Extra Haematology

Question 1

ARTERIAL THROMBOSIS

Answer 1

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Question 2

Why do you get rest pain in calves that is classically nocturnal in arterial thrombosis?

Answer 2

When you are lying down you have removed the resistance to gravity and there is reduced CO2 so the blood flow isn’t even helped by gravity so leads to Acute limb ischemia

Question 3

Describe the pathophysiology of arterial thrombus

Answer 3

1) Occurs as a result of an atheroma that forms in areas of turbulent blood flow such as the bifurcation of arteries
2) Platelets adhere to the damaged vascular endothelium and aggregate in response to ADP and Thromboxane A2
3) Plaque ruptures and leads to exposure of blood containing factor VIIa to tissue factor within plaque which may trigger blood coagulation and lead to thrombus formation
4) This can lead to complete occlusion of the vessel or embolisation that produces distal obstruction.

Question 4

DVT

Answer 4

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Question 5

Where are some unusual places for venous thrombosis to occur?

Answer 5

Venous thrombosis may also occur in the upper extremities or in more unusual sites, such as the portal, mesenteric, ovarian, and retinal veins, as well as the veins and venous sinuses of the brain.

Question 6

Name some provoked causes of DVT

Answer 6

• Surgery
• long haul flights
• leg fracture
• oral contraceptive pill

Question 7

Pathogenesis of DVT

Answer 7

• All factors lead to one element of Virchow’s triad.
• Venous stasis, Hypercoagulabity, Vascular injury.
• Venous thrombosis tends to occur in areas with decreased or mechanically altered blood flow such as the pockets adjacent to valves in the deep veins of the leg
• While valves help to promote blood flow through the venous circulation, they are also potential locations for venous stasis and hypoxia

Question 8

Name some genetic causes of DVT

Answer 8

These genes increase the chance of thrombus formation or lead to an antithrombin or protein C/S deficiency

1) Factor V Leiden (Factor 5 suffering)
2) PT20210A

Question 9

Name 3 acquired causes of DVT

Answer 9

1) Anti-phospholipid syndrome
2) Lupus anticoagulant
3) Hyperhomocystaemia

Question 10

How can you differentiate DVT from Cellulitis?

Answer 10

Duplex scan

Question 11

How does DIPRYMIDOLE work?

Answer 11

Inhibits the phosphodiesterase-mediated breakdown of cyclic AMP which prevents platelet activation.

Question 12

How does tissue plasminogen activator work?

Answer 12

Generates plasmin which degrades the fibrin clot.

Question 13

What is plasma D-dimer?

Answer 13

Type of fibrinogen degradation product that is released into the circulation when a clot begins to dissolve.

Question 14

G6PD deficiency pathophysiology

Answer 14

• G6PD protects cells against oxidative damage from compounds like hydrogen peroxide
• If there is a deficiency for this enzyme there is a REDUCED RBC LIFESPAN due to oxidant damage.

Question 15

Name 5 drugs that can cause acute drug-induced haemolysis

Answer 15

1) Asprin
2) Antimalarials: primaquine, quinine, chloroquine
3) Antibacterials
4) Dapsone
5) Quinidine

Question 16

LEUKAEMIAS

Answer 16

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Question 17

What is leukaemia?

Answer 17

Cancer of the white blood cells. Essentially leukaemia is the presence of rapidly proliferating immature blast blood cells in the bone marrow that are non-functional and defective. These can be the pre-cursors of RBC’s, platelets or white cells.

Question 18

What are the problems of leukaemia?

Answer 18

1) The leukaemia cells are dividing rapidly but they serve no function so this is WASTING ENERGY making useless cells and thus there is LESS ENERGY AVAILABLE to make useful functional cells.
2) The rapid replication of these cells means that take up a lot of space within the bone marrow meaning there are LESS SPACE AND FOOD for other cells to grow.
3) Because of this the bone marrow cannot make as many functional cells»>less functioning cells in blood&raquo_space;»symptoms of leukaemia.
4) When there is no more space in the bone marrow the leukaemia cella will be present in the blood too.

Question 19

Is leukaemia an age-specific disease?

Answer 19

They can occur at any age and the type of leukaemia varies with age. ALL seen in children, CLL seen in elderly.

