoalbumin (congenital)

Chemical inactivation of B12 (nitrious oxide gas use/smartwhip)

Parasitic infestation (rare tapeworm found in fish traps B12)

Some drugs chelate Intrinsic factor (hypercholestrolaemia drug Cholestyramine)

33
Q

Describe the role of haematinic replacement treatment

A

na

34
Q

Describe the complications associated with haematinic replacement treatment

A

na

35
Q

List the different causes of microcytic anaemia

A

T A I L S

  • Thalassaemia
  • Anaemia of chronic disease (sometimes)
  • Iron Deficiency
  • Lead Poisoning
  • Sideroblastic Anaemia
36
Q

Give examples of good dietary sources of haem iron

A

na

37
Q

Give examples of good dietary sources of non-haem iron

A

na

38
Q

Give an overview of iron absorption

A

na

39
Q

Give an overview of iron transport

A

na

40
Q

Give an overview of iron uptake

A

na

41
Q

Give an overview of iron storage

A

na

42
Q

Give an overview of iron metabolism

A

na

43
Q

Describe how iron deficiency leads to anaemia

A

na

44
Q

Describe how iron deficiency anaemia is diagnosed

A

na

45
Q

Describe how iron overload can occur

A

na

46
Q

Describe the aetiology (causes) of Hereditary Haemochromatosis

A

na

47
Q

Describe the treatment of Hereditary Haemochromatosis

A

na

MEH My own decs (13 decks)

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