Theme 7 Haemotology: Common causes of anaemia and thrombocytopenia

Question 1

Give all the causes of anaemia (other than blood loss)

Answer 1

• haematinic deficiencies (iron, folate and B12)
• secondary to chronic disease
• haemolysis - red cell lifespan reduced
• alcohol, drugs, toxins
• renal impairment
• primary haematological/ marrow disease

Question 2

If red cells are macrocytic, there is a raised MCV. What are the causes of this?

Answer 2

• B12, folate
• marrow damage (alcohol, drugs and marrow disease)
• haemolysis

Question 3

If red cells are normocytic, the MCV is the same. What are the causes of this?

Answer 3

anaemia of chronic disease/ inflammatory

Question 4

If red cells are microcytic, the MCV is reduced. What are thhe causes of this?

Answer 4

• iron deficiencies

- haemaglobin disorders

Question 5

Explain how iron concentration is balanced

Answer 5

• there is no excretion and limited absorption
• controlled at the level of the gut mucosa
• most iron is thus recycled
• absorbed in duodenum
• stored in ferritin

Question 6

How do we establish a patient has low iron?

Answer 6

• FBC and film
• ferritin –> if ferritin is low = iron deficiency
• % hypochromic cells

Question 7

What are the main causes of iron deficiencies?

Answer 7

• blood loss from anywhere
• increased demand - pregnancy/growth
• reduced intake - diet/ malabsorption
• menstrual loss

Question 8

How do we treat low iron?

Answer 8

• oral iron (often unreliable as some people do not absorb iron very well)
• IV iron - increased use

Question 9

What are the characteristics of megaloblastic anaemia?

Answer 9

• a characteristic cell morphology caused by impaired DNA synthesis
• abnormal appearance of red cells
• raised MCV –> big red cells
• less RBCs –> aren’t produced properly

Question 10

What are the causes of megaloblastic anaemia?

Answer 10

• B12 and/or folic acid deficiency
• alcohol
• drugs
• haematological malignancy

Question 11

How does a lack of B12 and folate cause anaemia?

Answer 11

• folates are required for the synthesis of purine/ pyrimidine bases
• B12 is essential for cell folate generation
• so low folate or B12 starves DNA of bases

Question 12

How do we absorb vitamin b12?

Answer 12

gastric parietal cells produce intrinsic factor which binds to B12 and is absorbed by receptors in terminal ileum

Question 13

What are the clinical features of B12 or folate deficiency?

Answer 13

• megaloblastic anaemia
• can have pancytopenia if more severe
• mild jaundice
• glossitis
• anorexia
• sterility

Question 14

What is pernicious anaemia?

Answer 14

anaemia caused by a deficiency of B12

-autoimmune associations

Question 15

What is SACDS?

Answer 15

• subacute combined degeneration of the cord
• B12 deficient neuropathy
• demyelination of the dorsal and lateral columns
• peripheral nerve damage

Question 16

How does SACDS present?

Answer 16

peripheral neuropathy
paraesthesiae
numbness and distal weakness
unsteady walking
dementia

Question 17

How do we treat SACDS?

Answer 17

• B12 and folate until B12 deficiency excluded

- B12 and folic acid for life to build stores

Question 18

What is haemolysis?

Answer 18

shortened red cell life

Question 19

What are the causes of haemolysis?

Answer 19

• haemaglobinopathy (sickle cell)
• enzyme defects (G6PD)
• hereditary spherocytosis / elliptocytosis
• antibodies
• drugs, toxins
• heart valves

Question 20

How do we test for the presence of haemolysis?

Answer 20

• anaemic
• high MCV, macrocytic
• high reticulocytes
• blood film
• raised bilirubin, LDH

Question 21

What is AIHA and how do we treat?

Answer 21

Autoimmune haemolytic anaemia

manage with steroids/immunosuppresion

Question 22

What are the features of anaemia of chronic disease?

Answer 22

• a common medical issue seen in malignant/ inflammatory/infectious diseases
• typically normal MCV
• reduced red cell production due to abnormal iron metabolism, poor erythropoietin response and blunted marrow response

Question 23

What is hepcidin?

Answer 23

a regulator of iron absorption (from gut) and release from macrophages

Question 24

What are the features of ACD?

Answer 24

• no other causes of anaemia (after other options have been eliminated)
• usually mild anaemia, normal MCV
• often raised inflammatory markers e.g CRP
• normal/high ferritin + low serum iron

Question 25

How do we treat anaemia of chronic disease?

Answer 25

• erythropoitein
• intravenous iron
• transfusion?

Question 26

What are the causes of thrombocytopenia?

Answer 26

-drugs, alcohol, toxins
-ITP
-liver disease/ hypersplenism
-pregnancy
-haematological/marrow diseases
-acute infection
-DIC
many more

Question 27

What is ITP?

Answer 27

Immune Thrombocytopenic Purpura:

• an immune disorder
• adult ITP does not precipitate a disease

Question 28

How does ITP present?

Answer 28

-bruising or petechiae or bleeding

Question 29

How do we treat ITP?

Answer 29

• steroids are first line
• IV immunoglobulin
• other immunosuppressives or splenectomy are next options

Question 30

What is TTP?

Answer 30

Thrombotic thromboytopenic purpura:

• rare but urgent diagnosis
• most are immune
• antibodies develop against ADAMS-13 enzyme which causes abnormal VW so you get endothelial and platelet damage
• suspect if thrombocytopenia and fever, neurological symptoms and haemolysis

Question 31

How do we treat TTP?

Answer 31

• plasma exchange with FFP/plasma
• steroids
• rituximab
• monitor ADAMS-13