Anaemia Flashcards
What is anaemia?
Reduced RCB mass
How can RBC be measured?
Haemoglobin conc
RBC conc
Mean Cell Volume
What are the normal ranges of haemoglobin conc?
Males- Hb 130-180g/L
Females- Hb 120-160g/L
How do you measure haemoglobin conc?
Spectrophotometer
Lyse cells, conjugate Hb into stable form, measure optical density at 540nm, increased density = increased conc
What is haematocrit a measure of?
% of blood that is RBC
How do you measure RBC conc?
Haematocrit
What are some issues with measuring haematocrit?
Massive haemorrhage means low RBC but normal ratio
Saline can increase blood volume therefore apparent ratio reduction.
What are the normal ranges of haematocrit?
Males- 38-52%
Females- 37-47%
What blood measurements can be calculated?
Mean cell haemoglobin
What is blood film used to look at?
Cell morphology
What is a reticulocyte count a measure of?
RBC production
Bone marrow activity
What are some general symptoms of anaemia?
Fatigue Headache Presyncope SOB Angina Palpitations Tachycardia Pallor Reticulocytosis
How long after the onset of anaemia does it take reticulocytosis to start?
Several days
When should a reticulocyte count be conducted?
If suspect haemolytic anaemia
How can reticulocyte count vary?
Increased/appropriate
Decreased/inappropriate
What causes an increased reticulocyte count?
Haemolysis
Blood loss
What should you look for if you see an increased reticulocyte count?
Bleeds
Haemolysis- increased breakdown products
What breakdown products suggest haemolysis?
Unconjugated serum bilirubin
Urinary urobiliongen
Splenomegaly
Why does reticulocyte count increase in haemolysis?
Trying and succeeding to cover blood loss.
What is haemolysis?
Premature RBC breakdown
What makes RBC very susceptible to breakdown?
Large surface area
Rely on glycolysis
Can’t generate new proteins.
What does haemolysis often do to RBC?
Create spherocytes
What is a spherocyte?
Spherical RBC
Why are spherocytes created?
Damaged RBC pass through spleen where damaged membrane is removed thus decreasing surface area.
What are the severities of haemolysis?
Compensated
Uncompensated
What is another name of uncompensated haemolysis?
Haemolytic anaemia
What two locations can haemolysis occur?
Extravascular
Intravascular
Where does extravascular haemolysis occur?
Reticuloendothelial system (spleen and liver)
What are the symptoms of extravascular haemolysis?
Hyperplasia at site of breakdown- hepatomegaly/splenomegaly
Release of protoporphyrin- Normal breakdown products but abnormal quantities
What are protoporphyrins?
Breakdown products of Hb
Give two examples of protoporphyrins
Unconjugated billirubin
Urobilinogenuria
What can unconjugated bilirubin cause?
Jaundice
Gallstones
Where does intravascular haemolysis occur?
Blood vessels
How dangerous is intravascular haemolysis?
May be life threatening
What can intravascular haemolysis give rise to?
Schistocytes
What are schistocytes?
Fragments of RBC
What are the symptoms of intravascular haemolysis?
Haemoglobinaemia- Free Hb in blood stream
Methaemalbuminaemia- Hb on albumin
Haemoglobinuria
Haemosiderinuria- Met to this by kidneys
What is haemoglobinaemia?
Free Hb in the blood stream
What is mathaemalbuminaemia?
Hb on albumin
What is haemoglobinuria?
Hb in urine
How does haemoglobinurea present?
Pink urine that turns black on standing
What can cause intravascular haemolysis?
ABO mismatch G6PD deficiency Falciparum malaria (Blackwater Fever) Paroxysmal nocturnal hemoglobinuria Paroxysmal cold hemoglobinuria
Describe Paroxysmal cold hemoglobinuria
Intravascular haemolysis after cold exposure
What categories of things can cause haemolysis?
Immune or mechanical premature destruction of normal RBC
Abnormal RBC membrane
Abnormal RBC metabolism
Abnormal haemoglobin
What can cause abnormal haemoglobin?
Sickle cell disease (HbS)
What two metabolic factors failure of which in the RBC can lead to abnormal RBC metabolism haemolysis?
Failure to cope with oxidative stress
Failure to generate ATP
What condition can cause a failure of RBC to cope with oxidative stress?
G6DP deficiency
What is G6DP needed for?
To produce antioxidants
What is a sign of G6DP deficiency?
Heinz bodies
What are Heinz bodies made of?
Denatured Hb
What do Heinz bodies cause?
Bite cells
What is a bite cell?
A RBC with a chunk taken out where Heinz body has been removed.
Can a normal RBC metabolically fail?
Yes is sufficiently stressed- dapsone (used for leprosy)
What acquired conditions can cause an abnormal cell membrane?
Liver Disease (Zieve’s Syndrome)
Vitamin E deficiency
Paroxysmal Nocturnal Haemoglobinuria
Toxins- Arsenic, Clostridium welchii
What toxins can cause an abnormal cell membrane?
Arsenic
Clostridium welchii
Describe Paroxysmal Nocturnal Haemoglobinuria
Cell surface membrane proteins make it more likely to lyse.
IgG lyses cells in the central circulation.
How do you detect Paroxysmal Nocturnal Haemoglobinuria?
Ham’s test
What is Paroxysmal Nocturnal Haemoglobinuria associated with?
Measles, mumps and chickenpox.
How common is an acquired cell membrane defect?
Rare
What are some symptoms of liver disease (Zieve’s syndrome) associated cell membrane defects?
Anaemia
Polychromatic macrocytes
Irregularly contracted cells
What are some causes of congenital cell membrane defects?
Hereditary Spherocytosi
Hereditary elliptocytosis
Reduced membrane deformability
Increased transit time through spleen
How is hereditary spherocytosis inherited?
Autosomal dominantly
Describe hereditary spherocytosis?
Lose part of membrane as pass through spleen therefore become spheroid.
Less able to pass through spleen so destroyed.
What are some symptoms of hereditary spherocytosis?
Jaundice
Anaemia
Splenomegaly
Pigmented gallstones
How do you diagnose hereditary spherocytosis?
Spherocytes and reticulocytes
Haemolysis evidence
Osmotically fragile
Coomb’s negative
How do you treat hereditary spherocytosis?
Splenectomy
What should you give to someone with a splenectomy?
Immunization
Lifelong penicillin prophylaxis
What is Hereditary elliptocytosis?
Similar to spherocytosis but less severe
What can cause Immune or mechanical premature destruction of normal RBC?
Autoimmune haemolysis
Alloimmune haemolysis
Mechanical
What mechanical stimuli can cause RBC destruction?
Metallic heart valve Coagulation- Due to burns Haemolytic uraemic syndrome- E. Coli 0157 Infection- Malarea March haemoglobinurea
Describe march haemoglobinurea
RBC damaged as pass through small vessels overlying feet during long distance marching.
Leads to haemoglobinurea.
What infection can cause RBC destruction?
Malaria
What can cause Haemolytic uraemic syndrome?
E. Coli 0157
What can cause alloimmune haemolysis?
Immune response
Passive transfer of Ab
Organ transplant
What is alloimmune haemolysis?
Ab against someone else’s blood
How can an organ transplant cause alloimmune haemolysis?
Donor lymphocytes reside in transplanted material.