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Flashcards in Anaemia Deck (50):
1

Anaemia definition

a condition in which there is a deficiency of red cells or of haemoglobin in the blood, resulting in pallor and weariness

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Signs of anaemia

Koilonychia - spooning of the nails Atrophic glossitis - smooth flat tongue Angular stomatitis - cracks at te corner of the mouth Oesophageal web - plumer vision syndrome Pallor (eg conjunctivae) Increased cardiac output a. angina b. flow murmurs c. palpitations d cardiac failur

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Symptoms of anaemia

Due to decreased oxygen-carrying capacity: -Fatige -dyspnoea palpitations headache tinnitus

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Classifcations of anaemia

Anaemias may be due to either decreased production or increased loss of RBCs 1. Macrocytic- large erythrocytes 2. Microcytic - smalle erythrocytes 3. Normocytic - normal-sized cells

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Causes of Normocytic anaemia

Normocytic normochromic

First step look for

  • -MCV = 80-95 femtolittres
  • -MCH >26pigograms

1. Acute blood loss 2. Anaemia of chronic disease 3. Bone marrow failire e.g post chemo, infiltration by carcinoma 4. Renal failure 5. Hypothyroidism 6. Haemolysis 7. Pregnancy

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Causes of Macrocytic anaemias

Macrocytic

First step look for

  • - MCV >95fl

Megaloblastic: -Vit B12 deficiency -Folate deficiency

Normoblastic: -Alcohol excess or liver disease -Reticulocytosis - Cytotoxic - Myelodysplastic syndromes -Hypothyroidisi

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Normal MCV

76-96 fl

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Anaemias which dont fit into the above classification

Haemolytic anaemias

- may be macrocytic or normocytic

Anaemia of chronic diseae can be either:

- RBC indices that are normocytic and normochromic suggest ACD of fairly recent onset.

-RBC indices and blood smear that are microcytic and hypochromic suggest ACD has been present some weeks or months

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Iron deficiency Anaemia transferrin levels

- 30% saturated with transferrin

- IDA liver responds to reduced levels, increased trasnferrin, saturation falls - 15%

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Three phases of iron deficiency anaemia development

Develops gradually over three phases 1. Low serum ferritin always indicated low RES iron stores 2. Iron lost first from RES iron stores, before Hb falls – latent iron deficiency 3. The process continues Iron becomes - iron availablty to red cells is reduced and patient develops iron deficiency anaemia

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Problem with serum ferritin

Acute phase protein In presence of tissue inflammation IDA can occur with normal serum ferritin levels (Rhuematoid arthiris and IBD)

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Causes of iron deficiency anaemia

1. Dietary- premature neonates and adolescent females 2. Malabsorption 3. Blood los Golden rule - IDA in males & post menopausal females is due to GI blood loss until proven otherwise - Young women; menstrual blood loss or pregnancy - GI investigations only for GI symptoms or positive FOBs

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Treatment of iron deficiency anaemia

- Treatment of IDA is iron replacement & not blood transfusion - Ferrous Sulphate -200mg tabs o 200mg = 60mg elemental iron - Ferrous Gluconate 300mg tabs (switch to this if GI toxicity) o 300mg = 36mg elemental iron - IV iron; can give 1G over 2-3 hours. Hb rises no quicker than oral replacement. - Main uses: o Intolerant of oral iron o Compliance o Renal anaemia & Epo replacement - Discover cause

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Anaemia of Chronic disease (ACD) causes

Failure of iron utilisation Iron trapped in RES Common In hospitlaised patients Causes - THREE FOLD -infection -Inleammation -Neoplasia

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Anaemia of chronic renal failure

is Anaemia of chronic disease + fialure of kidneys to produce EPO

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Lab values of Anaemia of chronic disease

MCV/MCH is normal or decreased

Cells may be normochormic normocytic or hypochromic microcytic RBCs ESR - raised

Ferritin - N or increased

Iron - decreased (chemokine release)

TIBC - decreasd (liver does not respond by increasing transferrin levels)

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Blood film of Anaemia of chronic disease

RBC roleux

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Pathophysiology of ACD

- RES Iron blockade; iron trapped in macrophages - Reduced Epo response - Depressed marrow activity; cytokine marrow depression

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Treatment of ACD

-treat underlying disorder

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Role of B12/ Folate?

- Essential for DNA synthesis and nuclear maturation - Required for all dividing cells, deficiency noted first in red cells - Deficiency results in megaloblastic anaemia inititally, but will effect other organs

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B12 os involved in which two processes?

- B12 (Cobalamin) necessary for 2 processes o Methylation of homocysteine to methionine o Methylmalonyl-CoA isomerisation

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Dietary sources of B12

o Synthesised solely by microorganisms o Meat (esp liver and kidney), small amount in dairy products o Normal Western diet 5-30ug/day

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Daily requirements of B12

1 ug/day

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Process of B12 absorption

- B12 ingested (in form of animal protein) -gastric parietal cells produces intrinsic factor - B12 binds to intrinsic factor (made by gastric parietal cells in funfus/ body of stomach) -IF-B12 complex binds to cubulin (receptor in the ileum) - B12 moves through the ileum and is absorbed via transcobalmin

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Total loss and stores of vitamin B12 ?

