Red Cells Flashcards by Sarah McGuckin

What is anaemia?

Reduction in red cells or their haemoglobin content

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What substances are required for red cell production?

Iron, copper, cobalt, manganese
B12, folic acid, thiamine
Amino acids
Erythropoietin, androgens, thyroxine, SCF

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What is the typically lifespan of red blood cells?

120 days

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What are red blood cells broken down into?

Globin

Haem > bilirubin

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What is the function of skeletal proteins?

Maintain red cell shape and deformability

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What can occur if there are skeletal protein defects?

Increased cell destruction

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What structural proteins are defected in hereditary spherocytosis?

Ankyrin
Alpha Spectrin
Beta Spectrin
Band 3
Protein 4.2

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What is the clinical presentation of hereditary spherocytosis?

Anaemia
Jaundice (neonatal)
Splenomegaly
Pigment gallstones

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What is the treatment for hereditary spherocytosis?

Folic acid
Transfusion
Splenectomy

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What is the function of the pentose phosphate shunt?

Protects from oxidative damage

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What is the function of glucose 6 phosphate dehydrogenase?

Protects red cell proteins from oxidative damage

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If G6PD deficiency is X linked, who is affected?

Affects males

Female carriers

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What is the clinical presentation of G6PD deficiency?

Neonatal jaundice
Drug, broad bean or infection precipitated jaundice or anaemia
Splenomegaly
Pigment gallstones

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What drugs can cause G6PD deficiency?

Antimalarials 
Sulphonamides and sulphones 
Antibacterials 
Analgesics 
Antihelminthics 
Vitamin K analogues

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What occurs in pyruvate kinase deficiency?

Reduced ATP
Increased 2,3-DPG
Cells rigid

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What is the clinical presentation of pyruvate kinase deficiency?

Anaemia
Jaundice
Gallstones

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What is the basic function of haemoglobin?

Oxygen to tissues

Carbon dioxide to lungs

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What is the composition of haemoglobin?

Haem molecule
2 alpha chains
2 beta chains

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What is the composition of sickle haemoglobin?

Haem molecule
2 alpha chains
2 beta (sickle) chains

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What are the consequences of HbS polymerisation?

Haemolysis, endothelial activation, promotion of inflammation, coagulation activation, vaso occlusion

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What are the complications of sickle cell disease?

Acute chest syndrome
Stroke
Pain episodes attributed to vasoocclusive tissue damage

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What is the clinical presentation of sickle cell disease?

Painful bone and chest vaso-occlusive crises
Stroke
Hyposplenism
Chronic haemolytic anaemia (gallstones, aplastic crises)
Spleen and liver sequestration crises

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What is the management of a chest crises?

Respiratory support 
Antibiotics 
IV fluids 
Analgesia 
Transfusion

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What is the clinical presentation of chest crises?

Chest pain
Fever
Worsening hypoxia
Infiltrates on CXR

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What is the life long prophylaxis for sickle cell disease?

Vaccination Penicillin (and malarial) prophylaxis Folic acid

What is the treatment for acute events due to sickle cell disease?

``` Hydration Oxygenation Prompt treatment of infection Analgesia (opiates, NSAIDs) Blood transfusion Disease modifying drugs (hydroxycarbimide) Bone marrow transplantation Gene therapy ```

What are thalassaemias?

Reduced or absent globin chain production | Mutation or deletion of alpha or beta genes

What are the clinical features of beta thalassaemia major?

``` Present at 3-6 months of age Expansion of ineffective bone marrow Bony deformities Splenomegaly Growth retardation ```

What is the treatment for beta thalassaemia major?

Chronic transfusion support 4-6 weekly Iron chelation therapy (desferrioxamine infusions, oral deferasirox) Bone marrow transplantation (curative)

What causes sideroblastic anaemia?

Defects in mitochondrial steps of harm synthesis

What factors influence the normal range of Hb?

``` Age Sex Ethnic origin Time of day sample taken Time to analysis ```

What is the Hb reference range for males under 70?

140-180

What is the Hb reference range for males over 70?

116-156

What is the Hb reference range for females under 70?

120-160

What is the Hb reference range for females over 70?

108-143

What are the general clinical features of anaemia?

``` Tiredness Breathlessness Swelling of ankles Dizziness Chest pain ```

What are the symptoms of anaemia with an underlying cause of bleeding?

Menorrhagia | Dyspepsia, PR bleeding

What are the symptoms of anaemia related to malabsorption?

Diarrhoea | Weight loss

What measurement are used when investigating red cells?

Mean cell volume (MCV) | Mean cell haemoglobin (MCH)

Where is hepcidin produced and what is its function?

Made in hepatocytes | Blocks ferroportin, reducing intestinal iron absorption

What are the clinical features of iron deficiency?

Koilonychia Angular cheilitis Atrophic tongue

What are the causes of iron deficiency?

GI blood loss (worms) Menorrhagia Malabsorption (gastrectomy, coeliac disease)

What is the treatment for iron deficiency anaemia?

``` Diet Ulcer therapy Surgery if bleeding Oral iron supplements Transfusion ```

What is a positive direct antiglobin test an indicator of?

Immune mediated haemolytic anaemia

What is a negative direct antiglobin test an indicator of?

Non-immune mediated haemolytic anaemia

What is the management of haemolytic anaemia?

Folic acid Immunosuppression if autoimmune Remove site of red cell destruction (splenectomy) Treat sepsis, leaky prosthetic valve, malignancy if intravascular

What are the causes of B12 deficiency?

Pernicious anaemia | Gastric/ileal disease

What are the causes of folate deficiency?

``` Dietary Increased requirements (haemolysis) GI pathology (coeliac disease) ```

What is the treatment for megaloblastic anaemia?

Replace vitamin B12 IM injection Oral folate replacement

What are the other causes of macrocytosis?

``` Alcohol Drugs (methotrexate, ART, hydroxycarbamide) Disordered liver function Hypothyroidism Myelodysplasia ```

What does the "Bohr effect" on an oxygen dissociation curve take into account?

Acidosis Hyperthermia Hypercapnia

What is sickle cell?

Mutations leading to structurally abnormal global chain

What is homozygous alpha zero thalassaemia?

No alpha chains | Hydrops fettles incompatible with life

What is thalassaemia major?

No beta chains | Transfusion dependent anaemia

What are the possibly morphological descriptions of cells within anaemia?

Hypochromic microcytic (little and pale cells) Normochromic normocytic Microcytic (big cells)

What does serum ferritin indicate?

Measurement of the body's iron stores

What would a low serum ferritin indicate?

Iron deficiency anaemia

What would a normal or increased serum ferritin indicate?

Thalassaemia Secondary anaemia Sideroblastic anaemia

Where is ferritin mostly found?

Liver

What are the investigations for iron deficiency anaemia?

Endoscopy | Barium studies

What are the causes of haemolytic anaemia?

``` Hereditary spherocytosis (HS) Enzyme deficiency (G6PD deficiency) Haemoglobinopathy (HbSS) Auto-immune haemolytic anaemia Mechanical eg.artificial valve Severe infection Drugs ```

How would you know if a patient is haemolysing?

FBC, reticulocyte count, blood film Serum bilirubin high, LDH high Serum haptoglobin low

What are the features of pernicious anaemia?

Antibodies against intrinsic factor and gastric parietal cells Malabsorption of dietary B12