Red Cell Disorders Flashcards by Anna Chin

Types of red cell disorders

Anaemia

Polycythaemia

How well did you know this?

Not at all

Perfectly

Types of anaemia

Iron deficiency
Megaloblastic
Haemolytic
Aplastic
Sickle
Thalassaemias

How well did you know this?

Not at all

Perfectly

Clinical signs of anaemia

Reduced levels of Hb
Symptoms depend on severity - SoB, weakness/lethargy, tachycardia
Severe - potential for angina
Glossitis and angular cheilitis
DPG may be elevated in RBCs so O2 more readily given up in tissues

How well did you know this?

Not at all

Perfectly

Characteristics of iron deficiency anaemia

microcytic, small, decreased MCV RBCs

How well did you know this?

Not at all

Perfectly

Cause of iron deficiency anaemia

iron input reduced - poor diet, surgical removal of stomach
output increased - chronic/heavy menstruation, gastrointestinal bleeding (colon cancer?), ulcers (NSAIDs?)
demand increased - pregnancy
iron deficiency where bone marrow and macrophage Fe stores depleted, causing anaemia

How well did you know this?

Not at all

Perfectly

Acute bleed

rapid blood loss as in haemorrhage
sever loss of blood
BP falls
over time there is haemodilution (more fluid in the blood)

How well did you know this?

Not at all

Perfectly

Chronic bleed

long term bleeding

eg. gastric bleeding, excessive menstruation

How well did you know this?

Not at all

Perfectly

How would Hb, haematocrit, MCV, retics, WBC, platelets, EPO and iron stores be affected 24 hours after an acute bleed?

Hb - decreased
haematocrit - decreased
MCV - normal
retics - normal
WBC - decreased
platelets - decreased
EPO - increasing
iron stores - normal

How well did you know this?

Not at all

Perfectly

How would Hb, haematocrit, MCV, retics, WBC, platelets, EPO and iron stores be affected after a chronic bleed?

Hb - decreased
haematocrit - decreased
MCV - decreased
retics - increasing 
WBC - normal
platelets - normal
EPO - increased
iron stores - zero

How well did you know this?

Not at all

Perfectly

Treatment for iron deficiency anaemia

find and treat underlying cause
give oral iron (FeSO4)
prophylaxis in pregnancy - oral iron folic acid
severe - transfusion

How well did you know this?

Not at all

Perfectly

What can renal anaemia lead to?

normocytic anaemia (normal size, not enough)
complicates chronic renal failure

How well did you know this?

Not at all

Perfectly

How to treat renal anaemia?

Fe and EPO

How well did you know this?

Not at all

Perfectly

How does pregnancy affect RBCs?

dilution/iron effiency

therefore normocytic RBCs as pregnancy increases MCV but iron deficiency decreases MCV

How well did you know this?

Not at all

Perfectly

What is megaloblastic anaemia?

abnormal RBC maturation due to defective DNA synthesis
out of step with cytoplasmic development, bone marrow contains megaloblasts
macrocytic

How well did you know this?

Not at all

Perfectly

What is a megaloblast?

larger than normal RBC

cytoplasmic development quicker than DNA synthesis

How well did you know this?

Not at all

Perfectly

What is the cause of megaloblast anaemia?

vitamin B12 or folate deficiency

How well did you know this?

Not at all

Perfectly

Symptoms of megaloblast anaemia

jaundice - XS breakdown of Hb due to increased ineffective erythropoiesis
many symptomless and diagnosed with blood test

What is B12 essential for?

cofactor for purine and pyrimidine synthesis (therefore cell division), requires intrinsic factor for absorption

Use of folic acid (folate)

essential for thymidylate synthesis

rate limiting step in DNA snythesis as thymidine is a pyrimidine base

Action of folic acid and B12

methyl tetrahydrofolate and B12 as co-factor
THF -> THF polygultamate -> DHF reductase
causes deoxy-uracilmonophosphate (dUMP) to become deoxy thymine MP (dTMP)
DNA

Issues associated with B12 and folic acid

methotrexate
pernicious anaemia
Crohn’s disease

Methotrexate

problem

used in chemo, immunosupressant, rh. arthritis

inhibits dihydrofolate reductase

Pernicious anaemia

problem

lack of intrinsic factor for absorption of B12 due to automimmune disease

Crohn’s disease

malabsorption of B12, folate or iron

What happens in haemolytic anaemias?

increased rate of RBC destruction | eg. megloblastic

Types of haemolytic anaemias

spherocytosis | acquired

Spherocytosis anaemia

type of haemolytic anaemis genetic abnormal reduction in RBC membrane protein, fragile cells

Acquired anaemia

type of haemolytic anaemia | haemolytic transfusion reaction, malaria, drug-induced

Give consequences of haemolytic anaemias

jaundice and enlarged spleen

Cause of sickle cell anaemia

genetic - single nucleotide polymorphism smino acid substitution, valine for glutamic acid abnormal Hb - insoluble forms crystals at low O2, RBC form sickle shapes and may block microcirculation

What can sickle cell anaemia cause?

haemolytic anaemia

Cause of thalassaemias?

genetic reduced rate of alpha/beta globin units production, variation deletion of both alpha genes leads to death in uterus as Hb (gamma4) produced one alpha gene deletion reduced RBC volume and haematocrit

What is aplastic anaemia?

insufficient production of RBCs, WBCs and platelets, although can be just RBCs

Consequences of aplastic anaemia

decreased resistance to infections, increased bleeding, increased tiredness

Cause of aplastic anaemia

``` viral, radiation, drugs cytotoxic agents chloramphenicol sulphonamides insecticides bone marrow failure ```

How to treat aplastic anaemia

bone marrow transplant with tissue match immunosuppressants to prevent immune destruction of stem cells colony-stimulating factors to increase WBC count

What is polycythaemia?

increased Hb content and haematocrit, resulting in increased blood viscosity and poor tissue perfusion

Symptoms of polycythaemia

``` ruddy appearance cyanosis headaches blurred vision hypertension ```

Causes of aplastic anaemia

primary - changes in bone marrow, stem cell defect | secondary - increased erythropoietin: altitude, smoking, renal, carcinoma

How to treat primary cause of aplastic anaemia?

venesection (bleeding) radioactive phosphorus - myelosuppression (bone mineralisation, kills off fast growing cells) cytotoxic agents - myelosuppression