- Loss o 1-2ug/d in urine/faeces - Stores – 3-4 years

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Dietary sources of folate

Green veg (destroyed by cooking unlike B12

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Stores of folate

- Stores – Few days only – Quickly used up if increased demand (ie increased cell turnover)

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Absorption of folate

- Absorption – most small bowel. No carrier molecule required

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pathophysiology of folate deficiency

- Dietary folates absorbed in small intestine - B12 required for conversion - Results in disparity in rate of synthesis of the precursors of DNA - Abnormality of cell division - megaloblastic anaemia

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Tissues affected by b12 or folate deficiency

All rapidly growing, DNA synthesising cells B12 or folate deficiency - Bone marrow - Epithelial surfaces – mouth, stomach, small intestine, urinary, female genital tracts

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Blood abnormalities of b12 deficiency

Megablastic anaemia (leucopenia, thrombocytopenia)

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Neurological manifestations of b12 deficiencys

o Bilateral peripheral neuropathy or demyelination of the posterior and pyramidal tracts of spinal cord o Biochemical basis inclear- likely related to problem with homocysteine --> methionine

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Blood abnormalites of folate deficency

Megaloblastic anaemia (leucopenia, thrombocytopenia)

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Growing fetus abnormalities of folate deficiency?

1st 12 weeks – deficiency can cause neural tube defects

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Signs/symptoms of b12/folate deficency

Symptoms of anaemia/cytopenia - Tired- macrocytic/megagolastic anaemia (common) - Easy bruising – thrombocytopenic Mild jaundice - Lemon yellow tinit- haemolysis Neurological problems - Nerve distrbances as a result of B12 def - Subacute combined degeneration of cord

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Causes of any defieicny

- Intake - Absorption - Utilisation - Loss

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Pathopysiology of b12 deficiencys

- Pernicious anaemia --> Problem producing IF, problem with gastric parietal cells - Gastrectomy/achlorhyda – acid content of stomach - Terminal ileum problem o Crohn’s o Resection

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Causes of folate deficencys

- Dietary - Extensive small bowel disease o Coeliac/severe crohsn - Increased cell turnover o Haemolysis (cannot recycle folate) o Severe skin disorders o Pregnancy

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Other causes of macrocytosis

- Reticulocytosis o 20% bigger than the average mature red cell - Cell wall abnormality (lipids) o Alcohol o Liver disease o Hypothyroidism (poorly understood) - With anaemia o Bone marrow failure syndromes

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What are haemoglobinoathies

Problem with globin chain Inherited conditions: - Relative lack of normal globin chains due to absent genes (thalassaemias) - Variant (abnormal) globin chain eg sickle cell disease

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Severity of haemoglobinopathies depends on?

- Amount of abnormal haemoglobin - Type of abnormal haemoglobin - Ameliorating factors

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Haemoglobin production process?

- Globin chains produced on ribosomes - Control of production is mainly at the transcription level and depends on the availability of haem - Beta globin gene - On chromosome 11 o Epsilon, gamma, delta, beta o 1 beta gene - 2 beta chains per molecule - Alpha globin gene cluster – on chromosome 16 o Zeta 2, zeta 1 – important in fetal life o Alpha 2 and alpha 1 – important in childhood Remember 2 chromosome 11 with two beta genes, two chromosome 16 with 4 alpha genes

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Which types of haemoglobin are important pre- birth and after birth

- HBa – adult, switched on shortly after birth - HbF – important pre birth (2 alpha and 2 gamma)

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Thalassemias

relative lack of globin genes 4 alpha globin genes (on 2 ch16) 2 beta globin gnees (on 2 Ch11)

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Types of alpha thalassaemias

Alpha + thal --> Missing one gene – mild microcytosis Homozygous alpha + thal or alpha zero thal - Missing two genes – microcytosis, increased red cell count and sometimes very mild (asymptomatic) anaemia HBH disease- Missing three genes – significant anaemia (Hb approx. 75g/l) and bizzare shaped small red cells Alpha thal major -Missing four genes – incompatible with life (need alpha chains for fetal haemoglobin)

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Causes of microcytic anaemia

Tells us that the red cells aren't making enough haemoglobin First step -MCV

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Pathogenesis of sickle cell disease

"Abnormal beta chains in haemoglobin leading to HbS producion, HBS becomes insoluble and leads to cell sickling in hypoxic concentration Chromosome 11 Single aminoacid substitution on B globin gene at position 6 Glutamine>valine = HbS Glutamine >lysins = HBC

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Problem with sickle cell disease

cant bend and block blood vessels Reduced red cell survival (haemolysis 10-20days) vaso-occlusion (tissue hypoxia) Multisytem disease

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Multi-system effects of sickle cell

SICKLE MNEMONIC Stroke/swelling of hands and feet/spleen problems (hyposplenic) Infections/infarctions Crises (painful)/ Cholesthiasis/Chest syndrome Kidney disease Liver disease/Lung problem s Erections sustanained /Eye problems

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Treatment of sickle cell disease

1. prevent crisis a. hydration, analgasia, early intervention b. Prophylactic vaccination and antibiotics 2. prompt management of crises -oxygen, fluids, analgaesia, antibiotics, specialist care -trasnfusion/red cell exchange 3. Bone marrow transplant in children