Question 20

Describe the aetiology of Leukaemias

Answer 20

1) Radiation (x-rays)
2) Chemicals and dyes (benzene)
3) Genetic (Ph chromosome, trisomy 21)
4) Viruses (retrovirus type 1)

Question 21

What is lymphadenopathy?

Answer 21

Enlargement of the lymph nodes

Question 22

What are reticulocytes?

Answer 22

Immature blood cells

Question 23

ANAEMIA

Answer 23

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Question 24

What controls the process of erythropoiesis? What nutrients are needed for it?

Answer 24

Erythropoietin = key hormone
Other hormones= testosterone, thyroid hormone
Nutrients= Iron, folate, B12

Question 25

What are the causes of Microcytic Anaemia? | TAILS

Answer 25

``` T – Thalassaemia A – Anaemia of chronic disease I – Iron deficiency anaemia L – Lead poisoning S – Sideroblastic anaemia ```

Question 26

What are the causes of normocytic anaemia? | 3A's 2H's

Answer 26

``` A – Acute blood loss A – Anaemia of Chronic Disease A – Aplastic Anaemia H – Haemolytic Anaemia H – Hypothyroidism ```

Question 27

What is the cause of macrocytic megaloblastic anaemia?

Answer 27

Megaloblastic anaemia is the result of impaired DNA synthesis preventing the cell from dividing normally. Rather than dividing it keeps growing into a larger, abnormal cell. This is caused by a vitamin deficiency. Megaloblastic anaemia is caused by: B12 deficiency Folate deficiency

Question 28

What is the cause of macrocytic normoblastic anaemia?

Answer 28

Normoblastic macrocytic anaemia is caused by: Alcohol Reticulocytosis (usually from haemolytic anaemia or blood loss) Hypothyroidism Liver disease Drugs such as azathioprine

Question 29

Causes of iron deficiency

Answer 29

1. Decreased iron intake: strict vegan diet, cereal-based diet, chronic undernutrition 2. Decreased iron absorption: hypochlorhydria(gastritis, PPI as iron absorbed here ), bowel disease(Celiac Disease, IBD, Whipple’s Disease), surgical resection of bowel 3. Increased demand: pregnancy, lactation, growth spurt 4. Increased iron loss: Chronic GI bleeding(cancer, ulcers, NSAIDs, hookworms), menorrhagia, bleeding disorders

Question 30

Pathophysiology of iron-deficient anaemia

Answer 30

Iron is required for haemoglobin synthesis If there is inadequate iron, there is less iron to form the heme component Less iron= less heme= less hemoglobin= ANEMIA

Question 31

How does iron travel around in the body?

Answer 31

Iron travels around the blood as ferric ions (Fe3+) bound to a carrier protein called transferrin.

Question 32

What is the Total iron-binding capacity (TIBC Total iron-binding capacity (TIBC

Answer 32

Total iron-binding capacity (TIBC) basically means the total space on the transferrin molecules for the iron to bind. Therefore, total iron-binding capacity is directly related to the amount of transferrin in the blood.

Question 33

Transferrin Saturation =

Answer 33

Transferrin Saturation = Serum Iron / Total Iron Binding Capacity

Question 34

Ferritin

Answer 34

- Ferritin is the form that iron takes when it is deposited and stored in cells. Extra ferritin is released from cells in inflammation, such as with infection or cancer. - If ferritin in the blood is low it is highly suggestive of iron deficiency. - If ferritin is high then this is difficult to interpret and is likely to be related to inflammation rather than iron overload.

Question 35

Serum iron

Answer 35

Serum iron varies significantly throughout the day with higher levels in the morning and after eating iron-containing meals. On its own serum iron is not a very useful measure.

Question 36

What two things can increase the values of all of these results giving the impression of iron overload?

Answer 36

Supplementation with iron | Acute liver damage (lots of iron is stored in the liver)

Question 37

Pathophysiology of anaemia of chronic disease

Answer 37

``` Inflammation🡪 Increase in cytokines and Hepcidin Hepcidin: Inhibits intestinal iron absorption Inhibits iron release from iron stores Inhibits EPO sensitivity Reduces erythrocyte life span Net effect= Anemia! ```