B3 - Anaemia Flashcards
haematocrit
○ Haematocrit: percentage of whole blood volume comprised of red blood cells
anaemia
- A reduction in haemoglobin (Hb) concentration below the normal range for the age and gender of the individual
- Usually accompanied by a reduction in red cell count and haematocrit
anaemia symptoms in old people
heart failure, chest pain - because rate is increased to compensate for low oxygen
tachycardia
Increased cardiac output: tachycardia; heart murmur
jaundice causes
□ Haemolytic - Red cells are being broken down in the spleen creating bilirubin, premature red cell destruction
□ Megaloblastic - bone marrow cannot make red blood cells properly due to low Vit B12 or folate so the red blood cells die within the bone marrow
□ eyes, skin colour appear yellow
koilonychia
severe long standing iron deficiency anaemia - dent in the fingernail
stool colour change in haemolysis
§ Stool colour change: haemolysis - from bilirubin being made from destruction of haem
2 main causes of anaemia
- reduced red cell production
- increased loss of red cells
reduced red blood cell production causes
a. Marrow failure (primary)
§ Aplastic anaemia (entire bone marrow)
□ Percentage of space that is cellular is 100% - your age
® Eg. A 40 yo person should have 40% fat and 60% cells
§ Pure red cell aplasia (just red blood cells)
§ Bone marrow dysfunction: myelodysplasia (abnormal production of bone marrow resulting in inadequate red blood cells being produced)
b. Another cause (secondary)
§ Insufficient nutrients eg. Iron, folate, B12, EPO
□ Patient history
® Dietary history
® Gut malabsorption
□ Typically anaemia without marked neutropenia or thrombocytopenia
□ Other symptoms of nutritional deficiency
§ Infection - supresses bone marrow function
§ Drugs eg. Cytotoxic chemotherapy
§ Marrow infiltration
□ Luekaemia/cancer - takes over marrow cavity and replaces cell production
□ Secondary cancer - can metastasize to the bone marrow and infiltrate
aplastic marrow failure anaemia
entire bone marrow
pure red cell aplasia bone marrow failure
just red blood cells
myelodysplasia
§ Bone marrow dysfunction: myelodysplasia (abnormal production of bone marrow resulting in inadequate red blood cells being produced)
percentage of cellular bone marrow
100% - age
secondary bone marrow failure
- insufficient nutrients
- infection
- drugs
- marrow infiltration
causes of increased loss of red cells
bleeding, haemolysis
bleeding/haemorrhage
§ Acute:
□ easy to identify - usually some who has had an accident and is suffering from acute blood loss
§ Chronic:
□ slow bleeding, usually gastrointestinal, cancer, menorrhagia (uterine blood loss)
□ May be secondary to anticoagulant drugs (blood thinners eg. Warfarin)
haemolysis
§ premature red blood cell breakdown (reduced red cell lifespan through cell destruction)
§ Inherited eg. Spherocytosis, pyruvate kinase deficiency etc.
§ Acquired eg. Secondary to infection
□ Eg. Malaria causing blackwater fever
® Dark urine resulting from burst red blood cells and free haemoglobin in blood vessel
® Hemoglobinemia - haemoglobin in blood
® Haemoglobinuria - haemoglobin in urea
§ Defect of the cell or environment (eg. Plasma)
□ Eg. Chronic renal failure creates abnormal biochemistry interfering with red blood cell membrane
□ Eg. Chronic liver disease especially secondary to excessive alcohol consumption, changes lipids in plasma which changes the makeup of the lipids in the phospholipid membrane making the membrane rigid like spherocytes which will be destroyed by the spleen, causing anaemia
inherited haemolysis causes
eg. Spherocytosis, pyruvate kinase deficiency etc.
