Anaemia Flashcards
what is the typical Hb count for a male and female
- male 135-175
- female 120-155 g/ (previously g/dl
what are the symptoms of anaemia
Symptoms relating to reduced O2 delivery
- short of breath
- muscle pain on exertion
- dizzy
- angina
clinical signs of anaemia
- Palor in skin and conjunctiva
- Tachycardia
- Rapid breathing
- Peripheral oedema if severe anaemia
- Signs relating to cause of anaemia
adaption to anaemia results in
- Mild anaemia likely to cause no symptoms unless extreme exertion
- Cardiac output increases- rate and stroke volume
- Changes in distribution of blood flow
- Change in O2 dissociation curve2,3 DPG
what are the classifications of anaemia
- Under-production or increased loss of RBC
- Congenital or acquired
- Acute or chronic
- By mean cell volume (MCV) – microcytic/normocytic/macrocytic
Classification by MCV (MCH and MCHC)
• MCV –mean cell volume
Haematocrit (Hct) (%) X10 / RBC count (number as 1012/l)
- MCH- mean cell Hb - Hb / RBC
- MCHC- mean cell Hb concentration- Hb / Hct
- RDW red cell distribution width is a measure of spread of RBC size eg retics/transfusion
classification by MCV
- Microcytic - MCV 60-80fl - iron def, thalassaemia
- Normocytic - MCV 80-100fl - blood loss, anaemia of chronic disease, renal impairment
- Macrocytic – MCV 100-120fl - megaloblastic anaemia- B12/folate deficiency, myelodysplasia
- (Hypochromic- MCHpg 22-26 iron def, thalassaemia)
Iron deficiency anaemia
-Typically reduction in MCV (microcytic) to 65-80
- then in Hb, low ferritin, low transferrin saturation with iron.
Rest of blood count normal- ?
raised platelets if bleeding.
- Poor intake
- Blood loss
- menstrual
- GI tract ?haematemesis or melaena eg peptic ulcer/cancer/angiodysplasia/hookworm
- Malabsorption
- coeliac disease
- Increased need eg growth spurt/pregnancy
Iron def- clinical features
- Pale
- Tachycardia
- Koilonychia
- Hair loss
- Pica
- Glossitis/angular stomatitis
- Features relating to the cause eg wt loss/abdo pain/bowel change/heavy periods
Iron def- investigation
• Be guided by history
- recent and past and clinical findings
• Confirm iron def by low ferritin and typical FBC
• Screen for coeliac disease (IgA tissue transglutaminase or tGA)
• Upper and lower endoscopy for all except pre-menopausal women
• Consider other imaging/capsule endoscopy
Iron def- treatment- oral
- Oral- replacement with sufficient iron for long enough period eg ferrous sulfate 200mg 2 or 3 per day- 65mg elemental iron per dose
- Side effects- nausea/abdo pain/constipation- dose related- may improve if changed to ferrous gluconate or fumarate
- Typically patients need 3 months of iron AFTER correction of anaemia to build up iron stores
- Treat the underlying cause
- Rise in Hb generally 10g/l per week if not bleeding
Iron def treatment- parenteral
• Intramuscular- not used now- painful, multiple doses, stains skin
• Intravenous Ferric carboxymaltose- ferinject- over 15-30mins.
Often needs 2 doses Iron dextran- cosmofer- over 4-6 hours after a test dose.
All IV iron preparations can cause ‘flu like symptoms and a small risk of hypersensitivity reaction or anaphylaxis
B12 deficiency
• Typically a macrocytic anaemia- MCV 100-120 and later a pancytopenia.
Often bilirubin and LDH raised
• Can also cause peripheral neuropathy- demyelination and posterior column damage
• B12 result can be falsely low in pregnancy/oral contraceptive/on metformin
• Pernicious anaemia- gastric atrophy and auto antibodies to parietal cells and intrinsic factor preventing absorption
• Strict vegan or terminal ileal disease also possible
B12 deficiency - treatment
- Hydroxocobalamin 1mg IM alternate days for 5 doses then 3 monthly if confirmed ongoing need eg pernicnious anaemia
- Cyanocobalamin available orally but not available on prescription
Folate deficiency
- Blood count and film appearance same as B12 def.
