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DMD2 sem 2 > Haematology 1 > Flashcards

Haematology 1 Flashcards

1
Q

What is the composition of haemoglobin?

A

Metalloprotein

Heme:
Ferrous + Protoporphyrin IX

Globin:
2 alpha chains
2 beta chains

2,3 DPG in central pocket

1Hb = 4O2

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2
Q

Where is haemoglobin produced before birth?

A

Yolk sack until about 6 weeks post conception

Liver from 6 weeks until 6 weeks after birth.

Liver and spleen from 15 weeks until 6 weeks after birth

Bone marrow takes over after this

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3
Q

When is anaemia diagnosed?

A

<12 - 13g/dl

Or more than 2 standard deviation below the mean of normal range in an age and sex-matched representative population

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4
Q

What causes hypoproliferative anaemias?

A

Primary bone marrow pathologies (Red cell aplasia, aplastic, anaemia, fanconi anaemia)

Inadequate supply of ingredients (Iron, folate, B12, erythropoeitin deficiency)

Cytokine dysregulation

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5
Q

What are the types of hypoproliferative anaemias?

A

Based on the average size of cells and MCV

Microcytic

Macrocytic

Normocytic

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6
Q

What is the most common cause of microcytic anaemia?

A

Iron deficiency

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7
Q

What causes iron deficiency?

A

Blood loss

Decreased GI absorption

Increased iron requirement (pregnancy or exogenous EPO)

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8
Q

What are the clinical symptoms of iron deficiency anaemia?

A

Dizziness, fatigue, pallor, SOB, rapid HR

Glossitis

Angular cheilitis

Koilonychia

Pica

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9
Q

How is iron deficiency diagnosed?

A

Ferritin (BEST TEST)

Low serum iron

High TIBC (Total iron bondind capacity reflected by transferrin)

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10
Q

How is iron deficiency anaemia treated?

A

Find the cause

Oral or IV iron replacement

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11
Q

What causes normocytic normochromic anaemia?

A

Anaemia of chronic disease most common

Anaemia of renal failure

Hypothyroidism

Acute blood loss

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12
Q

What does hepicidin do?

A

It blocks import of iron from the vilus cells and from the macrophages.

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13
Q

What causes anaemia of chronic disease?

A

Impaired absorption of iron from the GI tract

Mediated by hepcidin

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14
Q

What chronic diseases cause anaemia of chronic disease?

A

Infective endocarditis

systemic lupus erythematous

Vasculitis

Cancer

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15
Q

How is anaemia of chronic disease treated?

A

Treat the underlying cause

Exogenous EPO

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16
Q

What causes macrocytic anaemia?

A

B12 and folate deficiency

Alcoholic liver disease

Myelodysplasia

Reticulocytosis

Hypothyroidism

Medication induced

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17
Q

What causes B12 deficiency?

A

Very rarely due to dietary deficiency

Deficiency is usually caused by malabsorption caused by: Pernicious anaemia, partial gasterectomy, Crohn’s, ileal resection

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18
Q

How does folate deficiency relate to B12 deficiency?

A

Both take years to develop

Folate deficiency is caused by poor intake and high demand. B12 is caused by disease more often.

Symptoms of folate are similar to B12 minus the neurological components

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19
Q

What is the major sign of hyperproliferative anaemia?

A

High reticulocyte index

20
Q

What are the types of hyperproliferative anaemias?

A

Hereditary (Defects in RBC metabolism, defects in haemoglobin)

Acquired (Immune mediated (Direct coombs+) or non immune mediated (directed coombs -)

21
Q

How is the direct coombs test done?

A

Blood sample taken from a patient with immune mediated haemolytic anaemia

Patient’s washed RBCs are incubated with antihuman antibodies

RBCs agglutinate caused by links between the RBCs with antibodies attached

22
Q

What are the types of haemolytic anaemias?

A

Caused by environmental factors (acquired)

Caused by membrane defects (acquired)

Defects of cell interior (congenital)

23
Q

What antibodies are involved in autoimmune haemolytic anaemia?