acquired haemolysis causes
eg. Secondary to infection
□ Eg. Malaria causing blackwater fever
® Dark urine resulting from burst red blood cells and free haemoglobin in blood vessel
® Hemoglobinemia - haemoglobin in blood
® Haemoglobinuria - haemoglobin in urea
haemolysis caused by defect of cell environment
□ Eg. Chronic renal failure creates abnormal biochemistry interfering with red blood cell membrane
□ Eg. Chronic liver disease especially secondary to excessive alcohol consumption, changes lipids in plasma which changes the makeup of the lipids in the phospholipid membrane making the membrane rigid like spherocytes which will be destroyed by the spleen, causing anaemia
splenomegaly causes
§ Chronic haemolysis
§ Extramedullary haemopoiesis - red blood cells being produced in a site outside of the bone marrow
□ May be produced in the spleen - causing splenomegaly
extramedullary haemopoisis
red blood cells being produced in a site outside of the bone marrow
causes of iron deficiency
○ Reduced intake
§ Rare in developed world
§ Commonest form of anaemia in paediatrics
§ Mainly due to babies not starting to eat soon enough
○ Poor iron absorption/malabsorption
§ Stomach or bowel, gastrectomy,
§ Disease of upper small bowel eg. coeliac disease
§ People who don’t have a stomach
○ Chronic blood loss
§ Gastrointestinal: gastric ulcers, carcinomas of the colon (over the age of 60/70), oesophageal varices (expanded veins in the oesophagus, which occurs which severe alcoholic liver disease, causes backflow of the vessels and wide veins in the oesophagus causing bleeding with minimal trauma) diverticulosis, haemorrhoids (not common, blood loss is only a small amount)
§ Uterine: uterine bleeding
○ Increased iron usage
§ Neonates, puberty, pregnancy
clinical features of iron deficiency
○ Atrophic glossitis - smooth tongue without pappilae due to atrophy or death
○ Angular cheilitis - redness and fissures at the corners of the mouth
○ Koilonychia - spoon nails
blood film of iron deficiency anaemia
○ Hypochromic microcytic anaemia
○ Pale, small red blood cells, more than 1/3 central pallor
○ Pencil cells elliptical in shape / elliptocytes
lab features of iron deficiency anaemia
○ Mild thrombocytosis (increased platelet count)
○ Reduced reticulocyte count (insufficient new RBC being made in BM)
○ RBC
§ (RCC) Reduced cell count
§ (Hb) Low haemoglobin
§ (MCV) low mean cell volume
§ (Hct) low haematocrit
§ (MCH) Low mean cell haemoglobin
§ (RDW) High RBC distribution width - variance in size of red blood cells, varied due to compensating erythropoiesis
serum lab results in iron deficiency anaemia
○ Serum iron
§ shows how much iron is circulating in the plasma
§ Highly variable, not useful to asses iron stores
§ Likely reduced in iron deficiency
○ Serum transferrin (Tf)
§ reflects iron transporter protein
§ Increased in iron deficiency as a response to lack of iron
○ Transferrin saturation
§ % of iron transporter occupied by iron
§ reduced in iron deficiency
○ Serum ferritin
§ reflects body iron stores
§ Reduced in iron deficiency
serum iron in iron deficiency anaemia
§ shows how much iron is circulating in the plasma
§ Highly variable, not useful to asses iron stores
Likely reduced in iron deficiency
serum transferrin in iron deficiency anaemia
§ reflects iron transporter protein
§ Increased in iron deficiency as a response to lack of iron
transferring saturation in iron deficiency anaemia
§ % of iron transporter occupied by iron
§ reduced in iron deficiency
serum ferritin in iron deficiency anaemia
§ reflects body iron stores
§ Reduced in iron deficiency
Dimorphic blood film
(2 morphologies)
- Partially treated iron deficiency - Some red cells still iron deficient, some normal
Iron overload causes
○ Primary: genetic haemochromatosis (HFE gene)
§ Genetic mutation causing accumulation by over absorption
§ Venesect - take out a bag of blood every few months
○ Ineffective erythropoiesis with increased iron absorption: thalassemia
§ Excess iron due to bone marrow making red blood cells wrong, red blood cells due in bone marrow and iron is recirculated leading to accumulation of loose iron
○ Repeated blood transfusions
§ Can cause damage to heart, endocrine organs etc.
clinical features of iron overload
○ Organ dysfunction from iron deposition - significant in thalassemia patients who are transfusion dependant
○ Heart, endocrine system, liver
treatment of iron overload
○ Genetic: regular venesection to reduce iron level
○ Transfusion iron overload: Iron chelation therapy: given a drug to specifically remove iron from the body
iron chelation therapy
given a drug to specifically remove iron from the body
genetic haemochromatosis
§ Genetic mutation causing accumulation by over absorption
§ Venesect - take out a bag of blood every few months
○ Ineffective erythropoiesis with increased iron absorption: thalassemia
§ Excess iron due to bone marrow making red blood cells wrong, red blood cells due in bone marrow and iron is recirculated leading to accumulation of loose iron