- Limited stores of folate so deficiency can develop in weeks
- Poor intake, increased use eg pregnancy/haemolysis, malabsorption, drugs eg anti-epileptics or trimethoprim
- Replacement with oral folic acid 5mg per day
- Pre-conception folic acid reduces neural tube defects. Likely plan to add folic acid to flour
Anaemia- blood loss
- Hb immediately after blood loss will be normal
- Drop after fluid replacement
- Each 500ml loss gives approx drop of Hb by 10-15 g/l
- Retic response within hours/days
- May need blood transfusion to replace loss eg trauma/GI bleed/around delivery
Anaemia of chronic disease
- Typically a normocytic anaemia associated with chronic inflammatory disease
- Plentiful iron stores but poor transfer to RBC due to hepcidin and cytokines
- History of chronic disease, inflammatory markers increased eg CRP/ESR/plasma viscosity, exclusion of other causes
- Will respond to treatment of underlying disease
Anaemia of renal failure
- Drop in Hb once creatinine clearance drops below 20-30 ml/min chronically
- Mainly due to lack of erythropoietin
- Contribution from blood loss at dialysis, inflammatory disease
- Responds well to erythropoietin eg weekly or alternate weeks s/c
Anaemia- haemolysis
• Increased RBC destruction, marrow can increase production 5-10 fold
• Can be acute or chronic, congenital or acquired
• Issues to do with
- RBC membrane
- RBC enzymes
- Globin chains in Hb
Haemolysis- RBC membrane
• Congenital spherocytosisautosomal dominant defect in spectrin causing spherical cells – less able to deform so shortened survival
• Auto-immune haemolysis
- auto antibodies against RBC surface antigens
- Fc portion recognised by macrophages in spleen. Treated with steroids/splenectomy/rituximab
Haemolysis- RBC membrane and enzymes
Prosthetic heart valve- mechanical Disseminated intravascular coagulation (DIC)- eg in sepsis, prostate cancer causing RBC fragmentation by fibrin
RBC enzyme def eg G6PD or pyruvate kinase can cause shortened RBC survival
Anaemia- abnormal haemoglobin
- Haemoglobinopathy eg Sickle cell diseasesingle point mutation causing Hb polymerisation in hypoxic cells in homozygotes
- Shortened RBC survival, reduced production
- Chronic anaemia and bone/liver/lung/brain “crisis” ie acute infarction
- Treated by supportive care, hydroxycarbamide to increase HbF production, ??stem cell transplant
Anaemia- thalassaemia
- Inbalance of globin chain production • Beta thalassaemia- as Hb F (2 alpha, 2 gamma chains) declines after birth- progressive anaemia. Supportive care, transfusion, ?stem cell transplant
- Progressive iron overload
- Antenatal screen for Hb-opathy and thalassaemia
Anaemia- marrow infiltration
• MyelomaB cell malignancy of mature plasma cells
- produce monoclonal immunoglobulin or light chains Presents as chance finding, anaemia, renal failure, hypercalcaemia, bone pain or fracture Treatment
- supportive care, chemotherapy, radiotherapy
• Haematological malignancy eg lymphoma, acute leukaemia
• Diagnosed by sampling marrow- pelvis or sternum
• Treated by chemotherapy/immunotherapy
• Other “solid” tumours can spread to marrow eg prostate, breast, small cell lung
Anaemia- marrow failure
- Myelodysplastic disorders- progressive decline in Hb, neutrophils, platelets, macrocytosis. Tendency to progress to acute leukaemia. Treated by supportive care, chemotherapy or stem cell transplant in some.
- Aplastic anaemia- pancytopenia. Expected result post chemotherapy but can be drug induced eg NSAIDs, chloramphenicol or idiopathic. Treated by supportive care, anti- thymocyte globulin, stem cell transplant