A

Mostly IgG (warm (reacts at body temperature))

IgM reacts at room temperature. IgM activates complement

24
Q

What happens to RBCs attacked by antibodies in haemolytic anaemia?

A

They get taken up by the spleen to form spherocytes and then destroyed.

25
Q

What is Thrombotic thromboctopaenic purpura (TTP)?

A

A form of acquired non-immune haemolytic anaemia

26
Q

What causes TTP?

A

Can be sporadic: Deficiency in ADAMTS13 (remodels vWF) this is congenital and RARE. Acquired ADAMTS13 can also occur.

Allo-HCT caused by endothelial damage

Medications: Immune mediated (quinine, antimicrobials, gemcitabin, oxaliplatin, proteasome inhibitors) or toxicity/VEGF inibitors.

27
Q

What toxic agents can be causative of thrombocytopaenic purpura?

A

immunosuppressive agents (Esp calcineurin inhibitors and drugs of abuse)

28
Q

How does TTP present clinically?

A

Thrombocytopaenia

Macroangiopathic haemolytic anaemia

Renal failure

Neurological symptoms

29
Q

What are the laboratory findings associated with TTP?

A

Schistocytes

Normal PT, PTT, fibrinogen and D-dimer

Elevated LDH

30
Q

How is TTP treated?

A

Plasmapheresis with infusion of FFP (once started continue daily until the symptoms resolve. 20% relapse immediately after treatment)

31
Q

What is the mortality of TTP like?

A

10 - 15% which is down from 100%

32
Q

What are the clinical features of paroxysmal nocturnal haemolytic anaemia?

A

Haemolytic anaemia

Thrombosis

Impaired bone marrow function

33
Q

What causes paroxysmal nocturnal haemolytic anaemia?

A

Defective PIG-A gene leading to loss of protective proteins of RBCs

34
Q

What are the clinical features of paroxysmal nocturnal haemolytic anaemia?

A

Haemolytic anaemia

Thrombosis

Impaired bone marrow function

35
Q

What are some common hereditary anaemias?

A

Hereditary spherocytosis (defect in membrane proteins)

G6PD deficiency (Over 300 types all are X-linked)

Haemoglobinopathies (Thalassemia (Most common and 2 types alpha/beta) and sickle cell anaemia)

36
Q

What causes hereditary spherocytosis?

A

Defect in membrane proteins

37
Q

What are the signs of G6PD deficiency?

A

Denatured HgB leading to the formation of Heinz bodies

38
Q

What are the most common haemoglobinopathies?

A

Thalassemia

39
Q

What are the conditions associated with alpha thalassemia?

A

Silent carrier if there is one deleted gene

Trait is seen in 2 deleted genes

Hb H disease in 3 deleted genes

Hydrops fetalis in 4 deleted genes

40
Q

What are the characteristic blood cells of alpha thalassemia?

A

Target cells

41
Q

What are the types of beta thalassemia? How are they characterized?

A

Minor: Beta globin deletion, asymptomatic, microcytosis, mild anaemia, splenomegaly, and target cells

Major: Homozygous B gene deletion, rarely survive childhood, hepatosplenomegaly, iron overload, progressive pulmonary HTN, marked expansion of the marrow

42
Q

What causes sickle cell anaemia?

A

Autosomal recessive trait caused by Vernon substitution of GAG -> GTG resulting in glutamine to valine change in Hb (becomes HbS)

43
Q

What are the orofacial features associated with sickle cell anaemia?

A

Hyperplasia of bone

Hair on end appearance

Osteomyelitis

Parasthesia

Can be asymptomatic

Can result in pulpal necrosis

44
Q

What kind of anaemia does G6PD deficiency cause?

A

Normocytic anaemia

45
Q

What kind of anaemia does sickle cell anaemia cause

A

Normocytic anaemia

46
Q

What kind of anaemia does aplastic anaemia cause?

A

Normocytic anaemia

DMD2 sem 2 (97 decks)

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