Whole Handbook LETS GO Flashcards
(231 cards)
Microcytic and hypochromic anaemia red cell indices?
MCV and MCH low
Microcytic and hypochromic anaemia common examples:
- Iron deficiency
- Thalassaemia
Normocytic and normochromic anaemias red cell indices?
MCV and MCH normal
Normocytic and normochormic anaemias common examples:
- Blood loss (acute)
- Haemolysis (occasionally macrocytic)
- Chronic disease (occasionally microcytic hypochromic)
- Marrow infiltration
Macrocytic anaemias red cell indices?
MCV raised
Macrocytic anaemias common examples:
Megaloblastic anaemias
4 causes of anaemia
- Loss of red cells due to bleeding
- Increased destruction of red cells (haemolytic anaemias)
- Failure of production of red cells by the bone marrow
- Dilution of red cells by increased plasma volume (e.g. hypersplenism)
3 causes that lead to failure of production of red cells by the bone marrow
- Nutritional deficiency (e.g. iron, vitamin B12, folate)
- Reduced bone marrow erythroid cells (e.g. aplastic anaemia, marrow infiltration by leukaemia or malignancy)
- Ineffective red cell formation (e.g. chronic inflammation, thalassaemia, renal disease)
Normal lifespan of RBC
120 days
To maintain its integrity in circulation for its lifespan, non-nucleated red cell needs:
- Longevity
- Flexibility
- Enzymes to maintain: shape, membrane integrity, metabolism, haemoglobin in reduced state
Anaemia will result unless the bone marrow can increase its?
Increase its output of red cells sufficiently to compensate for increased rate of destruction.
Haemolytic anaemia is due primarily to?
Accelerated red cell destruction when BM is unable to compensate.
Intravascular haemolysis occurs when?
Severe injury to red cells (eg. by trauma or complement) can result in red cell destruction in the intravascular space.
Haemolytic anaemia: less severely damaged red cells are? Which one is this?
Trapped and destroyed by macrophages in the spleen, and to a lesser extent in the liver.
Extravascular haemolysis
Intrinsic red cell defects may be caused by:
- Membrane defects (e.g. hereditary spherocytosis)
- Haemoglobin defects (e.g. thalassaemias, sickle cell anaemia)
- Red cell enzyme defects (e.g. G6PD)
- The acquired disorder Paroxysmal nocturnal haemoglobinuria (PNH)
Extrinsic factors causing haemolytic anaemia can include:
- Burns
- Oxidant drugs and chemicals
- Red cell auto-auto-antibodies
- Splenomegaly
- Infections such as malaria
- Mechanical damage to red cells.
In all cases, increased red cell breakdown leads to increased?
Increased lactate dehydrogenase (LDH) release and increased formation of bilirubin.
Most helpful lab findings of haemolysis are?
- Raised serum uncojugated bilirubin
- Raised serum LDH (lactate dehydrogenase)
- Raised urinary urobilinogen (not bilirubin)
When intravascular haemolysis occurs, what is released? This leads to?
Haemoglobin is released leads to absent serum haptoglobin.
Haptoglobin binds to?
Haemoglobin
Methaemalbumin is composed of?
Albumin bound to heme
Intravascular haemolysis occurs shows a positive ____ and ____ and later _____.
Shows a positive Schumm’s test for methaemalbumin, haemoglobinuria and later haemosiderinuria.
Haemoglobinuria is?
Excretion of free haemoglobin in urine
Haemosiderinuria is?
Iron in urinary sediment