Anaemia Flashcards
What is erythropoiesis controlled by?
Erythropoietin secretion by kidneys
What nutrients are needed for erythropoiesis?
Iron
Vitamin B12
Folic acid
What is a major source of iron?
Red meat
Gastric and ascorbic acid keeps it in the Fe++ form so aids in absorption
What are the sources of Vitamin B12?
Liver
Fish
Eggs
What are sources of folate?
Liver
Yeast extract
Green leafy vegetables
What name is given to young RBCs?
Erythroblasts
Why are reticulocytes called this?
Still retain some ribosomes which produce a reticular when treated with special stains
What does the presence of reticulocytes suggest?
Bone marrow is active producing RBCs
Plenty of nutrients available for erythropoiesis
Where do old RBCs get sequestered and broken down?
Become entrapped in sinusoids of spleen
How is haemoglobin broken down?
Globin is degraded to amino acids and returned to general amino acid poll of the body
Haem is broken releasing iron to transferrin from which it can be recycled to bone marrow for new erythroblasts
Porphyrin ring is converted to bilirubin
What is the path and result of bilirubin in the body?
Transported to the liver bound to albumin
Taken up by the liver and conjugated with glucuronic acid
Excreted from liver into biliary system
Gives urine its yellow colour and faeces its dark colour
What is anaemia?
Decreased haemoglobin concentration below the normal range for that age and sex
When does anaemia occur?
Decreased rate of production of RBCs
Increased rate of destruction of RBCs
Loss of RBCs due to bleeding
Impaired production of RBC due to lack of one nutrient needed for the production
How can the type of anaemia be determined from the FBC?
Red cell indices:
Mean cell volume
Mean cell haemoglobin concentration
Mean cell haemoglobin
What is the most common form of anaemia?
Iron deficiency(microcytic) anaemia
What is a common feature of microcytic anaemia?
Increased platelet count
What are likely causes of iron deficiency anaemia?
Chronic Blood Loss
Malabsorption
Dietary Deficiency of iron
What may cause chronic blood loss?
Menstruation
Ulceration of stomach or duodenum (NSAIDS)
Colonic Carcinoma
Hookworm and schistosomiasis in developing countries
What may cause malabsorption?
Gastrectomy
Coeliac disease
What does transferrin do?
Plasma protein that iron attaches to to circulate in the blood
When are blast cells present in blood circulation?
Leukaemia
Why would a patient with leukaemia be at increased risk of infections?
WBCs produced are of one specific clone and are unable to respond to a range of infections
What procedure is used to confirm diagnosis of leukaemia?
Bone marrow biopsy - presence of abnormal blast cells suggest leukaemia
What is aplastic anaemia caused by?
Chemotherapy
Infections
Exposure to toxic chemicals
What hormone stimulates production of RBCs?
Erythropoietin
What are causes of normochromic normocytic anaemia?
Renal failure
Leukaemia
What form of anaemia causes Paraesthesia and extreme fatigue?
macrocytic anaemia
What are the causes of vitamin B12 deficiency?
Pernicious anaemia
Dietary deficiency
What is pernicious anaemia?
Autoimmune disease
Immune system attacks cells in the stomach that produce Intrinsic factor
Intrinsic factor is essential for absorption of vitamin B12 in the ileum
Why does pernicious anaemia cause paraesthesia?
Vitamin b12 is used in the maintenance of myelin sheaths
What demographic is at a greater risk for sickle cell anaemia?
Those of African heritage
What form of haemoglobin does a patient with sickle cell disease have?
Haemoglobin S
Beta-globin chain production affected
How does sickle cell anaemia occur?
E replaced with V in mutation
The abnormal beta chains within haemoglobin molecules polymerise to form a rigid structure deforming the cell into a sickle-shape
When may sickle cell trait manifest itself?
Exceptional circumstances such as climbing at high altitudes
Where would an individual with sickle cell feel pain and why?
Upper left quadrant of abdomen
Sickle cells unable to pass through the sinusoids of the spleen causing it to become engorged which stretches the capsule causing pain
What does the irregular shape of RBCs cause in response to minor stress for those with sickle cell disease?
Block capillaries causing painful sickle crises, jaundice, anaemia
Systemic response with tachycardia, sweating and fever
What places in the body are affected by sickle cell disease in adults and children?
Children - bones of hands and feet
Adults - humerus, femur, ribs, vertebrae, pelvis
If haemolysis is the cause of anaemia what type of RBC will be prominent?
Increase in reticulocyte count
What is a similar disease to sickle cell disease that may also cause anaemia?
Hereditary spherocytosis
How is hereditary spherocytosis caused?
Deficiency of spectrin, membrane protein
What chronic diseases is anaemia associated with?
Infections
Inflammatory conditions such as rheumatoid arthritis
Cancer
